THE ECOLOGY OF THE MEADOW SPITTLEBUG PHILAENUS LEUCOPHTHALMUS (L.)l FAMILY CERCOFIDAE

DISSERTATION

Presented in p artial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University

By DONALD ROY KING, B.S., M.Sc, M The Ohio State University 1952

I Approved by:

Adviser TABLE OF CONTENTS Page INTRODUCTION...... 1 LIFE HISTORY...... 2 ECOLOGY OF THE EGG...... 2 Egg Parasitism ...... 3 Effect of Temperature and Humidity on Hatching...... -7 Summary. * ...... 17 Embryonic Development and Mode of Hatching'...... 17 ECOLOGY OF THE NYMPH...... 19 Effect of Moisture on Nymph Development..• 19 Effect of Temperature on Nymph Development...... 27 Influence of Temperature and Humidity on Nymph Movement...... 30 Nymph H osts...... 31 Number of Nymphal In s ta r s ...... 43 ECOLOGY OF THE ADULT...... 46 Estimation of Adult populations...... 46 Early Summer Behavior ...... 46 Early Dissemination...... 47 Influence of Wind on Movements...... 49 Migration to New Hosts in the Field ...... 51 Corn...... 51 O ats...... 52 Wheat...... 55 P a stu re s...... 56 Fencerows and w astelands...... 60 Summary ...... 60 Migration into Second Growth Meadows ...... 61 OVIPOSITION...... 66 Initiation of Egg Development...... 66 Duration of Oviposition Period...... 67 LATE SUMMER BEHAVIOR...... 69 Influence of Cultural Management on Late Summer Movements...... 69 Summary.• • • • • • ...... 75 FALL BEHAVIOR...... 75 Influence of Oviposition Sites on Egg D eposition...... 77 Summary...... 84

i 829770 TABLES Page I. Percentage of Parasitized Eggs In Four Locations...... 6 II* Number of Hatched Spittlebug Eggs Under Varying Temperature Treatments...... 9 I I I . Number of Hatched Eggs Under Varying Humidity Treatments ...... 10 IV* Percentage of Spittlebug Eggs Hatched a t Varying Temperatures a t 80 and 100 Percent Humidity ...... * ...... 13 V* Actual Wet Yields of First Cutting Red Clover. . .Under Differing Levels of R a in fa ll...... 26 VI* Actual Wet Yields of Second Cutting Red Clover. . .Under Differing Levels of R a in fa ll...... 28 VII. Comparison of Nymph Head Capsule Measurements ...... 45 VIII* Effect of Adult Spittlebug Feeding on Corn, Oats and A l f a l f a ...... 53 IX* Numbers of Male and Female Splttlebugs Collected in Sweeps...... 70 X. Number and Location of Spittlebug Eggs in Different Ecological Situations ...... 79 XI* Locations of Spittlebug Eggs on Plant ...... 31 XII* Comparison of Number of Eggs per Female.**. 83

i i FIGURES

Figure Page I. Meadow Spittlebug eggs deposited between the sheath and stem of wheat straw * 4 3. Relationship of 50°-60°F. Mean Temperature for March, April and May to Spittlebug Hatching Dates •••••••• ...... 15-16 3. Equipment utilized in 1351 to test the relationship of moisture and spittlebug damage to red clover ...... «... 22 4* Number of Nymphal In stars AS Determined by Head Capsule Measurements ...... 44 5. Effect of First Cutting Management of Forage Crops...... 48 6* Seasonal Adult Spittlebug Populations ...... 54 7. Comparison of Adult Spittlebug Populations. 58 8. Effect of Rotational Grazing System of Alfalfa on Adult Spittlebug Behavior throughout the Season ...... 59 9. Effect of Second Cutting Management of Forage Crops..,...... 63 10. Recovery of Adult Spittlebug Populations in Birdsfoot Trefoil...... 65 II. Populations of Adult Spittlebugs in Old Meadows in Varying Condition...... 72 12. Comparison of Adult Spittlebug Populations in Clipped and Undipped New Seedings.... 74.

i l l ACKNOWLEDGMENTS

The author is particularly indebted to Dr* C. R. Weaver, Ohio A gricultural Experiment S tation, who directed the research, aided in the statistical analysis of data, supplied information on egg development, and with Dr. Alvah Peterson, Ohio State University, and Dr. C. R. Nelswander, OAES, edited the manuscript. Dr. H. A. Runnels, OAES, identified many of the plants noted in the host list. Dr. J. M. Beattie, OAES, performed the protein analysis for the moisture studies. Mr. Clark Robey provided the photographic work. The Author wishes to acknowledge the contributions of the following cooperators: L. C. Baker, A. Chyme, Holrnes- ville, Ohio; H. H. Palmer, Millersburg, Ohio; Harold King, P. E. Rogers, Walter Hach, and R. E. Piper, Medina, Ohio.

iv . INTRODUCTION

Increased populations of the meadow spittlebug, Phllaenus leucophthajmus (L.) have become of great concern to Ohio legume and strawberry producers in recent years. The damage occasioned by its attacks on these crops has marked it as an extremely important pest in the state. Feeding of the nymphs on alfalfa and red clover causes a characteristic stunting of the stems and rosetting of the leaves due to the shortening of inter­ nodes. Increases in yields of up to 55 percent, resulting from spittlebug control have been reported

( Weaver 195jO) for the two forage crops. Schuh and Z eller (1944) state that the f ru it spurs, leaves, and fruits of strawberry plants are distorted by the feeding of the nymphs. As a consequence both plant vigor and quality of the berries is reduced. The change of this insect from a relatively innoc­ uous species to a pest of such moment has necessitated the use of insecticidal treatments to reduce the damage caused by i t . As a re su lt nymph control methods developed in states where this species is a pest, have made i t possible for farmers to prevent incurring losses to their crops. The development of a fall insecticide treatment for adult spittlebugs(Weaver 1951a) which prevents their 2 . depositing eggs for the following year's generation, resulted from initial biological and ecological research in Ohio on this pest* This study, to a large;extent, represents a continu­ ation and expansion of such ecological work. Particular attention has been given to elucidation of the relationships between seasonal c u ltu ra l management and re su ltin g in fe s ta ­ tions of adults*

LIFE HISTORY

A discussion of the ecological relationships of the meadow spittlebug must be preceded by a brief review of the life history*

There is one generation annually* The winter is passed in the egg stage. Late in April, in the latitude of Ohio, the eggs hatch and the nymphs feed on the succulent foliage of a variety of hosts. The nymphs require a period of 40 to 52 days for development, depending on climatic conditions. The adults emerge in early June and lead a nomadic existence until the first week in September. During September and October eggs are deposited and the adult population declines* The majority of the adults are killed by the first hard freeze.

ECOLOGY OF THE EGG

The eggs are elongate ovoid structures, about 0*70 3 . mm. long and 0.30 mm. in width, which are laid in masses of from one to 26. Examination of 575 egg masses disclosed an average of 7.9 eggs per mass with a median of 7. These masses of eggs are held together by a white cement and are usually deposited between two apposed plant parts. They are found most frequently between the sheath and stem of grain stubble at about a 45° angle to the axis of the stem. Masses have been obtained at a height of ten inches from the ground but most of them are located between ground level and four inches. At times the only visible indication that eggs are contained on a particular straw is a thin line of cement protruding from the edge of the sheath. Figure 1.

c Egg Parasitism Studies were initiated in April of 1951 to ascertain the identity of egg parasites and the percent of parasitism. Three hundred and four eggs were collected in the field on April 6, and placed in vials with moist cotton plugs. Parasitized eggs were dark grey or black in contrast to the orange color of normal eggs. They were distinguished from non viable eggs by th e ir plump appearance in co n trast to the vacuous character of the latter. Emergence of adult parasites by means of a round hole cut in the side of the egg began in five days and continued until April 23. Adult transferred to fresh vials upon emergence did not oviposit in well-developed eggs. 4.

Figure 1. Meadow spittlebug eggs deposited between the sheath and stem of wheat straw. 5. Twenty-one adults were obtained and were identified by B. D. Burks# as Qoctonus amerlcanus Gir., family

Mymaridae, and a new species of the genus T u m id iscapus, family Eulophidae. The total percent parasitism accomplished by these two species was 6*9 in 1951. A number of eggs kept a t a temperature of 40-5Q°F. until July 18, 1951 yielded six specimens of Tumidlscapus sp. after being placed at room temperature. No hatching of unparasitized eggs occurred at this time. They appeared dried up and shrunken indicating that a compara­ tively high humidity must be maintained throughout the

egg stage. In 1952 these studies were extended to obtain a more accurate estimate of the incidence of parasitism. Five vials, each containing approximately 50 eggs gathered in four new meadows, were placed a t room temperature on April 2, 1952. The number of black or grey eggs was

noted and a percentage of 9.78 was recorded. Considerable variation existed among the four sampling locations. Table I. The apparent increase in parasitism in 1952 is probably of no significance. A larger number of samples

makes it a more reliable estimate than was obtained the

# U. S. Dept, of A griculture, Bureau of Entomology and Plant Quarantine, Division of Insect Identification. Table I

Percentage of P arasitized Spittlebug Eggs in Four Locations, Wooster, Ohio. April 1952.

Total eggs Parasitized Percent Location examined eggs parasitized

1. 279 33 11.8 2. 268 43 16.1 3. 885 23 8.1 4 • 252 17 6.7

Total 1084 116 x»10.7 7 . previous year. Another parasite species, not obtained in 1951, was identified by B. D. Burks as a new species ofl Centrodora, family Eulophidae.

Effect of Temperature and Humidity on Hatching As noted above spittlebug eggs failed to hatch after exposure to low humidities. To ascertain the influence of varying humidities and temperatures during egg develop­ ment an experiment was initiated in 1951 utilizing the following treatments. (A) Eggs were collected prior to frost, and remained at room temperature throughout the experiment. (B) Eggs were collected before fro st and stored at room temperature at high humidity until December 5, 1951, when they were removed and placed in a cabinet with a temperature of 40°F. They remained at this temperature until March 10, 1952 when they were transferred to a cabinet at 60°F. and 100 percent humidity. (C) Eggs were collected November 1, 1951 and stored outside in covered dishes at 100 percent humidity. On December 8 they were brought in and remained a t room temperature for the duration of the experiment. (D) Eggs were collected November 1, 1951, stored outside in covered dishes at 100 percent humidity and on December 3 were placed in a cabinet which was held at 40°F. They were removed on March 10, 1952 and transferred to a cabinet with a temperature of 60°F. and a humidity of 100 percent. On December 3 or 5 as noted In the treatments above, all eggs were treated with sulfanilamide to prevent fungus growth, and approximately 25 were placed in each of eight vials for each treatment. Humidity was maintained in these vials utilizing sulfuric acid as a dessicatlng agent after the method of Loveless (1951). These eggs were examined at periodic intervals and the number hatched was recorded. In order that the discussion may be facilitated, the number of hatched nymphs and the dates of eclosion for all four temperature treatments are recorded in Table II, and the effect of varying humidities in Table III. The nymphs emerged In treatm ent A without the eggs being subjected to cool temperatures*. It is interesting to observe, however, th at hatching began on December 31 in Treatment C while no nymphs emerged until February 1 in A. This would indicate that the eggs hatch in a much shorter time if they are exposed to cool temperatures. Similarly in treatments B and D no difference in hatching dates can be detected. Both lots were exposed to 40°F.. temperatures until March 10, the only variable being subjection to frost early in the season. Hatching upon transfer to warm temperatures In March proceeded very rapidly. Comparison of hatching dates in C and B reveals Table II Number of Hatch*

Room temperature to Outside to December 5, 1951 December 5. 1951 Treatment A Treatment C Date Number hatched Date Number hatched eggs eggs

«0 Room Feb.4,1952 ■"5 " Dec. 21, 1951 4 Tempera­ 11 4 26 4 ture 25 o Jan. 2 6 Dec >5,1951 Mar. 3 4 21 1 to March 10,1952 8 1

Treatment B Date Number hatched Treatment D eggs Date Number hatched eggs 40°F. Mar.14,1952 1 Mar.18,1952 2 Dec >5,1951 19 1 19 1 to 29 2 21 7 Mar.10,1952 31 1 Apr 8 Apr. 2 3 7 2 3 1 4 1 7 3 8 2 1? J 10 . Table III

Number of Hatched. Eggs Under varying Humidity Treatments from December 3, 1951 to March 10, 1952, (Approximately 100 eggs per Treatment). All Eggs at 100 Percent Humidity u n til December 3, 1951 and a fte r March 10, 1952

Percent Humidity Number Hatched Percentage Eggs of all Hatched eggs.

100 55 74.3 95 7 9.5 90 5 6.8 80 4 5.4 70 0 -

50 0 - 30 3 4.0 10 0 11. that cool temperature early in development is of greater significance than it is later in the season* figgs which were subjected to cool temperatures throughout the experiment in Treatment D hatched as rapidly when they were placed at 60°F. as did those which were kept at room temperature u n til December 5 and then placed at 40° until March 10. Treatment B)* This demonstrates that cool temperatures are not detrimental to nymphal development. Treatments A and D represent direct opposites in that the eggs in A were never exposed to cool tempera­ tures while those in D were subjected to them throughout the developmental period. It may be observed that only six weeks intervened between the first hatching dates for the two treatments. This would indicate that early development takes place at low temperatures but is arrested until a prolonged period of higher ones. In summarizing, it appears that early development occurs regardless of temperatures* but proceeds more rapidly at cool ones. Apparently a stage is reached at which growth ceases or proceeds at any exceedingly slow rate at cool temperatures. Development is resumed with the advent of warm temperatures. In this instance only four days at 60op. elapsed before hatching took place.

* This discussion does not include extremes, but only those temperatures normally experienced in the latitude of Ohio from September u n til the f i r s t of November and 4Qo to 80° thereafter. 18. conversely if warm temperatures prevail throughout the season, development is completed but not so rapidly as it is if the eggs are subjected to cool temperatures early in development. Humidity as well as temperature plays an important part in hatching. Ninety-six percent of the eggs which hatched were exposed to humidities ranging from 80 to lOOfo and nearly three-fourths of the hatching occurred under saturated conditions. On February 14, 1958, eggs were collected in the field and further studies were initiated to determine whether any real difference existed betvreen 80 and 100^ humidities at varying temperatures. Two lots of eggs, both kept at 100% humidity, were prepared to ascertain whether :rainfall during the latter stages of embryonic development speeded hatching. One of these lots was placed in water for an hour before being put in vials, while the other was not. No attempt was made to place a given number of eggs in each vial, but at least three masses were exposed to each treatm ent. Temperatures proceeding from 40° to 90°F. in 10 degree increments

were tested. The percentage of hatched nymphs for each treatment and their hatching dates are presented in Table IV* Although considerable variability existed in

hatching, it appears that soaking had no effect at this Table IV Percentage of Spittlebug Eggs Hatched at Varying Temperatures at 80 and 100 Percent Humidity. Eggs at 100 Percent Humidity Immersed or Not Immersed in Water for one Hour before Being Subjected to Temperature Treatments to Determine the Effect of Rainfall on Hatching. Wooster, Ohio. 1952.

Humidity 8 Of0

Not Immersed Dates Immersed Dates Not Immersed 6i Temperature °F. Percent Percent Percent Hatched Hatched Hatched

90 0 0 0 80 0 4.5 2/25 0 70 4.0 2/25 2.7 3/6 28.2 2/25-29 60 39.1 3/7-12 73.2 2/29-3/11 29.6 3/4-14 50 0 0 0 40 0 0 0 14. stage of development. Emergence took place at both 80 and 100£ humidity with apparently equal facility. So long as a relatively hi$h humidity exists in the environ­ ment, as it does under field conditions, subjecting eggs containing well-differentiated nymphs to rainfall does not speed hatching. No eclosion occurred at temperatures above 8Q°F. and below 5Q°F., while the first hatch at 80°F. and 70° preceded that at 60° by approximately six days. It is questionable whether a difference in hatching between these temperatures actually existed or was due to variation among masses. I t may be stated that emergence in the field probably does not take place at temperatures below 60° or above o 80 . Within this range little or no difference exists in rate of hatching. The study of a series of first field hatching dates in several localities bears out the theory that temperature is the motivating factor in nymphal emergence. Although records of the hatching dates are incomplete, it is apparent that there is a definite relationship between temperatures and spittlebug eclosion. (Figure 2,pp.15-16). Considerable variation in the hatching dates of the majority of the eggs in the field occurs due to the yearly fluctuations in temperature. Weaver (unpub. data) observed in 1950 that although the first eggs hatched 15. Figure 2 Relationship of 50°-60° Mean Temperatures for March, April and May to Spittlebug Hatching Dates. State Date of First Hatch Source North Carolina Late March, 1952 Correspondence with R. L. Rabb Oregon April 11, 1933 USDA Insect Pest Survey n March 29, 1938 N II it March 17, 1941 It II it Late March Schuh and Z eller (1944) Pennsylvania Late March and Menusan (1951) (southern) early April Indiana April 7, 1952 USDA Insect pest (southern) Survey Washington April 9, 1940 11 II Ohio, Columbus April 10, 1948 App, 5. A. (unpub. data) M April 11, 1949 « tt (1 18, 1950 M II tt 20, 1951 n ti 11 16, 1952 •i ii Wooster April 19, 1949 Weaver, C. R. (unpub. data) •i 27, 1950 H II 20, 1951 t t H 16, 1952 tl II Indiana USDA Insect Pest (northern) April 17, 1952 Survey Maryland April 19, 1952 It H Pennsylvania Late April and Menusan (1951) (northern) early May New York May 19, 1927 Cecil (1930) M 8, 1928 n H It April 22, 1929 ti tt New Jersey April and May Driggers and Pepper (1935) Wisconsin May 3, 1949 Chamberlin and Medler (1950) Massachusetts May 16, 1952 USDA Insect Pest Survey Maine Early June Osborn (1916) 16.

N OAK.

MARCH

APRIL

n n tn m n

MAY

-Figure 2* cont* 17. on A pril'27, a period of reduced temperatures held off eclosion of the greater number of nymphs until May 3 when warmer weather again prevailed. Chamberlin and Medlar (1950) observed similar effects owing to alternating periods of low and high temperatures. The first hatching date may be an untrustworthy index for the eclosion of the majority of nymphs in the population.

Summary Development and hatching of spittlebug eggs is conditioned largely by temperature and humidity. The rate of development decreases or ceases entirely during protracted periods of cold temperatures but proceeds at a rapid rate after subjection to them. Under experimental conditions no hatching was observed at temperatures above 80°F. or below 50°F. It is probable that the optimum temperature for eclosion is from 60° to 80°F. Humidities of 80 tolOO percent are necessary if maximum hatching is to take place. Submersion in water before emergence has no influence if the high humidity which exists under field conditions is maintained.

Embryonic Development and Mode of Hatching Examination of a series of eggs in various stages of development reveals a number of morphological changes 18. which are readily visible through the shell. Immediately after deposition the egg is uniformly light yellow in color. Before the onset of cold weather, however an orange spot appears in the anterior portion of the egg. No additional readily visible differentiation occurs under field conditions until the egg is subjected to warm temperatures in the spring. At this time the egg takes on an orange cast and the spot, becoming light red in color, moves posteriorly, purple eye spots appear and developing body and leg segmentation may be distinguish­ ed through the shell. Shortly afterward a subtriangular, clavate, black shield appears which extends from the region of the vertex to the mouthparts. By this time the nymph is well formed with the legs folded backward under the body. Just before hatching the shield is extruded, forming an opening in the end of the shell. The nymph pushes the shield forward and down as it emerges in a series of wriggling movements. After hatching is completed, the shield may be found inside the opening of the shell. 19. ECOLOGY OF THE NYMPH

Effect of Moisture on Nymphal Development It Is probable that the greatest mortality in the life cycle occurs during the period immediately following extrusion of the shield and eclosion since the nymph may die of desstcation before becoming situated on a host plant. Emerging nymphs, under conditions of low humidity, usually dry up before they are able to extricate themselves from the shell. In the event that they are successful in this attempt a number of experiments have revealed that they die before becoming established within a spittle mass. It is probable that the froth has more significance in maintaining a high humidity around the nymph than it has in protecting against

parasites and predators, a role that is assigned to it frequently in the literature. Rosenstlel C1951) states that two or three days elapse before spittle is formed. The author has observed, however, that spittle is produced immediately after feeding begins. parks (1948) noted that excessive rainfall during May and June promoted heavy infestations. A higher survival rate might be expected under such conditions of high hum idity. Menusan (1952) has observed that good legume stands are likely to show a greater profit than poor ones if spittlebugs are controlled. It is probable that this is 20. due in part to the b etter protection from drying winds and high temperatures afforded by thick foliage and the consequent higher rate of survival of newly emerged nymphs. This concentration is substantiated by the fact that the f i r s t hosts upon which the nymphs are found in the spring are those which exhibit a lateral dense growth such as thistle, fleabane, field peppergrass, and wild parsnip, in which humidity is higher and air movement less than, it is when growth is vertical and stemmy in nature. The author has observed that large nymph populations exist on the clovers before comparable numbers appear on alfalfa. However, as the season progresses and the a lfa lfa stand grows to the point where shading is substantially increased, air movement is reduced and an increasing proportion of the late hatching nymphs survives. As a result population counts taken in alfalfa less than two weeks after the first empty egg shells are observed may be misleading. Similarly low populations in timothy may be attributed partially to the low humidity occasioned by its growth characteristics not only immediately after hatching but throughout the period of nymphal development. Osborn (1916) states that it was difficult to establish Philaenus leucophthalmus nymphs on timothy. The author has never observed large nymph populations in pure stands of timothy 2 1. Moisture relationships not only play an influential part in spittlebug survival but also in host development. Weaver and Hibbs (1952) state that nymphal feeding appeared to be less damaging during excessively wet springs. This was attributed to the fact that plant growth was so rapid

and luxuriant under these conditions that yields were not so seriously reduced as they were during dry seasons. Accordingly, studies were initiated to test this hypothesis. On April 10, 1951 clover plants were brought in from the field and two were transplanted into each of 40 glazed pots set on the ground and filled with a half sand half compost mixture. Good drainage was afforded by means of holes in the bottoms of the p o ts. Water

was added three times weekly to give the equivalent of

the following four treatments: ( 1) trace amounts sufficient

to keep the plants from permanently wilting, (2) three Inches of water per month, (3) five inches per month, and (4) seven inches per month. The pots were covered with a roof of cello-glass to shelter them from rain. Figure 3. Moisture blocks, Bouyoucos and Mick (1940, 1946), were placed in the soil in three of the ten replicates as a measure of the amount of moisture available to the plants. Fifteen eggs were plaoed in each pot on April 19 and watering was initiated on April 23. None of the nymphs which hatched from these eggs were able to become established. The addition of 30. nymph was found in the field in 1949, while Cecil (1930) observed that 51, 48, and 58 days were required for nymphal development in 1987 , 1988, and 1929 respectively in New York. A period of 43 days in 1950 and 1951, and 40 days in 1952 elapsed before the first adults emerged in northern Ohio. It is apparent that there is considerable yearly variation in nymphal longevity, which may be largely attributed to temperature differences. This variation may amount to as much as twelve days under normal field conditions.

Influence of Humidity and Temperature on Nymphal Movement I t has been popularly supposed that there- is very little nymphal movement after feeding and froth formation

are initiated. To test the validity of this supposition a number of late instar nymphs were collected and placed on clover in the greenhouse. The majority of nymphs started feeding as soon as they found suitable locations , and remained situated throughout the entire stage. One nymph travelled a distance of 30 inches before completing development. However, in fields of clover where high humidities close to the ground prevail due to dense foliage, nymphs of several different instars may be found within a single sp ittle mass and others appear to travel freely up and down the stems. The greater number

of them feed near the base of the plant. Figure 3* Equipment u tilize d in 1951 to te st the relationship of moisture and spittlebug damage to red clover* 23. nymphs, (125 in each pot) transferred from various hosts was also an unsatisfactory method for obtaining a population. Some later instar nymphs were able to succeed but numbers large enough to cause measurable damage could not be obtained. The failure of this study was attributed to the inability of the nymph to withstand the low humidities occasioned by exposure to winds. Accordingly preparations were begun to repeat this experiment in 1952. A summer seeding of timothy and alfalfa was made on July 11, 1951 in a strip 80 feet by 20 feet. One-hundred twenty pots were established with their tops at ground level in two rows of 60 each in this strip. It was believed that the alfalfa-timothy mixture growing up around the pots would attract adults in the fall so a natural infestation would be obtained for the following year. By reduction of air movement a higher level of humidity would be maintained the following spring, thus increasing nymphal survival. The pots were filled with the same mixture as was used previously since a light soil was necessary for good drainage and maximum moisture effect. The pots were seeded to oats on July 11. This crop was cut on September 21 to provide stubble for ovipositlon sites. Cumberland red clover was planted in the pots on July 24 after lime and fe rtiliz e r had been added. Adults were swept 8 4 . periodically in adjoining fields and introduced into this strip. Early in April, 1952 the clover was thinned to two plants per pot and transplants were made where the seedings had failed. All transplants were included within the same blocks of the experimental design. A shelter similar to the one used in 1951 was constructed on April 16* Inform­ ation obtained in 1951 from .the moisture blocks indicated th a t the five inch and seven inch per month levels gave

little difference in yield. Consequently the amounts of water in the 1952 experiment were reduced. The four water treatments, consisting of the equiva­ lents of (1) trace amounts, (3) two inches per month, (3) four Inches per month, and (4) six inches per month added three times weekly were begun on April 28, 1952.

The following three treatments were included to determine the stages of nymphal development at which the greatest amount of feeding took place. (A) '"hen most of the eggs had hatched CMay 5) the nymphs were killed by hand, (B) when the first nymph was observed to reach the fourth instar (May 23), a spray of one part of actual methoxychlor to 400 parts of water was applied, (C) no insecticidal treatment. The experiment was laid out in a factorial randomized block design with ten subsamples in each category. 2 5 . The first cutting was taken on June 10, 1952 after the adults had emerged. Both wet and dry weights of the individual red clover plants were recorded. Since these two measurements yielded similar results only the analysis of wet weights is recorded in Table V along with the treatment wet yields.

There was a pronounced increase in growth dq# to

higher water levels. The difference in yield which may be attributed to nymph control is also significant at the 1$£ level. The interaction term, is not significant, however, indicating that the depredations occasioned by feeding did not vary differentially under the water treatments. Examination of the actual yields discloses that the same degree of damage is sustained by the plants regardless of the water treatment above trace amounts. In each instance the loss occasioned by feeding throughout the

nymphal stage was contained within the range of 0.72 to 1.00 pounds per square yard. Vfith this in mind it is apparent that it is of more advantage to control the nymphs during dry years since a greater proportionate Increase In yield may be obtained. Nitrogen analyses of the samples were made by the standard Kjeldahl method. They disclosed that the water treatments did not alter the nitrogen content of the plants. The mean percentage of protein in the treatments 26* Table V Actual Wet Yields of First Cutting Red Clover Subjected to Spittlebug Nymph Attacks of varying Duration under D iffering Levels of Monthly R ainfall Wooster, Ohio. June 12, 1952.

Actual Wet Yields in lbs. per Sq. Yd*

Water Treatment (Inches per month) i

Spittlebug Treatment Trace 2" 4 * 6" Sum

No nymphs 0.397 2.05 2.79 3.62 1.243 Nymphs of first three Instars 0.393 1.31 2.56 3.38 1.118 Nymphs of a ll five Instars 0.368 1.06 1.79 2.90 0.943 Sum 1.158 4.42 7.14 9.90

Analysis of variance

Source of Variation S. Sq. d . f . Mean Sq. F F05 F0 1 Total 149455 119 Moisture effect 81827 3 27276 51.46 3.98 Nymph effect 5489 2 2744 5.18 4.82 Block 7287 9 810 1.52 1.97 Interaction ’ Nymptobx Moisture 2395 6 399 - Error 58457 99 530 27.

to control spittlebugs ranged from 13.66 when the nymphs were killed, immediately after hatching, to 14.10 when control was withheld until the fourth instar had been reached, and to 14.62 when no nymphs were removed. Analysis disclosed that there was no difference in protein content due to spittlebug control. This is in agreement with the findings of leaver and Hibbs (1952) who were unable to discover any differences in nitrogen content of red clover due to nymph feeding. After the above yields were taken, the shelter was

removed and the clover permitted to recover. The experiment

was sampled again on July 23 to determine whether nymphal spittlebug feeding reduced second cutting yields. The analysis of wet weights and actual wet yields are presented in Table VI• Interpretation of the data disclosed that nymphal

spittlebug control did not increase second cutting red clover yields. The apparent percentage increases are within sampling variability. The effect of watering, however, is still significant at the 1% level, although water other than rainfall was never added after the first cutting was removed.

The Effect of Temperature on Nymphal Development Temperature is not only the major factor in inducing

hatching but also influences* the duration of nymphal life. Ahmed and Davidson (1950) were able to prevent a number of 28. Table VI Actual Wet Yields of Second Cutting Red Clover After the First Cutting was Subjected to Spittlebug Nymph Attacks of Varying Duration Under Differing Levels of Monthly Rainfall Wooster, Ohio. July 23, 1952

Actual Wet Yields in Pounds per Square Yard Water Treatment (Inches per month)

Spittlebug Treatment Trace 2* 4" 6N Sum No nymphs 0.620 0.903 0.819 0.880 3.222 Nymphs of f i r s t three instars 0.484 0.653 0.875 1.08 3.092 Nymphs of a ll five instars 0.533 0.748 0.716 0.769 2.766 Sum 1.637 2.304 2.410 2.729

Analysis of Variance

Source of Variation S. Sq • d . f . Mean Sq. F F05 F01 Total 8663 119

Moisture effect 1110 3 370 5.88 3.98

Nymph effect 152 2 76 1 .2 0 Block 344 9 94 1.49 Interaction Nymphs x Moisture 330 6 55 - Error. 6227 99 63 29. fourth Instar nymphs from moulting for a period of 35 to 40 days by keeping them at a temperature of 40°F ., thus extending the length of this instar from three and one half to four times its duration under greenhouse conditions. An experiment was conducted in 1952 to determine the longevity of the nymphal stage under different tempera­ ture conditions. Several egg masses were collected in the

field and placed on chrysanthemum plants in the greenhouse. These plants were transferred* one day after the first hatch was observed, to four cabinets, the temperatures of which were 50,60, 75 and SO°F. Unfortunately the thermo­ stat in the 80° cabinet failed to operate and the nymphs,

which were developing most rapidly, died due to the high temperature. The first adult emerged at the 75° tempera­ ture in 31 days. Shortly thereafter there were numerous fluctuations in the remaining two cabinets. Nymphal development was completed in the 60° cabinet in 69 days

and 100 days elapsed before the first adult emerged at 5 0°F. Undoubtedly considerably longer periods would have been necessary if the temperature regulator had functioned * properly, particularly in the 50° cabinet since very little differentiation had taken place before the fluctuations occurred. Chamberlin and Medler (1950) reported that some adults were present in Wisconsin 45 days after the first 31. On the other hand, nymphs on alfalfa appear to be distributed along the length of the stem although the majority of them are found near the ground. P etty and White (1952) state that the young insects move up the stems seeking tender new growth as the plants grow. It is probable that this movement is also related to temperature and humidity. Early in the morning, numerous s p ittle masses may be found near the growing tips of the plants, but as the temperature rises, these masses dry up as the nymphs leave them and move down the stem . Rainfall may appear to produce this same result, which has led to a popular belief among farmers that rain washes the nymphs off the stem. Actually the spittle: is carried away and the young Insects which are extremely difficult to wash off remain in the internodes or move down the stem out of the direct path of the drops.

Nymph hosts Although the discussion has been limited largely to the relationships of the meadow spittlebug to forage crops, the nytnph has an extremely wide range of host plants. The following host list is probably not complete but it shows the ubiquitous nature of this insect. Hosts enumerated by other investigators have been included. 3 8 . N*MPH HOST LIST

Common Hama Scientific Name alfalfa £,H* Medlcage satlva L. appla 11 Malus sp. apple Z U. malus (L.) ash, green 11 Fraxlnua pennsylyanlca .var* lanceolate Borkh. aster Z A ster sp* baby's breath, perennial 11 Galium sylyaticum L*

barberry, Japanese 11 Berberls thunbergll DC*

barley 10 Hordeum satlya? (vulgare)

bedstraw, yellow 11 Galium verum L*

beet 11 Beta vulgaris L*

bent, creeping 11 Agrostls alba var. stolonlfera (L.)

bergamot 11 Monarda fIstulosa l « bermuda grass 7 Cynodon dactylon Pers. bindweed, field 11 Convulvulus aryensls L* blackberry, high 11 Rubus alleghanlensls Port*

blackberry, Millspaugh's 10 R* canadensis L* blackberry, prickly Florida 6 R. penetrans Ball. blazing star 7 Trltonla

*See authors at end of host list* 33.

NYMPH HOST LIST cont.

Common Name Scientific Name bouncing bet 10 Saponaria officinalis broccoli 7, 10 Qrassica oleracea var. botrytris L*

brome grass 11 Bromus sp .

brussels sprouts 8 Brassica oleracea var. gemmifera DC.

burdock, common 11 Arctium minus sp . buttercup 1,2,4 Ranunculus sp.

buttercup, tall 2 R. acris L.

butterfly bush 11 Buddelia sp.

calendula 11 Calendula sp. cape gooseberry 6 Physalis peruviana L»

carnation, perennial 11 Dianthus sp. carrot, cultivated 2,7 Daucus carota L.

carrot, wild 11

catchfly, night blooming 11 Silene noctiflora L*

catnip 11 Nepeta cataria L» cat’s ear, long rooted 7 Hypochoeris radicata ]

celery 6,11 Celeri graveolens (L* centaury 7 Centaurium umbellatum

cherry, sour 2 Frunus cerasus L.

cherry, wild 2 P. avium L»

cherry, wild black 1 ,2 Fadus virginiana CL.) 34. NYMPH HOST LIST cont.

Common Name Scientific Name chickory 10 Clchorium Int.ybus L» chickweed, common 11 Alslne media L* chickweed, mouse war 11 Cerastlum vulgatum L* chrysanthemum 8,11 Chrysanthemum sp. cleavers, common 9 Galium aparlne L* clover 1,2 Trlfollum sp. clover, alslke 11 T. hybrldum L. clover, ladlno 11 T* repens L* clover, low hop 7 T. procumbens L. clover, mammoth 11 T. medium L. clover, red 11 . T. pratense L. clover, white sweet 11 Melllotus alba Desr. clover, yellow sweet 11 M* officinalis (L.) clover, toothed bur 7 Medlcago hlsplda Gaertn. clover, white Dutch 4,11 Trlfolium repens L» columbine 11 Aqullegia canadensis L» coprosma 7 Coprosma ernodeoides var typica coprosma 6 C. rhyncocarpa Gray corn 11 Zea mays L* crabgrass 7 Dlgltarla prurlens crane's bill, Carolina 6 Geranium carollnlanum var. australe Benth cudweed, purplish 7 Gnaphallum purpureum L. cup and saucer 11 Campanula medium var. calycanthema Hort. 3 5 , NYMPH HOST LIST con t

Common Name Scientific Name cyperus 7 Cyperus brevifoils dahlia 7 Dahlia sp. daisy 1,4 prob. Chrysanthemum leucanthemum L«

dandelion* common 11 Taraxacum officinale Web. day l i l y 11 Hemerocallls fulva L. dock, broad leaf 11 Rumex obtuslfollus L* dock, orange 1 prob. R. crlspus L. dock, yellow 11 R. crlspus L» dragonhead 11 Dracephalum parVtflorum Nutt. eld er 8 Sambucus sp. e ld e r, common 11 S. canadensis L. evening primrose, common 11 Oenthera biennis L* evening primrose 6 0. odorata Jacq. evening primrose 7 0 . s t r i a t a fig marigold 6 Meserobryanthemum sp. fleabane, Philadelphia llJErlgeron phlladelphlcus L< fleabane, white top 11 E* annus (L.) E . albidusfleabane 7 E. albidusfleabane five finger, common 11 Potentllla canadensis L* forget-me-not 7 Myosotls azorlca Wats. fu ch sia 8 Fuchsia arborescens Sims• fuchsia 6 F. magellanlca Lamb. 3 6 .

NYMPH HOST LIST con t.

Common Name Scientific Name garland flower 8 Hedychlum coronarlurn Koenig garlic, wild 10 Allium vineale L. geranium, rose 8 Pelargonium graveolens LHer german ivy 7 Seneclo mlkanloides Otto glory bush 7 Tlbouchlna semldecandra Cogn. goldenrod 2,10 Solidago sp. goldenrod, Canada 11 S. canadensis L. goldenrod, tall 7 3. altlssima L» gold flower 7 Hypericum moserlanum Andre ground ivy 11 Olecoma hederacea L. hawkweed, orange 4, 11 Hleracium aurantiacum L. henblt, common 11 Lam1urn amplexlcaule L. hickory, shagbark 11 Hlcoria ovata (Mill) holly 7 Ilex anomala hollyhock 11 Althaea rosa Cav. honeysuckle 10 Lqnlcera sp. honeysuckle, Japanese 8 L. .japonlca Thunb. horsetail, field 11 Equlsetum arvense L. hydrangea 10 Hydrangea sp. i r i s 10 Irld ls sp. ironweed 8 Slderoxylon sp. ironweed 0 Carplnus sp. 37. NYMPH HOST LIST co n t.

Common Name Scientific Name Job's tears 7 Coix lacrvma-Jobl L. kidney leaf crowfoot 11 Ranunculus abortlvus L* kokio 8 Kokla rockll Rock* lamb's quarter 11 Chenopodium album L. lettuce, garden 7 Lactuca satlva L* lettuce, prickly 11 Lactuca vlrosa L* lilac 2,10,11 SyrInga vulgaris l . loosestrife 7 Lythrum marltimum mahoe 7 Hibiscus tlllaceus L* maile 8 Gynopogon olivaeformls saff. mallow, bristly fruited 7 Modiola carollnlana (L.) maple 11 Acer sp. mint 6,11 Mentha sp. morning glory 10 Ipomoea sp. morning glory 8 I. congesta mugwort 7,9 Artemisia vulgaris L» mullein 11 Verbascum sp. mustard, tall hedge 11 Norta altlsslma (L*) nasturtium 8 Tropaeolum sp. nettle 11 Urtlca sp. nettle 8 Plpturus sp. oats 11 Avena satlva L.

ohelo 8 Vacclnlum retlculatum Hilleb.

onion 11 Allium oepa L* 38. NYMPH HOST LIST con t.

Common Name Scientific Name orchardgrass 7,10,11 DactylIs glomerata L* palm, dracena 7 Cordyline termlnalls Kunth. pansy, garden 11 Viola tricolor L* paragrass 7 Panlcum purpurascens parsley 6,11 Petrosellnum hortense Hoff. parsnip, cultivated 7 pastlnaca satlva L. parsnip, wild 11 H pea, garden 2,10 Pisum sativum L. peach 11 Amygdalus perslca L. peppergrass, field 11 Lepldlum campestre (L.) peppergrass, Virginia 11L. virginlcum L* periwinkle 7 Vinca sp. phlox 11 Phlox sp. pimpernel, scarlet 7 Anagallls arvensis L* pink, rainbow 7 D1anthus chlnensls L. plantain, common 11 Plantago major L. plantain, narrow- leaf 4,7,11 P. lanceolate L* plantain-leaf everlasting 11 Antennarla plantaglnlfolla (L.) plum 1,2 prunus sp. plum 11 P. domestlca L. 3 9 . NYMPH HOST LIST co n t.

Common Name Scientific Name poison ivy 10 Rhus toxicodendron L. poppy 10 Papaver sp. poppy, oriental 11 P. orientals L» primrose 1,8 Primula sp. privet 10 Llqustrum sp. privet 11 L. vulgare L* quackgrass 11 Agropyron repens (L.) quince, flowering 11 Chaenomeles sp. ragweed 11 Ambrosia sp. ragweed, fine cut 10 A. elatlor L* railliardia 7 Railliardia scabra raspberry, black 10 Rubus occidentals L. redtop 10 Agrostis alba L. rhubarb 7,11 Rheum rhapontlcum L. rose £,8,11 Rosa sp. rose, baby rambler 5 R. polyantha Hort. rose, China 10 R. chlnensls Jacq. rose, hybrid tea Rosa (hybrid) rosemary 9 Rossmarlnus officinalis L. ryegrass, perennial 11 Lolium perenne L* ryegrass, Italian 10 L. multlflorum Lam. 40. NYMPH HOST LIST cont.

Common Name Scientific Name saceiolepis 7 Saceiolepis contracts salvia 11 Salvia sp. sesuvium 8 Sesuvium portulacastrum L. Shasta daisy 6 Chrysanthemum maximum Ham* shepherd's purse 11 Bursa bursa-pastorls (L.) shrubby fleabane 7 Pluchea odorata CL.) snowberry 0 Symphoricarpos sp. sorrel, wood 10 Oxalis sp. sorrel, lady's 8 0* corniculata L* sorrel, sheep 7,10,11 Rumex acetosella L* sowthistle, common 7 Sonchus oleraceus L- Spanish needle 7 Bidens pilosa var. minor CBIO speedwell, purslane 11 Veronica peregrins L* speedwell 7 V. plebeia speedwell 7 Hebe sallcifolia spiderwort 7 Commelina diffusa spinach 11 Spinacia oleracea L* spiny bur 8 Acanthospermum australe (Loefl.) spirea 2,10 Spirea sp*

spring beauty 11 Claytonia virginica L. strawberry 2,6,11 Fragarla sp. strawberry 8 F. chiloansis Duch. 41. ITOffH HOST LIST cont

Common Name Scientific Name styphella 8 Styphella tamelamelae sumac 11 Rhus sp. sumac, smooth 10 R. glabra L« sunflower 1,8,10 He11anthus sp. sweet marjoram 9 Orlgana ma.jorana var. hortensls Moench. sweet pea 11 Lathyrus odoratus L. sweet potato 7 Ipomoea batatas Poir. swiss chard 8 Beta vulgaris yar. clcla Moq. sycamore 11 Platanus occldentatis L* tarragon 11 Artemisia dracunculus L. teasle, wild 11 Dlpsacus sylvestrls Huds. thistle 1 Clrslum sp. thistle, bull 11 C. lanceolatum (L.) thistle, Canada 8,11 C. arvense (L.) timothy 1*11 Phleum pratense L* tomato 8 Lycoperslcon lycoperslcon (L.) trefoil, birdsfoot 11 Lotus cornlculatus L* velvetgrass, common 7 Holcus lanatus L. yeryaln 7 Verbena lltoralls yetch, common 10 Vicla satlva L. 4 2 .

NYMPH HOST LIST c o n t.

Common Name Scientific Name weigalia 0,10 Weigalia ap. wheat 10,11 Trltlcum aestlvum L* wikstroemia 7 Wlkstroemla phlllyreaefolla willow 3 Sallx sp. wintercrass, yellow 10rll Barbarea barbarea (L.) wintercresa, early 10 B. verna (M ill.) yarrow 1,2,11 Achillea millefolium L»

* 0 . Lioent (1912) 1. Osborn (1916) 2. Cecil (1930) 3. Schimitschak (1937) 4. Wolcott (1937) 5. Doering (1942) 6. Krause (1945) 7. Davis and M itchell (1946) 8 . Davis and M itchell (1947) 9. DeLong and Severin (1950) 10. T aller (1951) 11. Ohio hosts 4 3 .

Number of Nymphal In stars Establishment of the number of Instars through which the nymphs pass has presented something of a problem* Five instars were recorded by Cecil (1930) and his work was corroborated by Mundlnger (1946), Teller (1951) and Weaver (unpublished data). Ahmed (1949) describes only four Instars. In order to clarify this point, 50 nymphs were collected every other day beginning one week subsequent to the first hatch in 1952 and terminating eight days after the first adult was observed in the field. The specimens were preserved in KAAD solution (Peterson 1947) and head capsule widths were recorded and compared with the measurements obtained by previous investigators. The results of this study are set forth in Figure 4* This graph indicates that there are five nymphal in sta rs. Comparison of measurements obtained correspond very closely with those of earlier workers. Table VII. iue » ubr f ypa isas s eemnd y ed asl measurements- capsule head by determined as instars nymphal Number of 4» Figure

F RE QUENCY 40 0 6 SC 3 0 O 0 155 105 SO 50 23 IS SCN TID FOURTH THIRD SECOND FIRST AS N MM. IN T N E M E R SU EA M ■j-rTT FIFTH Table VII

Comparison of Nymph Head Capsule Measurements Obtained by Various Investigators

Measurements of Head Capsules

Source HeadHeaa Capsules cant "ifrat&r Measured

Ahmed 453 Mean Width 0*35 0,67 0.895 1.76 Teller 105 Mean Width 0.48 0.64 0.91 1.34 1.97 Range 0.37-0.46 0.58-0.68 080-0.99 1.27-1.43 1.68-2.80 leaver 122 MeanWidth 0.40 0.67 0.947 1.39 1.99 Range 0.31-0.50 0.59-0.78 0.84-01.01 1.28-1.50 1.80-2.37 King 1150 MeanWidth 0.396 0.636 0.890 1.31 1.88 Range 0.23-0.50 0.51-0.80 0.81-1.05 1.07-1.53 1.56-2.13 46. ECOLOGY OF THE ADULT

Estimation of Adult Populations The accumulation of su fficien t amounts of data to obtain reliable information for such a study as this necessitates

(1) a large number of samples and ( 2) a rapid method of

acquiring them. In 1951 and 1958 a to tal of 148 areas were sampled weekly in the period during which they contained measurable popula­ tions. Records were kept of the condition of each field or fencerow and these were correlated with the number of adults collected.

A 15 inch sweep net of the type described by Dambach (1939) with modifications was utilized to satisfy the second requirement. A given number of sweeps was taken for each sample. This figure depended on the number of adults collected* Although the use of the sweep net as a means of measuring quantitative insect populations has been criticized (DeLong 1932 and Beall 1935), re liab le re su lts have been obtained. This is evidenced by correlating nymph counts with those acquired by sweeping adults immediately after emergence( and by comparing weekly counts in given ecological situations. To conserve space typical or composite populations have been utilized In the following pages for illustration of particular points. Early Summer Behavior

Emergence of the adults from the nymphal skins is accom- 4 7 . plished within the spittle mass in most instances as noted by Ashley (1919). Completely enclosed chambers of froth surround the insects during the last moult* These chambers are spherical and viscous, with the bubbles in the froth larg er than they appear, e a r lie r in the nymphal stage. Examination reveals the lig h t green adults which emerge from the mass and eventually take on th e ir c h a ra c te ristic color patterns. Great numbers of them may be seen clinging to timothy, clover and alfalfa stems as well as those of many weeds in the fields in which they emerge for a period ranging to two weeks depending on management and weather conditions*

Early Dissemination During this immediate post emergence period there is a gradual diminution of the population brought about by random movement out of the field. This tapering off persists for the remainder of the season in isolated uncut meadows. Figure 5A. Harvesting of the first hay crop and the consequent absence of succulent growth instigates a more abrupt decline in population due to the lack of feeding material. Figure 5B. In many Instances management of adjacent fie ld s influences this rapid decrease in numbers. If all the meadows in the immediate area are cut within a short space of time, as occurs frequently under strip cropping conditions, it appears that populations diminish more slowly* This may be attributed to Figure 5* E ffect of f i r s t cu ttin g management of forage forage of management g ttin cu t s r i f of ffect E 5* Figure

ADULTS PER SW EEP 40 20 20 10 O rp o aut pite migration* g u ittleb sp adult on crops ES TER MAUAIN P S T N A PL F O ATURATION M R E FT A EEKS W CUT A-FIRST CUTTING NOT B-FIR8T CUTTING REMOVED C-FIR8T CUTTING REMOVED- ISOLATEO REMOVED STRIP CROPPED 2 9 4 9 . the fact that the absence of feeding sites initiates random movements of the adults out of a given hay field into others which have also been cut. As a consequence samples taken in these fields appear inordinately large in view of the condition of the crop* Figure 5c*

Influence of rind on Movement Wind exerts a pronounced effect on the direction of population movement* The amount of th is influence was d eter­ mined by wrapping a series of seven six-inch tanglefoot bands around a pole 19 feet high* Counts were taken every other day and wind d irectio n was correlated with the number of adults caught throughout the season. Analysis revealed a correlation coefficient of 0.870 with 0.549 required for significance at one percent* This relationship persisted independent of the condition of adjacent meadows* Larger counts were obtained when these fields were cut, but wind direction overshadowed effects due to the direction of the

fields in relation to the pole. The greatest numbers of adults were collected on the south and west sides as indicated below, prevailing winds at Wooster, Ohio are from the southwest* North 24% East 16% South 26% West 34# Information on the altitude at which adults fly was also 5 0 * obtained* The heights at which the tanglefoot bands were placed and the percentages of adults collected at each altitude for the entire season are noted in the following ta b le • Distance above Percent adults ground in fe et collected 0.5 36 2.0 32 4.0 17 7.5 6 11.0 3 15.0 3 19.0 4 Although most of the spittlebugs were trapped near the ground, a number of them flew at the 19 foot level. Notwith­ standing that they are generally considered sluggish insects incapable of extended flight, it is probable that they are borne by the wind to even higher levels. The dissemination of the adults from the meadows initiates a concomitant increase in populations in other croplands. The duration of the adults' stay in the new areas is conditioned largely by the availability of succulent host plants. Large numbers of the insects appear on corn, oats, wheat and numerous other plants. To acquire some information on the variety of hosts upon which feeding takes place, the following experiment was under­ taken. Plants were selected and placed in vials containing a solution of radioactive phosphorus. The vials were plugged with cotton and placed in cages with adult spittlebugs for a 5 1 '. period of 24 hours. At the end of this period the Insects were removed and checked for radioactivity in a decimal scaler. In some instances dissections were made and the alimentary canal or blood was tested to verify the internal location of the material. Radioactivity beyond normal background counts was found in adults placed over all the plants tested. These Included peach terminal?,corn, oats, wheat, alfalfa and chrysanthemums. It is probable that the adults have a host list as extensive as that of the nymphs.

Migration to New Hosts in the Field Corn-Appearance of the insects on corn is influenced by the management of the meadows in the vicinity. Immediately after the hay is harvested large populations of adults may be found on the leaves and in the whorls of the corn plants. They disperse under normal conditions within two or three days although a few of them remain for some time. Parks (1943) states that the young plants may be seriously injured during th is period. Weaver (1951 b ), notes however, that damage by the adults to field crops has not been demonstrated. A cage test was conducted in 1952 to determine the extent of injury occasioned by this feeding. On June 16 ten cages 3x3x3 feet were placed over separate hills of corn contain­ ing three plants each. One hundred adult spittlebugs were placed in each of five of these cages on each of the following 5 2 . three dates, June 16, June 19, and June 34 while the other five remained uninfested. The cages were removed on June 25 and a l l of the plants were subjected to a natural in festatio n for the rest of the season. The corn was harvested on October 13 and results indicated that there was no difference in yield between the two treatments. Table VIIIA. This indicates that exceedingly high populations had little influence during the period of normal infestation immediately a f te r the hay is cu t. It was noted above that most of the insects utilize corn plants as temporary hosts, leaving the plants within two or three days* Figure 6A shows the decline in numbers throughout the season in corn as determined by counting the number of adults per h i l l . Additional cutting of hay crops has little or no influence on populations in corn. It is probable that the decrease in succulence of the corn as it matures and the lower concentra­ tion of adults later in the season are responsible for this lack of buildup. Qata-Mlgratlon to oats also takes place when meadows are harvested. Large numbers of adults may be found on the stems and at the base of the heads. Cage tests similar to those undertaken on corn were set up on oats on June 25, 1952 to ascertain the extent of injury 53. Table V III Analysis of Effect of Adult Spittlebug Feeding on Yields of Corn, Oats and Alfalfa in Replicated Cage Tests Conducted a t Wooster, Ohio* 1952.

Weight in grams per hill Spittlebugs No spittlebugs 680 680 624 680 624 567 539 709 907 680 X- 663 x=” ETb- t= 0.118 df = 8 P= 50% A* Corn Weight in grams per square yard Spittlebugs No spittlebugs 126 149 170 2 0 0 147 153 185 176 149 181 xm 155 x= 172 t= 1.28 d f = 8 P- 20-30% B» Oats Weight in grams per square yard Spittlebugs No spittlebugs 476 536 488 518 422 538 454 540 572 468 x— 482 *« 520 t* 1.36 d f- 8 P* 20-30% C. A lfa lfa 5 4 .

A-CORN

(A - j

i * §s

£ B-OATS & CO UJ 5 8 s O

C-WHEAT

«§ « Jtl

D-BLUEGRASS PASTURE

WEEKS AFTER FIRST CUTTING OF HAY

Figure 6. Seasonal adult spittlebug populations on corn* oats, wheat and bluegrass pastures. 5&. sustained by the p lan ts. One hundred adults were placed at this time in each of the five cages. Two hundred fifty adults were added on June 27 and again on July 1. populations under field conditions have never been observed by the author to exceed one adult per stem and then only for a period of less than one week. However, i t was deemed advisable to exceed normal levels for this preliminary study. The infestation in the cages was equivalent to approximately five per stem for seven days.

The cages were removed on July 8 , and the crop was harvested ten days later. The grain was threshed and the yields obtained are presented in Table VIIIB. The analysis indicates that there is no difference between yields in the treatments. Apparently numbers of adults which feed on oat* under field conditions have little influence on yields. Sweep samples taken in oats have disclosed that populations decline until the grain is harvested, probably due to the reduction in succulence. There is a slight increase in counts when the wheat is cut but the effect is only temporary and is conditioned by the physical location and cutting date of the particular wheat fields. Figure 6B. Similar effects may be noted in corn but in either case the sampling must be performed within a period of one or two days if this influx is to be observed* Wheat-populations in wheat normally decrease much more 56, rapidly than In oats since the decline in succulence occurs earlier in the season* For a brief time after the first cutting hay is removed the crop supports large numbers of adults. Figure 6C* The observation of this buildup by farmers has led many of them to believe that adult feeding is responsible for shrunken kernels which occur at the base of the head* This is a v arietal character, however, and has no relationship to the feeding of spittlebugs. Pastures-Bluegrass pastures are hosts to adults migrating from the fields in which they emerged for only a brief interval. Under management commonly practiced in Ohio, bluegrass is pastured during the spring months and is usually grazed by the middle of June to the point where l i t t l e new growth is observed* The absence of succulent growth at this time and throughout the season, since dry weather slows recovery and reduced moisture content until September, renders it an undesirable permanent host. Figure 6D» Although in itia l populations in legume pastures which are continuously grazed are higher than in bluegrass, populations decline in a similar manner. Rotational grazing systems in which several small plots are intermittently grazed and permitted to recover, afford the adults a greater selection of feeding sites. Contrasting the results of summing collections from six half-acre fields of alfalfa in such a system with a compar­ able three acre field which was being continuously grazed 5 7 * revealed the information in Figure 7. It would appear that early in the spring the more intense grazing in the smaller rotational plots caused the adults to leave shortly after emergence• By random dissem ination many of them came to and remained in the comparatively desirable continuously grazed field thus Increasing the number already present. However as th is fie ld became less attractive, new growth was appearing in the pastured rotation plots and consequent population buildups took place. Later in the season the greater succulence of the recovering crops in the rotational plots maintained a higher population than the hardened growth in the continusouly grazed fie ld . The population fluctuations within this rotational system are of in te r e s t. Each p lo t was grazed for one week, clipped and permitted to recover for five weeks before pasturing it again. Consequently the plants in all six plots were in different stages of growth. The results of sweeps taken weekly, disclosing the relationship of succulence and growth to adult spittlebug infestations, are presented in Figure 8 . Tracing the popula­ tion in any particular plot points out (1) the gradual increase in adults collected as the plants recover before grazing, (2) the decline following grazing, and (3) a sharp Figure

ADULTS PER SWEEP * oprsn f dl s tlbug ppltos In populations g u ittleb sp adult of Comparison 7* 1 “ I Or a lfa lfa fie ld s under continuous and ro tatio n al al n tatio ro and continuous under s systems. ld fie grazing lfa lfa a W E E K SA F T E RI N I T I A T I O NO FG R A Z I N G 58. CONTINUOUS — — — — onal a n io t a t o r Figure 8* Figure < »- (A . a K a 3 io u I - SWEEP 20 0 3 20 a s eover» v reco ts lan p fc o r atonal rzn sses f fal a lf a lf a of systems grazing l a n tio ta ro of ffect E follow ing cu ttin g and the increase as the the as populations increase the in the and decline throughout g ttin the cu behavior g ing g u icatin d follow in ittleb sp season lt u ad on WEEKS LT I PLOT PLOT 3 L T 5 PLOT fl£ t-

Migration into Second Growth Meadows As the forage crops recover from the first cutting there is a gradual increase in the numbers of adult spittlebugs u n til the second crop matures, is h a rv ested or is pastured. If the field is permitted to m ature fo r seed production there is a decline similar to that which occurred when the first cutting was not removed. This gradual tapering off persists throughout the season as growth slackens and the plants mature. Figure 9A. Another type of management involves harvesting the first cutting hay crop and pasturing the second. Figure 9B illu s tra te s the decrease in numbers which may be a ttrib u te d to the reduction in succulent fo lia g e due to g ra zin g . When the second hay is cut the build-up is terminated as soon as the field is harvested, precisely as occurred when the first cutting was removed. Figure 9C. Frequently when the crop is recovering from the initial harvest it supports excessively large numbers of adults. This may be due to the migration caused by cutting adjacent fields. Several observers have contended that feeding damage is Figure 9. E ffect of second cutting management of. forage forage of. management cutting second of ffect E 9. Figure

ADULTS PER SWEEP rp o aut pite igration. m g u ittleb sp adult on crops 30 0 3 6 2 O WEEKS AFTER MATURATION PLANTS OF A -S E C O N D C U TTIN G NOT NOT G TTIN U C D N O C E -S A SECOND CUTI ZED A R G G TTIN U C D N O C E -S B SCOND C TNG REMOVED G TTIN CU D N O SEC - C E ED V O REM 63V sustained by the growing plants under large adult infestations. Fisher and Allen (1946a and 1946b) in both field and cage teats have described the results of adult spittlebug attacks on alfalfa. The damage resembled alfalfa yellows in that dwarfing, rosetting, and blossom blasting occurred but there was no general discoloration. Small brown dead spots were noted on the leaves but the foliage retained its normal color or became a slightly darker green. Bissell (1952) reports that he has observed an example of adult spittlebug damage to alfalfa recovering from the first cutting. The alfalfa was cut May 26 and an adjoining clover field was harvested June 4. Adult sp ittleb u g s swarmed from the clover into the first 25 feet of new alfalfa and severely stunted it and turned it yellow. By June 27 there was some new growth on the Infested strip but it differed greatly in quality and height from the remaining portion of the field. Scholl and Medler (1947) have observed damage done by adults to alfalfa seed crops. They state that injury results in lower yields resulting from puncturing of pods and green seeds. Marshall and Gyrisco (1951) state that damage done by the adults is not so great as that occasioned by the nymphs, ho comparison of injury is given, however. Gage tests similar to those performed on corn and oats were se t up to determine the extent of damage sustained by recovering alfalfa. The equivalent of 1.5 adults per stem was placed over eight to twelve inch plants in five cages for ten days. This is a heavy infestation in Ohio since populations normally range up to 0*75 per stem on second cutting alfalfa plants at this stage of development. No difference in color or growth characteristics were apparent upon harvesting. Yields were taken and analyzed with the results set forth in Table VIIIC. No significant difference in yield was obtained. Apparently adult spittlebug damage to second cutting alfalfa is negligible under normal conditions. Similar results were obtained when this experiment was repeated using 0.30 adults per stem. Extremely large concentrations of adults,as observed by Bissell (1952), may be responsible for some injury to forage and seed crops. Treatments with insecticides to prevent this possible damage have been attempted by various workers. Wilson (1949) and Gyrisco and Marshall (1950) applied insecticides to control adults in July. Immediate control was satisfactory but popula­ tions increased with the decline in residual effect. The results of a similar experiment performed on birdfoot trefoil in 1951 are presented in Figure 10, and indicate the rapidity of reinfestation. The population reached its prespray level in three weeks. Thus It is apparent that post emergence and midsummer treatm ents would be in effectiv e due to the nomadic existence of the Insects during this period. iue 0 Rcvr o aut pite ouain in populations g u ittleb sp adult of Recovery 10* Figure

JULY 18 ADULTS PER SWEEP bird sfo o t tr e f o il meadow following in secticid e e secticid in meadow following July. il in o f e ent tr treatm t o sfo bird 65* SPRAY 25 &6 •

OVIPOSITION Initiation of Egg Development Considerable disagreement exists in regard to the time at which oviposltion commences* Mundinger (1946) states that egg-laying begins in July and is most intensive during September and October* Osborn (1916) and Weaver (1951b) note that they were unable to find well developed eggs in dissected females until August. Weaver further states that practical control of the nymphs in the spring can be gained by means of fall insecticide treatments which kill the adults before egg deposition takes place* Such treatments must be applied during the first week in September in Ohio if good control is to be obtained. Thus it is apparent that the greater number of eggs which survive must be deposited after this time. A study was initiated in 1951 to determine the factors influencing the initiation of egg formation in the females. On July 3 adults were collected in the field and subjected to a shortened day length of 13 hours which occurs normally in early September. Red clover was provided for a host plant. Females were removed and dissected at periodic Intervals until July 23 at which time the experiment was terminated due to the mortality caused by excessively high temperatures. No well-developed eggs were! found in any of the dissections. 67-. A similar test was conducted to ascertain the effect of reduced temperature on egg development. On July 3, a number of adults were exposed to a temperature of 5Q°F. and a day length of 13 hours. The temperature was raised to 65°F. on July £3, and to 70° on August 7. Periodic dissections until August £3 disclosed that no egg formation had taken place. This experiment was expanded in 195£ to determine the influence of reduced light and temperature. Approximately 1000 adults were introduced into each of three rooms on July 15. The temperature in a ll rooms was 70°F. and the day length 16 hours. Red clover and chrysanthemums were placed in each of the rooms for food. From July ££ to 30 the temperature reduced by five degree increments to 50°F* in one room, the light was decreased a half hour each day to 13 hours in another* and both light and temperature were reduced by the same increments in the third. No egg development had occurred by August 13 at which time the test was terminated. Dissections of field collected specimens revealed occasional females with well formed eggs, if changes in day length and temperature have a p art in in itia tin g egg formations, then their effects are more subtle than was possible to detect in this study.

Duration of Ovlposition Period The following experiment was undertaken to establish the period of most Intensive ovlposition. Fifty adult 68# spittlebugs were placed in each of four 3x3x3 foot cages* Four flats of chrysanthemums were provided for food in each cage and straw was supplied for ovipositlon s ite s . The adults were collected in the fie ld and placed in the cages on August 27, 1952. The cages were removed p erio d ically and counts of the eggs were made. The females in the f i r s t cage, which was removed on September 11, had deposited 204 eggs. On September 25, a total of 498 eggs was obtained, and 1033 eggs were counted in the cage removed on October 9. The latter figure is an average of approximately 41 eggs per female. This is in agreement with Mundinger (1946), who states that the females deposit from 18 to 51 eggs. Unfortunately many of the adults In the fourth cage died and only 315 eggs were obtained when i t was removed on October 23. I t becomes apparent th at the greater number of eggs is deposited in the period between the middle of September and the second week in October. Few eggs are deposited after this time since populations decline rapidly with the onset of cool weather. Concomitant with this decrease in population there is a change in the ratio of males to females as reported by CCcil (1930). His statement that the males died more rapidly in the fall in cage tests was verified in 1951 and 1952 by sweeping adults in the fall and ascertaining the proportion 6 9. "of males to females. Numbers obtained were compared with nymph and adult collections made during the spring and

3ummer. Table IX* Sex determinations in the nymphs were based on the morphological variations described by Kershaw and Muir (1922). Analysis of these counts revealed that the one to one ratio of males to females, which prevailed during the spring and summer, became in cre asin g ly unbalanced in October of 1951 and in September and October 1952. The proportion of males declined indicating that the females live longer in the f a l l .

LATE SUMMER BEHAVIOR Influence of C u ltu ral Managment on Late Summer Movements. It was illustrated in the above discussion that egg deposition is initiated after the first week in September and continues through October in Ohio. It is interesting to observe the movements of adult populations preceding and during this period and to correlate these movements with the condition of meadows of varying ages. Red clover has been the major forage crop in Ohio for a number of years. Typically it is managed under a two cutting system with the second cutting being removed in early August or grazed. The attractiveness of clover meadows as feeding sites for adult spittlebugs usually declines under this type 70* Table IX

The Numbers of Male and Female S pittlebugs Collected in Sweeps During the Summer and Fall. 1951, 1958.

1951 1952 Females Males Females Males June 9, 11 (nymphs) 63 72

June adults 853 878 57 68 Ju ly 150 133 150 169

August 816 805 112 95 September 137 145 1150 936** October 309 250# 35£ 195-*-*

# Differ from 1:1 ratio at the 5# level of significance. *» Differ from 1:1 ratio at the 1# level of significance. II* of late summer management. Very little migration into these fields occurs since the plants grow slowly due to dry conditions during August. In addition the stand of red clover is so reduced by this time that it is not considered satisfactory forage for the following year. In some instances, however, the stand is only slightly impaired by removal of the second cutting and populations of adults increase with the growth of the clover. Results of sweeps taken in meadows under these two conditions are set forth in Figure 11A. Grazing the second cutting initiating population declines since the reduction in foliage and consequently feeding sites, is similar to that which occurs when the crop is harvested. Figure 11B. Corn and weeds in wastelands and fencerows are also less desirable under normal conditions due to their advanced stage of maturity in late summer. Oat fields have been harvested and the land plowed for wheat planting. However, alfalfa and in some cases trefoil does not decline in succulence during the period immediately before oviposition. Alfalfa is capable of growth under dry conditions and the lateral growth characteristics of trefoil prevent its being grazed beyond recovery. The former crop is managed under both, two and three cutting systems. After the second cutting is removed, there is an influx of adults into the field as.the crop recovers* If the field is harvested only 78*

20 RECOVERY GOOD POOR to o A-RED CLOVER- M cond cutting removed

a s r oL B-RED CLOVER- tecond cutting grazed

LO O C-ALFALFA- two cutting* removed

OC lit Q. O-ALFALFA-three cuttings removed 1 0

40 o <

20

E-NEW SEEDING 013 e-20 e-27 9-3 19-tO 0 1 7 B i l i l i

Figure 1 1* Populations of adult spittlebugs in old meadows in varying condition and in new seedings preceding and during the oviposition period*

o 7 3 * twice during the season, a high population persists Into the fall. Figure 11C. Removal of the third cutting early In September causes the adults to disperse. Figure 11D. A more notable exception to this dedrease in available feeding sites occurs in new meadow seedings. It is common practice in Ohio to clip wheat stubble in July or early August after the crop is harvested. This is of distinct advantage to the new seeding underneath since weed competition is considerably reduced. As a consequence the p la n ts become well established by late August or early September. Since they offer attractive foliage they support an increasing population of adult spittlebugs. Figure HE* These insects, leaving less desirable areas, arrive by random movements and remain in the fields. This population build up in new meadows reaches a peak during late August and early September Immediately preceding the ovlposition p e rio d . It was noted that stubble is usually clipped shortly after the grain crop is harvested* The results of sweeps taken in a test comparing populations under this management with those in fields where the operation was not performed as presented in Figure IS. During August the best available feeding sites were located in the unclipped areas due to the growth of ragweed and foxtail. As these plants flowered and Figure Figure

1 ADULTS PER SWEEP 0 2 &.~ Comparison of adult sp ittleb u g populations in in populations g u ittleb sp adult of Comparison &.~ clipped and unclipped new seedings during during seedings new unclipped and clipped h oloiin ei . d perio ovlposition the 74. 9-5 D E P P I L C N U — CLIPPEO O E P P I L C — 9-18 ■ - 7 5 . went to seed they became lees attractive and the adults moved Into the better stand of legumes in the clipped portions just as ovlposition began* Another type of new seeding management involves planting legumes in early August in clean cultivated land. Little growth takes place before September and consequently the plants are not attractive to adult spittlebugs. Nymph populations the following spring are exceedingly small under these conditions.

Summary The period of ovlposition in Ohio begins in early September and extends through October as the population of adults declines. Under usual cultural management in the state the second cutting hay crop in old meadows is removed in August and the plants have not recovered by the first week in September. Consequently they are not attractive feeding sites for the adults. New seedings afford the most succul­ ent foliage at the outset of the ovlposition period and large population build ups take place in them. Figure 11.

FALL BEHAVIOR During the latter part of August and early September th?re is a gradual decline: in adult migration. It is this lessening of activity which forms the basis for the fall insecticide control developed by Weaver (1951a and 1953). T&m Control Is effective due to the fact that meadow manage­ ment in Ohio is usually culminated after the second cutting hay crop is removed* without interference from the farmer the adults tend to remain in the areas into which they moved before the ovlposition period began* A study was undertaken in 1951 to determine whether migration could be Induced in September by clipping new seedings* It was believed that this would reduce population size and conse­ quently egg deposition in a given field* One experiment consisted of a replicated series of four such treatments: (1) clipped on August 17, (2) on August 28, (3) on September 5 and (4) not clipped* Periodic sweep samples were taken in the fall and nymph counts were made the following spring* In each instance the sweeps revealed that populations declined immediately after clipping. However, they returned to their former levels within two weeks due to the small plot size and rapid recovery to the plants. As a result there was no difference in nymph counts in the spring. Another test was conducted which involved the clipping on September 6 of half of a two acre field which was seeded in alfalfa. Adult populations in the clipped portion had recovered to approximately 42$ of those in the other half of the field on September 26 when sampling ceased. Nymph counts the following year disclosed a reduction in population 7 7 . of 3l.9?£ due to clipping. This indicates that migratory activities are reduced in extent in early September but do not cease altogether. The efficacy of clipping as a control method is open to some question but population reductions can be obtained.

Influence of Oviposition Sites on Egg Deposition Although succulence and stand of host plants are probably the most significant Influences on the buildup of adult populations in new meadows in the fall, the availability of suitable oviposition sites has an important effect on egg deposition. The tendency of the females to deposit eggs in crevices between two apposed plant surfaces such as the stem and stipule of strawberry leaves or the sheath and stem of grain stubble is responsible for this influence. An experiment was initiated on August 31, 1953 to compare the location and amount of egg deposition when sites are not available with that which occurs when suitable sites are supplied. One hundred field collected adults were placed In each of six 3x3x3 foot cages. Threshed wheat straw which provides many suitable into which the eggs may be inserted, was placed in one of two cages which contained potted alfalfa plants. Two cages with pots of red clover and two with timothy were also set up; one containing straw and one with no straw. The cages were removed on October 37, and the eggs on 7 3 * the host material were counted. Their location on the green •or dead plant parts or straw was recorded and is set forth in Table X. It may be observed that 8*4 times as many eggs were deposited in the cages which contained alfalfa and straw, as there were in the alfalfa cage with no straw* The growth characteristics of this legume are such that few crevices may be found on the plants* On the red clover oviposition sites were available between the stems and stipules of the leaves and the same number of eggs was deposited in each cage. The dead parts of the timothy plants received a large number of eggs* Many of these were located between the sheath and stem of the stubble* In each instance more eggs were deposited on dead plant material than on green parts* A greater amount of oviposition took place on plant parts if straw was not supplied. On both timothy and alfalfa more eggs were found in the cages which contained straw. In order to determine the manner in which the egg masses are attached to plants the location of the eggs and the average number per mass was recorded. The former classification involved ( 1) eggs Inserted between two apposed plant parts, 2 () exposed eggs, which were merely glued to the surface of stems or leaves, and (3) eggs 79v Table X

Number and Location of Spittlebug Eggs In Different Ecological Situations Determined by.Cage Tests,

Green, plant Dead plant Straw Total parts parts

Alfalfa straw available 51 102 693 851 straw not available 70 234 554 Clover straw available 0 193 383 576 straw not available 67 510 577 Timotny straw available 0 267 371 638 straw not available 29 288 317

Total 217 1644 1452 Total straw - 2065 Total no straw- 1248. 6 0. cemented to the surface and covered with a dead leaf or b it of plant debris. The results of these counts are presented in Table XI. The greater number of eggs is inserted or covered with debris. It is apparent that more eggs are inserted on dead plant parts on timothy than there are on corresponding portions of alfalfa or red clover plants. This may be attributed to the presence of stubble on the timothy. If places where the eggs may be inserted are not available they are deposited on other plant parts and are covered with debris. In most cases a leaf is cemented over the mass. Eggs attached in this manner or exposed completely are Insecurely held and undoubtedly many of them drop off during the winter. Similarly those Inserted between the sheath and stem of grain stubble may occasionally fall to the ground with the sheath as it decomposes. This has led some investigators to believe that the eggs are deposited in the so il. The siftin g of soil samples in the spring yields a few masses but they are invariably attached to plant debris. Examination of the average number of eggs per mass in Table XI discloses that increasingly large masses are deposited as the selection of oviposition sites is improved. On a lfa lfa » in which the eggs must remain relatively exposed there are only 5.63 per mass while the masses on straw averaged 8.25 eggs. It is apparent that egg deposition is influenced by the 81. Table. XI Location of Spittlebug Eggs on Plant Material other than Straw and Average Number of Eggs per Mass on Each Material Compared with Straw.

Location Exposed Inserted Debris Total Covering

A lfalfa Green 23 5 93 121 Dead 13 133 240 386

Red clover Green 29 0 38 67 Dead 112 189 402 703

Timothy Green 18 0 11 29 Dead 42 443 70 555

Total 237 770 654

Eggs per Mass Exposed inserted Debris Covering X A lfalfa 5.14 5.13 5.50 5.63

Red Clover 5.04 7.00 6 .1 1 6.06 Timothy 8.57 7.64 7.36 7.68 Straw 8.25 Mean 6.25 6.59 6.32 availability of oviposition sites* This indicates that either egg development is arrested or the female is capable of withholding the eggs for a period of time until a suitable site is found* If the latter is true then a number of the females obtained in old meadows should contain more eggs than females in new seedings* To test this hypothesis ten females from both a new seeding and an old meadow were dissected at intervals from August 22, 1951 to October 29. The number of eggs obtained per female, and the dissection dates are recorded in Table XII. The analysis indicates that there are no more eggs in females during the ovlposition period in old meadows than there are in new seedings* It is probable that the females are capable of regulating egg development until suitable oviposition sites are found* Straw is utilized for this purpose whenever it is available* Consequently new meadows which are seeded in grain receive a greater number of eggs In the fall. Large nymph populations in the spring are due to the influence of oviposition sites coupled with the large number of adults in the fall in new seedings due to their greater attractiveness. Summer seeded meadows are usually not attractive to the adults because little growth has taken place by fall and no straw is available* On a replicated test there were 0*43 8 3 .

Table XII Comparison of the Number of Eggs p§r Female In a New Seeding and an Old Meadow, booster, Ohio 1951.

Data Old New

August 22 0.9 0.1 31 2.8 5.6

Sept. 8 6.8 6.0 14 11.0 15.3 21 10.5 13.0 Oct. 1 15.4 19.3

8 11.9 12.6 15 16.6 23.3 22 18.8 17.3 29 16.9 14.9

t = 1.723 P = 10-20% 84 .- nymphs per stem in a summer seeding and 3.72 per stem in plots seeded in grain* Similarly second or third harvest year red clover meadows in which the clover has died out and has been succeeded by timothy support low populations of nymphs.

Summary. Egg deposition is increased if grain stubble is available as an ovlposition site. Consequently new meadows seeded in grain receive a g reater number of eggs than do second or third year meadows in which the stubble has decomposed. The greater attraction of new seedings in the fall as ad u lt host p lan ts together with the increased number of eggs deposited per female are responsible for the large nymph populations the following spring when the meadows are in their first harvest year. 85. LITERATURE CITED

Ahmed, Dhia D. , 1949, L ife H isto ry and C ontrol of the Meadow Spittlebug, Phllaenus leucophthalinus (L.) Bomoptera, Cercopldae. Ph. D. Thesis. Ohio State University. ______and R. H. Davidson, 1950, Life History oif* the meadow spittlebug in Ohio. Jour. Econ. Ent. 43(6):905-908. Ashley, K., 1919. The froghopper or cuckoospit. Gardner's Chronicle, London LXV, No. 1681, Mar. 15, p . 1 2 2• Bailey, L* A_i. , 1922. The Standard Cyclopedia of H o rtic u ltu re , new e d i t . 6 vol. Macmillan and Co. N.Y. Beall, Geoffrey, 1935. Study of arthropod populations by the method of sweeping. Ecology 16:216-225. Bissell, T.L., 1952. Maryland Insect Notes. June 28. Britton, N. L. and A. Brown, 1936. An Illustrated Flora of the Northern United States, Canada, and the British Possessions. 2nd. edit. 3 vol. Lancaster Press, Lancaster, pa. Bouyoucos, G. J. and A. H. Mick, 1946, Improvements in the Plaster of Paris Absorption Block Electrical Resistance Method for Measuring Soil Moisture under Field Conditions. Soil Science 63:455-65. Cecil, Rodney, 1930, A biological and morphological study of a Cercopid, Philaenus leucophthalmus (L.). Ph. D. Thesis, Ohio State University. Chamberlin, T. R. and J. T. Medler, 1950. Further tests of in s e c tic id e s to c o n tro l meadow s p ittle b u g s on alfalfa. Jour. Econ. Ent. 43(6):888-891. Dambach, C. A. 1939. A Collecting Net with a Detachable Zipper Bag. Jour. Econ. Ent. 39(6):886-7. D avis, C. J. and A. L. Mitchell. 1946. Host Records of Philaenus spumarlus (L.) at Kilauaa, Hawaiian Nat'l Park. Hawaiian Ent. Soc. Proc. 12(6):515-516. 1947. Proc. Haw;. Ent. Soc. 13(1):30-31. 86. Degener, Otto. 1933-40. Flora Hawaiiensis. vol.1-4. DeLong, D. M. 1932. Some problems encountered in estimations of insect populations by the sweeping methods. Ent. Soc. Amer. Ann. 25(1):13-17. ______and Henry H . P. Sevsrin. 1950. Spittle- insect vectors of Pierce's disease virus. Hilgardia 19(11):339-376. Doering, K.C. 1942. Host plant records of Cercopidae in North America, North of Mexico (Homoptera). Jour. Kan. Ent. Soc. 15(2) and 15(3):65-92. Driggers, B.F. and B. B. pepper1. 1935. The spittle insect or froghopoer. N. J. Agr. Exp. Sta. Bull. 593, 4 p. Fisher, E* H. and T* C. Allen. 1946a. Spittle insect damage to alfalfa and red clover. Jour. Econ. Ent. 39(6):821-822• ______. 1946b. Alfalfa and clover severely damaged by spittlebugs. Wis. Agr. Exp. Sta. Bull. 469:15-16. Gyrisco, George G. and D. S. Marshall. 1950. The control of insects of alfalfa and red clover in New York, Jour. Econ. Ent. 43(4):438-443. Kershaw, J. C . and F. Muir. 1922. The Genitalia of the Auchenorhycous Homoptera. Ann. Ent. Soc. Amer. 15(3):201-12. Kraus, N . L. H. 1945. Proc. Haw. Ent. Soc. 12(2):220. Licent, P. Emile. 1912. Recherches D'Anatomie et de Physiologie Compar£es sur le Tube Digestif des Homopt^res Sup^rieurs. La Celluce 28(1):5-161. Loveless, A. R. 1951. Observations of the Biology of Clover Rot. Ann. App . Bio. 38(3):642-664. Marshall, D. S. and George G. Gyrisco. 1951. Control of meadow spittlebug on forage crops. Jour. Econ.Ent. 44(3):289-293.

Menusan, Henry Jr. 1951. Spittlebug control on alfalfa and clover. Pa. Ext. Serv. Leaflet 144* ______.1952. Control of spittlebugs and other insects on clover and alfalfa, pa. Ext. Cir. 396. 87, Mundinger, F. G. 1946. The control of spittle insects in strawberry plantings. Jour. Econ. Ent. 39(3): 299-305. Osborn, Herbert. 1916. Studies of life histories of froghoppers in Maine. Maine Agr. Exp. Sta. Bull. 254. Parks, T. H. 1948. Spittlebugs as vegetable pests. Ohio Veg. and Potato Growers Assoc. Proc. 33:59-62. Peterson, Alvah. 1947. A Manual of Entomological Equipment and Methods, parts I and II. Edwards Bros. Inc. Ann Arbor, Michigan. Petty, H. B. and C. E. White. 1952. Control of spittlebugs on legumes* Univ. 111. Ext. Circ. 689. Rosenstiel, R. G. 1951. Control of the meadow spittlebug in Oregon. Ore. Agr. Exp. Sta. Circ. of Info. 505. Schimitschek, E* 1937. The control of the Cercopid, A. Salicis Deg. Anz. Schadlingsk 13(6):72-77. Scholl, J. M. and J. T. Medler. 1947. Spittle Bugs in relation to alfalfa seed production in Wisconsin. Jour. Econ. Ent. 40(3):446-448. Schuh, Joe and 3. M. Zeller. 1944. Insect pests and diseases of strawberries. Ore. Agr. Exp. Sta. Bull. 419. 40 pp. Teller, Leslie W. Jr. 1951. The meadow spittlebug, Philaenus leucophthalmus (L.) in Maryland. Ph.D. Thesis, Univ. of Maryland. U.S.D.A Coop. Econ. Ins. Rpt. 1952. Vol. 2(1):5, (3):34, (4):47• U.S.D.A Ins. Pest Survey Bull. 1933. Vol. 13(3):87. U.S.D.A Ins. Pest. Survey Bull. 1938. Vol.18(3):120. U.S.D.A.Ins. Pest Survey Bull. 1940. Vol. 20(4):178. U.S.D.A.Ins. Pest Survey Bull. 1941. Vol. 21(2):49. Weaver, C* *v. 1950. Improvement in hay yields resulting from control of the meadow spittlebug. Jour. Econ. Ent. 43(1):7-ll• 88. ______.1951a. The seasonal behavior of the meadow spittlebug and its relation to a control method. Jour. Econ. Ent. 44(3):350-353. ______.1951b. Fall spraying induces spring infestations of spittlebugs. Ohio Agr. Exp. Sta. Farm and Home Research 36(271):53-54. July-Aug. ______.1952. Fall Applications of Insecticides to Control Spittlebug nymphs. Jour. Econ. Ent. 45(2):238-241. ______. and J. Hibbs. 1952. Effect of Spittlebug Infestation on Nutritive value of Alfalfa and Red Clover. 45(4):626-8. Wilson, M. C. 1949. Organic insecticides to control alfalfa insects. Jour. Econ. Ent. 42(3):496-498. Wolcott, G. N. 1937. An Animal Census of Two Pastures and a Meadow of Northern N.Y.Ecol. Mono. vii:l-90. AUTOBIOGRAPHY

I, Donald Roy King, was born In Lakewood, Ohio on January 22, 1927. I received my secondary education at Medina High School, Medina, Ohio. My undergraduate training was initiated at the Ohio State University in 1944. I served twenty months in 1945 and 1946 in the United States Army, eight of which were spent in the Army of Occupation in Berlin, Germany. I complated my undergraduate work at Baldwin-Wallace College from which institution I received my Bachelor of Science degree in 1949. The Master of Science degree was conferred upon me by the Ohio State University in 1950. I served as a

Research Assistant at the Ohio Agricultural Experiment Station during the summers of 1950, 51, and 52.