A Comparison of the Arthropods Found in Two Integrated Control Blocks, a Commercial Control Block, and an Abandoned Block of Apples in Hampshire County, Massachusetts
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Masters Theses 1911 - February 2014
1976
A comparison of the arthropods found in two integrated control blocks, a commercial control block, and an abandoned block of apples in Hampshire County, Massachusetts.
Edward J. Blyth University of Massachusetts Amherst
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A COMPARISON OF THE ARTHROPODS FOUND IN
TWO INTEGRATED CONTROL BLOCKS, A COMMERCIAL CONTROL
BLOCK, AND AN ABANDONED BLOCK OF APPLES IN
HAMPSHIRE COUNTY, MASSACHUSETTS
A Thesis Presented
By
Edward J. Blyth
Submitted to the Graduate School of the University of Massachusetts in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE
January 1976
Major Subject Entomology A COMPARISON OF THE ARTHROPODS FOUND IN
TWO INTEGRATED CONTROL BLOCKS, A COMMERCIAL CONTROL
BLOCK, AND AN ABANDONED BLOCK OF APPLES IN
HAMPSHIRE COUNTY, MASSACHUSETTS
A Thesis Presented
By
Edward J. Blyth
(Chairman df Committee)
G- (Head of Departk$nt)
January 1976 TABLE OF CONTENTS
Page
LIST OF TABLES. V
LIST OF FIGURES. viii
INTRODUCTION. 1
LITERATURE REVIEW. 2
A. Pest Control Development. 2
B. Control of Major Pests..... 15
1. The European Red Mite. 15
2. The Codling Moth. 2 6
3. The Apple Maggot. 4 3
4. The Plum Curculio. 57
METHODS AND MATERIALS. 6 7
A. General. 6 7
B. Overwintering European Red Mite Egg Samples.. 73
C. Leaf Brushing Samples. 73
D. Beating Samples. 74
E. Leaf and Twig Inspection Samples. 74
F. Fruit Inspection Samples. 75
G. Sweeping Samples. 75
H. Pheromone and Attractant Trap Samples. 75
in i TABLE OF CONTENTS--continued Page
I. Sticky Board Trap Samples. 76
J. Analysis of Data. 76
K. Abbreviations. 77
RESULTS AND DISCUSSION. 78
A. Overwintering European Red Mite Egg Samples.. 78
B. Leaf Brushing Samples. 81
C. Beating Samples. 92
D. Leaf and Twig Inspection Samples. 101
1. Apple Aphid, Aphis pomi DeGeer, and Its Syrphid and Cecidomyiid Predators. 101
2. All Other Arthropods Found. 107
3. Leaf Damage by Chewing Insects. 118
E. Fruit Inspection Samples. 121
F. Sweeping Samples. 12 9
G. Pheromone and Attractant Trap Samples. 139
H. Sticky Board Trap Samples. 143
SUMMARY AND CONCLUSIONS. 145
BIBLIOGRAPHY.. 14 7
APPENDIX.. 168
IV LIST OF TABLES
TABLE Page
1. Spray Schedule for 1972 for Alternate-Row and Regular-Spray Treatments. 71
2. Spray Schedule for 1972 for Minimum-Spray Treatments. 72
3. Overwintering European Red Mite Eggs Per Spur.. 79
4. Mites Per Leaf From Leaf Brushing Samples— Panonychus ulmi (Koch). 83
5. Mites Per Leaf From Leaf Brushing Samples— Typhlodromus pomi (Parrott). 84
6. Mites Per Leaf From Leaf Brushing Samples— Aculus schlechtendali (Nalepa). 85
7. Mites Per Leaf From Leaf Brushing Samples— Miscellaneous Mites. 86
8. Distribution and Abundance of Arthropods Found in Beating Samples. 93
9. Abundance of Arthropods Found in Five Minute Beating Samples, Grouped into Beneficial (B), Neutral (N), or Pest (P) Species Categories.... 98
10. Abundance of Aphis pomi DeGeer (A) and Its Syrphid and Cecidomyiid Predators (P) From Terminal-Inspection Samples. 102
11. Distribution and Abundance of Arthropods Found in Leaf and Twig Inspection Samples. 108
12. Arthropods (excluding Aphis pomi DeGeer and its syrphid and cecidomyiid predators) Found in Terminal Inspection Samples, Grouped into Bene¬ ficial (B), Neutral (N), or Pest (P) Species Categories. 115
v LIST OF TABLES—continued
TABLE Page
13. Damage From Leaf-Chewing Insects. 119
14. Insect Damage to Fruit. 122
15. Distribution and Abundance of Arthropods Found in Sweeping Samples. 130
16. Arthropods Found in Sweeping Samples, Grouped Into Beneficial (B), Neutral (N), or Pest (P) Species Categories. 137
17. Pheromone/Attractant Trap Catches... 140
18. Distribution and Abundance of Insects Trapped on Sticky Boards. 144
A-l. Abbreviations Used in Tables and Figures. 16 8
A-2. Mites Found in Leaf Brushing Samples. 16 9
A-3. Statistical Analysis of Leaf Brushing Data. 170
A-4 . Arthropods Found in Beating Samples. 171
A-5. Statistical Analysis of Beating Sample Data.... 177
A-6. Statistical Analysis of Data on Aphis pomi DeGeer and Its Predators. 178
A-7. Arthropods Found in Leaf and Twig Inspection Samples. 179
A-8. Statistical Analysis of Terminal Inspection Data. 185
A-9. Statistical Analysis of Chewing Insect, Leaf- Damage Data. 186
A-10. Statistical Analysis of Fruit Damage Data. 187
A-ll. Arthropods Found in Sweeping Samples. 188
A-12. Statistical Analysis of Sweeping Sample Data... 197
vi LIST OF TABLES—-continued
TABLE Page
A—13. Insects Trapped on Sticky Boards. 19 8
A-14. Statistical Analysis of Leafhopper Data From Sticky Boards. 199
yii LIST OF FIGURES
FIGURE Page
1. University of Massachusetts Horticultural Research Laboratory Experimental Blocks. 6 8
2. Abandoned Apple Orchard Experimental Blocks.... 69
3. Overwintering European Red Mite Eggs From Spur Samples. 80
4. Mites From Leaf Brushing Samples—Abandoned Orchard. 8 9
5. Mites From Leaf Brushing Samples—Minimum-Spray Blocks. 90
6. Arthropods From Beating Samples. 99
7. Apple Aphid, Aphis pomi DeGeer, and Its Syrphid and Cecidomyiid Predators From Terminal Inspections—Minimum-Spray Blocks. 103
8. Apple Aphid, Aphis pomi DeGeer, and Its Syrphid and Cecidomyiid Predators From Terminal Inspections—Alternate-Row-Spray Blocks. 104
9. Apple Aphid, Aphis pomi DeGeer, and Its Syrphid and Cecidomyiid Predators From Terminal Inspections—Regular-Spray Blocks. 105
10. Arthropods From Leaf and Twig Inspections. 116
11. Leaf Damage by Chewing Insects. 12 0
12. Insect Damage to Fruit. 126
13. Arthropods From Sweeping Samples. 138
14. Pheromone/Attractant Trap Catches. 142
vm 1
INTRODUCTION
Research on control of apple pests since about 1960
has emphasized an integrated approach which incorporates
chemical and biological control. The reason for this has been largely the result of two factors: Pest resistance to
chemical pesticides has necessitated the continuous develop¬ ment of new and increasingly expensive insecticides and
acaracides. Also, the growing awareness of the ecological
impact of these chemicals has demanded that alternative methods of control be developed and utilized whenever
feasible. The study described herein was undertaken to
examine two types of integrated control employed in an
apple orchard in Belchertown, Massachusetts. Pest control
from these two spray programs was compared with the control
obtained from a commercial spray program, in the same
orchard. A comparison was made between the arthropods
found in that orchard and those present in a nearby aban¬
doned orchard. 2
LITERATURE REVIEW
A review of the work done on all the arthropods found in this study is beyond the scope of this thesis, and so my review of the literature has included two major areas:
1) a general summary of the development of pest control in apple orchards, and 2) an extensive look at the progress in controlling the four major pests which occur in
Massachusetts apple orchards; i.e., the European red mite,
Panonychus ulmi (Koch); the codling moth, Carpocapsa pomonella (Linnaeus); the apple maggot, Rhagoletis porno - nella (Walsh); and the plum curculio, Conotrachelus nenuphar
(Herbst). This review was completed in August, 1973.
A. Pest Control Development
In 1914 Slingerland and Crosby (1914) reported that there were almost 500 species of insects which fed on apple trees. Oatman et^ al. (1964) conducted an ecological study of arthropod populations on apple in northeastern Wisconsin from 1959-1962. They recorded 763 species of insects from
158 families. From the same study Oatman (1963) reported
40 species of mites occurring on apple foliage. After a similar study in southern Indiana, Cleveland and Hamilton
(1958) reported 421 species of insects from apples during 3
1956 and 1957. Barnes' (1959) simple and direct statement is certainly appropriate: "The insect pests of apple trees are legion."
Certainly not all of these species can be considered as serious pests; some are transients, some are merely incidental pests and some are beneficial predators and parasites. However, there is a sufficiently large number of pest species to generate a complex problem of control.
"The problems of pest control on apple are without doubt more numerous and complex than on any other crop" (Glass and Lienk 1971). A total of 43 insect species is con¬ sidered economically important in Wisconsin (Oatman et^ al.
1964). Garman and Townsend (1952) list 54 pests which may require specific control measures in Connecticut.
In Massachusetts one can be fairly certain that the apple maggot, the codling moth, the plum curculio, and the European red mite will warrant control from year to year. One cannot be sure, however, which of the numerous other potential pests may prove economically important in any given year. Glass and Lienk (1971) monitored insect damage for ten years in an orchard which received no insecticidal or acaracidal treatment. A little known pest, the lesser appleworm, Grapholitha prunivora Walsh, caused no damage to the fruit for eight years, and then in the ninth year the larvae damaged 72 per cent of the fruit. These two phenomena, the large number of pest species and the inability to predict which ones will warrant con¬ trol, make apple pest management an especially difficult task. Prior to World War II orchardists employed an inte¬ grated control program before the term was ever applied to that type of control. Slingerland and Crosby (1914) stated that the use of pesticides alone was not always effective; additional measures were needed for sufficient control.
Under the heading of "clean farming" they suggested that dead leaves, grass, and weeds along fences or in hedgerows provided a winter haven for many insects. Stone walls,
stone piles, and other similar shelters enhanced plum cur- culio populations. Uncultivated apple orchards sustained more injury from plum curculio, apple maggot, leaf miners, and other insects with similar hibernating habits. For control of codling moth they suggested the use of burlap bands around the trunks of trees. Large numbers of the
larvae pupated under these bands, and weekly inspections
eliminated a large percentage of the codling moths. For
the plum curculio jarring the adults from the trees onto
large sheets was suggested.
Even at this early date, the use of chemical insecti¬
cides was given the greatest emphasis. Slingerland and
Crosby (1914) gave only a few paragraphs to non-chemical means of control while devoting a full chapter to insecticides. The various compounds of arsenic formed the backbone of the chemical arsenal. They were the cheapest and most efficient insecticides in common use. Other in¬ secticides included: sulfur, lime-sulfur solution, kerosene emulsion, distillate emulsion, carbolic acid emulsion, and miscible oils. Also included were two com¬ pounds which would today be called "organic" insecticides: hellebore and nicotine.
Then, as now, chemical insecticides were the most economically feasible method of controlling insect pests of apple. Slingerland and Crosby (1914) stated that in a properly sprayed orchard the use of burlap bands for con¬ trol of codling moths; for example, would not pay for the trouble and expense involved.
Pest control in the apple orchard could have been con¬ sidered somewhat successful before the development of the chlorinated hydrocarbons and organophosphates in the mid
1940's. When lead arsenate was the principal insecticide in the spray program, commercial orchardists could produce apples which were 85-90 per cent free from insect injury.
With the advent of DDT, apples were 95-100 per cent free from insect injury. By 1950 the red-banded lead roller,
Argyrotaenia velutinana Walker; the eye-spotted bud moth,
Spilonota ocellana Denis and Schiffermeuler; the apple aphid. Aphis pomi DeGeer; the European red mite; and the 6 two-spotted spider mite, Tetranychus urticae Koch, had be¬ come major problems in commercial orchards. Before DDT these were all considered minor pests which seldom became economically important (Oatman 1960, Oatman and Libby
1965).
It soon became apparent that DDT was not the answer to the apple growers' insect problems. New insecticides had to be added to the spray program. Timing, dosage, coverage, and compatibility were more important than ever. The prob¬ lems of residue, phytotoxicity, and mammalian toxicity became evident. Costs began to climb; the new insecticides were more and more expensive, new and bigger equipment was needed, and more highly skilled labor was necessary (Oatman and Libby 1965).
One of the most serious problems, however, was the development of resistance by the insect and mite pests. In
1921 the recommendation for Connecticut apple orchards was
five or six sprays using a total of six materials. Nineteen years later, in 1940, eight sprays and eight pesticides were used (Garman and Townsend 1952). Following the intro¬
duction of DDT, about 1946, and the resulting 95-100 per
cent clean fruit, decreasing attention was paid to coverage
and timing because DDT was generally acclaimed a miracle material for fruit insect control (Barnes 1959). In only
four years, by 1950, Connecticut orchards required 11 7
sprays, using 14 or more different materials (Garman and
Townsend 1952). For 1973 the Massachusetts and Connecticut
apple pest control guide recommends up to 12 sprays and
lists 44 materials which may be used (Savos et_ al. 1973).
The public has been conditioned to accept only the
highest quality fruit, and the growers now expect at least
95-98 per cent clean fruit; with the old spray schedules
such a high percentage of clean fruit was not possible.
Meanwhile, resistance to new materials by direct and in¬
direct pests has become commonplace (Glass 1960). Conse¬
quently, spray programs have been drastically revised in
recent years.
Although research on control of pome fruit pests since
about 1960 has emphasized an integrated approach, practical
control measures have remained largely chemical. Rapidly
developing pest resistance to spray chemicals and public con¬
cern against the ever-increasing use of pesticides have
demanded that alternative methods of control be explored
(Madsen and Morgan 1970). Any alternative, when used in
conjunction with chemical treatment, is termed integrated
control.
Integrated control as practiced today began to take
shape immediately following World War II, with the advent
of DDT and the subsequent modern pesticides (DeBach 1951).
The first use of the term "integrated control," with an 8 outline of its basic concepts, was published by Stern et_ al.
(1959). Studies in apple orchards were begun by Lord (1949) in Nova Scotia. The first practical use of integrated con¬ trol in commercial apple orchards in the United States was in the state of Washington in 1965 (Hoyt 1969).
Hoyt's (1969) study was an integration of mite control by the phytoseiid mite predator Typhlodromus occidentalis
Nesbitt with the chemical control of other pests by the use of selective pesticides, special timing of the sprays, and specialized application techniques. The primary mite pest was the McDaniel spider mite, Tetraychus mcdanieli
(McGregor), but the apple rust mite, Aculus schlechtendali
(Nalepa) and the European red mite were also present. If the McDaniel spider mite was the only prey available to the predator, a cyclic predator-prey response developed. If the apple rust mite was available, T. occidentalis fed on it but failed to control it. When both species of prey were available, the McDaniel spider mite rarely became numerous; the predator fed on the apple rust mite when populations of the McDaniel spider mite decreased. The populations of the apple rust mite caused no apparent damage. The European red mite populations were reduced by chemicals early in the sea¬ son, and predation by T. occidentalis prevented a later resurgence of populations of this species. Early season control by the predator is not possible because of the 9 differences in distribution of the European red mite and
T. occidentalis during May and June.
During 1966 approximately 9000 acres were under this program in Washington, and mite control was very good in most orchards. The program was expanded to approximately
40,000 acres in 1967. Although conditions in 1967 favored the development of high populations of the McDaniel spider mite, the integrated control program generally gave satis¬ factory results. It was necessary, however, to apply an acaricide to some orchards during the hottest part of the year to maintain a desirable predator-prey balance (Hoyt
1969).
A successful integrated control program in the apple orchard requires more than the development and adoption of new control techniques; a complete change of philosophy is needed on the part of many growers. Hoyt (1969) pointed this out when he said, "... in many cases it has become customary to control pests because they are present rather than because they are causing economic loss. One of the most difficult tasks involved in establishing a program of population management (rather than control) is to convince growers that certain levels of pest populations are not only nondamaging but that they may be desirable."
A very important aspect of integrated control is the economic threshold (van den Bosch and Stern 1962). 10
The presence of pests does not automatically mean an econom¬ ic loss will follow. With integrated programs certain pest species must be managed so as to obtain stability
(Hoyt 1969). Nicholson (1939) stated that the repeated use of an insecticide does not necessarily lower, over an extended period, the population of the pest species against which it is directed. Failure to recognize and use economic threshold levels may lead to unnecessary spray applications which can result in problems connected with the selection of resistant strains; it can also mean excessive destruction of beneficial species, either directly from pesticide toxicity or indirectly by destroying food sources (Hoyt 1969).
Integrated control in deciduous fruits is more compli¬ cated than in field crops because of the need for fungicides, minor elements, growth-regulating hormones and fertilizers, in addition to insecticides and acaricides. A successful integrated control program in Denmark, for example, where it is necessary to apply 15 or more sprays for disease con¬ trol, would be difficult. Implementation would be equally difficult in Israel where, at present, monthly sprays of broad-spectrum insecticides are needed to control the codling moth. These examples emphasize the point that inte¬ grated control programs must be developed separately for each area (Madsen 1968). 11
The codling moth has been the basic pest around which most apple spray programs have been developed. Lack of control of this pest renders the entire crop virtually worthless. At present the only commercially successful method of control is chemical. In most apple orchards codling moth control requires from two to four applications of insecticides. While control of the moth is usually attained, predator and parasite populations are reduced, resulting in an increase in mite, aphid and scale insect populations. The traditional solution has been to add to the spray program pesticides necessary to control these other pests (Davis 1970).
Davis (1970) outlined the following integrated control program:
1. Pre-blossom and delayed dormant sprays are neces¬ sary to control many pests and must be applied in an inte¬ grated control program. In early spring the tests are on the twigs and branches while the predators are under the bark on the trunk. Therefore, only the twigs and branches should be sprayed; spraying the trunk should be avoided.
2. Predators are very susceptible to carbaryl, which is used for fruit thinning, and to several other materials used to control insects and powdery mildew. The pests remain on the twigs and new foliage while the predators are still around the base of the tree until about the middle of 12
June (in Utah). Until this time sprays should be directed to the periphery of the tree and applied so as to avoid excessive runoff.
3. From mid-June until the end of the season, only those materials which are least toxic to predators and para¬ sites should be used. Applications of pesticides should be at the minimum recommended rate. Pesticides currently in use which are especially suited to an integrated control program are: Guthion, Imidan, Zolone, diazinon, Omite,
Karathane and Morestan.
4. If it becomes necessary to supplement the biological control of mites with miticides, use Karathane, Morestan, or
Omite.
Davis (1970) reported that 18 orchards in Utah were under an integrated control program following the guidelines given above. Most of the results have been satisfactory.
Savings of between 25 and 50 per cent had been realized on the total spray bills. Control of the McDaniel and two- spotted spider mites had usually been equal to or superior to that obtained from a strictly chemical program. In addi¬ tion, problems with aphids were reduced. One of the major disadvantages of the program was that it took two seasons to achieve a satisfactory population of predators, during which time excessive damage sometimes occurred. Also, the 13 orchardist had to pay much closer attention to the ecology of his orchard.
As of 1970 in the state of Washington, about 75 per cent of the major apple orchards were under some form of integrated control. A similar proportion was reported in
British Columbia (Davis 1970). Asquith and Colburn (1971) I began an integrated control program in Pennsylvania in 1968.
Large airblast sprayers were used to apply sprays to altern¬ ate sides of the trees. This method of spraying tended to leave havens for predators which were not as susceptible to low concentrations of pesticides; this resulted in the build¬ up of certain predators in the orchard. This was especially true when Guthion and lead arsenate were the only insecti¬ cides used. The coccinellid predator of mites, Stethorus punctum (LeConte), and several species of predatory mites tolerated moderate use of Guthion. S^. punctum, however, was the only predator of mites which occurred in sufficient numbers to significantly contribute to the control of phyto¬ phagous mites. For the three years prior to publication
Asquith and Colburn's (1971) integrated spray schedule con¬ trolled mites and other insect pests very well.
In central Ohio the European red mite was controlled by naturally occurring predators for four years (1966-1969) in an experimental apple orchard. Some damage from codling moth was incurred, however. Spray cost savings of 25 per 14 cent could be realized from the biological control of mites, but this savings was nullified by losing as little as two per cent of the crop to codling moth damage. A reduced lead arsenate spray program allowed more than two per cent damage to Jonathan but resulted in less than two per cent damage to
Delicious, Golden Delicious, and Rome Beauty. "... Ohio growers will not accept integrated control unless it offers substantial savings in addition to the control of acaricide- resistant mites." (Holdsworth 1970)
Clancy and McAlister (1956) investigated the possibili¬ ties of integrated control of apple pests in West Virginia orchards from 1952 through 1956. They concluded that the method was unsuccessful there because of the scarcity and inefficiency of beneficial species.
Much success has been achieved in apple orchards of eastern Canada as a result of the selective use of pesti¬
cides which has effected a conservation of the naturally
occurring beneficial species (Morris 1968).
Asquith and Horsburg (1969) made an appropriate state¬ ment concerning the current status of integrated control in
apple orchards: "We are simply pointing out a way to start,
indicating that there is much to learn, and emphasizing
that it is subject to possible failure, especially on the
first attempt. Failure to achieve integrated control need
not lead to disaster, however. In our arsenal of pesticides 15
there are materials that may be used to correct almost any pest problem quickly and surely. Hence, the element of risk would depend almost entirely on the attentiveness and
judgment that the manager of the orchard devoted to the attempt to get integrated control underway."
B. Control of Major Pests
1. The European Red Mite
The more important species of phytophagous mites of apple trees are: the European red mite; the brown mite,
Bryobia rubrioculus (Schueten); the McDaniel spider mite;
the Pacific spider mite, Tetranychus pacificus McGregor; the two-spotted spider mite; the four-spotted spider mite,
T^. canadensis (McGregor) ; and the apple rust mite (Madsen
and Morgan 1970). Of these, only the European red mite and
the apple rust mite were found in my study orchards in
sufficient numbers to cause damage.
High populations of European red mites may cause severe
bronzing of the leaves (Oatman 1959b). As a result, the
vitality of the tree, the yield, and the quality and flavor
of the fruit may be adversely affected (Chapman eit al^. 1952,
Lienk et: al^. 1956) .
The European red mite was a constant threat in most
orchards from 1929 to 1945 when sulphur was the commonly
used fungicide (Lord et al. 1958). Cutright (1944) noted 16 that there was less European red mite damage with a reduc¬ tion in sulphur use. The sulphur killed the predators but was not nearly so harmful to the European red mite. At that time sulphur was about the only effective apple fungi¬ cide in use.
"It is well known that phytophagous orchard mites, mainly Tetranychidae, emerged as a major problem with the evolution of modern, intensive programs of chemical control"
(Chant 1963). There have been numerous documentations of the relationship between the use of pesticides and the out¬ break of the European red mite. Putman and Herne (1959,
1960) reported that in Ontario peach orchards DDT and carbaryl were detrimental to predaceous mites and other predators and thus favored increases in European red mite populations. In West Virginia, Clancy and McAlister (1958) observed a proportional increase of European red mites with
the destruction of Typhlodromus mite predators by various pesticides. In the Netherlands several workers have attri¬ buted European red mite outbreaks to the destruction of
their predators by pesticides (Kuenen and Post 1958; van de
Vrie 1962, 1964; van de Vrie and de Fluiter, 1958). Lord
(1949, 1956, 1962), Pickett and Patterson (1953), MacPhee
and Sanford (1956, 1961), and Sandford and Lord (1962)
reported from Nova Scotia that many pesticides had a detri¬ mental effect on predators and favored phytophagous mite 17
increases. Swift (1968) stated that an increase in the
European red mite population was due to pesticide toxicity
to the phytoseiid predator Typhlodromus fallacis (Garman).
As early as 1946 Pickett et_ al_. (1946) criticized the
failure of entomologists to consider the latent effects of
sprays on the fauna of the orchards, even though the imme¬ diate effects against a particular pest may have appeared desirable.
The control of mites continues to be one of the most
serious problems in the growing of apples throughout the world, chiefly because mites are able to develop strains
that are resistant to most acaricides, especially the organo¬ phosphorous compounds (Madsen and Morgan 1970). By 1964
resistance to organophosphates in the European red mite had
been reported from all continents except Africa (Helle
1965) .
European red mite resistance to parathion was reported
for the first time in 1951 in Washington State (Newcomer
and Dean 1952). It occurred in an apple orchard that had
been sprayed with parathion only three times. Resistance
to parathion was reported in 1952 in New York (Lienk et al.
1952) and in Ohio (Cutright 1956). Cutright (1956) reported
that the acquired resistance was maintained after a one
year cessation of parathion use. After two years the
resistance was reduced but was quickly reacquired. 18
Forsythe (1965) reported that in Ohio orchards the European red mite developed successive resistance to parathion, demeton, ovex, Guthion, Kelthane, and tetradifon from 1953 to 1963. There are numerous other reports of pesticide resistance in European red mite populations (Collyer and
Kirby 1958, Ghate and Howitt 1965, Hoyt and Harries 1961,
Madsen and Westigard 1960).
Asquith (1961) reported on a method of delaying resist¬ ance in mite populations. In Pennsylvania when Kelthane or tetradifon was used separately as the only acaricide, resistance to both compounds developed in three years.
When the same two acaricides were used alternately or mixed together at one-half standard concentrations, resistance did not develop in three years.
Helle (1965) stated that as late as 1964 there were no clear-cut cases of resistance in predatory orchard mites.
Since then, resistant predators have been found, but only infrequently, and thus their potential role in control of pest species has received limited attention (Croft and
Jeppson 1970) . When biologists began to appreciate and exploit the fact that predators also developed resistance, integrated control of mites became a real possibility
(Madsen and Morgan 1970).
Huffaker and Kennett (1953) reported that field popu¬ lations of Typhlodromus occidentalis, a predator found on 19 strawberries, were resistant to parathion. Resistance in this and other species of mite predators has been reported by several workers (Croft and Jeppson 1970, Davis 1970,
Hoyt 1969, Hoyt and Caltagirone 1971, Morgan and Anderson
195 8, Motoyama et^ ad. 1970) .
The development and success of an integrated control program for the McDaniel spider mite in Washington has already been discussed (Hoyt 1969) on page 8. This program was effective partly because of strains of Typhlodromus occidentalis which were resistant to the pesticides used in controlling the other pests present in the orchard.
With the use of DDT, additional acaricides were needed for effective mite control. Considerable success has been achieved in apple orchards of eastern Canada because the use of selective chemicals has permitted conservation of beneficial species (Pickett and Patterson 1953, Pickett et ad. 1958, Sanford 1967, Sanford and Herbert 1967). Lord et al. (1958) observed that glyodin had some acaricidal action and was relatively innocuous to predators. When it was used alone a rapid reduction of phytophagous mites occurred.
Croft and Barnes (1971) demonstrated that successful mite control could be obtained in a single season by the introduction of predatory mites. A resistant strain of
Typhlodromus occidentalis was introduced into a California 20 apple orchard to control the McDaniel spider mite. The
McDaniel spider mite population was maintained at a low enough level so as to require no acaricidal treatments.
Croft and McMurtry (1972) found that release rates of 32,
64, 128, and 256 Typhlodromus occidentalis per tree were all
successful in maintaining populations of the McDaniel spider mite below 15 mites per leaf. The most satisfactory release
rate was 128 predators per tree, at which rate the host mites were maintained at a stable level of two to four mites
per leaf. These two experiments suggest the feasibility of
a predator release program for control of phytophagous mites.
Croft and Barnes (1972) were able to genetically intro¬
duce pesticide resistance into a susceptible strain of preda¬
tory orchard mites. Two introduced, resistant strains of
Typhlodromus occidentalis hybridized with a native, suscept¬
ible strain and resistance was transferred.
The predatory mite Phytoseiulus persimilis Athias-
Henriot has been introduced into the USSR and has been used
extensively and successfully in European red mite control on
apples (Bondarenko and Yemel'Yanov 1970).
Insuring a sufficient food supply for the predatory
mites is one of the major management problems of an inte¬
grated mite control program. Asquith (1973) found that in
an integrated control program, two back-to-back applications
of acaricide reduced European red mite populations below 21
levels attractive to predators.
In Nova Scotia, Herbert and Sanford (1969) reported
that when the European red mite populations were depleted, either from use of pesticides or by excessive activity of predators, the apple rust mite, if present, provided an alternate food source. This enabled survival of a suffi¬
cient number of predators to prevent resurgence of the
European red mite within the same season. Collyer (1964)
showed that the predators Typhlodromus pyri Scheuten and
T. finlandicus (Oudemans) increased more rapidly and were better able to control the European red mite if provided with the eriophyid mite, Aculus fackeui (Nalepa) as an
alternate food.
In Oregon the use of Karathane, plus carbaryl as a
fruit thinning agent, may have been responsible for the
virtual absence of the apple rust mite from commercial
orchards. As a result, the predator Typhlodromus occiden-
talis had no alternate prey, and the two-spotted spider mite and the McDaniel spider mite were a problem during mid¬
summer. Thus, one or more applications of a selective
acaricide was necessary to reduce pest mite populations
enough for effective late season control by T. occidentalis
(Zwick 1972).
Besides using predator resistance to an advantage,
biologists also began to re-evaluate the practicability of 22 using new formulations of older materials such as petroleum oils for the control of the European red mite. Petroleum oils fit well into an integrated control program for several reasons: They have no history of resistance. They cost
less than most acaricides. They have a very low toxicity to man and other animals. They are commonly applied in the pre¬ bloom stage of tree development when the least damage is done to predators and parasites (Madsen and Morgan 1970).
Oils are especially effective in controlling those
species of mites which overwinter in the egg stage, notably
the European red mite (Chapman 1967). Bobb's (1969) experi¬ ments showed that overwintering European red mite eggs be¬
came increasingly susceptible to killing by oil as the
hatching period approached. Oils applied at green-tip stage
of bud development or before gave no practical mite control.
Maximum control was obtained when the oil was applied just
prior to full bloom. On Delicious trees, however, severe
reduction in fruit set occurred when oil applications were made later than the half-inch-green stage.
Oils are also effective against the San Jose scale and
overwintering aphid eggs (Chapman 1967). In the past, oils
have been used effectively for control of the fruit tree
leaf roller, Archips argyrospilus Walker (Chapman 1941) , and
the apple red bug, Lygidea mendax Reuter (Dean and Chapman
1946) . 23
Petroleum oils have been used in the United States to control insect and mite pests of deciduous fruit trees for over 90 years, second only to the arsenicals in length of use. Kerosene was the first seriously used petroleum product. By 1880 it was the standard treatment, as a ten per cent emulsion, for the control of aphids and other soft- bodied insects, and at 25 per cent for scale insects
CEbeling 1950, Lodeman 1896). After 1923, petroleum oils gradually became the primary dormant or semi-dormant treat¬ ments used in deciduous fruit orchards (Chapman 1967).
Today, most apple pest control schedules, and especially integrated control programs, begin with the application of oil sometime during the pre-bloom period (Bobb 1969, Chapman
1967, Downing 1967, Downing and Arrand 1968y Hoyt and
Caltagirone 1971, Oatman 1965a).
Hoyt and Caltagirone (1971) reported that the European red mite was not controlled by the predacious mite
Metaseiulus occidentalis (Nesbitt) in the early growing season in Washington. A single pre-bloom spray of petroleum oil and 0.16 pound of ethion per 100 gallons of water pre¬ vented the usual late June early July build-up of the
European red mite and did not affect the predator population.
M. occidentalis was then effective in controlling the Euro¬ pean red mite for the remainder of the season. 24
In the area of Mid-Columbia, Oregon, the European red mite was controlled by a pre-bloom petroleum oil spray plus
two to four applications of the fungicide-acaricide
Karathane (Zwick 1972).
In Wisconsin, Oatman (1959b) showed that pre-blossom
sprays will give season-long control of the European red mite under normal seasonal weather. At the same time, his
studies showed that in the absence of pre-blossom sprays, numerous acaricides will give good control with one applica¬
tion if properly timed and thoroughly applied.
Cutright (1944) noted that dormant oil usually resulted
in adequate control of the European red mite for that season, but if omitted the next spring, excessive mite injury almost
invariably developed that summer. Since that time, pre¬
blossom applications of oil have become an essential part
of integrated control programs. Oatman's (1965a) studies
indicated that once a pre-blossom spray is used it must be
used every year to avoid serious mite injury. Oatman (1959b)
found that pre-blossom application of miticide prevented the
European red mite from reaching an economically important
level for the entire growing season in Wisconsin. However,
these mites laid more overwintering eggs at the end of the
season. Thus the next year began with a larger mite popula¬
tion which increased to earlier and higher peaks. This
phenomenon was also reported by Morgan and Anderson (1958) 25 in Canada and by Collyer and Kirby (1958) in England.
The tendency of European red mite populations to pro¬ duce more overwintering eggs following suppression was hypothesized to be an example of the "compensation principle" which states that one biological phenomenon affects another to maintain stability in nature. This may be an explana¬ tion of the ability of mites to rapidly become resistant to chemicals which had been effective (Oatman 1965a).
Previously described integrated control programs for the European red mite have all used predacious mites as the principle control organism. In Pennsylvania, Asquith and
Horsburg (1969, and personal communication) have established a successful integrated control program for mites by using
the coccinellid predator, Stethorus punctum, as the control
agent.
It would appear at this time that predators are the only practical biological control agents which can be uti¬
lized in an integrated control program for the European red mite. There have been no parasites or bacterial infections
reported from the European red mite (Huffaker et_ a^L. 1969) .
Steinhaus (1959) was the first worker to report a virus
disease in the European red mite. Putman (1970) reported
that a rod-shaped, non-inclusion virus (a different virus
than the one Steinhaus described) infects all post ovarial
stages of the European red mite in Ontario. Innoculum from 26 excreta or oral secretions are picked up orally by non- inf ected mites while feeding. Suspensions of infected mites in water or various solutions were ineffective innocula.
Although introduction of the virus quickly reduced popula¬ tions, the disease did not naturally become effective soon enough to prevent serious foliage damage. In some seasons, however, the disease destroyed most of the mites before they laid overwintering eggs. Natural epizootics have been found only in dense populations. If the density which will sup¬ port an epizootic is near or above the economic threshold, as the field observations suggested, the virus appears to have no potential for practical use.
Leatherdale (1965) found that the fungus Paecilomyces eriophytis (Massee) was infective to the European red mite; no comment was made on possibilities for control.
Integrated control of the European red mite, and other phytophagous mite pests, has been shown to be economically
feasible, and indicates definite possibilities for more widespread application in the future.
2. The Codling Moth
It is a generally accepted conclusion among workers in
the field that the codling moth is the oldest, best known,
and most destructive pest of apples (Knight 1922, Proverbs
1970, Wood 1965, Holdsworth 1970). Dickson's (1949) dis¬
covery that photoperiod is the controlling factor for 27 induction of diapause in the codling moth was probably the single most important development in recent codling moth research. This discovery allowed laboratory rearing for study and later for sterile release programs (Barnes 1959).
MacLellan (1960) reported that 85 to 90 per cent of codling moth larvae in Nova Scotia select the trunk for over¬ wintering sites; a heavy mortality resulted when other sites were selected. Early workers used this fact in their con¬ trol efforts. Corrugated paper bands impregnated with beta naphthol-oil or alpha naphthylamine-oil-paraffin were successfully used as a supplementary control measure for the codling moth in Indiana (Steiner and Marshall 1931). Bands impregnated with five per cent pyrethrum extract and cotton¬ seed oil emulsified with blood albumen were almost 100 per cent repellent to codling moth larvae seeking overwintering sites (Yothers and Carlson 1944) . Yothers et; aj^. (1943) reported that 95 per cent of the overwintering larvae were killed with a dormant spray of 4,6-dinitro-o-cresol and stove oil. Although Hamilton and Fahey (1958) reported that high percentages of cocooning larvae were killed with para- thion, Guthion, and diazinon when applied to tree trunks and ground debris, Madsen and Morgan (1970) state that attempts to control larvae seeking overwintering quarters have not been generally successful. 28
Lead arsenate was the major chemical material used in controlling the codling moth prior to World War II. In
New Hampshire lead arsenate in the third spray controlled brood one and in the fifth spray controlled brood two
(Sanderson 1908).
Objections to arsenic residues on apples were first raised in 1926 (Webster and Marshall 1934). By 1938 it was apparent that lead arsenate was killing the beneficial orchard insects to the detriment of the control programs.
Cox and Daniel (1935) in New York observed that parasitism of the codling moth by Ascogaster carpocapsae Viereck was greatly reduced in lead arsenate sprayed orchards. Driggers and Pepper (1936) found that egg parasitism was markedly reduced in orchards sprayed with lead arsenate and oil.
Sprays of nicotine and oil and nicotine alone resulted in
68 and 126 per cent, respectively, more parasitism than when lead arsenate was used. The same study also showed that apple leafhoppers were less numerous and more heavily para¬ sitized in orchards sprayed with lead arsenate and oil from the first brood of the codling moth and nicotine tannate on the second brood than where lead arsenate and oil were used for both broods. Driggers and O'Neil (1938) reaffirmed that spraying with lead arsenate was deleterious to codling moth parasites. 29
Driggers and Pepper (1936) found that codling moth larvae and pupae were more heavily parasitized in sprayed and weedy orchards than in sprayed and cleanly cultivated orchards. Leius (1967) reported five times as many parasi¬ tized codling moth and lesser apple worm larvae in orchards with rich undergrowth as in orchards with poor undergrowth.
Many adult parasites feed on wild flowers.
In the early 1940's, many workers began to suspect that the codling moth was developing resistance to lead arsenate
(Steiner et^ al. 1944). Steiner and his co-workers dis¬ covered a behavioral resistance. Larvae of lead arsenate resistant strains crawled shorter distances over sprayed fruit and entered more quickly than the susceptible strains.
Childs (1947) reported that in a lead arsenate sprayed sec¬ tion of an apple orchard only 46.9 per cent of the fruit was
free from codling moth damage, while in a DDT sprayed sec¬
tion 95.2 per cent of the fruit was clean. As late as 1958
lead arsenate was still commonly used to control codling moth in England; it gave only moderate results and its use was restricted because of residue problems (Chiswell 1962).
Use of DDT in large orchard plots began in 1945
(Hamilton 1956). Many reports of early orchard experiments with DDT were accompanied by observations of great increases
in mite populations. In many fruit producing regions,
however, this fact was insignificant when compared with the 30
codling moth control obtained (Barnes 1959). The ineffec¬ tiveness of lead arsenate had necessitated as many as 11 cover sprays and still resulted in poor control and severe residue problems (Cutright 1953). With DDT as few as two to four cover sprays were required (Barnes 1959). Wood (1965) noted that in New Zealand DDT gave almost 100 per cent con¬ trol for codling moth but killed the beneficial arthropods.
Rumors that the codling moth might be resistant to DDT started in 1952 (Hamilton 1956). In an apple orchard in southern Ohio, DDT had not been effective since 1952
(Cutright 1954). By 1954 in southern Indiana, southern
Illinois, and Kentucky, control with DDT was becoming more and more difficult. In one orchard in 1943, the use of DDT, beginning with the seventh cover spray on July 22, had com¬ pletely stopped codling moth entries into the fruit. In
1950 entry holes averaged 0.3 per 100 apples after seven applications, and in 1954, there were 71.1 entries per 100 apples after nine applications (Hamilton 1956).
DDT was the principal chemical used to control the codling moth in the 1950's, but resistance necessitated the development and use of other insecticides (Madsen and Morgan
1970). In 1958 Asquith (1958) reported that several insec¬ ticides, including Guthion and carbaryl, when used with the fungicide captan or glyodin, gave better results than did
DDT with either fungicide. 31
Putman (1963) stated that the difficulty of codling moth control was proportional to the number of generations.
In North America the codling moth has two generations in most fruit growing regions; it is univoltine only along the northern fringe of the apple range (Oatman and Libby 1965).
During lead arsenate use the early portion of the first generation was the critical one to be controlled. Since organophosphate compounds have been used, the first portion is rarely a problem, and the last portion of the first gen¬ eration has become the problem. This may be a result of selection by the codling moth in response to changed spray schedules (Asquith 1960).
Numerous insecticides have been experimentally and commercially tested for controlling the codling moth.
Hough (1948) reported that when first applied, parathion was more effective than DDT but had shorter residual action.
Diazinon, EPN, and malathion have effects closely approach¬ ing those of parathion (Glass 1954, Hamilton ej: al. 1954).
Madsen and Hoyt (1958) tested and obtained promising results for Trithion, Delnav, ethion and especially carbaryl and in Guthion. Guthion and carbaryl have given the best residual control, but mite increases have been observed following the use of carbaryl (Chiswell 1962). In most current spray programs Guthion is the preferred insecticide for the codling moth. 32
Several broad spectrum insecticides which have proven effective against the codling moth have also been dentri- mental to parasites and predators, and are, therefore, not good for an integrated control program (Batiste et_ al.
1970) ; others can be used. Hoyt ert al^. (1967) showed that lower dosages of Guthion (2.5-4 pounds of 25 per cent wettable powder per acre) were less toxic to predatory mites than the recommended dosages (4-5 pounds per acre). Madsen and Williams (1968) showed that this lower dosage adequately controlled the codling moth. If applied with oil the ini¬ tial deposit was less and persistance was greatly reduced when compared with Guthion used alone. Phosalone gave good control of the codling moth and the white apple leafhopper,
Typhlocyba pomaria McAtee, and also suppressed the apple aphid and was not toxic to phytoseiid mites, thus no phyto¬ phagous mite outbreaks occurred (Madsen 1970).
Researchers are continually looking for ways to reduce the number of sprays necessary to control the codling moth in order to develop integrated control programs for other pests of the apple and for the codling moth itself.
Gaprindashvili and Novitskaya (1967) reported that in some orchards under chemical control in the USSR, damage from the codling moth was as high as 40 per cent. This would seem to be justification for research into alternate methods of control. 33
One way to reduce the number of sprays is to spray only when necessary. Chemical control of the codling moth
is dependent upon proper timing which must be adjusted for
local conditions (Madsen and Morgan 1970). In California, by carefully timing two treatments of Guthion against the moths of the overwintering generation and the first genera¬
tion larvae, no treatment was needed for the second genera¬
tion. In Chile, with similar climatic conditions, three or
four sprays were being used to control the codling moth.
By carefully monitoring the populations the two-treatment
program was tested. At harvest not one codling moth injury was found in a sample of 2000 apples (Barnes et al. 1969).
Batiste's (1972) study suggests that with surveillance of
codling moth flights, the benefits of reduced dosages can
be realized while maintaining a high level of codling moth
control. Pheromone traps can be used to estimate popula¬
tion levels to determine the need for treatment (Madsen and
Vakenti 1972). Some Europeans use cages with overwintering
larvae in them to time sprays with emergence (Madsen and
Morgan 1970).
LeRoux (1971) reviewed attempts at biological control
of the codling moth over the last 110 years (1860-1970).
Every case was a failure. Modified spray programs, however,
have allowed biological control of a few other apple pests
(Madsen and Morgan 1970). Putman (1963) advanced an 34 explanation for the failure in biological control attempts with the codling moth: "The high intensity of infestation in the apple-growing regions of Europe and eastern Asia, where the codling moth is native, even where apples are grown under primitive conditions, is presumptive evidence that effective biotic control factors are lacking."
Over 100 parasites, predators and diseases are known to attack the codling moth in various parts of the world
(Lloyd 1961), but with one exception they fail to give con¬ trol at a satisfactory economic level (Wood 1965). Only in the northern limits of the apple growing range, as in Nova
Scotia where reproduction is limited, can currently known biotic factors keep the codling moth at commercially accept- ible levels (LeRoux 1971). Only predation by woodpeckers in winter is significant (LeRoux 1960). In Nova Scotia woodpeckers were efficient predators of overwintering codling moth larvae and frequently reduced the pest popula¬ tion to a level where other natural agents were able to prevent the succeeding generation from causing economic damage to the fruit (MacLellan 1959). Woodpeckers attack the codling moth at a stage in its life cycle when the pest is lowest in numbers. They frequent orchards according to the density of codling moth larvae, and on many occasions have reduced the codling moth in individual orchards from potentially harmful levels to non-economically important 35 levels for a particular year (MacLellan 1970).
The mortality of codling moth larvae overwintering on tree trunks was examined from 1954-1969. Woodpeckers accounted for about 90 per cent for those 16 years
(.MacLellan 1958, 1970) . MacLellan (1963) observed that the predators and parasites of codling moth eggs increased in integrated control orchards in Nova Scotia. The predators included mirids, coccinellids, pentatomids, clerids, and thrips. MacLellan (1962, 1963) showed that predation on eggs and first instar larvae was responsible for control in Nova Scotia integrated control orchards; the damage at harvest was 0.5-2.4 per cent.
From 1930-1939 Trichogramma minuturn Riley and Macro- centrus ancylivorus Rohwer were colonized in commercial peach and apple orchards in Georgia. These two parasites and the native parasite Ascogaster carpocapsae were esti¬ mated to have destroyed 64.6 per cent of the codling moth population (Webb and Alden 1940). Mass rearing and release of Trichogramma spp. received considerable attention in the
United States during the ten year period prior to World War
II. Results at control were generally inadequate; they could not compete with results obtained from chemicals.
In recent years orchard growers in Europe have shown an in¬ creasing interest in mass releases of Trichogramma spp., often as part of an integrated control program (Dolphin and 36
Cleveland 1966). Although parasites have contributed to codling moth population reductions, biological control has not been practical in apple orchards (Madsen and Morgan
1970) .
Gaprindashvili and Novitskaya (1967) reported several larval parasites: three species of Ichneumonidae; seven species of Brachonidae; and three species of Tachinidae.
These parasites were effective only in unsprayed orchards and were low in numbers or absent in orchards sprayed with
DDT or Guthion. Pickett (1959) noted an increase in para¬ sites reared from codling moth larvae in orchards where selective sprays were used. In New Zealand, Wood (1965) observed that natural egg mortality, which resulted from inviability and disappearance from the tree, was low (4.7-
6.9 per cent) in an integrated control orchard. There was
25.8 per cent mortality of eggs (14 per cent due to para¬ sitism by Trichogramma spp.) in an orchard which had never been sprayed with broad-spectrum insecticides. Natural mor¬ tality of young larvae on unsprayed trees was ten per cent; no predation was observed, and none was suspected. Dolphin and his co-workers (1972) released Trichogramma minutum and
T. cacoeciae Marchal at the rate of 70,000 per eight foot tree per week and got only partial control. They concluded that several times this number would be necessary to be effective even on semidwarf trees. MacLellan's (1962, 1963) 37 work indicates that successful control (less than two per cent damage) can be obtained, at least in single generation areas, by mortality factors operating on the egg and first instar larva stages.
One of the more promising methods of codling moth con¬ trol which may supplement, or in some cases replace chemical control, is the release of sterile moths. Proverbs and
Newton (1962) stated that the ratio of sterile to fertile males should be twenty to one to cause a rapid decline in the indigenous population. Three years of releases of ster¬ ile male moths in an abandoned apple orchard in British
Columbia reduced injuries from second brood larvae from 4.94 to 0.05 per cent (Proverbs ei: al_. 1966). Release of sterile moths, male and female, in a two hectare abandoned apple orchard in British Columbia reduced the number of apples
injured by codling moths from 60 per cent before release to
1.6 per cent after the first year and to 0.3 per cent after the second year (Proverbs et_ al. 1967) .
An extensive sterile codling moth release program was undertaken in Washington between 1964 and 1967. Control was
comparable to that obtained by insecticides (Butt et_ al.
1970). In 1971 a sterile release program in Washington reduced the number of overwintering larvae 92 per cent, and
only 0.005 per cent of the fruit produced mature larvae
(Butt et al. 1973). Release of radiation-sterile moths in 38 a commercial orchard in the Okanagan Valley of British
Columbia from 1966-1968 resulted in 0.003, 0.095 and 0.710 per cent injured fruit at harvest. No insecticides were used for codling moth until July 1968 when two thirds of the orchard was sprayed with Guthion because of an accidental release of substerile moths. Sprays for mites and other pests were timed so as not to interfere with the sterile moths. This test indicated that sterile moth release is a commercially satisfactory method of control in certain situ¬ ations (Proverbs e_t al_. 1969) .
Proverbs (1970) reviewed sterile release experiments in British Columbia from 1962-1970. Very good control was achieved in all experiments where fully sterile moths were released. Results from 1970 suggest that release of partial¬ ly sterile males plus fully sterile females may have been more effective than release of fully sterile moths of both sexes; sterile males are not as competitive as fertile males. In orchards where the codling moth was controlled, the apple aphid and the woolley apple aphid, Eriosoma lani- gerum (Hausmann), were of no economic importance. The
European red mite was no problem in one orchard and required only one spray in another. The McDaniel spider mite was held in check by predators, and rust mites needed no treat¬ ment. The eye-spotted bud moth and the white apple leaf- hopper, normally two serious pests, required no specific 39 sprays. Results of those tests are promising, but it is yet to be determined if control is feasible on a large scale.
Several codling moth pathogens have been reported. A few may have a place in an integrated control program. In nature fungi attack the overwintering larvae (Russ 1964).
Jaques and MacLellan (1965) surveyed commercial orchards in
Nova Scotia from 1951-1958 and found that only 1.7 per cent of the codling moth larvae had been killed by fungi; this was 3.3 per cent of the total mortality. In 85 per cent of their samples no fungus deaths were found, although fungi were found in most orchards. By far the most prevalent fungus was Beauveria bassiana (Balsamo). Isolates of this fungus were highly virulent for codling moth larvae in the laboratory. Boyce (1941) believed that fungi were of little significance in codling moth larval mortality in apple orchards of Ontario. Conversely, Jaynes and Marucci (1947) in West Virginia showed that B. bassiana was very patho¬ genic to codling moth in the laboratory and in the field.
Michelbacher el: al^. (1950) found that fungi (principally
B. bassiana) killed nearly 70 per cent of overwintering larvae under the bark of walnut trees in California. Russ
(1964) reported that B. bassiana significantly reduced codling moth populations in the field. In three years
Gaprindashvili and Novitskaya (1967) found 21 species of entomophages and five species of pathogenic fungi affecting 40
codling moth in Soviet Georgia. Of these, seven entomo- phages and two pathogenic fungi were important in reducing the numbers of codling moths, but these were effective only in unsprayed orchards.
Infections of Beauveria spp., however, were much greater in orchards sprayed with DDT than where no toxic sprays had been used. The same effect was observed with phosphamidon and Dylox. This is a good indication that this fungus may be useful in an integrated control program.
Hughes (1957) reported a polyhedros-virus disease of codling moth. Tanada (1964) reported a granulosis-virus disease caused by a virus in the group Bergoldiavirus. In laboratory tests larvae were fed apples which had been dipped in virus suspensions. No infected larvae matured to adults; death resulted in 5-12 days. Falcon ed ad. (1968) reported that a granulosis virus sprayed on trees at peak codling moth egg laying activity resulted in heavy larval mortality. Some larvae died before feeding, but most died soon after feeding on the epidermis of the fruit. Of those which entered the fruit, most died. The results of the experiment indicate a potential for use in integrated con¬ trol and in sterile moth release programs.
Bacillus thuringiensis Berliner sprays were ineffec¬ tive in field trials, although a 50 per cent reduction of
fruit injury was realized (Oatman 1965b). An integrated 41 control program using ryania-B. thuringiensis gave good re¬ sults for codling moth but did not adequately control the red-banded leaf roller, the European red mite or the eye- spotted bud moth (Oatman 1966).
An important preparatory measure for many types of con¬ trol, especially for sterile release programs, is sanitation.
By removing 2400 abandoned trees during the spring and summer of 1970 and spraying or destroying the remaining abandoned trees, the codling moth populations in the four commercial orchards in Wenas Valley, Washington, were re¬ duced 96 per cent in 1970 (Butt et al. 1972).
Nova Scotia workers have pioneered research on inte¬ grated control in apple orchards, and the methods have been adopted by the growers (Madsen and Morgan 1970). Woodpeck¬ ers and other predators play a significant role in reducing the overwintering larvae populations (MacLellan 1959).
The main insecticide for codling moth in this program was ryania, and when combined with a program of selective sprays for other pests, it permitted the survival of arthropod predators (MacPhee and Sanford 1961). Only rarely are broad spectrum pesticides resorted to. Codling moth levels were higher under the integrated control program than with chemi¬ cal control, but damage to harvested fruit in commercial orchards was only slightly higher than where there was gross use of broad spectrum pesticides (MacLellan 1970). 42
About 90 per cent of Nova Scotia commercial apple and
pear orchards have adopted an integrated control program based on ryania. Integrated control is successful in Nova
Scotia because: 1) the codling moth is univoltine and
2) a high proportion of Nova Scotia apples are sold for
processing, thus a higher degree of damage is tolerated
(Madsen 1968).
The use of either ryania or lead arsenate with glyodin
has formed the basis of integrated control programs in
several other areas where the codling moth is univoltine
(Wood 1965) or where populations are low (Oatman 1966). In
a two year test in Ontario, ryania compared favorably with
DDT (Patterson and MacLellan 1954). In ryania programs in
New York and Indiana, Hamilton and Cleveland (1957) found
indications that beneficial insects were more abundant in
ryania plots than in DDT-parathion or DDT-malathion plots.
Holdsworth's (1970) studies, previously cited (page 14)
indicated only marginal success for a lead arsenate based
integrated control program. He suggested that after a two
or three year period of integrated control, it may be
necessary to revert to complete chemical control to reduce
codling moth populations. In older, commercial, integrated
control orchards, natural controls require an occasional
assist by chemical treatment to contain the codling moth
below economically acceptable levels (MacLellan 1972). 43
At the present time commercial, integrated control programs for the codling moth are being practiced only in the northern apple growing regions where the moth is uni- voltine. Research has indicated that sterile moth releases may be successfully incorporated into integrated control programs in the future.
3. The Apple Maggot
For more than a century the apple maggot has been a major pest of apples in northeastern United States and southeastern Canada, and in many home orchards it regularly infests up to 100 per cent of the apples (Dean and Chapman
1973, Moore 1969, Oatman 1964a, Prokopy et_ ad. 1971) .
Rivard (1968) indicated the importance of this pest by list¬ ing over 1500 titles in his bibliography of the apple maggot.
The apple maggot, a native of North America, occurs from southern Canada to central Mexico, east of the Rocky
Mountains. The original host is believed to have been hawthorn, Crataegus spp. Since the introduction of the apple from Europe, it has become an extremely important pest in the northeastern portion of its range. South of southern
Indiana and Illinois, it is a less significant pest, prob¬ ably because the cover sprays directed against the codling moth also control the apple maggot (Kamasaki et_ ad. 1972).
It has not been reported outside of North America (Madsen and Morgan 1970). 44
By 1867, when Walsh described the apple maggot, it was already well-established in New England. In eastern
New York all apple varieties are susceptible to attacks
from the apple maggot, and although some are more suscepti¬ ble than others, all require an equal amount of protection.
Infestations of more than 100 egg punctures per apple are not unknown (Dean and Chapman 1973). Commercial apples often exceed 70 mm in diameter and can support 15 or more
larvae to maturity (Prokopy 1972a).
Neilson (1971) released strontium 90 labeled adults
and reported short dispersal flights and a tendency of the
population to remain in the orchard. The distribution within the orchard was influenced by the tree variety and
the presence or absence of apples; the flies were more
prevalent on the early and mid-season varieties. Adults
did some feeding in areas adjacent to orchards, and some
returned to the orchards. Maxwell (1968a) showed with
released, marked flies that there was an even dispersal
throughout the orchard which extended for 250 feet from the
release point. Dean and Chapman (1973) stated that the
flies did not travel more than a quarter of a mile, and
usually less. Oatman (1964b) reported no difference in
adult activity related to the four quadrants of the tree,
although more were trapped on the south side. Adult flies
were most active from noon until 7:00 P.M. with almost no 45 activity from 7:00 P.M. until 7:00 A.M.
Adult apple maggots cannot survive and reproduce on the substances usually present on the surface of the fruit and foliage. Honeydew from aphids, mealybugs, and scale insects may be the principal natural source of adult nutri¬ ent requirements (Neilson and Wood 1966). Dean and Chapman
(1973) reported that the evidence strongly indicated that, in the natural environment, apple maggot adults utilize insect honeydew as food. The honeydew, with the assistance of microorganisms, may provide both carbohydrate and nitro¬ genous dietary elements.
The apple maggot overwinters as a pupa. The initiation of pupal diapause is regulated by photoperiod and tempera¬ ture, the larva being the sensitive stage for photoperiod and both larva and pupa for temperature. Larval food has no effect on the initiation of diapause (Prokopy 1968a).
Lathrop and Dirks (1945) reported that timing apple maggot emergence by using temperature, rainfall and petal fall date was accurate enough for control. Oatman (1964b) reported that adult emergence, averaged over six years (1958-
1963), began 32 days after petal fall, peaked 9 to 12 days after first emergence, and continued until 75 days after first emergence. The period of emergence averaged 55 days.
Higher temperatures caused earlier emergence. Adult emerg¬ ence began sooner, peaked earlier and continued for a 46 shorter period when the larvae developed in early maturing apple varieties. Dean and Chapman (1973), however, reported different results: Neither the time mature larvae left the fruit to pupate, the variety of apple in which they developed, weather conditions, nor locations where they entered the soil, appeared to exert a consistent effect on the time of adult emergence. They concluded that the use of emergence cages or traps remains the most effective method of determining emergence.
The apple is the site of mating and oviposition
(Prokopy et al. 1971). Prokopy et a^U (1972) found that the flies have little tendency to arrive on the fruit until they are ready to mate and lay eggs, which is 7 to 10 days after emergence. An unidentified chemical deposited by both sexes (more was deposited by mature females) caused arriving males to spend twice as much time on the apples.
i The chemical did not attract the males (Prokopy and Bush
1972). Mating and oviposition occurred predominantly during
the afternoon on days when the sun shone brightly (Prokopy
et a]^. 1972). Neilson and McAllan (1965) observed that
females mate many times; frequent mating was necessary to
insure a high degree of egg fertility.
Hall (1937) reported the regular occurrence of a par^
tial second generation in Ontario. Knight (1922) reported
a partial second generation in New York. Dean and Chapman 47
(1973), however, state that the evolution of a bivoltine strain in New York is unlikely since the flies appear so late in the season.
Dean and Chapman's (1973) data indicated only a few multi-year cycle flies. Lathrop and Newton (1933) reported high percentages of multi-year flies from Maine.
Cultivation did not destroy a significant number of pupae (Card and Stene 1905), although most larvae pupate within the first one or two inches of soil, or with sod conditions, in the matted grass (Dean and Chapman 1973).
Another cultural control practice which has proven more successful is destruction of alternate host plants.
Neilson (1971) wrote that the removal of adjacent host trees has always been a part of control recommendations in
Nova Scotia.
Parasites of the apple maggot have been widely re¬ ported from northeastern North America: Connecticut
(Porter and Alden 1921), Maine (Woods 1915, Marlott 1933),
Massachusetts (Bourne 1935), New York (Middlekauf 1941),
Quebec (Rivard 1967). Parasites have not become numerous in any place, moreover, they are not consistently found from year to year (Monteith 1971b).
Prior to 1930 no comprehensive study was conducted on any biotic agent for control of the apple maggot. After control was accomplished with arsenicals and later with 48 other insecticides, little interest was shown in biological control. Recently there has been an interest in biotic agents (Monteith 1971b).
Larvae and pupae are subject to attack by several hymenopterous parasites, most of which are braconids:
Opius melleus Gahan, 0. lectus Gahan, and 0. alloeus Muese- beck being the most common. In studies from 1933-1969 in
New York, Opius parasitism in emergence cages was 0.05-29.4 per cent from unsprayed orchards. In general, Opius was not considered to exert much effect on the apple maggot popula¬ tions (Dean and Chapman 1973). In a four year study in southern Ontario, the only parasites found were O. melleus and O. lectus. The parasite population was low and was found only in or adjoining unsprayed trees where there was shrubby undergrowth. Control of the apple maggot by para¬ sites is very limited, since distribution is excluded from chemically treated orchards. Parasites in adjacent areas may reduce the number of apple maggots that disperse into commercial orchards (Monteith 1971b). No parasites of the adult are known (Monteith 1972).
In five years of observations in southern Ontario,
Monteith (1972) found no evidence of predation on the adult apple maggot. He stated that the flies alertly avoided ap¬ proaching objects, and that they appeared to be avoided by hunting spiders. Brittain and Good (1917), however. 49 reported that the adults were attacked by a jumping spider,
Dendryphantes militaris Emerton in Nova Scotia. Dean and
Chapman (1973) found hemipterous predators, asilids and web¬ spinning spiders in apple maggot emergence cages. They stated that these predators were probably of little impor¬ tance under natural conditions.
Monteith's (1971a) laboratory observations revealed that crickets can detect, disinter and consume apple maggot pupae in simulated natural surroundings. He found large numbers of field crickets, Gryllus pennsylvanicus
(Burmeister) and Nemobius fasciatus (DeGeer), under trees in unsprayed orchards. No crickets were found in sprayed orchards. The apple maggot larvae emerged from fallen apples, entered the soil and pupated when the cricket popu¬ lation was the highest. Very few, if any, other potential predators of pupae were found. There are no reports of cricket damage to apple trees although they feed on damaged, fallen apples which are of little commercial value*
Monteith concluded that crickets probably make a major con¬ tribution to the reduction of apple maggot populations and appear to be suitable for use with other non-chemical methods of controlling the apple maggot.
In Quebec a mite, Proctolaelaps hypudaei (Oudemans), destroyed small numbers of apple maggot eggs (LeRoux and
Mukerji 1963). 50
Jaques et^ ad. (1969) described a bloating disease, possibly caused by bacteria, in laboratory-reared apple maggot adults. Dean and Chapman (1973) observed a similar disease in their cultures in 1932, 1935, and 1938. That disease was known only in laboratory cultures. Dean and
Chapman stated that disease may be an important cause of pupal death, since in rearing, it was observed that large
numbers died from disease. In general, biotic agents have
had little effect in reducing infestations of apple maggots
(Monteith 1972).
As early as 1913, egg and larval mortality were found
to vary in different hosts (Ross 1913). This was attributed
to the rate of softening of the fruit (O'Kane 1914). Egg
and larval mortality was lowest in early soft varieties and
highest in hard, winter apples where mortality sometimes
reached 100 per cent (Dean and Chapman 1973). There are
several reports of egg mortality ranging from 0.4-36.3 per
cent (Caesar and Ross 1919; Dean and Chapman 1973; Good
1915; LeRoux and Mukerji 1963).
High natural mortality during the larval stage in the
fruit has been reported. In a three year study from 1931-
1933, Dean and Chapman (1973) found that larval mortality
varied from 2.3-100 per cent in 20 varieties of apples.
This compares with average larval mortality of 64.2 per
cent CO'Kane 1914), 79.6 per cent (Brittain and Good 1917), 51
84.5 per cent (Caesar and Ross 1919), and 55 per cent
(LeRoux and Mukerji 1963).
Natural pupal mortality is also high. Good (1915) and
Brittain and Good (1917) reported pupal mortality of 81.5-
95.5 per cent. They attributed it to parasitism, predation by birds and insects, and disease. Caesar and Ross (1919) reported 47-73.1 per cent pupal mortality and attributed it to the weather. Whitcomb (1948) reported pupal mortality of about 50 per cent for Massachusetts from 1943-1946.
Oatman (1964b) reported 41 per cent emergence of 9072 larvae which had entered the soil to pupate. Wide fluctuations in apple maggot populations have occurred in New York, and Dean and Chapman (1973) attributed much of the cause for that to pupal mortality.
All the natural controls together do not exert enough influence on apple maggot populations to eliminate the need for artificial controls in commercial orchards (Dean and
Chapman 1973).
Much work has been done in the area of attractants and traps for the apple maggot. The goal for such research is an effective monitoring system for timing spray applica¬ tions, or possibly even a non-chemical means of control.
Both sexes of the apple maggot are attracted to yellow rec¬ tangles over other colors, to dark spheres over other colors, to spheres over other shapes, and to dark sphere-yellow 52 rectangle combinations most of all (Kring 1970; Maxwell
1968b; Prokopy 1968c, 1972b). In the early 1940's it was found that aqueous solutions which gave off ammonia were effective attractants (Hodson 1943, 1948). Several workers have reported on various kinds of traps using real and arti¬ ficial apples and many different attractants (Moore 1969;
Oatman 1964a; Prokopy 1968b; Still 1960). In 1967 in
Connecticut, Prokopy (1968b) hung red balls coated with TM Strkem in some dwarf apple trees in an orchard; there was
24-45 per cent less fruit injury in those trees. In addi¬ tion, there was less injury in the whole orchard, because the spheres had captured flies from the entire orchard.
Prokopy commented that this might be a possible means of control for the home orchardist, especially with dwarf
trees.
The apple maggot is a persistant pest which requires
annual spraying to keep populations at low levels, and during the past 50 years most insecticides have been
evaluated for its control (Neilson 1971). The object of
foliar sprays is to poison the adults during the pre- oviposition period (Dean and Chapman 1973). The materials
and number of spray applications vary, but in most areas
contact poisons, especially organophosphates, are used.
Some areas still use arsenicals or a combination of arsenic-
als and other insecticides. Control failures are not 53 uncommon and have often been attributed to insufficient applications, improper timing, inadequate materials, and to migration of flies from unsprayed into sprayed areas
(Neilson 1971).
The biotic potential of the apple maggot is such that near perfect control is necessary if the treatment is to be economically feasible (Oatman 1959a). At present insecti¬ cides provide the most effective control (Moore 1969).
Dean and Chapman (1973) have said that insecticides applied to apple trees, during the time the adults are present, have given excellent control of the pest without leaving harmful residues on the harvested fruit or causing noticeable pollu¬ tion of the environment.
The development of control methods based on arsenicals for adults began about 1910 (Dean and Chapman 1973).
Arsenicals have been used in Nova Scotia since 1914 and are
still recommended in other areas (Neilson et_ al. 1968). In
1920 two sprays of lead arsenate gave adequate control of
apple maggots in New York, provided that the nearby
abandoned apple trees had been removed (Herrick 1920). In
New Brunswick two cover sprays of lead arsenate in July had been recommended since the early 1920's until the mid 1950's.
Earlier sprays of calcium arsenate, as a general insecticide,
undoubtedly contributed to arsenical residues which main¬
tained control of the apple maggot. By the time mild 54 organic fungicides came into use, calcium arsenate was no longer used, and lead arsenate failed to give control. In
New Brunswick from 1957-1960, lead arsenate was not effec¬ tive even with five or more sprays (Maxwell et_ ctU 1963;
Neilson et; al^. 1970) .
The establishment of residue tolerances encouraged the search for other insecticides to replace lead arsenate.
Substitutes were found for the codling moth, but these were ineffective against the apple maggot. Not until DDT did the spray program change, and use of DDT resulted in increases in the apple maggot populations. Although DDT was highly toxic to apple maggot adults and acted faster than lead arsenate, its period of residual effectiveness was much shorter. Control of the first brood of the codling moth was so complete with DDT that later sprays were eliminated and apple maggot control suffered (Dean 1948; Dean and Chapman
1973). The addition of DDT to the lead arsenate cover
sprays improved control for moderate infestations but was not effective for severe infestations (Maxwell et^ al_. 196 3) .
Three sprays of DDT were needed; whereas, only two of lead
arsenate had been previously used. Where migrations from
outside the orchard were likely, DDT was applied later in
the season than had been lead arsenate (Dean 1947). Dean
(1951) reported that late season spraying led to problems
of excessive residues at harvest. 55
Guthion, carbaryl, diazinon, dieldrin, dimethoate,
heptachlor, malathion, methoxychlor, parathion, and
Strobane have all been reported as highly effective for
apple maggot control when proper timing, correct dosage,
and adequate coverage are adhered to (Dean 1954; Libby and
Oatman 1963; Maxwell et: al. 1963; Neilson et_ al. 1968, 1970).
Dean (1951) found that under field conditions, chlordane,
toxaphene, dieldrin, and parathion failed to give adequate
protection.
Dolphin et^ al. (1970) weekly applied a bait spray
(technical malathion in a corn protein hydrolysate bait) to
the trunk and scaffold limbs. The number of adults trapped was reduced 99.4 per cent in one year, and larval fruit
infestation was reduced by 93 per cent. Neilson and Maxwell
(1964) did not get satisfactory control by using poison bait
sprays of malathion and Staley's insecticide bait number
seven even though fruit injury was reduced by up to 50 per
cent.
Control by foliar application in Wisconsin was effected
by one or more materials applied at 10 to 14 day intervals,
beginning 7 to 10 days after the first adults emerge. Three
or more sprays were normally required. Thorough coverage and
proper timing were essential (Oatman 1959a). Since 1955 the
apple maggot has caused no significant damage in well-
managed orchards in New York, because of the widespread use 56 of Guthion (Dean and Chapman 1973). In Massachusetts and
Connecticut, Savos et_ al_. (1973) have recommended that
Guthion, Gardona, Imidan, phosalone, carbophenothion, or carbaryl be used in the fourth (early July) through the seventh (mid-August) cover sprays.
Oatman (1959a) tested a few soil insecticides and found endrin to be effective, giving a 96 per cent reduc¬ tion in damage. Dieldrin, aldrin, and heptachlor gave inadequate control as soil applications. Maxwell et al.
(1963) reported that fumigants showed more promise than soil insecticides.
The possibilities for an integrated control program for the apple maggot have not been extensively explored.
Neilson ejt al. (1968) described a reduced spray program which was compatible with the then current integrated con¬ trol programs in Nova Scotia. In 1961 in an isolated orchard, there was an extremely heavy infestation of apple maggots which resulted in no marketable fruit. One spray of lead arsenate was applied each year in mid-July from
1962 through 1966. By 1963 there were almost no maggots in the fruit. It was found that lead arsenate acted as a chemosterilant and drastically reduced ovarian development; no eggs were laid for five weeks after a spray application.
Neilson ert al^. (1968) concluded that one or two applications of lead arsenate, depending on the prevalence of apple 57 maggots, were adequate if infested trees in the vicinity were either removed or treated.
Utilizing pheromones for control has limited possibili ties. No sex pheromones have yet been found in the apple maggot (Dean and Chapman 1973). There is, however, a mark¬ ing pheromone. After oviposition the females deposit a marking pheromone insuring uniform dispersal of eggs among the available fruit. The amount of fruit surface area marked following a single oviposition is related to the amount of food or space required by one larva to grow to maturity. The pheromone could be sprayed on nine of every ten trees to deter oviposition on those trees. The tenth tree could be equipped with traps. The females move from tree to tree quite regularly, and perhaps an acceptable level of population supression could thereby be achieved
(Prokopy 1972a).
Much more research is necessary to establish a success ful integrated control program for the apple maggot.
4. The Plum Curculio
The plum curculio is native to North America where it bred on wild plums and hawthorne before the introduction of cultivated fruit. It occurs as a pest east of the Rocky
Mountains throughout the United States and southern Canada
(Metcalf et al. 1962). As early as 1736 it was reported 58 as a serious pest of garden plums around Philadelphia
(Whitcomb 1929). Harris (1863) devoted four pages to a discussion of the plum curculio and stated that it was frequently responsible for great losses in some orchards and gardens; often a crop of plums was entirely ruined.
During the nineteenth century no other pest of tree fruits was more written about and apparently more feared than the plum curculio (Chapman 1938). It is generally accepted that the plum curculio is one of the most serious pests of pome and stone fruits (Barnes 1959, Forsythe and Rings 1965;
Glass and Lienk 1971, Stearns 1931, Whitcomb 1952).
In 1928, the plum curculio was the most serious insect pest of apples in Massachusetts, frequently damaging more
fruit than all other insects combined. In some abandoned and poorly cared for orchards, 100 per cent of the fruit at harvest was damaged; most apples had three or more punc¬
tures. Even in orchards where an average spray schedule was
followed, damage was often 30 per cent and occasionally 60 per cent. In confinement, adults made an average of 236
feeding punctures per pair, and feeding accounted for only
64 to 83 per cent of the total punctures (Whitcomb 1929).
Efforts to get adult female plum curculios to feed or ovi¬
posit in substrates other than small fruits have not been
successful (Yonce et_ ad. 1972). In New York a one acre
orchard was normally maintained except that no insecticides 59 or acaricides were used. The damage from plum curculio steadily increased from 7 to 46 per cent over a period of
10 years (Glass and Lienk 1971). Smith (1957b) reported that a bushel of infected apples may yield as many as
10,000 plum curculio larvae.
Adults will fly at least half a mile to find hibernat¬ ing sites in the fall. The beetles prefer the leaf cover for hibernation (Whitcomb 1929). Smith and Flessel (1968) reported from New York that fewer than five per cent entered the soil; the rest hibernated between the leaf cover and the soil. Bobb (1949) observed in Virginia that most of the beetles hibernated in the second or third inch of the soil.
Smith (1957b) found that diapause was obligatory in univoltine strains and facultative in multivoltine strains.
Padula and Smith (1971) observed a reduced fecundity and fertility when univoltine males were crossed with multivol¬ tine females. The females were somewhat reluctant to mate although insemination occurred with mating.
A large percentage of overwintering plum curculios die before spring. In New York, winter mortality was 23 to 59 per cent from 1954 through 1963; there was slightly greater mortality among males (Smith and Flessel 1968). In Massa¬ chusetts 60 to 75 per cent died during the winter (Whitcomb
1929) . 60
Over a five year period in New York, 33 to 62 per cent of the total emergence from hibernation occurred on a single day. There was a lag of several weeks from the time of emergence to appearance in the host trees (Smith and
Flessel 1968). Migration to the trees in the spring is dependent on the temperature. Few adults fly to trees until the temperature after blossom attains a maximum of 75 de¬ grees Fahrenheit or the mean temperature of 60 degrees or higher for two consecutive days (Chapman 1938). Chandler
(1953) reported that adults began to appear at pink stage, peaked during bloom, and decreased rapidly after petal fall.
Rings (1954) released radioactive adults and found that
73 per cent remained near the tree of release, 12 per cent moved from one row to the next, and only 15 per cent moved farther than one row. The greatest distance any recovered beetle moved was 360 feet; the average movement was 24 feet.
Mampe and Neunzig (1967) reported that after plum curculios moved from hibernation sites in North Carolina to blue¬ berries, there was little movement from plant to plant.
Smith and Flessel (1968) reached different conclusions from their work. They found that after releases only a low pro¬ portion (7 to 53 per cent) of the beetles could be captured on a single day. Under optimum conditions the plum curculio was more active than had previously been supposed, and the beetles did not continuously stay in the trees; temperature 61 and humidity influenced their movement.
When females enter hibernation they are unmated, and oogenesis has not begun. In the spring, they appear in the trees at full bloom; mating occurs; eggs mature by petal fall; and oviposition continues for four weeks (Smith and
Salkeld 1964). Knight (1922) reported that females began laying eggs when the apples were one-fourth inch in dia- mater; these apples then dropped. When oviposition occurred in apples larger than one-half inch, few dropped; the eggs were killed by the rapidly growing apple tissue. In
Massachusetts oviposition occurs from June through August with maximum oviposition from June 21-30 (Whitcomb 1929).
Early orchardists practiced some mechanical and cultur¬ al control. Whitcomb (1929) recommended that the growers burn leaves and debris along fences and walls, and that they burn brush piles and undergrowth in the orchards and in adjacent woods, if possible. He also recommended the destruction of fallen apples between June 20 and July 20, since virtually 100 per cent of the apples with live larvae in them fall, and the larvae remain in the apples for about ten days after falling. Also, cultivating the orchard destroyed many of the pupae.
Adult plum curculios have been found in the stomachs of orioles, grosbeaks, barn swallows, vireos, and thrushes
(Quaintance and Jenne 1912). The larvae are eaten by 62 various ground beetles and ants; lacewings attack the larvae
in the fruit. These predators do not provide any signifi¬
cant control in Massachusetts (Whitcomb 1929).
During observations of rearing several thousand plum
curculios in 1926 and 1927 in Massachusetts, no parasites were found. In 1928 six Triaspis (= Aliolus) curculionis
Fitch (Hymenoptera) were found (Whitcomb 1929). In North
Carolina in 1964 Aliolus rufus Riley accounted for 2.9 per
cent mortality of 207 larvae from blueberries. A. rufus
and T. curculionis accounted for 2.7 and 5.4 per cent mortality, respectively, of 258 larvae from wild plums
(Mampe and Neunzig, 1967) . Records from other states showed
a maximum parasitism of 25 per cent although the general
average was less than three per cent (Quaintance and Jenne
1912) .
The possibilities of control by sterilization are just
beginning to be investigated. Cobalt 60 irradiated plum
curculio adults produced 87 per cent fewer adults and
31 per cent lower F^ progeny (Lippold et_ al_. 1968). Jacklin
et al. (1970) found that when a substerilizing dose of gamma
radiation was given to plum curculios and a high ratio of
sterilized males to normal curculios was maintained in the
laboratory, the number of larvae was reduced by 90 per cent.
Part of the reduction was due to harassment of the females
by the large number of males, but the results did appear
promising. 63
The only known means of effective control for the plum curculio is through residual insecticides (Glass and Lienk
1971). Prior to the introduction of the synthetic organic insecticides, lead arsenate was the standard insecticide used for plum curculio control for over 40 years (Smith 1954,
1957a). Chapman (1938) reported that lead arsenate had given excellent results against the summer brood adults but was less effective against the overwintered adults. Smith
(1954) , however, found that lead arsenate was most effective against the adults which had just emerged from hibernation, and that its efficiency was increased where the plum cur- culios had access to surface water. Three sprays of calcium or lead arsenate beginning at the petal fall stage gave 90 per cent or better control. Pre-blossom spraying was inef¬ fective (Chapman 1938; Whitcomb 1929). Experiments on apples in southern Illinois in 1951 and 1952, however, showed that there were five times as many stings in apples in blocks where spraying was delayed until the petal fall stage as where it was started in the pink stage (Chandler
1953). Wylie (1951) stated that lead arsenate was toxic but acted slowly, especially in cool weather, and in some cases caused injury to the trees. Chandler (1950) and Snapp
(1952) reported that lead arsenate was no longer effective as a spray against the plum curculio in Illinois and Georgia.
Glass and Lienk (1971) reported from New York that the plum ) 64 curculio was controlled by two sprays, one at petal fall and one with the first cover spray seven to ten days later.
Control measures are not required against the summer brood adults in the north since oviposition does not occur and late summer and fall feeding damage is only slight (Smith
1954) .
Control by lead arsenate is obtained as a result of several factors: Residues are distasteful to the plum cur¬ culio, causing many of them to go elsewhere. Those remain¬ ing feed at subnormal levels, resulting in reduced oviposi¬ tion (oviposition is proportional to feeding). Continued feeding on apples covered with residues ultimately results in death (Smith 1957a).
With the advent of the modern pesticides, following
World War II, came much research to find a replacement for lead arsenate. DDT, which had proven immediately success¬ ful for so many pests, was not so effective against the plum curculio. DDT was ineffective when applied to the soil, even at the rate of 12 to 25 pounds per acre (Bobb
1946). Wylie (1951) reported that, as a spray, DDT was ineffective against the plum curculio on peaches in
Arkansas. Dieldrin, parathion, methoxychlor, EPN, Guthion,
Imidan, Mesurol, carbaryl, and Perthane have all been con¬ sistently reported as effective sprays (Bobb 1957, Chandler
1950, Forsythe and Rings 1965, Oatman and Lichtenstein 1961, 65
Rings 1958, Smith et_ al. 1956, Snapp, 1952, 1960a, Whitcomb
1952, Wylie 1951, 1954). Chlordane, aldrin, heptachlor,
toxaphene, ryania, TDE, malathion, diazinon, Chlorthion,
and Strobane have been reported as ineffective sprays
(Chandler 1950, Snapp 1948, 1960a, Wylie 1951). When at¬
tempting control of the plum curculio, thoroughness and
correct timing are extremely important in the spraying oper¬
ation (Savos et_ ad. 1973, Whitcomb 1929).
Tree applications are directed against the adult
beetles. Since some insecticides are slow acting and allow
oviposition before the female is killed, it would appear
desirable to attack the plum curculio before it attacked
the fruit. Many workers have reported on soil insecticides which were directed against the larvae and pupae (Fluke and
Dever 1954).
In orchard tests on peaches in Georgia, one ounce of
dichloroethyl ether per gallon of water per square yard
caused complete mortality of pupae. Against larvae, one
third of an ounce per gallon per yard allowed only 0.9 per
cent to survive; there was no fruit damage (Snapp 1939) .
In soil box experiments, aldrin and dieldrin prevented
emergence of plum curculio adults for eight years, hepta¬
chlor dust for seven years, and heptachlor granules for
four years. A soil treatment with 2.3 pounds of aldrin
per acre in a peach orchard in March, 1957, held the 66 percentage of harvested, infested peaches to 1.6 in 1957,
2.9 in 1958, and 0.07 in 1959 without the aid of insecti¬ cides applied to the trees (Snapp 1960b). Reasonably low dosages of aldrin, dieldrin, chlordane, and heptachlor in the soil have provided control for several years with a single application (Fluke and Dever 1954, Snapp 1953, 1957,
Stelzer and Fluke 1958). Oatman and Lichtenstein (1961) reported that endrin gave a 96 to 99 per cent reduction of emerging adults. Stelzer and Fluke (1958) reported that aldrin, dieldrin, and heptachlor gave better control when used as a wettable powder with much water. Also, control was better in cleanly cultivated orchards than in heavily sodded orchards. Different soil types in different loca¬ tions altered the effectiveness of soil applications
(Chandler 1950).
The current recommended apple spray program for
Massachusetts and Connecticut calls for four sprays of
Guthion, Gardona, Imidan, or phosalone beginning with the petal fall stage and continuing through the first three cover sprays (Savos et_ al. 1973) .
There is little evidence to suggest any success with an integrated control program directed at the plum cur- culio at this time. I
67
METHODS AND MATERIALS
A. General
During the summer of 1972 the insect and mite popula¬ tions were closely monitored in two apple orchards, one treated and one abandoned, in Belchertown, Massachusetts.
The treated orchard was part of the Horticultural Research
Laboratory of the University of Massachusetts. It was divided into three sections, each containing seven year old dwarf McIntosh and Delicious apple trees on EM VII root- stock. The abandoned orchard was located 1.4 miles north of the Horticultural Research Laboratory. It contained full size, mature McIntosh and Delicious apple trees which had not been cared for subsequent to 1961. Figures 1 and
2 are diagramatic representations of these two orchards.
One section of the treated orchard received the cur¬ rently (1972) recommended, commercial application of pesticides. In the second section an alternate-row-spray program was employed. The pesticides used and the spray schedule were the same as in the commercially-sprayed sec¬ tion. However, the sprays were applied to alternate rows, with the resulting effect that only one half of each tree received spray from any one application. At the next 68
X 0 fd X p X Q Q Q a a a 0 3 0) rH 0 X 0 X OiMH M3 rH X O 04 O P 3 >1 + + O 0 td o X p Q Q Q a a a 1-1 £ rH’P G 17> 0 PQ 1—1 o X 0 G X 0 p o p o •H fd >i •H o o 0 G p * * fd O 0 CM ffi •n •P 0 Q Q Q a a a P P G M3 0 X a. 0 O X 0 0 X 0 03 E 3 X G PI 1 E M3 0 X >i O P o G X rH O X Q Q Q a a a fd u fd fd x 0 U rH 0 X 0 P 3 fd G 0 0 0 • fd Cn fd M3 P •H P 0 0) 0 03 -P O 0 M3 X 04 0 Q Q Q a a a PS fd ■H 0 M3 0 0 0 £ p £ G E 0 P PS 3 •H E X 0 CM fd 3 •p + rH 44 £ M3 fd P Q Q a a a O MH M3 0 0 - P P >i 0 P G P 0 0 0 3 0 1—1 fd 0 •H 0 o X P X £ 0 X P X rH a. Q M3 X 0 X l 3 Q Q Q a a a 03 l—1 rH X •p O 0 MH 0 p X X •P £ 03 -P 0 •H 0 0 0 O -P O X a X 0 > 0 -P P ■K * PS O 0 £ £ X X 0 Q Q Q a a a 1 O £ 0 >i 0 G 0 X 0 rH •H P 0 X rH H -P PH p 0 0 04 O tT> 03 (d 0 0 0 0 04 a g -P 3 04 G p £ 0 •p -P Q Q Q a a P 0 (nX 0 G 0 0 0 X 0 •H 03 -P 0 G 3 3 a 0 3 rH 0 P 0 0 0 X X < X 0 04 0 •H *• G OX Q Q Q a a a -P £ 0 p 0 0 rd 0 M3 0 0 O w X MH -P G G > P 0) o 0 0 0 0 X 0 fd o 0 X 0 rH Q Q Q a a a -P 0 * X X 0 P PQ 03 0 XI 0 0 •H 3 X MH X 0 -P 3 0 £ 0 0 rH O £ P O 0 • •P 0 0 O XI 0 >1 0 O >1-P Q Q Q a a a rH -P G O X P X •H -P G PQ P •P 3 0 o i—1 •H 0 0 0 rH O X o 0 - 03 g >i G XI 0 03 0 X Q 0 P *P ■K * 0 -P Q P X 04 0 P Q Q Q a a a P 0 0 o 0 0 > 0 04 1—1 G G X X rH P •P 04 03 •P O 0 X 0 0 0 X g x 1 £ M3 X X 0 D W + + E X G G X 0 Q Q Q a a a 3 MH • OOX0 0 G E rH M3 O O B O 0 • •H 0 P p -p •P £ 1—1 X fd X • 0 P M3 0 CN •P X P >i 0 0 G P 0 Q Q Q a a a a 0 o 0 0 0 04 •P 0 P G p 0 X X 3 / O 0 Q 0 PS 0 Q 04 tn >» -H • • fc. a »H CM Figure 2. Abandoned Apple Orchard Experimental Blocks •P ^fd -P U) Ti fd T3 43 43 0 rd W r—1 tJ
Pesticides in the third section of the treated orchard were not applied on a regular basis but only when warranted by pest population pressures. Chemical applications were used only when necessary, and even then selective chemicals which were least damaging to beneficial species were used
(e.g., lead arsenate, captan, and Kelthane).
Tables 1 and 2 contain the spray schedules used in the treated orchard.
To better understand and correlate the results of the treated sections, it was important to know what species were present in the natural reservoir. To accomplish this, the abandoned orchard was utilized as a fourth test section.
It was thought that there would be differences between the two varieties of apples, so data was collected separate¬
ly from the eight blocks; i.e., from the abandoned, the minimum-spray, the alternate-spray, and the regular-spray
sections for both the McIntosh and Delicious varieties.
Several sampling methods were employed to learn what impor¬
tant insects and mites were present and to determine how
these species might affect the fruit. Unless otherwise 71
Table 1. Spray Schedule for 1972 for Alternate-Row and Regular-Spray Treatments
Amount.per Date Material Formulation 100 gall<
1 May - Green tip Cyprex 65 WP 1/2 lb. 3 May - Green tip Cyprex 65 WP 1/2 lb.
5 May - 1/2" Green Superior Oil 60 Sec 2 gal. Thylate 65 WP 1 1/2 lb 8 May - 1/2" Green Cyprex 65 WP 3/8 lb. 12 May - Tight cluster Guthion 50 WP 1 lb. Thylate 65 WP 1 1/2 lb
15 May - Pre-pink Cyprex 65 WP 1/2 lb. Imidan 50 WP 1 1/2 lb 19 May - Pink Cyprex 65 WP 1/2 lb. Imidan 50 WP 1 1/2 lb 30 May - Petal fall Guthion 50 WP 1/2 lb. Thylate 65 WP 1 1/2 lb
5 June - 1st Cover Imidan 50 WP 1 1/2 lb Thylate 65 WP 1 1/2 lb 12 June - 2nd Cover Imidan 50 WP 1 1/2 lb Thylate 65 WP 1 1/2 lb 22 June - 3rd Cover Imidan 50 WP 1 1/2 lb Thylate 65 WP 1 lb. 7 July - 4th Cover Imidan 5 0 WP 1 lb. Captan 50 WP 5/8 lb.
20 July - 5th Cover Imidan 50 WP 1 lb. Captan 50 WP 5/8 lb. Thylate 65 WP 1 lb.
31 July - 6th Cover Imidan 50 WP 1 lb. Omite 30 WP 1 lb.
14 Aug. - 7th Cover Zolone 3 EC 1 pt. Captan 50 WP 5/8 lb. 72
Table 2. Spray Schedule for 1972 for Minimum-Spray Treat¬ ments
Amount per Date Material Formulation 100 gallons
1 May - Green tip Cyprex 65 WP 1/2 lb.
3 May - Green tip Cyprex 65 WP 1/2 lb.
5 May - 1/2" Green Superior Oil 60 Sec 2 gal. Thylate 65 WP 1 1/2 lb.
8 May - 1/2" Green Cyprex 65 WP 3/8 lb.
12 May - Tight cluster Guthion 50 WP 1 lb. Thylate 65 WP 1 1/2 lb.
15 May - Pre-pink Cyprex 65 WP 1/2 lb.
24 May - Blossom Captan 50 WP 2 lb.
30 May - Petal fall Lead Arsenate 2 lb. Captan 50 WP 2 lb.
2 June Lead Arsenate 2 lb. Captan 50 WP 2 lb.
7 June Lead Arsenate 2 lb. Captan 50 WP 1 3/4 lb.
12 June Lead Arsenate 2 lb. Captan 50 WP 1 3/4 lb.
15 August Re 1thane 35 WP 2 lb. 73
specified, samples were taken from each of the eight blocks.
Except for those specimens requiring identification in the
laboratory, all those collected by means of beating, sweep¬
ing, and inspecting leaves and twigs were released after
counting. Where applicable, statistical analyses were used
to compare data.
B. Overwintering European Red Mite Egg Samples
In March of 1972 and 1973 (before and after the summer
study was done), one year old spurs were collected and
examined under a microscope for overwintering European red mite eggs. Within each block trees were randomly selected,
and spurs were taken from each of four different locations
on each tree: 1) the lower half of the tree near the
center, 2) the lower half near the periphery, 3) the upper
half near the center, and 4) the upper half near the peri¬
phery. The same trees were sampled both years. The
abandoned orchard was not sampled the first year.
C. Leaf Brushing Samples
Twelve leaves per tree from four randomly chosen trees
per block were brushed for mites as described by Henderson
and McBernie (1943). The same trees were sampled each time.
Medium sized leaves were randomly selected from midway
between the trunk and the periphery of the trees 74 approximately five feet above the ground. The leaves from each tree were sealed into separate polyethylene bags which were then placed in an ice chest for transportation to the laboratory. The leaves were refrigerated until they could be brushed. All mites were then counted under a micro¬ scope. Rust mites, however, were not counted prior to
26 July except for very early in the season.
D. Beating Samples
Using a beating sheet thirty inches square, each block was sampled for any arthropods present in the foliage or twigs. Sampling began with a randomly selected tree (dif¬ ferent for each sample date) and was continued for five min¬ utes. The beating sheet was held under a branch which was shaken vigorously. Sampling was conducted between 9:00 and
10:00 A.M. Since the more active arthropods would have flown or crawled away prior to the end of the sampling period, they were counted or placed in vials for later identification as they fell onto the sheet.
E. Leaf and Twig Inspection Samples
The terminal two feet of one branch per quadrant on each of eight trees per block was inspected for whatever arthropods were present and for leaves damaged by chewing insects. Eight trees were randomly selected, and these 75 trees were used throughout the study. The branches were selected randomly for each sample. This sampling technique was employed especially to determine aphid populations; it also supplemented the beating sample information.
F. Fruit Inspection Samples
Twelve apples per tree, three per quadrant whenever possible, were inspected for insect damage. The apples were selected randomly each time from the same trees used for the leaf and twig inspections. The apples were not picked but were examined on the tree. Some trees, particularly later in the season in the abandoned orchard, had fewer than twelve apples, in which case as many as possible were checked. The final inspection was conducted when the apples were picked for harvest.
G. Sweeping Samples
A sweep net was used to sample those arthropods in¬ habiting the ground cover beneath the trees. Eight trees per block were randomly selected for sampling. A single sample consisted of twenty sweeps per tree, the same trees being used for each sampling period.
H. Pheromone and Attractant Trap Samples
Pheromone and attractant traps were placed in the orchards as shown in Figures 1 and 2. The effective range 76 of the traps was too great to differentially sample each block. Only a comparison of the catches from the two orchards was attempted. TM Yellow 3M Sectar traps containing Zoecon
"Maggattractant" were used for capturing apple maggot flies.
White 3M Sectar traps containing Zoecon "Orfamone" were used for capturing male Oriental fruit and lesser appleworm moths and those containing Zoecon "Redlamone" were used for the male red-banded leaf roller and oblique-banded leaf roller moths. White Zoecon pheromone traps containing
Zoecon "Codlamone" were used for capturing male codling moths. The apple maggot attractant was changed weekly, and the moth pheromones were changed at six-week intervals.
I. Sticky Board Trap Samples
Yellow boards, 15x22 cm, coated with "Stickem" were hung in all the blocks, one per fifteen trees (Figures 1 and 2). These were intended primarily for apple maggot fly sampling but proved to be of little value.
J. Analysis of Data
Data from all the sampling methods were subjected to analysis of variance tests to determine significant differ¬ ences among spray treatments, varieties of apples sampled, sampling dates, and all possible interactions. 77
Any significant differences in sampling dates merely showed that population sizes, and the resulting damage, changed throughout the seasons and were of little interest in this study.
Differences between the varieties were non-significant in all except for the fruit damage samples. (Varietal dif¬ ferences were significant, but just barely, for the neutral species in the beating samples. The significant difference between varieties in the leaf damage samples was a result of mathematical rounding of the calculated mean squares.) For these data Duncan's new multiple-range test was used to identify significant differences among variety-spray inter¬ action means. In all other cases Duncan's test was used to determine specific spray-treatment mean differences.
The data were transformed as indicated in the appro¬ priate tables in order to better fulfill the requirements necessary for the application of these statistical tests.
All statistical analyses were performed in accordance with Steel and Torrie (1960).
K. Abbreviations
All abbreviations used in Tables and Figures are identified in Table A-l. 78
RESULTS AND DISCUSSION
A. Overwintering European Red Mite Egg Samples
Table 3 and Figure 3 show the mean number of over¬ wintering European red mite eggs per spur sampled.
One must be cautious in his evaluation of these data.
The trees received different spray treatments for the two years involved. In 1971 all trees were treated by the alternate-row-spray method; in 1972 they received the treatments previously described. There are, however, some interesting comparisons and correlations which can be made even though the data were insufficient for statistical analysis.
In the treated orchard the regular-spray blocks yielded the fewest numbers of overwintering eggs. The sprays were effective enough to maintain low mite populations throughout the season and thus result in few overwintering eggs. The abandoned blocks actually had the fewest overwintering eggs overall. The major contributing factor there was that the abandoned trees had not been fertilized and were severely infected with apple scab and thus were nutritionally of too poor a quality to support many European red mites. Another factor was some biological control by predators which were more abundant because of the lack of pesticides. Table 3. Overwintering European Red Mite Eggs Per Spur w i—i Eh -P CQ 5 QJ P 0 IH P 0 0 0 g o o I CM ■—I w Q -p Q < a Q Pi Q CQ < Q PQ CU td 0 o CO ■—i a\ t"> i—1 rH r-' —* *—N. CM >—I co ■—* ✓—■. lO in CO o in 00 CM in CM CO 00 m CO O CM iH oo o CM r- 00 CO o r-« r* in a w o § o § 1 • • • • r—\ rH a* C4 0 0 in rH co co ■—1 cn CM CTt i—I CO
The minimum-spray and alternate-row-spray blocks had more mites and consequently more overwintering eggs. These trees were fertilized and were nutritionally favorable to red mites. At the same time there were few predators present. An additional factor favorable to red mites in these blocks was that these two spray programs were not as efficient at chemical control as was the regular-spray program.
While the minimum-spray blocks had the highest mite populations during the summer, it was the alternate-row blocks which contained the most overwintering eggs. The high summer mite populations in the minimum-spray blocks may have "preprogrammed" these mites to lay fewer over¬ wintering eggs, and the mites in the alternate-row blocks may have been "preprogrammed" to lay more overwintering eggs because of the compensation phenomenon reported by
Collyer and Kirby (1958), Morgan and Anderson (1958), and
Oatman (1959b, 1965a). I described this on pages 24 and 25.
B. Leaf Brushing Samples
Table A-2 lists all the species of mites found in the leaf brushing samples. For purposes of analysis the mites were combined into four groups: the European red mite, the phytoseiid predator, Typhlodromus pomi (Parrott), the apple rust mite, and all others found. Tables 4-7 include the 82 distribution and abundance of these mites. Other species of predators were found in very low numbers; all these specimens were sent for identification, but no reply was ever received. I am thus unable to report what species they were. The fourth group was formed because, if taken separately, no one species in this group was collected in sufficient numbers to warrant individual analysis. Also, none of these species is economically important except the two-spotted spider mite, of which I found only 20 specimens.
Typhlodromus pomi is common in abandoned orchards and is one of the first predators to become established in orchards in which spraying has been discontinued. It will feed on the European red mite but very much prefers rust mites (Clancy and McAlister 1958).
Table A-3 shows the results of the analysis of vari¬ ance and the Duncan's new multiple-range tests for the four categories of mites. In each case there was no significant difference between the apple varieties, but there was a significant difference among spray treatments. Duncan's test shows which spray-treatment means had significant differences between them.
Analysis of the European red mite data indicates a sig¬ nificant difference among the variety-spray interactions.
Inspection of the data clearly shows that the minimum-spray delicious block supported by far the highest populations. CN Table 4. Mites Per Leaf From Leaf Brushing Samples —Panonychus ulmi (Koch) 1— co CQ Eh a -P fd p fd u b o o cu >1 o 0 1 co 1—1 i co Q +> a Q < 2 § J>] Q q -s< S < OQ Q ct eg & i CU 0 fd 0 CO o LO o o o o o 00 o cp CN O O CN rH i—1 O O O o o a a fd >i o co fd e cu 0 VO o CM o 00 o VO rH 1— o o o o o VO o VO a ;3 0 w (d e a* 0 •-1 rH LO cp 1— rH 1— CM o VO o o 00 C" o VO *"D o o o CM o o o £ o o 00 00 rH CM CM CO co CM I—1 r- VO O O O CM o o o rH h> O O o O 3 b o o o rH CO VO VO rH CM o CM CP 00 o rH o o o o o o CN CM O VO CM o 3 i—1 i—1 rH CO CM 00 00 rH O co o CM o o o VO o h> o o CO o rH r" O CN b rH rH CN VO CM CN VO rH CN CN (Ti O CO CN co CP rH i—1 LO o LO rH vo 1- 1- CM b rH rH 1^* CO 1— rH o LO co r- VO CT> VO U0 CO uo rH < o LO VO VO o VO 00 o o o b cn rH CN I—1 CP vo vo
•H CM 00 CM CM o MO in 00 oo rH g O VO MO rH o CO in o M0 in 0 rtj 04 PQ O o o in in cn o cn 00 M0 CO CM 03 3 CM 03 03 g cn rH rH 0 CD CM CM p -p Q g g in 00 CM 00 MO Td •H < fd id CM rH CO r- r- CO o o S PQ 03 03 • rH rH CO in o cn CM
The density in the minimum-spray McIntosh block was about one third as great, and the other six blocks were nearly equal with far fewer European red mites.
For both the apple rust mite and the European red mite, the-largest numbers were found in the minimum-spray blocks.
Here the trees were nutritionally favorable, and miticides had not been used often enough to maintain adequate control.
Although there were more Typhlodromus pomi predators in these blocks than in the other treated blocks, the predators were present in very low densities until mid-August and even then their densities were still too low to effect any con¬ trol on the large populations of the rust mites.
Lower densities of the apple rust mite and the European red mites were present both in the abandoned blocks, because of lower nutritional value, and in the other treated blocks, because of chemical control. The differences in the rank¬ ings of densities of these two species within these blocks were due to different nutritional requirements and different susceptibility to the pesticides used.
By far the largest numbers of mites within the miscel¬ laneous group were found in the abandoned blocks. Well over half of these mites were Czenspinskia lordi Nesbitt which is a fungus feeder (Lord 1949). While apple scab, Venturia inaequalis (Cooke), and other fungus diseases were rampant in the abandoned blocks, they were virtually non-existent 88 in the treated orchard. The other mites in this group were probably susceptible to the pesticides used and hence their low numbers in the sprayed orchard.
For Typhlodromus pomi the order of abundance in the different spray-treatment blocks is exactly as one would expect based on the amount of pesticides used and on the number of prey available. The highest density was found in the abandoned blocks where no sprays were used and ade¬ quate prey were available. The second highest density occurred in the minimum-spray blocks where the predators had abundant prey and were subjected to a minimum number of sprays to which they may have developed a slight resistance.
In the alternate-spray and regular-spray blocks, the predators could not have survived even if they had developed complete resistance to the chemicals used; there were insuf¬ ficient prey to sustain a predator population.
Figures 4 and 5 graph the mite population samples for the abandoned and the minimum-spray blocks. Not enough mites were found in the other two treatments to make mean¬ ingful graphs. The curves for the non-predatory mites represent cumulative totals; i.e., each curve serves as the base line for the curve above it. The groups of mites not represented on the graphs were not present in sufficient quantities to register on the scale used. Non-predatory Mites Per Leaf (Log Scale) Figure 4.MitesFromLeafBrushingSamples—Abandoned Orchard Sample Date i 1.0 0.10 0.1 89 Typhlodromus pomi CParrott) Per Leaf (Log Scale) Non-predatory Mites Per Leaf (Log Scale) Figure 5.MitesFromLeafBrushingSamples--Minimum-Spray Blocks Sample Date
Typhlodrottms pomi CParrott) Per Leaf (Log Scale) 90 91
Unfortunately, I gathered no data on the apple rust mite prior to 26 July (except for very early in the season) and consequently missed the population peaks. As Typhlodro- mus pomi peaked on 14 July, I can deduce that the apple rust mite populations peaked before this. Either the apple rust mite populations had been suppressed and controlled by
T. pomi or they succumbed to increasing nutritional deficien¬ cies in the leaves. Probably both factors were involved.
In the minimum-spray blocks a shortage of rust mite data makes accurate interpretation difficult. Because of the very high apple rust mite and European red mite popula¬ tions and relatively low T. pomi populations, the decrease in rust mites after 26 July was probably nutritionally governed. T. pomi and the European red mite were undergoing an essentially logarithmic growth rate until the 15 August acaricide was applied.
Results from this set of sampling experiments indicate that predatory mites can be induced to survive in a minimum- spray situation after only one year. Selective use of acaricides to suppress the apple rust mite while preserving
T. pomi could lead to biological control of this pest.
Longer term programs may encourage biological control of the
European red mite also. 92
C. Beating Samples
More than 67 species of arthropods were found by means of beating samples; these are listed in Table A-4. Table 8 shows the distribution and abundance of these species throughout the sampling period. As no one species was col¬ lected in sufficient quantities to yield meaningful statis¬ tical analysis, all the species found were grouped into three categories: 1) beneficial species: predators and parasites, 2) pestiferous arthropods, and 3) neutral arthro¬ pods—neither beneficial nor harmful. Table A-4 indicates into which category each arthropod is placed. Table 9 sum¬ marizes and Figure 6 diagrams these groupings. The results
i of the analyses of the three categories are reported in
Table A-5.
The differences between the two varieties were signifi¬ cant only in the neutral category, and then the difference was just barely significant. In all three categories, spray treatments contained significant differences which were specifically identified with Duncan's new multiple-range test. There were also significant differences among the variety-spray interaction in all three categories. In the treated orchard there was a very slight preference for the
McIntosh blocks, while in the abandoned orchard there was a substantial preference for Delicious trees. Table 8. Distribution and Abundance of Arthropods Found in Beating Samples CM
\ Spray-Treatment Block \ Q < < 0$ -p Q Q PQ j§ u u 0 0 cu BAD •H r—1 TJ l£> t) -p o 0 P o P P >1 p 1 1 s-,'-'0(Njror'\MfO(Tiinoocr\ixii^onLor' invDHHHHHMCMMnnn^^LrnnvovD rH CM CM in rH r- in • •••••••••••^ • Sw>rH ..fit • • PH*>1 o CM in • • • o CM in • • • m pq0^‘S'SpTpmz3S'(n2 2■? o CM m • • • CM o in • • • CM o in • • • rH CM in • rH • • • • • • • • • CM in o o r" in 1—1 r- in CM o m CM O in • • • o CM in • rH • • • CM o in • • • CM O in CM o in t"» o m o in O o ^ r- CM r> in in 3. 0. o r-' o in in o rH CM rH CM CM in O in H (Nn^LOU3 --->-- --AOQ 2 PQpqipq CTi CO in o in O • •••••• • rH CM in
• i—I • • • 0. in o in o 1. CM o o o in o ro r- in l—1 o o CM r> in l—1 o o 94 o in o o in •
continued •H X rH CO 'd EH •P d U (U o £ c d Spray-Treatment Block XI < -p < Q < Q PQ u u o 0 o. i—1 r—1 •"0 -P O 0 >1 0 C C d CD 1 1 r—ii—icNCNCNCNCNCNcocococoininin'sOio on is»o\Or-imnoooMn>ooo>orgnini>' ^ in o o CN o in • «—1 in o o in • o CN in • o • • in • CN • rH • CN • in o CN in • CN • • • • o • in • o • o • o • in o in • • • PM • o • CN • in o CN in CM r^- CN in ^ CNinONOH h o(nin mom o • CO in o r-~- in o Hro^mmt^HHH ^ ---r—IM3 continued 96 in • • in o • • • o in • o . in uo in o • • • CN • • cn m • • • m • o • CN CN in • • • o • • o o • • • o co • CN • o •N1 o r> • • • continued • lo in . o o in . o in o o in o in • in o . o • CN CN • in in • o CN o in r> o m • cn m • in • o o • OHh • ^ O ^ H 0OH O • o o • o • r-H • iH • • i—| • • i—| •••••••• • i—| •••••••• CN CO CO • •HH • • • TJ in • in • O in o O o • • in • • o o • o • o CN • . O r* o in in • • CN • • in in • o . o o • r—1 • ro cn CN o 00 • • o • • o o • rH . r- : • • • • • • • 0 • • • • • • 0) • • • • • • -p • • • • • • 2 • • • • • • G • • • • • • •H in in o in in in in o in o in in in m in o Q cn (N in t^- c\ (N o cm in CN CN Is CN O < 0 p O O O CN O 00 rH CM H ^ o o HOH > • *H 03 M-l 0 -rH P O 0 0 MH ft CN 03 TJ 0 -P 2 0 G 0 •H ft -P o G II o CN CN 0 r—| O P P Td -P G 1 0 G 0 < 0 0 ■H n 0 0 • O -p i—I • CN i—I CN 0 H ^ 0 0 P XI O ft P < tj P ft fd 2 O 0 0 G 03 0 2 -P p -H ft 2 G fd 0 0 e 01 G •H • -p MH i •H Q -p • 1—1 CN • G uo rH -P G 2 P 1—1 2 G V S O • C7> 0 1 p •H O O • 0 mh < 2 o O 1 P XI 0 0 •H I 1 0 p 0 mh M-l 1 T5 -P tn 1—1 03 • 0 0 • • • • • • g • • • • • • • • • • • • j G 0 X mh G 00 ft 2 • • • ft • • • 0 • • • • • • • ft • P • • • • -H P 2 0 03 s-> O tn • • • '—* • • • -p • • • • • • • —* • • • • • 1—1 0 Eh XI 0 P 2 CN ft • • • oo CN x—* 04 ,Q G 1—1 £ p iz; ID ft ft p S h* P VO P 53 s s 0 2 II < ft 5 Z 0 -- XI -P 1 —* CO ft ft P —> —> —■> ■_> I ( 1—> V“^ -* fu 3 (D The abandoned orchard contained greater numbers of all three categories of arthropods, a result of no spraying at all. Within the treated orchard the minimum-spray blocks contained the highest numbers of beneficial and neutral arthropods and the lowest number of harmful arthropods. This desirable effect demonstrates that this reduced spray program maintains low harmful arthropod populations and allows an increase in the beneficial arthropods, at least for the species sampled by beating. The alternate-row and regular-spray blocks were statis¬ tically indistinguishable and yielded the lowest numbers or specimens of arthropods of all three categories. The minimum-spray blocks were grouped with the other treated blocks in the harmful arthropod category. It is clear that the regular-spray and alternate-row-spray treatments con¬ trolled all species collected. The low numbers of arthro¬ pods in the minimum-spray blocks may be attributed to the fact that the pesticides applied were enough to suppress the harmful species, but not enough to severely affect the > beneficials which may have contributed to further suppres¬ sion of the pests. The beating samples provide additional evidence that a reduction in pesticide application may adequately suppress pests and at the same time encourage beneficial species. 101 D. Leaf and Twig Inspection Samples 1. Apple Aphid, Aphis pomi DeGeer, and Its Syrphid and Cecidomynd Predators As the apple aphid populations reached relatively high levels, I evaluated them and their chief predators, aphidophagous syrphid and cecidomyiid larvae, separately from the other arthropods found by this sampling technique. These data are contained in Table 10. A low level of hymenopterous parasitism was evident from the few aphid "mummies" found. Statistical analysis of parasitism, however, was not warranted because of its infrequency. The seasonal population growth of the apple aphid and its predators is diagramed in Figures 7-9. The populations from the abandoned orchards were not graphed because of the low numbers found there. Table A-6 gives the results of the statistical analyses of these populations. There was no statistical difference in the aphid or predator populations on the two varieties of apples. There was, however, a great difference among the spray-treatments, and Duncan's new multiple-range test showed that all four treatment groups maintained significantly different aphid populations. While the predator populations were not all significantly different, they occurred in the same order of abundance as the aphids. The ranking of these populations was just as one might expect. The lowest numbers of both 102 o o o o o o LO T5 CM •H CO •H >1 £ o TJ •H i—I "sf1 o o o o CM 0 U O O O o o o •3 G fd lO CO LO r> LO r- CM CN CM r> co 3 CO •H X • XrH LO LO P 0 CN >1 (U CO iH X CM o CM LO LO 00 LO 0 0 g o CM r- CM r*. 0 x 0 CN O P H CO 0 0 3 g G G O td *h LO 0 X CN X ^ o < 0 3 — a LO o LO O LO i—l o 0 CO LO c- O LO X P G CN 00 r> LO 0 0 H LO £ 0 I O rH X • 0 0 o o o 0 X Q G • 0 3 •H 0 0 •H £ LO CO o LO o o i—i 0 P £ P LO LO 0 9 p CM O 0 iH co G 0 Q) 0 QJEh •H G 35 P £ 0 0 0 £ p •H 0 X ■H o LO 0 X LO 0 rG p -P 0 S CM Em •H G <51 CM > 0 LO o o LO LO O CM co 0 X x cm r- LO LO C" CM LO P X X O '— LO CN t"> rH x X 0 LO 00 0 X p 0 w 0 0 X O P 3 X X G O LO CTi 0 p 0 s 0 -P LO -P 0 0 0 nzJ 0 0 X P p G 3 •H CP CP 3 0 co 0 rH XI P LO LO O LO LO co G S 0 s Total Nuiriber of Predators (Log Scale) 104 105 Figure 9. Apple Aphid, Aphis pomi DeGeer, and Its Syrphid and Cecidomyiid Predators From Terminal Inspec¬ tions!—Regular-Spray Blocks Sample Date ^Each sample consisted of thirty-two terminals. 106 aphids and predators occurred in the abandoned orchard where nutrition was the limiting factor for the aphids and hence the predators. The relative abundance of the apple aphid in the treated orchard was negatively corre¬ lated to the amount of sprays received. Figures 7-9 show a very rapid predator response to the presence of the apple aphid. I am reluctant, however, to attribute the rapid decline of the aphids after the 27 July sample entirely to the predators. Trees begin "hardening off" in late summer and so become nutritionally less desir¬ able to aphids. This was probably the major factor in the apple aphid decline. I should point out that many dead, shriveled bodies of aphids were observed during the 10 August sampling. These may have resulted from predation, in which case the predators at least contributed to the apple aphid population decline. These data show that fewer sprays permit higher popu¬ lations of aphid predators. They also indicate a possibil¬ ity for control by the predators. It is true that fewer sprays also resulted in more aphids, but none of the popu¬ lations found in my study were economically important. If higher populations were encountered, selective use of pesticides could depress the populations and allow for con¬ trol by these dipterous predators which my data have indi¬ cated respond very rapidly to the presence of aphids. 107 2. All Other Arthropods Found Listed in Table A-7 are the more than 69 species of arthropods found in the leaf and twig inspection samples. Table 11 gives their distribution and abundance. As with the beating samples these arthropods have been grouped into three categories for analysis (Table 12). The graphic representation of the categories is shown in Figure 10, and the results of the analyses are in Table A-8. These analy¬ ses exclude data on the apple aphid and its syrphid and cecidomyiid predators which were discussed in the previous section. In all three categories the analysis of variance test reveals significant differences among spray treatments but none between the two apple varieties. Duncan's new multiple- range test further discriminates spray-treatment differences. Significant differences occurred among the variety-spray- interaction blocks for both the neutral and pest species. The abandoned blocks clearly yielded the highest numbers of arthropods with the Delicious trees containing the most. The abandoned Delicious trees were much less affected by apple scab than the McIntosh trees and as a result contained more healthy leaf tissue and thus could support more arthro¬ pods. This is also evident from the beating samples. In the treated orchard, the minimum-spray blocks yielded the most arthorpods, but there the McIntosh trees contained more. Table 11. Distribution and Abundance of Arthropods Found in Leaf and Twig Inspec¬ tion Samplesi CN t) 3 continued Table 11.—continued •H l-" rH t> +J o 0 £ >1 c G £ rH a) co 1 1 '—‘in CO co ^ .. I—I ...... 00 ••••••••• CM r**. .. .rH•.O rH •iHU0CNCOin(N•rHrHCN rH CN00CO• • • • • • ...... CO ...... • . o .CN rH•..CN .CN •» v_> co in cm • • • x. CO 00 CN CM 1 • N1 H1 CM • • • • s. ^ 1 h1 r-~ in CM CO • ^ • • CM CN ,—^ VO in PQ • • • • ^—„ VO VO 2 • • • • *■—N VO r-*- 2 • • • • VO 00 2 • • • • 1—1 rH r- i~o >1 2 -> rH CN 2 • • • .in ...... rH.....O .•••••••• • rH*in • rH*.HCD • CN**...... C'• • CNI—IrH CN cq pq2; • • '-'-- CO H* • • • rH /-N '-- in • • • ■—* VO • • • - iH CM • • • /-> /"> rH CN —" —> CT> OrH pq cqCQCM • • • .in • OrH • CN» in .-- /^N CN cn in • %. • • —> CN r-» CM • • • -- CN CTi rH 22ft • • co oo O CN 110 • * • . O • in . o . in . vo . in . o , o . CN . in .H1 continued Table 11.—continued •H rH• r—I t> TJ • -p • 3 o • o • 3 uoo (D^r c: • £ cm I ^-,N-tn 11i^4 —*—''—* cocococoncoM'M'ininininioioio coH'iniDCooH’ooHcMior^'noocri ID iH CO o o. sSSS's C" • LO CM•i—I co o•^ 00 CM cn 10 CO •CMin rH '•i—I•CM • •••••••• CM VOOCO • CM h inco CM CO• • rH • i—I CM c* r—I t> 3 H OOO^OH0^r )(N(v)|s /-s rncQmn«ni (N COinVOi—IHCM CM rH • CO CM• • CM • •CM•••••• • i—ICM • rH • in • rH00 i—I continued Table 11.—continued *H CM I"" r—I >"D -P 3 o H o a d continued Table 11.—continued -H T5 < -P -p 3 a tn 3 in o o a 2 Q) i i —*—*—>—«—>—' —to —>I•—>—*—*—*—*—>—' cNCNOjojfococococofOfO^'j'^inininin (N^cotriHojco^inr'OOco^inrMcoinio in o ro oo r o r- in cm in in in oo in CM co in CM in iH co CO o CFi —' in vnfflzz CO CM d) m I /-N /-so in m incn • • • • • • • • • • • LO CM *W» in ,0 m -P Q) g U 0* continued Table 11.—continued LO •-H w -p TJ -P u 0 a 0 0 o o G G g 0 * 1 0fNroio^'Oon^O(\vor'^inoo mronronro^^ininmiovovovo CQ —"LOIw w| 1—1 • • rH • o • LD • rH • co • CO • co • Oi—I • O00 • VO •^ VO Pl4Pj'^S^PCMP4^^2^0CQCQ52: rH CM CO • • VO • • i—1 • i—1rH • *CM • p4 • 04COVOiH • 5 6 1 * •rH 3 CM 2 • • rH CM • • • • T* MH •H X! -P MH -P rH 4H -P -P 4H XI -P XI O m 0 01 01 G 0 0 -p 0 0 M g 0 G d £ 0 0 0 0 2 M M 0 o CO G 0 a u M 0 0 o M o g •rl 01u +) 0m XI -0 MH II XI 01 H CM Eh -P rtj -H x: H •H MH M rH XI 0 GXI oi u -p add 0 rHXj O XI 01 0> 0 a g 01-H PQ G-rl d 3 0-P 0 G U PM01 M 0 O. g 0 d 0 G d 5h a 0 oi 0 oi G 0 • 0 G 0 O l 0 II d • -P M W rtj53O5 G O -H 01 O oi ro^mvoo _ G3 • g G M 0 • m • ■rH •H rH MH -p d X! d 0 oi G 0 0 • •H oi g G d 01 oi • 114 Table 12. Arthropods (excluding Aphis pomi DeGeer and its syrphid and cecidomyiid predators) Found in Terminal Inspection Samples, Grouped into Beneficia (B), Neutral (N), or Pest (P) Species Categories pH HIDQYU0LOCM in nHrH10mrocnidco ro cmpHuoinr-^ pH O pH CMU0O pH O CM r o in^rr-cm of families 115 Fi.cfu.re 10. Arthropods From Leaf and Twig Inspections pogooiIOD joqtimjsiTt?qo,i co See Table A-l for abbreviations. 117 No varietal preference was apparent among the other treated blocks. The rank of abundance of arthropods within the spray treatments is the same for the three categories, and is negatively correlated to the amount of spray used, as one might expect. The regular and the alternate-row spraying maintained the same low level of arthropods in all three categories. The minimum-spray treatment allowed higher neutral and pest population, but exhibited the same level of suppression on beneficials as the other two treatments. In the abandoned orchard were slightly higher populations of beneficial species, but significantly higher levels of the other arthropods. In the treated orchard most of the pest species ana¬ lyzed in this section were aphids, other than the apple aphid, and leafhoppers, neither of which were abundant enough to cause economic damage. Most of the beneficial species in both orchards were spiders. Keeping these two observations in mind, one may conclude that all three spray treatments successfully controlled the pest species sampled by this method. And, although the beneficials were sup¬ pressed, they were mostly spiders and of questionable value in the biological control of apple pests. 118 3. Leaf Damage by Chewing Insects Table 13 reports the amount of leaf damage done by chewing insects. This damage is represented in Figure 11. The analysis of these data is contained in Table A-9. The analysis of variance shows a significant difference between the two varieties of apples, but this difference is a result of mathematical rounding of numbers and the extremely small error mean square. There is a real, significant dif¬ ference, however, between the abandoned and the treated orchards. Every block in the treated orchard had virtually no damage. In the abandoned orchard, damage was consider¬ able as might be predicted from the greater numbers of pests found there. It was sometimes difficult to separate insect damage from apple scab damage. By the end of July virtually every leaf in the abandoned, McIntosh block had some evidence of apple scab, and by the end of August there were few leaves remaining on the trees. The abandoned, Delicious block was about 75 per cent infected with scab, but the infestation was not nearly so severe as in the McIntosh trees. These data revealed no unexpected results. The aban¬ doned orchard was heavily damaged by leaf feeding insects. Each of the three spray treatments was completely effective against this type of pest. CM Table 13. Damage From Leaf-Chewing Insects CM i—I •“D o CO CM CM ■'tf G G CM 00 hi CM CM CO G G CM O CD CM i—I (Tt 3 • CO o CM in co CO CM G CM r—I CO o l"D O ID CM o CM en e'¬ 3 . i—I o Each reported rating equals the mean of the 32 subsample ratings. 119 Figure 11. Leaf Damage by Chewing. Insects c pabeuiPQ seAPag goabeguaDjatf T CM o O I ~r CM o o E I 2 E. Fruit Inspection Samples The major damage to the apple fruit was inflicted by the plum curculio, the codling moth, and the apple maggot. Other damage was done by the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), sawflies (probably the European apple sawfly, Hoplocampa testudinea (Klug), although I never collected any), and green fruitworms, Lithophane spp. The data on these last three insects were included in one group (the miscellaneous group), and along with the data on each of the first three insects, were sub¬ mitted to statistical analysis. Table 14 contains the results of the fruit damage samples, and Figure 12 shows these results graphically. The outcome of the analysis of variance and Duncan's new multiple-range tests is reported in Table A-10. All four categories of damage showed significant differences among spray treatments. As plum curculio damage and miscellaneous damage were both significantly different between the two varieties (the Delicious were preferred) and among the variety-spray interactions, I applied Duncan's test to the variety-spray-subclass means rather than to the spray-treat¬ ment means. All four damage categories were tested alike. Only the four spray treatments were graphed (Figure 12), however, to facilitate comparisons with the other methods of sampling. Table 14. Insect Damage to Fruit •H rH Oi ^ -P •-1 rC •rH -P rH tn 0 a c a 43 PQ t tn E-i P-i O fa 3 £ 0 G tn 04 0 04 tn 0 td i—i P cd w G 0 G P U 0 G 12 Oct (96) 0(0%) 3(3.1%) 7)7.3%) 5(5.2%) 1(1.0%) 0(0%) continued 122 123 g u TJ 0 0 12 £ cA° cA° cA° £ £ -P V N O O rH •H 0 -H CfP o\o cAP o\o cA° cA° cA° cA° o\o • • • 0\0 0 £ o o O O O O O O O rH 1-1 CM O P P V-' -- --- '-- O fa o o o O o o o o O rH 1-\ CM O —>. >i cA° cAO 0\0 cAO t3 tn 0 £ ,£ PQ CO cAO o\° o\o cAP o\P o\o •H -P O O I—1 O O rH £ £ cAP oP o\° cAO • cAP • • • 0\0 CAP • • p fd o o O O 1-1 O rH CM rH O O rH CM fd i—i v—• Eh fa o o O o rH o i—1 CM i—1 O o rH CM -P o\P cA° CA° o\o CAP o\° o\° CAP o\° 0 O O CM CM rH rH O CM co 1-1 rH in • cA° o\o • • • • • cAO o\o • • • fa in 1-1 o O m CO CO rH O O m CM fa fd * * 'W' < a rH o O in co CO rH o O in r- CM __^ in £ cA° 0 •H rH £ ^—s ✓—v ^-*s X—V ^-N X—s -- 6 U o\o o\o 0\0 o\o c*P CAP cAP o\o o\o o\o o\o cA° 0\0 3 P O o O O O O o O O O O O O TJ rH £ * ^-" 0 fa 0 O o O O o o o o O O O o O £ £ ■H -P £ O O I I AO AO AO AO AO AO AO AO AO AO AO AO AO cAO oP cAP T5 tr> 0 d x m w cap o\o o\o •H -P o ,—* v rH o d d • cAP o\o cA° cA° o\o • • OP oP cAP cAP oP ..—.. *—- c\° -—^ ,-N ,—» cA° -P o\o cAO CAP CAP VD cAP cAP cA° CAP 0 0 -—.. i—1 OH C7> CM • .—^ O i—1 H i—1 • rH tj> cAP cAP • • • • CN OP o\° • • • • MO P4 tP O O CO -^r 00 ro rH O O i—1 OH ro ro i—1 ■>_-■ 04 0 '—' >—* * ■—1 -- —' '—^ '—' >—- '—- -—- < g o o CO ■*r 00 ro CM o o rH OH ro ro MO rH •—1 tr> d o\o o\o cA° cA° ■H 1—1 OH rH s s ^—, -—^ O rH X oP oP c\o • • • cAO o\o cAP oP cAP cAP cA° • T3 -P O O o OH OH rH O O O O O O O i—1 -_■> 0 0 ^—’ 1—- '—1 '—- —1 —^ 1—' ■—^ -— U g O o o OH OH i—1 o o o o o o o i—1 0 •H <—- i—1 o\o CAP d —.. i—1 ..—.. „—s ,—.. ^-s ✓-s ^—s O ^^ ^—» ✓—* E o o\o cAP • oP cA° cAO o\o o\° OP cAO • a u o £ __ *N oP. oP oP dP dP dP r- dP dP g -p 00 00 H CM CM • H O 0) *H o\o dP CM • • oP oP dP 0 2 D H 1-1 O O rH CM O O O i U P * --' v—1 --- V—^ -- i h* LO •—1 1-1 O o oo CM H o o o dP --- >1 dP dP dP CO dP dP rH CM oo CO • O O 4h • oP • • CM dP dP dP • • OP dP dP z rH O H< 00 H O O O CM CM o O O i fd V-’ -- i w i—1 o o o o o 1-1 1-1 o o o H 0 3 ,3 PQ o\o o\o CO oP dP dP 00 O o\° •H -P 00 H • • 00 3 P dP • • • h< o • d° dP dP oP oP dP u fd O CM '*V r-" H H 00 O O O O O O i fd i—i N-—' >—* ^' --- i Eh CM o CM H1 ID CM D 00 O o o o o O H oP oP dP dP oP oP -P o\o oP 00 in CO o\o dP dP dP m dP 0 0 CM O • • • • o D 1-1 O • • O i—1 tP • • in D r" 00 o • • • H H* O i CM tn H D I—1 OO oo OO H in H CT» H i CM fd v—’ v— N—'' C 2 i—1 in CO H oo oo •—1 CM CM co 00 H H 00 r- in OO H tn dP oP dP 0\0 s dP o\o dP P dP CO CO c- dP dP dP Ch in uo c\o •H CM • • • • O O 00 • o\o • • O iH ,3 • O I—1 OO o o • CM D 00 CTi O id -P 1-1 CO 00 00 00 rH H CM H1 m 00 00 H i 0 0 v—' i O 2 H ID r- in H o H CM 1-1 00 co H CM ID r- D oo CM CM CM H ___ 0 dP oP cjp OP OP dP dP dP o\° dP dP dP •H O CM 00 CO CO O 00 D 00 o H 00 3 co CM CM CO UO in CO o CO D dP 6 O 0^ 00 00 00 00 cn UO 00 in CO O 1 T3 3 P — -—- —' ■- ■—1 —' ■—' —1 — ■—■ ■—' '—' '— 1 (U rH P 00 cn 00 o rH rH fa CO . -P •H 0 n [ 111111111 w///mmfjim//////mmw/7^ CO G fa 0 -P O O -H i « u 0 P £ $ CO 0 m G -H •H > 0 ,G P O P □ ffimmni i wzzzzzmzzzzzzizzzzzznjgz\ ^ fa G X! fa 0 fa fd < w p £ m • o Q -P 4-1 00 O VO 0 rH fa CO I < tn G < a m^////////////////(/jnirm •H fa! B 0 0 rH ~ i- i - ^ttI G P O fd 31 Eh 0 G -P fd 0 fa >i fd rG 0 m^7//r/7777/////////J////T7^^ i—I Q P CO CN ^ »~D 0 0 0 rtj rH P in r- fa fd m 0 • £ For the plum curculio, the codling moth, and the apple maggot, the damage was not significantly different in any of the blocks in the treated orchard. In the abandoned orchard, the Delicious apples were preferred although the codling moth showed no significant preference. In the miscellaneous group, damage was negatively correlated to the amount of spray used, except that the abandoned, McIntosh block received less damage than expected. It is possible that some of the damage attributed to the codling moth was caused by the lesser appleworm. Damage from these two species is indistinguishable without cutting open the infected fruits, and the pheromone trap catches did show the presence of lesser appleworm adults. By 7 July in the abandoned, McIntosh block 100 per cent of the apples exhibited apple scab injury, and by 27 July every apple in the abandoned orchard had sustained insect damage of one kind or another. The fruit was so badly damaged in the McIntosh block that at harvest time (14 September), I could not find a single apple remaining on the trees. The plum curculio, the codling moth, and the apple maggot each inflicted extensive injury to the fruit, while the miscellaneous group was responsible for less damage. While I identified a large number of apple maggot stings in the treated orchard, I found very few apple 128 maggots. Only three adults were found in the bait traps all summer, and no larvae were ever found in the fruit. It is possible that 100 per cent of the apple maggot eggs or larvae were killed by the growing apples (Dean and Chapman 1973). Although these stings were indistinguishable from those in laboratory apples known to have been made by apple maggots, it is possible that they were not. Xn the treated orchard I found only one apple with plum curculio damage during the entire season. Codling moth damage remained below economic levels until the harvest sample in which the minimum-spray blocks suffered 2.5 per cent damage. The majority of the damage resulted from what I identified as apple maggot stings. The miscellaneous group inflicted a substantial portion of the total damage. Within this group the tarnished plant bug was the most injurious. The sweeping samples revealed that large numbers of tarnished plant bugs were living in the ground cover beneath the trees. The regular-spray treatment controlled the codling moth and the miscellaneous group better than the other two treat¬ ments did. With all three treatments, damage well above the economic threshold was sustained. The total damage may not be quite as bad as the graph (Figure 12) indicates. I failed to note in my sampling when more than one type of damage occurred on the same fruit. And so the graph would 129 represent an apple damaged by three insects, for example, as three separately damaged apples. In any event, control cannot be considered successful unless one attributes what I identified as apple maggot stings to a non-degrading feature of the apple. If this is done the regular-spray treatment was effective. F. Sweeping Samples Table A-ll lists over 112 arthropods which were found in the sweeping samples. Table 15 provides their distribu¬ tion and relative abundance. Once again these arthropods were divided into three categories for analysis (Table 16). Figure 13 graphs these categories, and Table A-12 shows the results of the analysis. Fully two thirds of the species found were neither beneficial nor harmful to apple trees. Of the beneficial species, the vast majority were syrphids, coccinellids and spiders. Almost all of the pests were of one species: the tarnished plant bug. Some arthropods had undoubtedly fallen or been knocked from the tree; e.g., plum curculio, red- banded leaf roller, oblique-banded leaf roller, and apple maggot. For all three categories there were significant differences among the spray treatments but not between the varieties. Table 15. Distribution and Abundance of Arthropods Found in Sweeping Samples CM continued 130 Table 15.—continued *iH T3 l~3 4-> 3 >i O 0 0 G I I V_> --->s_>S_>>w>> > v_>|SV;■'«->'V_> '>V_>%» rHrHrHcNjojcNjojojnoooo^^Nf^^^^inioininiovovovovDvo invoooHojvoO'CTiiHooo^OrHCNjoovooocriooH'vooocrxM^invDtN CN rHCNJ•OH00i—ION*001—100*1—1H(J'Is •••••••••CM.00..I • • i—ILOr—|Os]i—|*1—1ONOVOO'^ • .i—100CNJi—IOHVO • •••••rH* • rH00«—1 rH •00 H vo • O*1—1 • rH PQ 00 • r—ini • rH00 UO VO CNJ . O' rH CNJ *1—11—1 ON r» •rH ON 00 VO HNf • LOi—1 • inLO 00 • VO rH * 1-1 • O • CH • OH • *00 • oo 131 continued Table 15.—continued rH W Eh -P CQ s P (d rd P G o o 0. H (D (D I T3 ,g Q < -P s < Q < CQ Q pq P P 0 0 Q* •rH i—1 T5 00 1— o 1-0 -p o 0 G G g >i g a) i i S--* Vo 00 r- •^r CM •rH continued 133 • • CM H in • CM CM CM • CM • • in oo cm • • . CM 00 • continued rH VO • i—I i—I • • • • ^•OCOChH^r'-ChHCO . ^ H • • • CO . O ..iH • • • * • • • • CT> • CTi 00 • H pH • • O • i—I C- • • • • • i—I i—1 CM • CM CM • • CO. • co • • •ho'>cocoo'» • • • • i—i m •O^CMCO • • • r—I • CO H • • .rH • • • CT» * * rH • r- * 00 • • • • * CM • »H 'l1 • • • • • CM • * * •••••• rH * rH CM ..... r—1 ...... . i—i . . . • vo • t''- t . * » • *in • * h Is .CM • • CM.CM • • • • * in • • * - • co i—i cm r . . co i—i * i—i >—i • cm C'* • • <—i • • <—i • r-4 • .CM • . .. ...... -—- /-> . . . . . 2 ...... »«..».»P?J2»»».» ■—* ... 222 2 ^m w ^ v_> *->^ 2: : wffl w z v_>ft s_>2 | „ w*2 2 n_> | rovo oH'j,oonfMi¥)vrmifliNooo^ocM^icrsooincooHcoiDOOoo M,M,^|M,'^inininininininin'x>ioioiDiou)r^r^oooooocoo>HHH Table 15.—continued •H <7t rH -p P >i o o p a p d) i i o a 3Z CM O rH CTi o CN co CM -p P tn p w ws^wws--^v^^r^HCMinoo(Mro(nHM,i^oocjninio HCNro^invooooiHCMCMCMCMcofOfo^'M'^^inininin 2CQCQCQCQPQ22'^^'-''-''^"-' I— — CM CM CM VO CM O i—I CM o r~- CM cm vo CO PQ in co co CM co CM CO CO 'sT CM CM VO CO CM vo in CM 134 CM o cr\ co CM CM in in continued 135 CN in co CO CN ID CO in CN O ■^r co i—i CN co ID CN in CN CN ID CN co in CN in in CN a) CN in ID CN rH r- 3 a •H -p a o u i i -P -p cn w a z 3 m 3 CN Cn tn -—- id — O 3 co 3 < ^^^^^^^CQjzici^ropq z < ^ — I ^ ^ i n* m oo cn o 2 ffl « ffl 2 2^^^ I w w mhooinmcotTiOooooH cr> — '-'•-'nr^conoH CN inioior^oooooooiHHHHH CN HCON'iniDOOOlrHHHCO^N' 136 ID • • r- rH • CM (N Ok VD • H H • CM rH pH i—I CM .in .. • • • • CM • M1 • CO O CM • i—I i—| • • CM i—I • • ••••••• ^ ^ • • f——j •••••• • rH •r-'CTir-'i-H • cm in mo • • • 00 . co 0 •H O • 0 0 04 • • • O CM M1 (N • CM M* H 0 CO • • • in • CM • • • • H P -P -P CO P 0 0 CU 0* II CO 0. • 04 0 1—1 • cm 00 H • • co o • f—1 0 1—1 • O i—| 1—I • • • t''- CO • • Z 1 CO CO < 0 •H 0 (D O CM 1—1 0 rQ & X Cd • CO ■p Eh 0 • • • 00 CTl rH • CM rH •H G rH • • • [■" CM. S G 2 cd •H ho P CO • -P 0 P co ao 0 CD 0 g CM 0 P Q 0 G -P •H G 3 -P 0 II o'i • . cm in C' 00 G CCJ MO CO. •H G 4H CO > 0 0 0 0 r* ’rH P cd CO TJ O rQ -P 0 0 0 rQ •H T5 -P Q. cd CO O 0 CO CO 0 0 G • H M1 H • CM CM in • CM • rH • • • • •H P rH 04 g • ••in •CM«»»CMrH»»»»»»»» CO 0 0 CO •rl G -P 4H E -p 0 cd 1—1 0 co iH co cd p • •H u 0 0 < tn U I rH 4H G -P I Ou 0 0 *p 4H -p £ P •—1 Q4 0 CO .. CO X) 0 G G .52 . CO P cd 0 0 tn 0 Eh £ XJ G CO— O CQ CQ 2 2 2 2 x O CO < u 0 II — —'— >— •— >-r w w ■*-* | «.| ro^mmoH cd p 0 0 ,—> —■ ,—„ '— --- P-N —' --s — ,—^ — —' -■—- p»» — —' —v •—I 89 i—1 O r- co vo CM w in co pH ^ CM CO pH ' ^ CO l"D pH ' 294 658 ■—•' p-* (CT) p-x ,—s '—' „—v /-s —■* -- >_•> .__ pH ^—■* „—* -—» --s vo p-«. ^—* — ..—. cm —1 ■— ✓—- (13) (21) <7> i—1 pH > i—1 rH s,./ ^ CN 1—1 in m ™ vo CN w rH rH ^ 3 hi LO w r* LO LO w rH CN I rH CM ^ ^2 rH * vo w lo co w O CN rH V-) ^ r*. oo co in cm in s—* vo in CM pH s-> r- co co w pH CM •^r G\ pH CM pH *-* 00 vo pH 2 284 279 ^— p-^ ■—* p^ p-v —* ..—.. ,—„ *—.. '—* '— N. Cl 9) '«S Cl 3) CM i—1 pH CO in 3 r- 9 cr> cm co w VO pH CM 3 CN rH < LO CN i—1 w' LO CN w VO rH rH v—’ CN 00 3 r- 2 CO ^ pH CO vo VO CO CO VO pH CM w i—1 pH pH ' O t"- 1—1 ' m pH co r- vo — co r- CM 3 °s in co CM pH 196 ^^ -- v—' ^-V x—n For the total number of arthropods, the beneficial species, and the neutrals, abundance was negatively corre¬ lated to the amount of spray used. For the pest species, most of which were tarnished plant bugs, this same correla¬ tion was valid in the treated orchard. The abandoned orchard contained the fewest number of pests, probably a result of fewer, nutritionally poorer apples, which reduced the tarnished plant bug numbers, and some biological con¬ trol. Certain arthropods inhabiting the foliage under the trees can have a definite influence on the trees. The tar¬ nished plant bug is one example shown in this study. Evidence for the effect of syrphids has been presented in the section on apple aphids. The coccinellids also are - probably beneficial. The spiders and hymenopterous and dipterous parasites may be involved in the biological con¬ trol of apple pests. G. Pheromone and Attractant Trap Samples Table 17 lists the trap catches of the six insects for which traps were utilized. As the effective range for these traps exceeded the size of the entire sprayed orchard under study, the results could not be separated by spray treatment. The abandoned orchard was far enough away to avoid inter¬ action with the treated orchard, and so the two orchards 140 co f p- o o o o o f o o o o co o o o o o 1—1 1 1 1 1 • 1 • o o o o o o o o o o o o o o o o o 00 CM CD o o o o o o o o o o o o o o o o o o o 1 1 1 1 o o o o o o o o o o o o o o o o o o o f o cr> CM o CO rH CPi CO o o o o o rH o UO CM CD o CO 1—1 r-H CD o o 1 1 1 1 1 1 • o o o o o o o o o CO f P" F CM rH o o CO f CM o o o o o o o o o o o o o o o o o o o 1 1 • 1 1 o o o o o o o o o o o o o o o o o o o o 00 1—1 co 1—1 o F o o 00 o o o LO o o CO CM CM 1—1 o uo o 1—1 1 1 1 1 1 1 • o 00 o CM o o o o o rH o o o o o o o CM 1—1 00 p- 00 CD CD ["• 1—1 o o o o 1—1 rH CM CM o o o o o o o o 1—1 o 1—1 1 1 • 1 1 o o o o 1—1 o CM o o o o o o o o o o o o CO CO 00 00 o f o o o o o o 00 o F o o o o o o in 1—1 1 1 1 1 1 1 • o o o o o o o o o o o o o o o o o to CD & O -P 00 00 F p- CD o rd o o o o o o o o o CO o o o o o o o co rH U 1 1 • 1 1 o o o o o o o o o o o o o o o o o o o a. d CD 00 CM u o o o o o o o o o o 00 o r- o >1 I>i >1 >1 c a a G C p p p pi—1 1—1 rH tn tn tP tn tn CLi 04 0 rd rd cd rd 2 p p p p p p p p p p p p p p p p 0 0 r-H cn -Q See Table A-l for abbreviations - indicates trap not checked. rd o in CD r- CM co "vF 1—1 p" o\ CD •^F rH rH o 00 1—1 CM 00 Catch per trap day. Eh rH CM CO 1—1 1—1 1—1 CM CM CM rH CM I—1 rH CM co rH rH CM co 141 were compared. The information desired from this sampling method was the activity period for these pests. No attempt was made to correlate the trap catches with the actual populations present. Figure 14 displays the activity periods and the number caught for the six pests. The traps in the abandoned orchard caught more codling moths, lesser appleworm adults, and apple maggot adults than those in the treated orchard. Very few red-banded leaf rollers, oblique-banded leaf rollers or oriental fruit moths were trapped in either orchard. The activity periods of these pests were the same as reported by Metcalf et al. (1962) and Chapman and Lienk (1971) (Figure 14). The apple maggot has one generation (there is some evidence for a partial second (Hall 1937)) with peak activity around the first of August. The lesser appleworm has two and a partial third generations per year. My samples showed the first generation peak to be very dis¬ tinct in the first week in June. The red-banded leaf roller has two generations per year, both shown clearly in my samples, although few were caught. The codling moth has one and a partial second generation per year with activity extending throughout the entire summer. The oriental fruit moth is reported to have from one to seven generations per year. My sampling indicates three generations although so Figure 14. Pheromone/Attractant Trap Catches -p a •r| rH o CM -P 43 -p p (D 0 fd p G -P G O L deaj, aajAeacuaa;gghnuoaaqumw •—1 This sampling technique showed that there is a sub¬ stantial reservoir of codling moths, apple maggots, and lesser appleworms in the Belchertown area. Without adequate control measures, any one could destroy a large portion of the apple crop in surrounding orchards. H. Sticky Board Trap Samples Table A-13 lists the insects trapped on the sticky boards, and Table 18 shows their distribution and abundance. Some smaller insects were also trapped, but were impossible to identify because of their entanglement in the "Stickem." Very few apple maggot flies were caught, and then only in the abandoned orchard. Six species of leafhoppers were caught. I did subject the leafhopper data to statistical analysis, and although there was a significant difference between the two orchards, I attach little value to it be¬ cause of the low numbers of insects involved (Table A-14). The data from this sampling technique revealed nothing which was not shown by the other sampling methods. Table 18. Distribution and Abundance of Insects Trapped on Sticky Boards VO 1—1 p HM- IP rH CMin CM rH r—| VO 1-0 1— CM co Hcom IP CO o o cor-' rH r—ICM CO • • rH tn rH vo < CM i—I rH CMcoU01Q) o co r--C'r- O CMCOm co • ». • rH rH VO CO CM co CM CM 1— rH in1 H i—ICO O CO CO o • rH vo H 00 co i—1 -H rH TJ ,P Eh CM oo t) 10 O p p O4 cu P 0 P O p 0 P P 10 O P P P 0 • CM Ip -H •H s i—1 T5 -P jo -P i—1 i—i co P Eh < 3 p P o CO CD P 0 0 CO cu 0 o CO P CO O 0 P p 0 l CO ,p u -P -P P O P 04 P P 04 0 • JO 1— ip 1— •H CO JQ Eh < -P p 0) (D 0 O P P P > 0 P o CO p 1 144 • in JO JP £ ip ,P P -p P -P 0 p 3 £ P p p U P 0 P tr> 04 0 p p p 04 P £ 0 P 0 0 P P CO 04 • 145 SUMMARY AND CONCLUSIONS The research reported in this thesis has some shortcom¬ ings which must be kept in mind as one evaluates the results. The study covered only one growing season, a situation I would have remedied had more time been available to me. The effect of the mite damage, for example, on fruit production in the minimum-spray blocks was virtually impossible to assess, but I am sure the damage was sufficient to adversely effect the fruit for the next year. It often takes more than one year for certain predators and parasites to become effective in an integrated control situation. In short, it is difficult, if not impossible, to fully determine the dynamics of an orchard ecosystem unless several years data are available. Comparisons between the treated and the abandoned orchards must be tempered with realization that unaccounted variables compounded the differences. The trees in the two orchards were different sizes. The abandoned trees had not been fertilized for several years, and certainly the result¬ ing nutritional deficiencies greatly affected the arthropods occurring there. Nevertheless, the results proved valuable in evaluating the two integrated control programs tested. In general, the 146 minimum-spray and the alternate-row-spray programs were favorable to increased numbers of beneficial arthropods. At the same time, however, there was an increase in the pest species. When one evaluates the fruit damage, the ultimate test, it is apparent that the regular-spray treat¬ ment and the two integrated treatments are equally effective against the plum curculio, the codling moth, and the apple maggot. The tarnished plant bug, on the other hand, was much more destructive in the integrated blocks than in the regular-spray blocks. The increased numbers of beneficial arthropods in the integrated control blocks is encouraging. The ground cover was shown to be a haven for tarnished plant bugs, and with control directed at this pest the integrated control pro¬ grams tested could be on a par with the regular spray program. The pheromone trap studies indicated the presence of oriental fruit moths, lesser apple worms, oblique-banded leaf rollers, and red-banded leaf rollers, any one of which is capable of destroying a large portion of an apple crop under the right conditions. Continued vigilance is manda¬ tory to prevent problems from previously non-harmful pests, especially when attempting to implement an integrated control program. 147 BIBLIOGRAPHY Asquith, D. 1958. Spray combinations for control of the codling moth and the red-banded leaf roller of apples. J. Econ. Entomol. 51:378-379. Asquith, D. 1960. Insecticides change the importance of segments of insect generations. J. Econ. Entomol. 53:694-695. Asquith, D. 1961. Methods of delaying selection of acari- cide resistant strains of the European red mite. J. Econ. Entomol. 54:439-441. Asquith, D. 1973. European red mite control with some new acaricides. J. Econ. Entomol. 66:237-240. Asquith, D., and R. Colburn. 1971. 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Insecticide tests against plum curculio. J. Econ. Entomol. 44:665-668. Wylie, W. D. 1954. The plum curculio on peaches in Arkansas. Arkansas Agric. Exp. Stn. Bull. 542. 46 p. Yonce, C. E., J. A. Payne, and R. R. Pate. 1972. Feeding and oviposition preferences of female plum curculios. J. Econ. Entomol. 65:1206-1207. Yothers, M. A., and F. W. Carlson. 1944. Chemicals to destroy overwintering codling moth larvae in the soil at the base of apple trees. J. Econ. Entomol. 37: 448-450. Yothers, M. A., F. W. Carlson, and C. C. Casil. 1943. Tests of 4,6-Dinitro-o-cresol emulsion against over¬ wintering codling moth larvae. J. Econ. Entomol. 36:882-884. Zwick, R. W. 1972. Studies on the integrated control of spider mites on apples in Oregon's Hood River valley. Environ. Entomol. 1:169-176. APPENDIX 168 Table A-l. Abbreviations Used in Tables and Figures Spray Treatments M = Minimum spray A = Alternate-row spray R = Regular spray AB = Abandoned orchard TRT = Treated Orchard Spray-Treatment Blocks MD = Minimum-spray Delicious AD = Alternate-row-spray Delicious RD = Regular-spray Delicious BAD = Abandoned Delicious MM = Minimum-spray McIntosh AM = Alternate-row-spray McIntosh RM = Regular-spray McIntosh BAM = Abandoned McIntosh Statistical Analysis df = Degrees of freedom MS = Mean square F = F ratio 169 1 Table A-2. Mites Found in Leaf Brushing Samples Anoetidae Histiosoma sp. Eriophyidae Aculus schlechtendali (Nalepa) Oribatulidae Scheloribates sp. Phytoseiidae Typhlodromus pomi (Parrott) Saproglyphidae Czenspinskia lordi Nesbitt Tar sonemidae Tarsonemus summersi Smiley Tarsonemus sp. Tetranychidae Bryobia rubrioculus (Scheuten) Panonychus ulmi (Koch) Tetranychus urticae (Koch) Trombidiidae Allothrombium sp. Tydeidae Triophytdeus sp. Tydeus kochi Oudemans Identified by E. W. Baker and R. L. Smiley, USDA, Agr. Res. Ser., Agr. Res. Ctr. (West), Beltsville, Maryland 20705; and G. N. Oldfield, USDA, Agr. Res. Ser., Western Region, Riverside, California 92502. cm Table A-3. Statistical Analysis of Leaf Brushing •H •H iH 44 > < w o C id >i W rd u s O d) pH ■H ■H oil 43 rH 43 En I <\ •H T5 4-> a a P £ 44 o a e w O h rondim > COP O CMi—I cm coiH di nmcoocji rl ro(M(TlH(N (T> cmro00ID co rooO H ro00nCOO* 'J Ohffl^o 44 O idLOro rH o inhm 0 0 00 O CM 0 uo O iH COCPP-U0 O 00 O CPCOrHi—ICMr—I O ^ID O (31MH(N O -sT<0ro o 4 Q rd ftIdWQ >1 Q CL) >i • ••••• He He * r- 00 rH He He CO — un ro O CM O ro in in 1—1 0 CM He 00 He He He rH 1—1 1—1 I—1 0 CO UO CM He He CO ro CM ARACHNIDA Acarina Eupodoidea 1. (N)^ Undetermined family Trombidiidae 2. (B) A1lothrombium sp. Araneida Clubionidae 3. (B) Undetermined species Salticidae 4. (B) Metaphidippus insignis (Banks) Thomisidae 5. (B) Undetermined species Phalangida Phalangidae 6. (N) Undetermined species INSECTA Coleoptera Buprestidae 7. (N) Melanophila sp. continued 172 Table A-4.—continued Cerambycidae 8. (N) Undetermined species Chrysomelidae 9. (N) Phyllobrotica limbata (Fabricius) 10. (N) Undetermined species Coccinellidae 11. (B) Adalia bipunctata (Linnaeus), two-spotted lady beetle 12. (B) Adalia frigida Schneid. 13. (B) Chilocorus stigma Say, Twice-stabbed lady beetle 14. (B) Cycloneda munda Say 15. (B) Hyperaspis binotata Say Curculionidae 16. (N) Aphrastus taeniatus Gyllenhal 17. (P) Conotrachelus nenuphar (Herbst), plum curculio 18. (N) Undetermined species Elateridae 19. (N) Limonius sp. 20. (N) Ludius inflatus (Say) Lampyridae 21. (N) Lucidota spp. continued 173 Table A-4.—continued Meloidae 22. (N) Undetermined species Scarabaeidae 23. (P) Macrodactylus subspinosus (Fabricious), rose chafer 24. (P) Popillia japonica Newman, Japanese beetle Dermaptera Forficulidae 25. (N) Forficula auricularia Linnaeus, European earwig Diptera Asilidae 26. (B) Undetermined species Chloropidae 27. (N) Thaumatomyia sp. Syrphidae 28. (B) Undetermined species, aphidophagous larva Hemiptera Miridae 29. (P) Heterocordylus malinus Reuter, dark apple red bug 30. (P) Lygidea mendax Reuter, apple red bug 31. (P) Lygus lineolaris (Palisot de Beauvois), tarnished plant bug 32. (N) Pilophorus sp. continued 174 Table A-4.--continued 33. (N) Stenodema trispinosum Reuter 34. (N) Undetermined species Nabidae 35. (B) Undetermined species Pentatomidae 36. (N) Undetermined species Reduviidae 37. (B) Undetermined species Homoptera Cercopidae 38. (N) Philaenus spumarius (Linnaeus), meadow spittlebug Cicadellidae 39. (P) Edwardsiana rosae (Linnaeus), rose leafhopper 40. (P) Empoasca fabae (Harris), potato leafhopper 41. (P) Qrientus ishidae (Matsumura) 42. (P) Typhlocyba pomaria McAtee, white apple leafhopper 43. (P) Undetermined species Flatidae 44. (N) Qrmensis pruinosa Say Membracidae 45. (N) Telamona sp. 46. (N) Undetermined species continued 175 Table A-4.'—continued Hymenoptera Ichneumonidae 47. (B) Undetermined species Lepidoptera Coleophoridae 48. (N) Coleophora serratella (Linnaeus), cigar case-bearer larva Lymantriidae 49. (P) Hemerocampa leucostigma (J. E. Smith), white-marked tussock moth larva 50. (P) Porthetria dispar (Linneaus), gypsy moth larva Noctuidae 51. (P) Lithophane spp., green fruitworm larvae Saturniidae 52. (N) Hyalophora cecropia (Linnaeus), cecropia moth larva Miscellaneous Caterpillars—Undetermined species 53. (P) Coleophoridae 54. (P) Geometridae 55. (P) Lasiocampidae 56. (P) Noctuidae 57. (P) Notodontidae continued 176 Table A-4.—continued 58. (P) Nymphalidae 59. (P) Psychidae 60. (P) Sphingidae 61. (P) Tortricidae 62. (P) Undetermined families Neuroptera Chrysopidae 63. (B) Chrysopa sp., adult and/or larva Orthoptera Acrididae 64. (N) Undetermined species Gryllidae 65. (N) Oecanthus spp., snowy tree crickets Tettigoniidae 66. (N) Ambylcorypha sp. Psocoptera Psocidae 67. (N) Undetermined species p j ^B = beneficial species, N = neutral species, P = pest species. Table A-5. Statistical Analysis of Beating Sample Data •H IH > 0 03 P ftf o p COQ > o rocdloi—i -P ^ O CT> OCN00rHCD h 00OCOH •^ CD * -K cn roorH in ro^ooco co cnrooo^h o r- ^ t—loooorocn I''- LOr—I(Ni—I00ro OOH^O^D o ro Table A-7. Arthropods Found in Leaf and Twig Inspection Samples ARACHNIDA Acarina Eupodoidea 1. (N)1 Undetermined family Araneida Clubionidae 2. (B) Undetermined species Salticidae 3. (B) Metaphidippus insignis (Banks) Thomisidae 4. (B) Undetermined species Egg Mass 5. (B) Undetermined species Phalangida Phalangidae 6. (N) Undetermined species Coleoptera Cerambycidae 7. (N) Brachyleptura rubrica (Say) Chrysomelidae 8. (N) Undetermined species continued 180 Table A-7.—continued Coccinellidae 9. (B) Adalia frigida Schneid. 10. (B) Brachyacan ursinatha (Fabricius) 11. (B) Coccinella novemnotata Herbst Curculionidae 12. (P) Conotrachelus nenuphar (Herbst), plum curculio 13. (N) Undetermined species Elateridae 14. (N) Limonius sp. Lampyridae 15. (N) Lucidota spp. 16. (N) Photuris pennsylvanica (DeGeer) Scarabaeidae 17. (P) Macrodactylus subspinosus (Fabricius), rose chafer 18. (P) Popillia japonica Newman, Japanese beetle Diptera Cecidomyiidae 19. (B) Undetermined species - aphidophagous larva Syrphidae 20. (B) Mesogramma sp. 21. (B) Undetermined species - egg and/or larva continued 181 Table A-7.—continued Tachinidae 22. (B) Undetermined species Tephritidae 23. (P) Rhagoletis pomonella (Walsh), apple maggot Hemiptera Anthocoridae 24. (B) Orius insidiosus (Say) Miridae 25. (P) Heterocordylus malinus Reuter, dark apple red bug 26. (N) Hyaliodes sp. 27. (P) Lygidea mendax Reuter, apple red bug 28. (P) Lygus lineolaris (Palisot de Beavois), tarnished plant bug 29. (N) Undetermined species Pentatomidae 30. (N) Undetermined species, egg mass Reduviidae 31. (B) Undetermined species Homoptera Aphididae 32. (P) Aphis pomi DeGeer, apple aphid, apterous form 33. (P) Aphis pomi DeGeer, apple aphid, alate form continued 182 Table A-7.—continued 34. (P) Dysaphis plantaginea (Passerini), rosy apple aphid 35. (P) Eriosoma lanigerum (Hausmann), woolly apple aphid 36. (B) Undetermined species - aphid mummy Cercopidae 37. (N) Philaenus spumarius (Linnaeus), meadow spittlebug Cicadellidae 38. (P) Edwardsiana rosae (Linnaeus), rose leaf- hopper 39. (P) Empoasca fabae (Harris), potato leafhopper 40. (P) Qrientus ishidae (Matsumura) 41. (P) Typhlocyba pomaria McAtee, white apple leafhopper 42. (P) Undetermined species 43. (P) Undetermined species - egg Diaspididae 44. (P) Lepidosaphes ulmi (Linnaeus), oyster- shell scale Fulgoridae 45. (N) Undetermined species Membracidae 46. (N) Undetermined species continued 183 Table A-7.—continued Hymenoptera Braconidae 47. (B) Undetermined species Formicidae 48. (N) Undetermined species Ichneumonidae 49. (B) Undetermined species Lepidoptera Arctiidae 50. (P) Hyphantria cunea (Drudy), fall webworm larva Coleophoridae 51. (N) Coleophora serratella (Linnaeus) cigar casebearer larva Gracilariidae 52 (P) Lithocolletis sp. Lymantriidae 53. (P) Hemerocampa leucostigma (J. E. Smith), white-marked tussock moth larva 54. (P) Porthetria dispar (Linnaeus), gypsy moth larva Tortricidae 55. (P) Argyrotaenia velutinana (Walker), red- banded leaf roller larva 56. (N) Undetermined species continued 184 Table A-7.—continued Miscellaneous Caterpillars - Undetermined species 57. (P) Geometridae Ln 00 • (P) Lasiocampidae 59. (P) Noctuidae 60. (P) Notodontidae 61. (P) Psychidae KD (N • (P) Sphingidae 63. (P) Undetermined families Neuroptera Chrysopidae 64. (B) Chrysopa sp. 65. (B) Undetermined species, larva and/or egg Orthoptera Gryllidae 66. (N) Qecanthus spp., snowy tree crickets Phasmatidae 67. (N) Undetermined species Psocoptera Psocidae 68. (N) Undetermined species Thysanoptera Phlaeothripidae 69. (N) Undetermined species 1B = beneficial species, N = neutral species, P = pest species. CN Table A-8. Statistical Analysis of Terminal Inspection Data ■H •H 5 i—I > o p rd >1 CO CO 0 0 £ O Table A-9. Statistical Analysis of Chewing Insect, Leaf- Damage Data^ Analysis of Variance Source df2 MS F3 Variety (V) 1 0.01 5.00* Spray (S) 3 0.59 295.00** Date (D) 6 0.01 5.00** VS 3 0.003 1.50 VD 6 0.0 0.0 SD 18 0.01 5.00* VSD 18 0.002 4 Duncan ' s New Multiple-Range Test A R M AB 1.225 1.23 1.23 1.64 ^i/X+h data transformation used for analysis, o See Table A-l for abbreviations. 3* indicates significance at the 5% level, ** at the 1% level. 4 Tested at the 5% significance level. 5 Transformed data spray-treatment mean. rp Q -P id Table A-10. Statistical Analysis of Fruit Damage Iti •H •H rH 4H <2 > P c id 01 01 O G >1 id id O 03 CN •H rH •H rH rH CM 40 u rH •H u 2 < +3 2 i—1 -M rH a 3 g o P p o P 0 G 01 0 53 01 0 CM 03 id 01 03 O id a 03 03 O P 03 co p 44 40 01 (M 01 2 03 S (M C/5 Pm 2 Ol a p o p o *H rH -p w co in in o 01 00 CN VO CO V0 ip CN01O CN m 01 00 in co in *3* * * CN CN p >1 Q 0) rH p in rH He Ol Q> co co co He rH 01 co 00 o p 00 CO rH CN He He o 00 01 00 p in O co o 00 co He He o o CN oi CO C" rH r* He He o 01 01 01 P -P rd 03 CM rd01 >1 f" o CO o o 01 co p rH He He co O CN rH 00 CO CN in 00 VO r" He He o o He o o X) p CN p1 He 0i %» VO m CN p CN He He CO VO V0 r- rH V0 10 in CN 01 CO CN CM O o iH V0 i—I rH in rH rH He 01 o co P He 01 CM rH > p CO V0 01 p o 00 CN m •—1 oi ["• 01 p o oi 00 rH rH in x> CN rH p rH He He r- V0 vO CN o 00 01 Q 00 co p in CN VO m He He i0 01 CO in rH r* CO in CN He CN CN in r** rH CO He He 00 co • r- m CN > 01 Q CO m CN in rH VO co 01 CO VO rH 10 CO in •H rH rH p 2 -P a Eh -P 2 3 £ c3 G CM <3 o C/3 03 £ P 03 G 0i 03 <13 oi 1 *P fH u CM J5rt 2 00 P o 2 o 2 q o Cm • < • q oo ^ * 2 p CQ r—1 2 CQ 00 ^ • P m p P p o o id 0i 03 VO rH o CN o VO m P in 10 CO • •P *0 I—I X u 2 Q -M 2 q 2EJ Q fr, < p § idj • a cn 2 VO a o o a 01 P r- o id 0i 03 o r-' o 00 CN CN CN p" CO CN co m co CO vo in in 10 i0 co • • • • • I—I < 2 -p 2 q < p Dh pH id; 2 p CQ 2 a < p Ol CM id 01 01 o o id 01 03 f" CN 0i t"* rH in in 00 m vO rH o 00 CO o o vo »H rH cn m in r- co Ol co • • • • • • • • •H s p § < • Q X) 2 p 1 03 01 o CM p 01 o 03 o 03 a id 03 id 01 03 • •H Ip TO XX -p 40 •H 4-1 -p id s 03 03 CM 01 p 03 id a p 01 a 03 03 p p § B id 01 03 44 •H •H a rp r-H EH a < -p 03 o p id p 03 > id o g 03 I •P •P •P ■P •H He 44 40 X m He He -P i—1 rH ►G -P -P (H i—1 +3 r—1 dP •P dP C3 id 03 1/3 l/l 0i G o 10 G G o 03 id 03 03 > 03 id 03 0) > 03 m X) •P •P •p 0! in 44 40 ip rH -P -P ■P dP EH id Q3 03 01 G O 03 03 01 03 u > 03 03 • Transformed data variety-spray-treatment mean 187 188 Table A-ll. Arthropods Found in Sweeping Samples ARACHNIDA Acarina Eupodoidea .1. (N)^ Undetermined family and species Trombidiidae 2. (B) Allothrombium sp. Araneida Araneidae 3. (B) Araniella displicata (Hentz) Clubionidae 4. (B) Undetermined species Salticidae 5. (B) Metaphidippus insignis (Banks) Thomisidae 6. (B) Undetermined species Phalangida Phalangidae 7. (N) Undetermined species INSECTA Coleoptera Chrysomelidae 8. (N) Trirhabda virgata LeConte continued 189 Table A-ll.—continued 9. (N) Undetermined species Cleridae 10. (N) Undetermined species Coccinellidae 11. (B) Coccinella novemnotata Herbst 12. (B) Hyperaspis sp. 13. (B) Psyllobora viginti-maculata Say 14. (B) Undetermined species, larva Curculionidae 15. (N) Aphrastus taeniatus Gyllenhal 16. (N) Brachyrhinus ovatus (Linnaeus), strawberry root weevil 17. (N) Calomycterus setarius Roel. 18. (P) Conotrachelus nenuphar (Herbst) plum curculio 19. (N) Nicentrus sp. 20. (N) Undetermined species Elateridae 21. (N) Limonius sp. 22. (N) Undetermined species Lampyridae 23. (N) Lucidota spp. Languriidae 24. (N) Undetermined species continued 190 Table A-ll.—continued Leiodidae 25. (N) Leiodes sp. Meloidae 26. (N) Undetermined species Scarabaeidae 27. (P) Macrodactylus subspinosus (Fabricious), rose chafer 28. (P) Popillia japonica Newman, Japanese beetle Diptera Anthornyiidae 29. (N) Scatophaga sp. Asilidae 30. (B) Leptogaster sp. j 31. (B) Undetermined species Chloropidae 32. (N) Thaumatomyia sp. Syrphidae 33. (B) Melanostoma sp. 34. (B) Mesogramma spp. 35. (B) Metasyrphus sp. 36. (B) Platycheirus sp. 37. (B) Syrphus sp. 38. (B) Undetermined species, adult continued 191 Table A-ll.—continued 39. (B) Undetermined species, larva Tachinidae 40. (B) Undetermined species Tephritidae 41. (N) Euaresta bella (Loew) 42. (P) Rhagoletis pomonella (Walsh), apple maggot Tipulidae 43. (N) Undetermined species Hemiptera Alydidae 44. (N) Protenor beltragei Haglund Anthocoridae 45. (B) Orius insidiosus (Say) Miridae 46. (N) Capsus ater semiflavus (Linnaeus) 47. (N) Chlamydatus associatus Uhler, ragweed plant bug 48. (N) Collaria oculata (Reuter) 49. (P) Heterocordylus malinus Reuter, dark apple red bug 50. (N) Ilnacora malina (Uhler) 51. (N) Leptopterna dolabratus (Linnaeus) 52. (P) Lygidea mendax Reuter, apple red bug continued I 192 Table A-ll.—continued 53. (P) Lygus lineolaris (Palisot de Beauvois), tarnished plant bug 54. (N) Megaloceraea spp. 55. (N) Plagiognathus spp. 56. (N) Stenodema trispinosum Reuter 57. (N) Stenodema vicinum (Provancher) 58. (N) Undetermined species Nabidae 59. (B) Undetermined species Neididae 60. (B) Berytinus minor Herrich-Schaeffer Pentatomidae 61. (N) Moridea lugens (Fabricius) 62. (N) Undetermined species Homoptera Aphididae 63. (P) Aphis pomi DeGeer, apple aphid 64. (P) Dysaphis plantaginea (Passerini), rosey apple aphid 65. (B) Aphid Mummy—undetermined species 66. (N) Undetermined species Cercopidae 67. (N) Philaenus spumarius (Linnaeus), meadow spittlebug continued 193 Table A-ll.—continued Cicadellidae 68. (N) Athysanus argentatus Metcalf 69. (N) Colladonus clitellarius (Say), saddled leafhopper 70. (N) Draeculacephala mollipes (Say) 71. (N) Graphocephala coccinea (Forster) 72. (N) Gyponana striata Burmeister 73. (N) Latalus sayi (Fitch) 74. (N) Undetermined species Delphacidae 75. (N) Liburnia spp. 76. (N) Liburniella ornata Stal Dictyopharidae 77. (N) Undetermined species Membracidae 78. (N) Acutalis sp. 79. (N) Undetermined species Psyllidae 80. (N) Undetermined species Hymenoptera Braconidae 81. (B) Undetermined species Chalcidoidea 82. (B) Undetermined family continued 194 Table A-ll.—continued Ichneumonidae 83. (B) Undetermined species Tenthredinidae 84. (N) Dolerus sp. 85. (N) Pteronidea sp. Lepidoptera Lymantriidae 86. (P) Porthetria dispar (Linnaeus), gypsy moth larva Olethreutidae 87. (P) Carpocapsa pomonella (Linnaeus), codling moth Tortricidae 88. (P) Argyrotaenia velutinana (Walker), red- banded leaf roller 89. (P) Choristoneura rosaceana (Harris), oblique-banded leaf roller Miscellaneous Caterpillars—Undetermined species 90. (N) Arctiidae 91. (N) Danaidae 92. (N) Drepanidae 93. (N) Gelechiidae 94. (N) Geometridae 95. (N) Hesperiidae 96. (N) Noctuidae continued 195 Table A-ll.—continued 97. (N) Nymphalidae VD 00 • (N) Papilionidae 99. (N) Pieridae 100. (N) Pyralidae 101. (N) Sphingidae 102. (N) Undetermined families Neuroptera Chrysopidae 103. (B) Chrysopa sp. 104. (B) Undetermined species, larva Orthoptera i Acrididae i 105. (N) Chorthippus longicornis (Katreille) 106. (N) Melanoplus sp. 107. (N) Orphulella speciosa (Scudder), pasture locust 108. (N) Undetermined species Gryllidae 109. (N) Oecanthus spp., snowy tree crickets Tettigoniidae 110. (N) Amblycorypha sp. Ill, (N) Neoconocephalus sp. continued 196 Table A-11.—continued Psocoptera Psocidae 112. (N) Undetermined species = beneficial species, N = neutral species, P = pest species. Table A-12. Statistical Analysis of Sweeping Sample Data •H •H r—I m < > 01 (d in o P (U c >1 0 0 o G •H 4-1 •H •h n •H •H fa w fa fa -p fa in -p G Table A-13. Insects Trapped on Sticky Boards Diptera Syrphidae 1. Mesogramma sp. 2. Syrphus sp. Tephritidae 3. Rhagoletis pomonella (Walsh), apple maggot Hemiptera Miridae 4. Lygus lineolaris (Palisot de Beauvois), tarnished plant bug Homoptera Cercopidae 5. Philaenus spumarius (Linnaeus), meadow spittlebug Cicadellidae 6. Colladonus clitellarius (Say), saddled leaf- hopper 7. Edwardsiana rosae (Linnaeus), rose leafhopper 8. Graphocephala coccinea (Forster) 9. Latalus sayi (Fitch) 10. Orientus ishidae (Matsumura) 11. Typhlocyba pomaria McAtee, white apple leaf- hopper 199 Table A-14. Statistical Analysis of Leafhopper Data From Sticky Boards^ Analysis of Variance Source df2 MS F3 Variety (V) 1 0.09 0.46 Spray (S) 3 4.38 22.27** Date (D) 3 1.62 8.24** VS 3 0.36 1.83 VD 3 0.59 3.00 SD 9 0.94 4.78* VSD 9 0.20 4 Duncan's New Multiple-Range Test R A U AB 0.825 1.03 1.28 2.47 \/x+h data transformation used for analysis. 2 See Table A-l for abbreviations. ■^indicates significance at the 5% level, **at the 1% level. ^Tested at the 5% significance level. 5 Transformed data spray-treatment mean.