ANNUAL REPORT, 1943-44 39 



Massachusetts for several years, it has never been so destructive as it was in 

 some orchards this year. Many of the infested trees lost one-third or more of 

 their leaves and the remainder were badly mined. 



Reports indicate that this leaf miner is not likely to be an annual pest but may 

 be abundant for 2 or 3 years after which it is held in check by parasites. Satis- 

 factory control should be obtained by spraying with nicotine sulfate when the 

 moths are flying and laying eggs. There are usually three generations annually; 

 but if the first generation is controlled by spraying at about the pink bud stage, 

 further infestations will be prevented. 



Biology and Control of the Grape Plume Moth and Grape Cane Girdler. 



(W. D. Whitcomb and Wm. E. Tomlinson, Jr., Waltham.) Studies of the Grape 

 Plume Moth were completed and the results were published as Bulletin 409. 



Insectary studies of the grape cane girdler were conducted on potted grape 

 vines. The first eggs were laid by caged beetles on June 2 and oviposition con- 

 tinued until July 14. The^ greatest number of eggs was laid June 3 and 4, and 77 

 percent were laid from June 3 to 21. The average number of eggs laid was 10.5 

 per female, but two beetles laid 16 eggs each. The average length of life from 

 oviposition to adult was 47.5 days of which 20 were spent as a boring grub in the 

 grape cane. Limited observations on caged beetles indicate that they hibernate 

 under stones and long grass rather than under fallen grape leaves beneath the 

 vines. 



Spraying the vines with cryolite 3 pounds and Fermate 1 pound gave better 

 protection than applications of lead arsenate and bordeaux mixture or wettable 

 derris powder. 



Biology and Control of the Celery Plant Bug. (W. D. Whitcomb, Waltham.) 

 The celery plant bug {Lygus campestris L.) continued to be destructive to celery 

 in the Boston market garden area in 1943, and some fields suffered losses as high 

 as 50 percent of the early crop and from 10 to 25 percent of the late crop. The 

 loss on the early crop was correlated with hot weather during the early part of 

 the growing season which caused heart rot and seed stalk development that was 

 easily confused with plant bug damage. Severe heart rot and dwarfing of the 

 plant was definitely connected with plant-bug injury in cages where celery con- 

 fined with 2 bugs per plant was severe!}' injured; while celery from which plant 

 bugs were excluded, and where the heart stalks were punctured by a needle to 

 imitate plant-bug injury, grew normally. 



The bugs spend the winter as adults, and in 1943 they first appeared in the 

 celery plantings about May 15. There are two generations during the summer. 

 The number of first generation bugs per 100 plants was greatest from June 26 

 to 29 soon after the majority of the nymphs had hatched. During hot weather 

 the period from hatching to adult is about 35 days, and 98 percent of the bugs 

 had become adult on July 10. At Waltham the white celery varieties such as 

 Supreme Golden and Early Fortune were most heavily infested, having 173 to 

 199 bugs per 100 plants at the peak of infestation. 



The first infestation on late celery was observed about July 13, about 2 weeks 

 after the plants were set out, and nymphs were found on July 20. Two peaks 

 of infestation of the second-generation bugs developed on the celery, first on 

 August 17 and again on September 11 to 14. 



Insectary studies in late August and September showed the average period 

 from egg to adult to be 45 days. This period varied from 39 to 43 days while 

 the mean daily temperature was 66° to 67 °F., and from 48 to 50 days when the 

 mean temperature was 61° to 62°. Incubation of the egg required 9 to 13 days, 



