Effect of Artificial Control Practices on the Parasites and Predators of the

H. A. JAYNES and P. Eo MAI\UCCI, a.S.D.A., Agr. Res. Adm.., Bureau of Entomology and Plant Q1~arantinel

Although the codling moth, Carpocapsa thereafter the orchard was pruned and p01nonella (L.), is the major pest thoroughly scraped. On April 6, 1936, of apples in this country, very little work sodium nitrate was applied at the rate of has been done on its control by biological 7 pounds per tree. This was the first com- measures. In 1936 a biological-mechanical mercial fertilizer that the orchard had codling moth control project was started ever received. The same amount of so- by the Bureau of Entomology and Plant dium nitrate was applied the next spring. Quarantine in cooperation with the West In April 1937 the orchard was thoroughly Virginia Agricultural Experiment Station, disked and seeded to yellow and white to determine whether, under conditions sweetclover and winter hairy vetch. A prevailing in West Virginia, it was prac- 4-12-4 fertilizer was used at the rate of 300 pounds per acre. The orchard was ticable from the commercial point of view Downloaded from to reduce or eliminate the spray schedules kept in sod with clean cultivation beneath but to continue all other control measures. the trees, and weed growth being care- In West Virginia a high degree of control fully removed by hand. of the codling moth is not usually at- The trunks and all main scaffold tained, even when 4 to 7 c~)Versprays are branches were banded with untreated 2-

applied. Fruit infestation is not limited to inch corrugated-cardboard bands. These http://jee.oxfordjournals.org/ 5 per cent or less, as it is in some other bands were removed at 7- to lO-day inter- sections of the country when this number vals throughout the season and replaced of sprays, or even fewer, are used. In 1938 with new bands. Care was taken to remove the work was extended to include a study all larvae on the tree under the bands. The of the relative value of various natural- infested bands were placed in a screen control factors and the effect of the arti- cage, centrally located in the orchard, ficial-control practices on these enemies of where the moths and parasites were al- the codling moth, and to develop methods lowed to emerge but only the parasites could escape into the orchard. A few of of sampling for parasite, predator, and by guest on June 9, 2016 host populations and of evaluating and the larger species of parasites, which were comparing natural-control values in unable to escape through the 12-mesh sprayed and unsprayed orchards. The re- wire screening, were captured in vials and sults of the Bureau's studies in two liberated. orchards in 1938, 1939,' and 1940 are A commercially sprayed orchard lo- re1;>,0rtedin this paper. cated just north of the biological-control THE EXPERIMENTALORCHARDS.-An orchard and separated from it by 21 18-acre orchard about 30 years old, lo- rows of apple trees was selected for com- cated 12 miles west of Kearneysville, was parison. This orchard was comparable to utilized for the biological-control experi- the biological-control orchard and con- ment. It contained 574 trees, including 255 tained 148 York Imperial and 196 Ben York Imperial and 96 Ben Davis (Ga- Davis trees. The commercial orchard was noes), the varieties chosen for this study. pruned each winter, and some of the The orchard is located on deep, fertile roughest bark was scraped. Commercial soil, which is well drained for both air fertilizer was applied each spring. All and water! bearing trees were banded with chemically In the \vinter of 1935-36 and each year treated bands, except the count trees, the trunk and main scaffold branches of which

1 The writers are indebted to C. P. Clausen. in char((e of tbe were thoroughly scraped and then banded Division of Foreign Parasite Introduction, for suggestIOns and criticism during the experiments here reportcd and in the prepa- with 2-inch strips of corrugated card- ration of the manuscript. They wish to express their gratitude board. to Edwin Gould, of the West Virginia Agricu]tural Experiment Station, and E. O. Hamstead. of the Division of FrUIt Inseet Since the end product by which codling Investigations and J. H. Gei9S1~ formerly of that Division for their full cooperation; also to w. G. Cushwa and W. Gatrell, moth control is adjudged is the amount of uwners of the orchards used in these experiments. Acknowledg- injury to the fruit, it seems advisable to ment is due members of the Division of Insect Identification for tletenuinntion of the parasites and predators. indicate the infestation records of the two 9 10 JOURNALOFECONOMICENTO:\!OLOGY Vol. 40, No.1 orchards before discussing the biological- calcium arsenate, lime, and copper sul- control factors that were in operation. fate; and the fourth of a commercial According to unpublished data of Mr. summer spray oil containing nicotine. Gould and Mr. Geissler, the commercial In 1940 the commercial orchard re- orchard had higher percentages of total ceived a dormant oil spray with tar oil sound fruit (harvest and drop fruit) in all added; a pink spray of lime-sulfur; and a three years. The percentages of sound petal-fall spray of lime-sulfur, lime, and fruit in the commercial orchard were 56.0, lead arsenate. The first cover spray con- 69.9, and 75.0, as compared with 37.5, sisted of copper sulfate, lime, and lead 38.3, and ~8.0 in the biological-control arsenate, with nicotine added for three- orchard for the years 1938, 1939, and fourths of the trees; the second of copper 1940, respectively. sulfate, lime, and lead arsenate; and the In the commercial orchard 7~ per cent third of·nicotine, lime, and summer oil. of the harvested fruit was sound during NATURALCONTRoL.-The natural ene- the three years, and in the biological- mies found attacking the codling moth in control orchard 50 per cent was sound. the apple orchards of West Virginia con-

In all three years, at the beginning of sisted of parasitic and predaceous Downloaded from the second brood, the biological-control 'and a fungus disease. orchard had a much higher p'opulation of EGGPARASITES.-Todetermine the ex- worms than did the commercial orchard. tent of parasitization by Trichogramma However, despite the fact that the com- minutum (Riley), search was started on mercial orchard carried on with a typical May 13, 1938, and continued until June

commercial spray program at the begin- 14, for codling moth eggs on the foliage http://jee.oxfordjournals.org/ ning of the second brood, and consid.ering and fruit in both the biological-control the comparative population, the number and the commercial orchards. It soon be- of injured fruits while this brood was came evident that not enough eggs could present was proportionately much higher be found to give a satisfactory comparison than in the biological-control orchard. of the parasitization in the two orchards. SPRAYSCHEDULEs.-Forthe five years Methods were then developed-to induce 1936 to 1940, inclusive, the biological- the codling moth to deposit eggs on cello- control orchard was given a dormant or phane paper in cages. The cellophane

delayed-dormant oil spray, followed by a paper bearing freshly laid eggs was cut by guest on June 9, 2016 pink spray of lime-sulfur and a petal-fall into small sections containing 1 to 3 eggs spray of lime-sulfur, lime, and lead ar- each, and the sections were pinned to the senate. No cover sprays were applied to leaves on 6 to 1~ trees, from 5 to II being this orchard. placed on each, throughout the two or- The sprays applied to the commercial chards. These sections were gathered be- orchard, especially the cover sprays, fore the eggs hatched, and records were varied considerably during the three taken of the number of cggs parasitiz€d seasons. In 1938 this orchard received a and the number of sections on which par- late delayed-dormant oil spray, a pink asitized eggs were found. spray of lime-sulfur, and a petal-fall The parasitization recorded for codling spray of lime-sulfur, lime, and lead ar- moth eggs placed in the two orchards senate. The first cover spray consisted of while the first and second broods were lime-sulfur, lime, and lead arsenate; the present is summarized in table 1. The second of nicotine, summer oil, lime, and greatest difference occurred in 1938,when lead arsenate; the third and fourth of com- parasitization was considerably higher in mercial nicotine bentonite and summer the biological-control orchard. In only oil; and a fifth of a commercial nicotine- one set of eggs exposed in the commercial summer oil preparation. orchard did the parasitization exceed 10 In 1939 the commercial orchard re- per cent. These eggs were exposed from ceived a dormant oil spray with tar oil August 1 to 4, and 35.3 per cent were par- added for control; a pink spray of asitized, as compared with ~8.8 per cent lime-sulfur; and a petal-fall spray of lime- in the biological-control orchard. On sulfur, lime, and lead arsenate. The first August 17 another set of eggs, placed on cover spray consisted of lime-sulfur, liIpe, the same trees and left until August 20, and lead arsenate; the second of lime and gave 2.1 and ~8.7 per cent parasitization, lead arsenate; ·the third of lead arsenate, respectively. Apparently the spray ap- February 1947 JAYNES & MARUCCI: NATURAL ENEMIES OJ!'CODLING MOTH 11

plied to the commercial orchard on August set of fruit, were selected for band-collec- 4 reduced the activity of Trichogramma tion studies. The same trees were not used considerably. This spray consisted of 3 in successive years. Two-inch corrugated- pounds of commercial nicotine bentonite paper bands were placed about the trunk and! gallon of oil to 100 gallons of water. and main lateral branches, and were re- moved periodically for examination. A Table I.-Field parasitization of codling moth eggs on cellophane by Trichogramma. record was kept of the larvae, pupae, par- asitized larvae, larvae or pupae that had EGGS been attacked by predators, and diseased OIlCHAHD AND DATE EGGS PARASI- larvae. All uninjured larvae and pupae OF EXPOSURE EXPOSED TIZED were retained for emergence of parasites, Number Per cent and the results of rearing this material 19J8 to the adult stage are given in table ~. Biological-control: It will be noted that the parasitization June ll-July ~ 8,478 !l8.0 was low in both orchards, the highest July !l8-August 80 1,!l48 !l7.8 Commercial: being 5.7 per cent in the biological-control June ll-July !l 3,617 8.0 orchard in 1939, while in the commercial Downloaded from July !l8-August 80 1,844 5.4 orchard the figure was less than 1 per cent in 1938 and 1939. Ascogaster quadri 1939 Biological-control: dentata Wesm. was the dominant parasite May !l~-July 4 915 10.6 in the biological-control orchard, where it July 81-August !l7 366 7.7 was responsible for 94 per cent of the Commercial:

total parasitization during the three years. http://jee.oxfordjournals.org/ May ~~-July 4 9'l8 9.5 July 81-August ~7 319 3.0 This percentage includes the Ascogaster attacked by Perilampus capitatus Smul- 1940 yan. In 1939, 15.7 per cent were destroyed Biological-control: by this secondary species. Only 34 other June 18-~5 13'l 4.5 August 9-September 2. 884 4.2- • specimens of parasites were reared from Commercial: the material in the biological-control or- June 18--!l5 un 3.1 chard, these being M aciocentrus instabilis August 9-September !l 858 5.4 Mues., Tritneptis hemerocampae Gir., Bassus carpocapsae Cush., Microgaster by guest on June 9, 2016 In the biological-control orchard there ecdytolophae Mues., Eubadizon pleurale was very little difference in the amount Cress., Ephialtes aequalis (Prov.), Ephi- of parasitization between the :first- and alte8 n. sp., Phanerotoma tibialis (Hald.), second-brood eggs. In the commercial or- M eso8tenus gracilis Cress., Glypta ruft- chard parasitization of second-brood eggs scutellaris Cress., and HYPo8oter sp. in 1938 and 1939 was appreciably lower Parasite species collected as adults in than that of first-brood eggs, but in 1940 the band cage, but not reared from iso- there was a slight increase in the para- lated cocoons, were Calliephialtes varia- sitizaton of second-brood eggs over that tipes (Prov.), Mastrus carpocapsae of the first brood. It is believed that the (Cush.), Pristomerus ocellatus Cush., En- sharp decline in parasitization of the dasys subclavatus (Say), Hemiteles melli- second-brood eggs in 1938 and 1939 may cornis Ashm., and Lixophaga variabilis be attributed to the intensified spraying (Coq.). in the commercial orchard at the time of In order to ascertain whether the small second-brood oviposition. In 1940 one parasitized larvae leaving the fruit would spray was applied during this period, and seek hibernating places before reaching this was attended by a slight increase in the lower bands, ~oo small pieces of cor- parasitization. However, only 4 rows rugated paper were fastened around the were treated under good conditions for twigs immediately back of infested fruit nicotine spraying, the other 13 rows in each orchard in 1938. Seven collections being sprayed on windy and rather cool in the biological-control orchard yielded days, when conditions were not suitable a total of 564 stages, of which 5.~ per cent for effective application of nicotine sprays. were parasitized, while from the large PARASITIZATION OF LARVAE IN BANDS. lower bands on the main branches of the -Twenty trees, distributed throughout same trees 9 collections yielded 9l,9l76 the two orchards and each having a good stages, of which 5.36 per cent were para- 12 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 40, No.1 sitized. In the material from the small sitization of larvae from the drop apples bands and the large lower bands 28.6 and in the two orchards thus corresponded 25 per cent, respectively, of Ascogaster very closely to that of larvae from the were parasitized by PerilampU8. large corrugated-paper bands. In the commercial orchard 7 collections In 1939 applies containing codling moth from the 200 small bands yielded a total larvae were selected at random from both of 221 stages, of which only 1 was para- orchards for rearing observations. They sitized. From the large lower bands of the were cut open, the live larvae were re- same trees 9 collections produced 1,353 moved, and each larva was placed on a stages, of which only 3 were parasitized. clean, uninfested apple in a jelly glass. A The records from both orchards show that piece of corrugated paper was placed in the small bands placed back of the infested each glass so that when thc larva matured fruit collected no more small parasitized it could spin a normal cocoon. Six collec- larvae than did the large lower bands. tions were made between June 26 and

Table 2.-Parasites reared from codling moth larvae and pupae collected on bands.

PARASITES REARED Downloaded from TOTAL ORCHARD TOTAL PARASITIZA- Peri- MacTo- AND YEAR STAGES TION Ascogaster lampus1 centTltS Bassus Others

Number Per cent Number Number Number Number Number Biological-control:

1938 7,474 4.6 306 ft3 S ft 7 http://jee.oxfordjournals.org/ 1939 ~J481 5.7 107 ftO 10 0 ft 1940 3,685 ft.9 87 9 5 1 4 Commercial: 1938 2,184 0.9 13 1 0 6 0 1989 878 0.8 1 0 0 2 0 1940 440 2.5 4 0 0 7 0

I Parasite of Aacogastcr.

Parasitization records for larvae ob- September 18, and 573 larvae from the tained from bands placed above and be- biological-control orchard and 567 from by guest on June 9, 2016 low tanglefoot on trees in 1938 showed the commercial orchard were placed on that 4.23 per cent of the descending larvae clean apples. and 3.30 per cent of the larvae from the A total of 72.8 per cent of the larvae ground were parasitized. from the biological-control orchard and PARASITIZATION OF LARVAE IN DROP 75.3 per cent from the commercial orchard ApPLES AND IMMATURE FRuIT.-Drop formed cocoons. When reared through to apples from the banded trees were gath- the adult stage, the material from the bio- ered and cut open to determine whether logical-control orchard showed a para- the parasitization of the larvae from these sitization of 15.9 per cent, 15.2 per cent apples was higher than that of larvae ob- by Ascogaster and the remainder by tained on the bands. The larvae found Bassus. Only 4.0 per cent of the material were placed in jars with fresh, uninfested from the commercial orchard was para- apples. Between July 12 and the first of sitized, 1.46 per cent by Ascogaster and October 926 larvae were obtained from 2.56 per cent by Bas8Us. This higher rate apples collected in the biological-control of parasitization as compared with that orchard and only 356 larvae from those in obtained from the band records for 1939 the commercial orchard. The drop apples (see table 2) indicates that a large number collected in the biological-control orchard of the parasitized larvae do not reach the revealed a parasitization of 5 per cent of corrugated bands on the trunk and main the larvae by Ascogaster. Only a single lateral branches. The percentages of para- specimen of one other primary parasite, sitization recorded from the small bands MacrocentrU8 instabilis, was obtained. The just back of the infested fruit, the large drop apples in the commercial orchard corrugated bands, and the drop apples showed a parasitization of 2.2 per cent corresponded very closely in the two or- of the larvae by Ascogaster. The para- chards, but were considerably lower than February 19J,.7 JAYNES & MARUCCI: NATURAL ENJ';MlES OF CODLING lVloTH 13 of the larvae collected from infested fruit adults of L. maZi were observed many on the tree. Therefore, to obtain the times feeding on codling moth eggs in most accurate figure for parasitization by the orchard and in confinement. Bailey Ascogaster, the larvae should be taken (1940) gives a complete record of the his- from infested fruit and reared to the adult tory, economic importance, biology, dis- stage. tribution, and host plants of this thrips, PREDATORS ATTACKING THE EGG.- Table 4.-Populations of LeptothTiPa mali on When the codling moth eggs, laid on apple foliage in 1939 (Z-hour counts). cellophane, that were placed in each or- chard for parasitization by Trichogramma J3IOJ,OGICAL-CO~TROL COMMERCIAl, were examined, the number of eggs that ORCHARD ORCHARD had been fed on by predators was also Adults Nymphs Adults Nymphs recorded. The percentage of eggs thus June 6 69 158 35 89 10 Lead arsenate-lime Bprny destroyed is given in table 3. Although 1~ 67 156 7 62 the percentage attacked in 1939 was 15 Lead arsenate-lime- copper Bullate sprRY greater than in the other two years, the 18 89 236 21 33 21 First mowing of cover differencc is not significant. 26 First mowing or cover Downloaded from July 7 328 45 408 13 Table 3.-Percentages of codling moth eggs H ·Second mowing of cover - - laid on cellophane that were attacked by pred- 17 - - Second mowing of cover 31 276 152 356 156 ators. Aug. 1 Nicotine-summer oil spray 7 210 224 172 172 PERIOD EGGS 25 16 168 22 152 WERE EXPOSED ORCllARD 1938 1939 1940 Sept. 18 8 8 May 22-July 4 Biological-control 18.5 http://jee.oxfordjournals.org/ Commercial 6.8 June 18-25 Biological-control 7.6 which is known as the black hunter. How- Commercial 7.6 July 23-Aug. SO Dialogical-control 3.4 21. 9 ever, there apparently has been no previ- Commercial 1.3 16.6 Aug. 9-Sept. 2 Diological-control 9.S ous published record of its feeding on Commercial 8.5 codling moth eggs. The thrips were observed not only on Search was made for egg predators on apple foliage but alsq on the flowers of the leaves, but no direct evidence of feed- the common perennial daisy and other ing was observed in 1l)38. In August 1939 plants. Population counts were made peri- the predation averaged 15.1 per cent in odically in 1939 and 1940, to determine by guest on June 9, 2016 the biological-control orchard and 15.6 the relative number of thrips on apple per cent in the commercial orchard. In foliage and on daisy flowers in both or- August 1940 predation of eggs on the chards, and to determine the effect of foliage in the biological-control orchard sprays and of mowing the cover. was 4.8 per cent and in the commercial The counts of thrips on apple foliage orchard 6.6 per cent. The actual preda- during 1939 are given in table 4, and the tion was probably much higher, as eggs counts on daisy flowers during June of destroyed by predators are very difficult that year in table 5. These tables show to see on the foliage. the effect of spraying on the population The only predator observed feeding on of thrips as well as on the migration of codling moth eggs in the orchard in 1939 this insect from daisy and other weeds to and 1940 was a small black thrips, Lepto- apple foliage. The lead arsenate sprays thrips mali (Fitch). Observations and ex- applied on June 10 and 15 in the commer- periments with this thrips are discussed cial orchard brought about a decrease in in the following section. Coccinellid larvae populations of both nymphs and adults, confined with codling moth eggs did no whereas in the biological-control orchard feeding; adults of Anatis quindecimpunc- the population was increasing rather tata (Oliv.), Hippodamia convergens sharply. This increase, which was con- Guer., and Cocinnella novemnotata Hbst. current with a sharp decrease in the num- fed on eggs in confinement, but adults of ber of adults in daisy flowers after the CycZoneda munda (Say) and Scymnus in- peak of daisy bloom had passed, suggests dutus Csy. failed to do so. Neither newly the beginning of a seasonal migration of hatched nor older chrysopid larvae fed on thrips adults from daisy flowers to apple codling moth eggs. foliage. Leptothrips maZi.-Both nymphs and The most pronounced increase on apple 14 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 40, No.1 foliage was from June 18 to July 7. This 1939 were evidenced, except that the was probably due to accelerated migration migration from daisy flowers to apple foli- induced by the mowing of the cover crop age was considerably lighter. Although in both orchards in the latter part of the population of thrips in daisies was es- June. The second mowing of the cover timated to be about three times as great crop in the middle of July helped to main- in the commercial orchard, the migration tain the peak of adults from July 7 to to apple foliage a few days after mowing 31. Very few nymphs were found in the resulted in an increase of 24~ per cent in daisy flowers at this time, though large the commercial orchard, as compared with numbers of adults were in them early in the season. However, there was a gradual Table 5.-Numbers of Leptothrips mali on field increase of nymphs on the apple foliage, daisies in 1939 (2-hour counts). unless retarded by sprays, and this in- ADULTS crease was augmented by the movement DATE. PER 100 of adults from the daisies to the apple JUNE FLOWERS ADULTS NYMPHS FLOWERS foliage for egg laying. On August 1 a summer-oil spray con- Commercial Orchard 6 391 ~60 16 70 Downloaded from taining nicotine was applied to the com- 12 110 29 0 26 mercial orchard. It definitely retarded the 18 113 25 0 22 thrips population. There was a very sharp Biological-Control Orchard drop in the adult population and a slight 6 301 141 2 47 12 115 40 1 35 increase in the number of nymphs. In the 18 111 38 0 34

biological-control orchard there was also http://jee.oxfordjournals.org/ a decrease in adults, but not so great as in the commercial orchard. The increase an increase of 540 per cent in the biologi- in nymphs at this time was much greater cal-control orchard.' Thesc data furnish in the biological-control orchard, despite another illustration of the adverse effect the fact that prior to the application of of a nicotine spray, which was applied in the spray there was a much higher adult the commercial orchard about the time of population in the commercial orchard. mowing. Froin June 6 to 18 the average number In 1940 the presence of Leptothrips mali

of thrips collected in the biological-control on apple foliage in larger numbers con- by guest on June 9, 2016 orchard was ~58 per ~-hour count. The currently with the second brood of the predation of first-brood eggs placed in host than with the first brood was not this orchard during this period was 16.4 accompanied by an appreciable increase in per cent. During the same period the the number of eggs destroyed, as was the average number of thrips in the commer- case in 1939. This is probably because the cial orchard was 66, and 6.~1 per cent of thrips migrated to apple f{)liage in 1940 the eggs placed there were destroyed. between the first- and second-brood ovi- Thus, more than four times as many position periods, and also because of a thrips were found in the biological-control greater concentration of alternate host in- orchard and almost three times as many sects (leaf roller eggs and red mites) on eggs were destroyed by them as in the apples in 1940. The observations during commercial orchard. From July 31 to these two years suggest the possibility of August ~5 the average number of thrips slightly increasing biological control of collected in the biological-control orchard the codling moth by timely mowing ofthe was 349 per ~-hour count, and the attack cover crop. on second-brood host eggs exposed during PREDATISMUNDERBANDs.-When the this time average ~1.9 per cent. In the corrugated-paper strips around the trunk commercial orchard during the same and main lateral branches of the trees period the average number of thrips were removed to obtain the larvae and collected was 344, and attack on host pupae for parasite records, a count was eggs amounted to 16.6 per cent. Thus, also kept of the larvae and pupae that first-brood eggs were fed on as extensively had been attacked by predators. In 1939 as those of the second brood, and this the average predatism was 7.87 pcr cent may be correlated with the thrips popula- in the biological-control orchard and 4.99 tion on apple foliage during these times. per cent in the commercial orchard. Most

In 1940 the same trends observed in of the predators were antsl especially February 1947 JAYNES& MARUCCI:NATURALENEMIESOFCODLINGMOTH 15

Solenopsis molesta (Say). In 1939 the av- Approximately 4,000 cocoons were llsed erages were 14.40 and 8.68 per cent, re- in each orchard. spectively. However, in the period be- The rates of predatism obtained in tween July ~7 and August ~5 the five these tests indicated that very close to 100 bands removed in the biological-control per cent of the cocoons placed in each of orchard showed an average predation of the orchards would be destroyed by 25 per cent, the highest for anyone date predators if they were allowed to remain being 34 per cent. During the same period exposed to the natural enemies for periods in the commercial orchard the average equivalent to the normal time spent in predation was ~3 per cent, the highest that stage. being 26 per cent. In 1940 the averages The cultural practices in the two or- were 8.6 and 4.0 per cent, the lowest re- chards were practically the same during corded in the three-year period. 1938 and 1939. However, early in the When the bands were removed from springof1940the ground under the 9 rows the trees, a great number of cocoons de- of York trees in the commercial orchard stroyed by predators were observed, but was thoroughly disked to control mice, the exact species responsible were un- whereas the 13 rows of Ben Davis trees known. However, in a number of in- were not cultivated, in order to determint' Downloaded from stances the predator was feeding on the the effect of cultivation on the activity of larva or pupa within the cocoon. The ground predators. number of larvae observed being attacked Cocoons were placed under 27 of the plus the cocoons showing the small char- York trees that had been disked and ~3 of Solenopsis mo- acteristic holes caused by the uncultivated Ben Davis trees. After http://jee.oxfordjournals.org/ lesta amounted to 38.3 per cent of the 14 to 18 days of exposure, 368, or 62.4 cocoons found attacked in the biological- per cent, of the cocoons under the uncul- control orchard in 1938, 64.~ per cent in tivated trees had been attacked, as com- 1939, and 4~.5 per cent in 1940. In the pared with only ~68, or 48.4 per cent, commercial orchard this species was re- under the cultiVated trees. Soil examina- sponsible for ~.56 per cent of the total tions from these cultivated rows in May number of cocoons consumed by preda- and June showed a much lower carabid tors in 1938, 41.9 per cent in 1939, and population than in the other rows of the 4.8 per cent in 1940. In the biological-con- commercial orchard. That cultivation de- trol orchard 0.8 per cent of the total creases the activity of ground predators by guest on June 9, 2016 predatism in 1939, and 14.3 per cent in becomes still more significant from the 1940 were observed to be by adults of the predation records for 1939, when the per- ostomid Tenebroides corticalis (Melsh.). centage of predation under the York In the commercial orchard 3.~ per cent trees was consistently higher than under of the larvae in 1939 and 14.3 per cent in the Ben Davis trees. 1940 were observed being attacked by In order to determine which predators this species. On only a few occasions have were responsible for the attack, the dam- cantharid larvae, Chauliognathus penn- aged cocoons were placed in the following sylvanicus (Deg.) and Chauliognathus sp., five classifications when examined in 1939 been observed feeding on codling moth and 1940: Large hole in cocoon; medium- larvae within cocoons in the bands. sized hole in cocoon; small holes in cocoon; PREDATISM OF COCOONS ON THE cocoon mostly eaten with only slight GROUND.-To test the extent of feeding remnants left; cocoon entire with dead by predators on cocoons that have been larva, hard and rusty brown in color, spun up on the ground, codling moth giving the appearance of having been cocoons formed in corrugated-paper strips burned. In three of these groups the dis- were placed on the soil and under trash in tinction is rather sharp. It is known that both orchards. From 10 to 25 cocoons the cocoons with small holes were at- were placed under each of 8 to ~O treJs tacked only by Solenopsis and Monomori- in each orchard. The cocoons were dis- um. Those cocoons in which there is only tributed from the trunk to the outer cir- a slight remnant left may be attributed to cumference of the branches. They could .. the wireworm Conoderus lividus (Deg.), be left out for weeks in the fall and early· the only predator ever observed attacking in the spring, but in warmer seasons they a cocoon in this manner. Those cocoons were usually exposed for only 4 to 7 days. that are entire but contain dead, burned 16 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 40, No.1

larvae can be attributed to the two by its being responsible for approximately fusca L. and F. pallide-fulva 10 per cent of the predation in thc biologi- scha1lfusBi incerta Emery. Cocoons with cal-control and 5 per ccnt of that in the large holes may be attributed to predator commercial orchard. activity of all the Carabidae in both the Although Formica fusca was never ob- adult and larger larval stages and to the served to attack cocoons, the percentage larva of Chauliognathus marginatus (F.). of predation of cocoons placed on the The group with medium-sized holes repre- ground close to a colony of these ants was sents possible predatism by ants of much higher than in cocoons farther A phaenogaster fulva aquia (Buckley), away. The empty cocoons had large holes, caespitum (L.) and Phaidole typical of the kind made by F. fusca. In pilifera (Roger), as well as some of the general, the proximity of cocoonsto colo- smaller carabid larvae and predaceous nies of Aphaenogaster, Tetramorium, Mon- ostomid larvae. omorium, and Solenopsis usually resulted Analysis of these groupings for 1940 in a high predation of the type attributed shows that in April and May 65 and 69 to these ants. per cent of the total destruction of the On October 25, 1940, 40 corrugated- Downloaded from cocoons in the biological-control and com- paper strips, each containing at least 5 mercial orchards, respectively, was caused codling moth larvae, were pinned on 20 by carabid adults and larvae, and by trees in the biological-control orchard and Chauliognathus larvae. During July pred- screened with half-inch mesh hardware atism by these species was consider- cloth to protect them from birds. The ably less, being only 21 and 25 per same number of strips were placed in the http://jee.oxfordjournals.org/ cent of the total predation in the re- commercial orchard, and both scts were spective orchards. However, in the fall left on the trees until late in April. In the this type of predatism amounted to 78.3 biological-control orchard 219 codling and 87.1 per cent of the total of the co- moth stages were recorded, 11 of which coons in the two orchards. During the had been attacked by predators. In a summer the predominant type of preda- total of 217 stages from the commercial tion was that caused by Solenopsis and orchard only 3 had been attacked by ]fonomorium. These ants caused 52 and predators. This cxperiment showed that there was practically no predaceous at- 53 per cent of the total predation in the by guest on June 9, 2016 biological-control and commercial or- tack on larvae within the cocoons on the chards, respectively, while in the spring trees during the winter and the early part only 6 and 4 per cent and in the fall 6 and of the spring. The strips could not be left 1 per cent, respectively, were of this beyond the date indicated because a great type. Thus the percentage of larvae con- many larvae had changed to pupae. Ants sumed by Solenopsis in the summer is of the species Formicafusca were observed usually high enough to overshadow and crawling up the trunk and limbs of many minimize the role of the carabids in de- of the trees containing the strips. Later stroying cocoons on the ground. observations showed that F. fusca at- The following species were occasionally tacks not only naked codling moth larvae . found feeding on cocoons: Solenopsis mo- but also larvae within the cocoons, often lesta, Monomorium minimum (Buckley), killing them without visibly damaging the a wireworm, probably Conode1'Us lividus, cocoon. Tetramorium caespitum, Aphaenogaster Codling moth cocoons in corrugated fulva aquia, the larva of Chauliognathus paper were also placed in trees in each sp., a malachiid larva, Collops quadrimacu- orchard in July and August. Predatism latus (F.), a staphylinid (which escaped), in the biological-control orchard Deroceras laeve (Muller), centipedes, and amounted to 25 per cent and in the com- predaceous mites belonging to the family mercial orchard 28 per cent. Although Parasitidae. Since these predators con- only a few cocoons were used, the experi- sume a cocoon very quickly, it is only ment indicated that a greater percentage rarely that their feeding occurs simultane- of cocoons were attacked by predators in ously with the examination. The impor- the summer than in the winter or spring, tance of the wireworm Conoderus lividus when they were exposed for a longer as a predator of cocoons hibernating on period. the ground early in the spring is indicated SOIL EXAMINATIONS FOR PREDATORS.- February 1947 JAYNES & MARUCCI: NATURAL ENEMIES OF CODLING MOTH 17

In order to compare the number of chard 74 were found under the mulched ground predators in the two orchards, soil trees and 76 under thc unmulched trees. examinations were made, and two types In July and August 13 examinations in of cages were used. The top inch of soil each orchard gavc an average of 57 taken from one quarter of an area 10 feet Carabidac per examination in the biologi- in radius from the trunk of the tree was cal-control orchard as compared with 41 in the commercial orchard. Table 6.-Number of predators collected in soil examinations and traps in two orchards, 1938-40. In May 1939 two examinations in each orchard showed 12 predators from both BIOLOGI- places. In September of that year the area COM- CAL- examined under each tree was reduced to SPECIES MEUCIALCONTROL 9 square feet, and collections were made Carabidae: from 32 such plots in each orchard. These AgonodeTUs indistinctus Dei. 2 6 examinations resulted in 189 predators Agonum punctifomlis (Say) 8 41 from the biological-control orchard and sp. 3 5 171 from the commercial orchard. Amara muscula (Say) 68 19

sp. 197 427 In 1940, 40 of the small plots were ex- Downloaded from Amphasia interstitialis (Say) 1 18 amined in each orchard, and 545 preda- Anisodactylus (Oynandro/arsus) ceous insects were taken from the bio- agricola Say 26 30 logical-control orchard and 421 from the duleicallis (Laf.) 8 0 rusticus (Say) 63 75 commercial orchard. The lower count in sp. 7 0 the commercial orchard was probably the GCllaUms gregarius Dei. 30 41 result of the thorough disking given a http://jee.oxfordjournals.org/ opaculus Lee. 314 358 large part of it early in the spring. Calosoma calidum (F.) 11 3 CMaenius tomen/osus (Say) 4 1 Since the soil-sifting method of estimat- Colliuris pennsylvanica (L.) 6 3 ing the population of ground predators Dysidius mutus Say 3 5 was likely to collect more of the sedentary Evarthrus furtivus Lee. 0 6 forms, two trapping methods were used to sp. near sodalis 0 16 collect more active insects. One method Ilarpalus caliginosus (F.) 57 14 compar Lee. 2 12 was by weighting down to the ground conuivlls Lee. 5 1 large fertilizer bags that had been split II arpallls dichrous Dei. 5 9

open. The mulch that formed under these by guest on June 9, 2016 erythropus Dei. 6 9 bags and the high moisture content of the faunus Say 102 46 pennsylvanicns Dcg. 301 288 soil provided an attractive resting place Percosia obesa (Say) I 7 for several kinds of ground predators. Poecilus lucublandus Say 13 35 Ten bags were placed in each orchard, and Scarites subterraneus F. 5 1 in 9 examinations from August 7 to Stenocellus rupestris (Say) 1 13 Stenolophus conjunctus (SfLy) 12 11 September 10, 1938, a total of 118 cara- Tachistodes paupeTculus bids were obtained in the commercial (Dei·) 4 15 orchard, as compared with only 60 in the Miscellaneous carabids 30 31 biological-control orchard. This method, Elateridae: ConodeTUslividus (De.) adults 33 35 however, collected only 12 species of larvae 47 102 Carabidae, as compared with ~6 species Cantharidae: Chauliognathis sp. 79 93 taken in the soil-sifting method. Ostomidae: Tenebroides corti- Another trap for ground predators was calis (Melsh.) 1 4 made by burying tin cans, 6 inches deep Staphylinidae 58 108 Spiders 174 177 and 5 inches in diameter, in the ground so that the top of each can was flush with 1,687 2,060 the soil surface. Eight traps were placed in each orchard in May 1939, and 4 collec- run through a mechanical soil sifter. In tions yielded 34 carabids in the com- ApriJ and May 1938, 12 such examinations mercial orchard and 3 tenebrionids and 23 were made, 4 in the commercial orchard carabids in the biological-control orchard. and 8 in the biological-control orchard, 4 The most numerous predators collected if which were of soil under mulched trees in the two orchards in the soil examina- and 4 of soil under unmulched trees. In tions and predator traps during the three the commercial orchard 72 Carabidae seasons are listed in table 6, which shows were founo; in the biological-control 01'- the relative abundance of each species. 18 JOURNALOFECONOMICENTOMOLOGY Vol. 40, No.1

No record was kept of the spiders after Formica, Jusca var. subsericea Say, a the first season. In addition to those listeJ large black , is a very important preda- in table 6 the following species were also tor of codling moth larvae seeking hiber- encountered: nation quarters. The larva is subdued by an ant in a very short time, and is then Carabidae: Agonum crenistriatum (Lee.) dragged to the colony site and immedi- cupripenne (Say) ately taken below the surface of the soil. placidum (Say) Larvae are attacked by these ants on the n,Lripe8 (Zimm.) ground, as well as on the trunk of the trees, Amara exarata Dej. Ani80dactylus interpllnctatu8 Kby. where the ants are rather numerous if the melanopus Hald. foliage is infested with . These ants Ani8odactylu8 (Gynandrotar8u8) oVlIlari8 Csy. have also been known to attack the larva Apene8 8inuate (Say) within the cocoon by making a large hole Cratacanth118 dllbiu8 (Beauv.) Cyminidis planipenni8 Lee. in the cocoon and then withdrawing the Dicaellls amb-igllus I.af. larva. F. Jusca often injects formic acid elongatus Bon. into the larva in the cocoon, thus killing furuus Dej. and it, and then fails to make a hole re- Downloaded from Dyschirius gtobulo8Us Say sp. move the larva. However, its principal Galerita jenus (F.) role as a predator is in destroying larvae l/arpalus nitidulus Chd. that are seeking places for hibernation. HeUumorpha sp. Formica pallide-Julva schauJussi incerta Notiophilus semi.~triatus Say Patrobus longicornis (Say) Emery is a large, reddish-brown ant that

Pterostichlls adoxu8 (Say) runs very rapidly. When it encounters a http://jee.oxfordjournals.org/ PterosticllUs (Amaseus) caudicalis (Say) codling moth larva, the larva is im- Scaphinotus elevatus F. mediately paralyzed and dragged into the Scarites sp. Selenophorus opalinus Lee. nest. These ants are much more active sp. than F. Jusca and subdue a larva much Stenolophus sp. more quickly. However, they were not Xestonotus lllgubris (Dej.) nearly so numerous and probably do not Malaehiidae: Collops quadrimaculatus (F.) Staphylinidae: influence the codling moth population Lathrobillm sp. nearly so much. F. pallide was never ob- Quedius sp. served to attack a codling moth cocoon by guest on June 9, 2016 Staphylinus cinnamoptenls Grav. and remove the larva, but all the larvae Tenebrionidae : Opatri7ius minimus (Beauv.) within cocoons placed near a colony of Cleridae: this species were killed, probably by Cymatodera sp. formic acid injected through the cocoon. undulata (Say) Aphaenogaster Julva aquia (Buckley), Enoclerus ichneumonells (F.) a medium-sized reddish ant, attacks both PREDACEOUSANTs.-In studying the larvae seeking hibernation and those predaceous ants in the two apple orchards, within the cocoons. In attacking a cocoon several experiments were conducted dur- this ant makes a medium-sized hole ing the three years. Before these experi- through which to withdraw the larva. It ments are discussed, the information ob- does not seem to have the power, as has tained on each species of ant and its Formica, of weakening its prey by inject- relative value as a predator of the codling ing a fluid. Codling moth larvae are moth will be summarized. capable of freeing themselves of one or Solenopsis molesta (Say), the thief ant, two ants, but when three ants become has minute yellow workers which are very affixed to a larva, its chance of survival is important as predators of codling moth small. These ants are rather clumsy larvae and pupae within the cocoon. They fighters and often hinder each other. How- also attack the naked full-grown larva ever, in many instances a large percentage while it is spinning its cocoon. Codling of larvae released near a colony of moth larvae passing near a colony site of Aphaenogaster were destroyed before they Solenopsis have been attacked and killed could make their cocoons. by large numbers of ants within two to Tetramorium caespitum (L.) attacks five minutes and consumed on the spot. naked codling moth larvae and also Solenopsis is most important, however, as larvae within cocoons. It takes three or a predator of the cocoon stages of the four ants about 10 minutes to subdue a codling moth. larva, and then they drag it into their February 1947 JAYNES & MARUCCI: NATURAL ENEMIES OF CODLING MOTH 19

nest. Larvae released near a colony of 196 larvae were released under 18 trees, Tetramonum were usually able to reach and 33, or 16.8 per cent, were attacked and the corrugated-paper strip, but later ex- killed by predators. A spider killed 1 amination showed that most of them had larva, Monomorium killed another, and been killed while making the cocoon or the other 31 larvae were killed by F.fu8ca. after completing it. At one location 7 of the 11 larvae released Monomorium minimum (Buckley), a were killed by F. fusca. minute black ant, attacks naked larvae, When the larvae were released, it was but usually has great difficulty in sub- noted that the trunk of the tree had no duing them unless they are weakened or particular attraction for them. They are confined so that they cannot escape. would apparently go in any direction and However, when a larva is attacked by seek hibernation in any suitable place many ants of this species it is soon killed. encountered. A total of 343 larvae reached These ants are· effective predators of a hibernation place and only 31, or 9 codling moth larvae within cocoons. per cent, reached the tree before stopping. Among the species of minor importance, These 31 larvae traveled an average

Pheidole pilifera (Roger) has been ob- distance of 10 feet. This indicates that a Downloaded from served to attack both naked larvae and large number of the larvae that fall to those in cocoons; Lasius niger alienus the ground as exposed larvae or in drop americanus Emery and L. niger val'. apples spin cocoons in the trash on the neoniger Emery, Prenolepis imparis (Say), ground. A large percentage of the cocoons and integra N yl. attack placed on the ground were consumed. active larvae only; and Tapinoma sessile Observations had been made of preda- http://jee.oxfordjournals.org/ (Say) and Cre1natogaster lineolata Val'. tory attack on larvae seeking hibernating near cerasi (Fitch) have been found to places and also of attack on fully formed prey only on the larvae in cocoons. cocoons. No record had been taken of ATTACK Olf ANTS UPON ACTIVE LARVAE. predation during the time when the larvae -Codling moth larvae were· released, one were spinning up their cocoons. To obtain at a time, 5 feet from the base of a tree and such a record larvae were released within were observed until they entered a hiding barriers. place, which was then marked. Forty- Wooden frames 3 feet square were

eight larvae in the biological-control made with three layers of corrugated by guest on June 9, 2016 orchard were watched in this way and 11 paper tacked around the bottom and one in the commercial orchard. Of these larvae layer around the outside of the frame, to 10 were attacked by ants and dragged to cover the ends of the paper. The soil was the nest and 1 was killed by a spider. leveled off so that the paper strips rested When the places where the larvae had evenly on the ground, and a small amount stopped were examined 24 hours later, 12 of dirt was placed around the outside of good cocoons had escaped attack, 11 the frame. When larvae were released in larvae were actually seen being attacked, the center of the frame, some would crawl and 7 empty or partially formed cocoons up on it, and these were replaced in the were found, showing evidence of preda- area until all had entered the corrugations. tism. Probably a few of the other 29 larvae Twenty frames were placed in each were able to escape and spin up cocoons, orchard during the period July 12 to but they were not found. September 15, 1939. Approximately 50' In 1939 mature codling moth larvae larvae were released in each frame, and were released in both orchards and ob- the frames were distributed throughout served until they had reached hibernating the two orchards, being placed under places or were attacked by predators. The large trees having no apples or near small larvae were placed on the ground under reset trees. The larvae were left undis- the trees at distances from 5 to 12 feet turbed for a week and then examined. from the trunk and at different points A large number of newly formed around the tree. A total of 197 larvae cocoons were found to have been attacked were released in the biological-control by Solenopsis. Many of the empty cocoons orchard under 16 trees, and 27, or 13.7 had one large hole, and many of the per cent, were attacked and killed by partially formed cocoons or webbings predators. A spider attacked and killed 1 contained no larva or pupa. It is known larva., and the other 26 were killed by that a codling moth larva may make a Formica fusca. In the commercial orchard partial cocoon and then, if disturbed, ~o JOURNAL m' ECONOMIC ENTOMOLOGY Vol. 40, No.1 move on and make another. The webbings cent. In'the commercial orchard 53.2 per of larvae disturbed by Solenopsis show cent of the cocoons on the ground and 27.1 small characteristic holes. In many in- per cent of the larvae in the frames were stances the total number of larvae, destroyed, making a total predation of coccons attacked by predators, and 80.3 per cent. In both orchards these webbings found in the corrugated-paper figures are very close to those obtained strips exceeded the number of larvae for larvae in the frame barriers. released, and this difference is referred to This experiment shows that a con- as a surplus. Therefore, in comparing the siderable amount of predation on codling number of larvae destroyed from the time moth larvae takes place in the period they entered the barrier until 1 week between the time when they reach suitable later, it is probably best to consider the hibernating places on the ground and the difference between the number entering completion of their cocoons.

Table 7.-Numbers of colonies of the most common species of ants found in the biological-control and commercial orchards, 1939-40. Downloaded from 1988 1989 1940 Biological- Com- BiologicaI- Com- Biological- Com- SPECIES Control mercial Control mercial Control mercial

A phaenogasterfulva aquia (Buckley) 31 ~ 49 2 135 3

Formicafusca.var. subsericea Say 40 11 ~6 16 41 J5 http://jee.oxfordjournals.org/ pallidc-fulva schallfussi incerta 5 1 13 5 '27 7 Emery Lasius (Acanthomyps) claviger (Roger) '24 1 30 7 54 (, Lasius nige·ralienus americanus Emery 9 (, '2 H H 13 Monomorium minimum (Buckley) 2 g 55 1 86 fj Pheidole pilifera (Roger) 5 2 7 5 21 9 Prenolepis imparis (Say) 2 7 6 6 !J 4 Solenopsis moles/a (Say) 80 31 197 168 149 10·t Te/ramorium co.espitum (J~.) 1 '23 5 59 43 69 Miscellaneous species 10 11 8 8 10 1 by guest on June 9, 2016 Total 159 97 898 291 539 236

the barrier and the number of live larvae EFFECT OF SPRAYS ON ANT POPULA- or pupae recovered. In the biological- TIONS.-To determine the relative popula- control orchard 980 larvae reached the tion of predatory ants and the' effect of barrier and 425 larvae and pupae were sprays on them, plots in the commercial recovered, a difference of 555, or 56.6 per and the biological-control orchards were cent. In the commercial orchard 976 examined during the three seasons. The larvae reached the corrugations, but only plots were selected at random through- 162 larvae and pupae were recovered, a out the two orchards by using maps. Each ilifference of 814, or 83.4 per cent. plot. p.onsisted of the area enclosed by four The foregoing data do not show the apple trees, about 36 feet apart; thus, an number of larvae that were attacked in area of approximately 1,296 square feet the early stages of cocoon forming. If the was examined in each plot. This ground number of webbings and the number of was gone over thoroughly, and all ant missing larvae are added and the surplus colonies were plotted and sample speci- is subtracted from this total, the approxi- mens taken. mate number of larvae attacked before A consistently larger number of colonies making complete cocoons is obtained. On were found in the biological-control this basis 167, or 17 per cent, of the larvae orchard than in the commercial orchard. in the biological-control orchard were at- This is attributed to the cumulative tacked before making complete cocoons. pft"ct of sprays applied in the latter. Since predation of cocoons placed on the E: ;hteen plots were examined in each soil in this orchard amounted to 42.~ oTl.hard in 1938, 13 in 1939, and 14 and per cent, the total predation was 59.2 per 10, respectively, in the biological-control February 1~47 .JAYNES & MARUCCI: NATURAL ENEMIES OF CODLING MOTH n and commercial orchards in 1940. In table biological-control orchard had an esti- 7 are listed the 10 most common species of mated 289 colonies per acre as compared ants encountered in the two orchards in with 183 colonies per acre in the com- West Virginia during the three seasons. mercial orchard. There were 12 additional species, which In 1939, 5 plots in the biological-control were relatively scarce, as follows: Lasius orchard were examined for ants between niger neoniger Emery, Las'ius niger var., April 25 and May 5, and 64 colonies were M yrmica scabrinodis sabuleti Meinert, found, or a rate of 403 colonies per acre. Tapinoma sessile (Say), Polyergus lucidus Between June 21 and July 11, 6 plots in Mayr, Formica pallide-fulva nitidiventris the same orchard yielded 242 colonies, or Emery, Crematogaster lineolata var. near 1,270 colonies per acre. Examinations of cerasi (Fitch), Formica fusca var. sub- the commercial orchard between May 2 aenescens Emery, Brachymyrmex heeri and May 11 yielded 41 colonies in 5 plots, depilis Emery, Brachymyrmex sp., Strumi- or 275 colonies per acre. Between June genys ?'ejlexa \Vesson and 'Vesson, and 21 and August 9, 6 plots in the same Formica rufa integra Ny!. orchard gave 212 colonies, or 1,184

In 1938 search for ant colonies was colonies per acre. Downloaded from made in 18 locations in each orchard. Ap- Some of the plots examined in June proximately the same number of Solenop- and July 1939 had been examined pre- sis mole.~ta colonies were found in each viously, and Solenopsis appeared to be orchard (table 7~. However, very few greatly increased .. If the number of ant colonies of this species were found in the colonies found in in these plots, exclusive

commercial orchard after the middle of of Solenopsis, is computed to an acre http://jee.oxfordjournals.org/ June. Nearly four times as many colonies basis, there were 283 colonies per acre in of Formica fusca were found in the bio- the biological-control orchard in April logical-control orchard as in the com- and May, and 566 colonies per acre in mercial orchard. The 11 colonies in the June and July, or an increase of 100 per commercial orchard were all found in cent. In the commercial orchard there June. were 215 colonies per acre in May, and in Aphaenogaster fulva was much more the period June to August 363 colonies numerous in the biological-control orchard per acre, or an increase of 69 per cent.

whereas with Tetramorium caespitum the The biological-control orchard had more by guest on June 9, 2016 colonies in the commercial orchard greatly ant colonies per plot than the commercial outnumbered those in the biological- orchard, but this difference was not so control orchard. This difference was also great as in 1938. If the Solenopsis colonies noted in 1939 and 1940. Tetramorium was are omitted, the commercial orchard had rarely found in the same plot with only 51 per cent as many colonies as the A phaenogaster. biological-control orchard in 1938 and 68 Mon01n01·ium minimum was much more per cent as many in 1939. numerous in the biological-control orchard The great increase in the number of in 1939 and 1940 than in the commercial Solenopsis colonies in the areas that were orchard. reexamined in June and July may have A considerable drop in the average been due to the following factors: (1) The number of colonies found per examination date of examination, as by the later date was noted after the middle of June. This more colonies would have been established decrease was much more noticeable in the naturally; (2) the fact that this species commercial orchard, and is especially im- seemed to like hard, compact soil and was portant because it was largely in two often found in or near the roads. Many species, Solenopsis molesta and Formica Solenopsis colonies were found under the fusca, which are outstanding predators of roots of narrow-leafed plantain. The the codling moth. This decrease " s ground had been disturbed, practically all probably due to the frequent sprays and the large weeds and grass had been pulled to the kinds of sprays applied in the com- out, and plantain had replaced the original mercial orchard. cover. This changed the habitat and, as In 1938, from the 18 plots in each the rain packed the soil, the location was orchard, 159 colonies were located in the made more suitable for Solenopsis. biological-control orchard and only 97 Because more ant colonies were being colonies in the commercial orchard. The found per plot in 1939 than in the previous JOURNALOFECONOMICENTOMOLOGY Vol. 40, No.1 year, one plot in each orchard that had whether certain insects found in the soil been examined in 1938 was examined on were active predators on either naked July 11, 1939. In the biological-control codling moth larvae or larvae within the orchard only 2 colonies of Formica fU8ca cocoons. The insects werc placed in jelly had been found in 1938, but in 1939, 11 jars with tin covers and two-thirds filled Solenopsis, 3 Formica, 1 Monomorium with moist soil containing plenty of root minimum, 4 Aphaenogaster fulva aquia, fragments and decayed organic matter, and 1 Tetramorium caespitum colonies so that natural food would be available. were found. In the commercial orchard Naked codling moth larvae and pupae, only 1 Prenolepis imparis and 1 Tetra- as well as cocoons, were placed on the morium colony had been found in 1938, surface of the soil, and examined periodi- but 12 Solenopsis, 1 Formica, and 7 cally. Tetramm'ium colonies were found the fol- In 1938, 34 separate tests were run with lowing year. These data show that a con- only naked larvae and exposed pupae. siderable change in the ant population Eleven species fed on the codling moth may take place within a given area from larvae or pupae. In 1939 a total of 125

year to year. Some of the increase in- individual specimens were used in the Downloaded from dicated may be due to error of sampling, predator-confinement tests. Either naked inasmuch as some small Solenopsis codling moth larvae or larvae within colonies may have been overlooked in cocoons, sometimes both, were placed in 1938. However, it is certain that large the jar with the predator. Many predators colonies of Formica, Aphaenogaster, and failed to feed, and some individuals of a

Tetramorium would not have been missed. species would not feed while others of the http://jee.oxfordjournals.org/ This increase of ant colonies in the com- same species fed on several larvae, either mercial orchard may explain in part the naked or within the cocoon. Fifty-five large percentage of predation obtained in specimens did no feeding, while 70 did that orchard in 1939. some feeding. In 1940, 321 colonies were found in 10 The results of two seasons tests gave'l8 plots in the biological-control orchard and species that fed on both naked larvae and 236 colonies in 10 plots in the commercial larvae within cocoons, 10 species that fed orchard. When these totals were compared only on larvae (or pupae) within cocoons,

with the numbers of ants found during the and 11 species that fed only on naked by guest on June 9, 2016 corresponding seasons in 1938 and 1939, larvae and exposed pupae. The type of it was seen that there had been a slight feeding by the various species of predators increase each year in the biological- is shown in the following tabulation (1 control orchard. There were 95 colonies of indicates attack on larvae or pupae within Aphaenogaster fulva aquia in the biologi- the cocoon; 2, attack on naked larvae or cal-control orchard and only 3 in the com- exposed pupae; and 3, attack on both mercial. Colonies of Formica fU8ca var. naked larv~e and those within cocoons):

subsericea, F. pallide-fulve schaufU8si in- COLEOPTERA certa, and Monomorium minimum were Carabidae: more numerous in the biological-control Agonllm (Circinalia) sp. 1 orchard. However, there were two and Agonllm plinctifoNne (Say) 2 Amara sp. 1 one-half times as many colonies of Anisodactyllls (Gynandrotarsll .•) oVlIlaris Csy. 11 Tetramorium caespitum in the commercial T1IstiC1lS(Say) 2 orchard. The numbers of Solenop,sis Calathus gregarius Dej. 3 molesta colonies found in the two orchards opaC1llus Lee. 11 Colosoma calidllm (F.) 11 in July averaged about the same--that is, sp., larva 11 approximately 8 colonies per plot. During Chlaenills tomentosus (Say) 11 May and June they had averaged 10 Collillris pennsylvanica (L.) ~ colonies per plot in the biological-control EvarthrllU sp. near sodalis 1 orchard and 12 colonies per plot in the Galerito janus (F.) 3 Galeriia sp., larva ~ commercial orchard. Therefore, the great- H arpalus caliginosus (F.) 11 est reduction of this species took place in compar Lee. 11 the commercial orchard. dichrous Dej. 1 FEEDINGTESTSWITHPREDACEOUSIN- erythropus Dej. !l faunus Say ~ SECTS.-To supplement field observations penn81Jlt'aniC1ls Deg. 11 feeding tests were made to determine Patrobllslongicornis (Say) 11 February 1947 JAYNES & MARUCCI: NATURAL ENEMIES 01<' CODLINGMOTH ~3

Poecilus lucublandus (Say) 3 made in such a manner as to prevent con- Pt/l'rostichus sp., larva I tamination. The inner vials were not Scaphinotus ·levatus (F.) !l SelenophoTUs sp. (gagatinus group) I opened, and the observer's hands were Ostomidae: . sterilized with hypochlorite solution after TenelJroides corticalis (Melsh.) I each examination. sp. larva I The results of these tests revealed that Tenebriollidae: Opatrinus 11Iini11lus (Beauv.) I Malachiidae: Callops quadri11laculatus (F.), larva I the fungus was definitely pathogenic. The Staphylinidae: percentages of dead larvae 3, 6, and 20 Quedills sp. !l days after treatment are shown in table 8. Staphylinlls cinna11loptcrlls Grav. g All larvae that survived attained the moth Cleridae: CY11latodcra undulato (Say) 3 stage. Enoclems ichnc1l7noncus (F.) ~ . Cantharidae: Chauliognathus pcnnsylvanicus Table 8.-Mortality of codling moth larvae in (Deg.), larva 3 fungus disease tests. sp., larva g Elateridae: Conod8TUS lividus (Dej.), larva 3 TIME sp., larva 3 AFTER INOCU- CON- TREATMENT DUSTED LA'fED TROLS1 HEMIPTERA Downloaded from Reduviidae: PscllioPlis cinctus F. Days Per Cent Per Cent Per Cent 3 35 25 0 A FUNGUS PARASITE OF CODLING 6 65 55 10 MOTH LARVAE.-While a search was 20 90 100 !lO being made for codling moth larvae in orchards in Bridgeton, N. J., in March 1 Both punctured and untreated controls showed the BUDIe percentages. http://jee.oxfordjournals.org/ 1938, many dead larvae were found, their bodies overgrown with a white fungus. The inception of infection was out- This organism was isolated in pure culture wardly manifested by dark-brown lesions by S. R. Dutky and determined as prob- over the epidermis and a weakened condi- ably Beauvaria bassiana (Bals.) Vuill. It tion of the larva. Mummification soon was later given the same determination by followed as the penetrating hyphae began Vera K. Charles, of the Bureau of Plant to consume and displace body tissue. This Industry. change soon became outwardly mani- A small-scale experiment was conducted fested by a white mycelium growth, fol- by guest on June 9, 2016 to ascertain whether the fungus was. lowed by sporulation. In a few tests larvae parasitic or simply saprophytic. Four showing only a few lesions were able to series of overwintering larvae that ap- recover. peared healthy and vigorous wcre treated Additional tests with slight variations as follows: In the first series the epidermis were conducted with healthy larvae that of the third ventral abdominal segment had just spun up in bands. The larvae wa.s pierced with a fine sterilized needle were kept at room temperature, and only that carried spores; in the second series half of ~hem were provided with humidi- the larva.e were permitted to come in fiers. It was found that the fungus is contact with spores, without any rubbing capable of killing the larvae even when no or friction at the point of contact; in a moisture is provided, but is not capable of third or control series the larvae were producing the external mycelial growth, punctured as in the first, but with a with its consequent sporulation and dis- sterilized needle bearing no spores; and in semination of spores. However, as late as a fourth series the larvae were not treated five months after the tests were termi- in any way. After being treated, each nated, mummified larvae from these larva was placed in a small individual tests became covered with the typical glass vial containing a piece of corrugated white mycelial growth whenever moisture paper for cocooning, and the vial was was supplied. capped with a fine-mesh bronze screen. A small-scale experiment was conducted This small vial was then placed in a larger in the summer of 1939 to determine vial containing wet cotton at the bottom. whether artificial dissemination of spores The larger vial was corked tightly and would increase the mortality of larvae served as a humidifier. All vials were under field conditions. Twenty petri dishes placed in an incubator at a constant having a heavy growth of mycelium and temperature of 86° F. Observations were spores were obtained by midsummer from 24 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 40, No.1 the original pure culture. The spores from growth of Beauvaria bassiana. The growth 10 of these dishes were incorporated in in these dishes originated in, or centered calcium caseinate dust as a carrier and about, 6 larvae. It is therefore probable sticker, and this rnaterial was dusted over that 6 of the 10 larvae had been infected the trunk and main branches of a tree by B. bassiana. having a moderate crop and a moderate Apples containing various-sized live infestation. A water suspension, made larvae, which had burrowed at least a half with the spores from the remaining 10 inch into the apple, were then collected dishes, was sprayed on the trunk and main from the biological-control orchard. branches of a tree in another part of the Twenty of these applies werc spr8yed same orchard. The larvae from the bands with a suspeqsion made by triturating 4 on these trees were retained separately dead larvae containing a heavy fungous and kept under the same rearing conditions growth in an evaporating dish and diluting as the bands from the regular-count trees. to 400 m\. with tap water, 20 others wcre From the bands on the dusted tree 122 dusted with spores from 4 diseased larvae, larvae were collected, of which 32, or and 20 untreated apples served as a 26.2 per cent, died; whereas from the check. All 60 apples were placed singly in Downloaded from sprayed tree 90 larvae were collected, of rearing jars containing larvae and cor- which 33, or 36.7 per cent, died. These rugated bands to allow spinning of figures are in contrast with the low mor- cocoons. tality of 9 per cent among 16,508 larvae Of the larvae in the sprayed apples 11 collected from the regular-band trees, and died before becoming full grown, and of indicate a significant increase as a result the 9 that became full grown 2 died before http://jee.oxfordjournals.org/ of spore application. attaining the adult stage. Of the larvae These tests indicate that many mature in dusted apples 14 died before growth larvae may die in the field from attack by was complete, and :3 of the remaining 6 the fungus Beauveria bassiana. Mortality individuals died later. The total mortality among the younger larvae should be much from spraying was 65 per cent and from higher because of the moist medium of dusting 85 per cent, which indicates that their habitat. A high mortality of small, great numbers of spores sprayed or dusted newly hatched larvae has been observed on the cuticle of an apple are capable of

in the biological-control orchard, even on killing larvae already established in the by guest on June 9, 2016 unsprayed apples. In the spring of 1939, apple. particularly, the mortality of first- and In another experiment 20 clean apples second-instar larvae was unusually high. were sprayed with spore suspension, 20 The large number of apples showing were dusted, and 20 were held as an un- stings but no worms indicated that some treated check. The spraying and dusting natural-control agent was operating. The were done in the same manner as in the season had been unusually rainy and the preceding experiment, and the apples were complex conditions brought about by the then placed in jars, each with two fresh rains were exerting an unfavorable in- eggs on cellophane. Of the larvae in fluence. The first-brood infestation counts sprayed apples, only three of 29 attained made by Mr. Gould showed 13,710 worms full growth, and one of them died after and 7,382 stings, or a ratio of 1.86 worms cocooning, and on the dusted apples per sting. In 1938, a much drier season, only 2 of 26 survived, whereas in un- similar counts revealed 67,419 worms and treated apples 15 of 27 reached maturity. 13,805 stings, or a ratio of 4.88 worms per These data indicate that ingestion of sting. Small-scale experiments were con- spores is lethal to newly hatched larvae. ducted to determine whether this high and that they are less resistant than mortality could be attributed in some larger larvae. It is obvious that the fungus measure to the parasitic fungus. Beauvaria bassiana is a natural-control On July 4, 10 dead larvae taken from agent of immature as well as of mature stung apples were placed in 5 petri dishes larvae. into which the culture medium had been It is probable that other diseases exert poured. These petri dishes were allowed to some degree of natural control. Occasion- remain in the dark, cool basement of the ally mature larvae with a fleshy fungous laboratory, and examination on July 10 growth emerging from the body were en- showed that 4 dishes had a mycelial countered. C. F. Taylor, of the West Pebrl/.ary 1947 JAYNES& :MARUCCI:NATURALENEMIESOl!'CODLINGMOTH ~5

Virginia Agricultural Experiment Station, Tetramorium caespitum (L.), Solenopsis isolated this fungus and determined it as molesta (Say), and Monomorium minimum Isaria sp. In addition, dead mature (Buckley) were also important predators larvae showing symptoms that suggested of mature larvae. All these species of ants a bacterial disease were sometimes ob- except T. caespitum were more numerous served. They were usually found in in the biological-control orchard, in- cocoons of normal appearance, and had a dicating that the spray program in the deceiving healthy pink color, but were commercial orchard tended to reduce their soft to the touch. Later these larvae be- populations. came flaccid and watery, and their color The parasitic fungus Beauveria bas- changed from brown to black. siana (Bals.) exerts a small degree of SUMMARYAND CONCLUSIONs.-Insect natural control on the larval population parasites and predators exert a strong in- in all stages. Laboratory tests showed it fluence on different stages of the codling to be highly pathogenic when spores of moth. The eggs are attacked by Tricho- the organism were either dusted upon or gramma minutmn (Riley), which para- innoculated into healthy hibernating or sitizes up to 28 per cent of the first-brood freshly spun-up summer larvae. Small- eggs in some years, but fails to build up scale field tests showed that artificial dis- Downloaded from as the season progresses, being less effec- semination of spores on the foliage effected tive against the second brood, though eggs a significant increase in mortality. Labora- are more numerous at that time. The eggs tory tests revealed that spore dust or are also attacked by the nymphs and spray applied to infested fruit prevented 8 adults of a predaceous thrips, Leptothrips the newly hatched larvae from making http://jee.oxfordjournals.org/ mali (Fitch), which is not a voracious successful entrance and also killed the feeder but attacks a wide variety of hosts, larvae after entry. This fungus is partic- thereby minimizing somewhat its value ularly important in cool, wet seasons. against the codling moth. First-brood eggs The cocoon stage is probably the most are seldom attacked by these thrips, but vulnerable from the standpoint of attack as the season progresses they migrate by predators. Predation under the bands from daisy flowers and other cover-crop is high, considering the short time of ex- plants to apple foliage, and the feeding posure, and high percentages of cocoons on second-brood eggs is increased. on the ground and in trash are con- by guest on June 9, 2016 Parasites have a discouragingly small sistently destroyed by predators. The influence in reducing the larval popula- important predators of this stage arc the tion. The most common species is Asco- ants, particularly Solenopsis molesta, gaster quadridentata Wesm., which par&.- Monomorium minimum, Aphaenogaster sitizes only a relatively small number of fulva aquia, and Tetramorium caespitum. larvae. However, it was far more numer- In general, the adverse effect of sprays ous in the biological-control than in the on the natural enemies of the codling commercial orchard. moth was indicated by the fact that the A number of predators attack the most important parasites and predators mature larvae while they are seeking were less numerous in the commercial places to spin their cocoons. Experiments orchard than in the biological-control in 1938 showed that 30 per cent or more of orchard. Though the egg parasite Tricho- the larvae released were attacked by gramma and the larval parasite Ascogaster predators within 24 hours, whereas in 1939 were not numerous, the parasitization by 14 per cent were destroyed in the biologi- them was consistently higher in the cal-control orchard and 17 per cent in the biological-control orchard. Sprays, espe- commercial orchard. Ants were largely cially those containing nicotine, reduced responsible for this mortality, Formica the population of the predaceous thrips. fusca val'. subsericea Say accounting for Predatory ants were less numerous in the over 90 per cent of the total. Formica sprayed orchard, and tests with sprays pallide-fulva schaufussi incerta Emery, greatly reduced certain species, especially Aphaenogaster fulva aquia (Buckley), A phaenogaster. -11-~9-46.

LITERATURECITED

Bailey, S. F. 1940. The Black Hunter, Leptothrips mali (Fitch). JOUR. ECON. ENT. 33(3): 539-43.