RESEARCH ON THE BIOLOGY km CONTROL OF 



ORCHARD INSECTS AT THE VjALTHAII REELD STATION 



l/^lhen the original orchard at the lYaltham Field Station \;as planted in 1926, 

 it consisted of 12 trees each of the Nev/ England Seven varieties set in adjoin- 

 ing rows so that sprays applied to rows vrould shou the pest control, foliage 

 injury and fruit russet from a pesticide treatment on each of these varieties. 

 Since then, rows of Golden Delicious, Ilacoim, Kendall and a block of miscell- 

 aneous varieties have been added. Recently, about 70 trees mostly Mcintosh, 

 Cortland and Delicious were planted, and vfhen these reach bearing age, many of 

 the older trees vri.ll be removed to release the land for other use. In addition, 

 there is an orchard of about 60 trees consisting of Baldvfin, Golden Delicious, 

 Starking and luacoun on Mailing Stock III, IV and V \vhich was planned by Dr. J. K, 

 Shaw before his retirement* 



These trees are used entirely for pest control studies, a part by the Depart- 

 ment of Botany under the direction of Dr. E. F. Guba and a part by the Department 

 of Entomology under the direction of Prof, U. D. VJhitcomb, 



Early in the \Tork, the orchard was found to have an extremely high infestation 

 by the plum curculio often suffering 85 - 9^% stung fruit on trees unprotected by 

 an adequate insecticide. Consequently the insect work has emphasized the evalua- 

 tion of materials and spray schedules for curculio control. 



This Tfork is organized under State Project - Entomology 5023, Studies in 

 this project have developed methoxychlor into the No, 1 insecticide to control 

 heavy infestations of the plum curculio and shovm that it is compatible vjlth the 

 common fungicides and raiticides. It was found that dieldrin was effective against 

 curculio at the amazingly small dosage of l/U pound actual toxicant in 100 gallons, 

 but that this insecticide had no value against codling moth. Although the organic 

 phosphates such as parathion, EPN and malathion kill the beetles, they have a 

 short residual period and are unsatisfactory unless applications are repeated each 

 U or 5 days. 



By omitting some of the regular sprays, it v/as found that the calyx applica- 

 tion Tfas the most important in 1955. This is contrary to the general belief that 

 the 1st Cover spray is most timely and the tests will be continued. 



New insecticides are evaluated each season. Our trials have shown unsatis- 

 factory control of ciurculio from TDE, which is closely related to methoxychlor j 

 from endrin, which is closely related to dieldrinj and from diazanon, a phosphate 

 similar to parathion, 



A new insecticide called Guthion which has shoim promise for the control of 

 both insects and mites will be tested for its effectiveness under Massachusetts 

 conditions and its compatibility vd.th common fungicides. 



Emergence cages for apple maggot flies to aid in timing insecticide appli- 

 cations to combat this destructive insect have been operated for many years and 

 similar cages for use by Agricultural Agents in nearby counties have been stocked. 

 The effect of soil insecticides on the emergence of apple maggot flies has been 

 studied and a practical treatment with dieldrin and similar materials has been 

 developed for use in small areas where infested apples have been stored, 



— ¥, D, Whitcomb 

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