ANNUAL REPORT, 1934 49 



The primary purpose of the experiment was to determine the relative numbers 

 of codling moth, the time of emergence, and the possible control of the pest by 

 means of the light traps. Seasonal catches of this insect showed that the stragglers 

 from the first brood were present in the orchard until July 14. The second brood 

 appeared a few days later and reached a peak of moth emergence on August 10, 

 then receded slowly to the last night the light traps were operated, August 28. 

 A comparison of these figures with emergence cage figures in 1924 (Massachusetts 

 Agricultural Experiment Station Bulletin No. 233) shows that emergence from 

 the cages was a few days slower than in the orchard, as indicated by the light 

 traps, making allowance for any differences in seasonal emergence in the two 

 years in which the records were taken. This seems to indicate that the light 

 traps are perhaps more valuable than the emergence cages in determining the 

 correct timing of orchard sprays for codling moth control, and that their chief 

 usefulness lies in the accurate data they furnish on the seasonal abundance of 

 the insect rather than in its actual destruction. 



Counts of all kinds of insect injury on Mcintosh apples in the orchard gave the 

 following results: The row of electrocutor traps had 93.1 percent clean fruit while 

 the bulb and pan row had 92.5 percent clean fruit. On the unlighted row adjoining 

 the first-named row 95 percent was clean, whereas the third row adjoining con- 

 tained 86.1 percent clean fruit. Codling moth injury in the row trapped by the 

 electrocutor traps was .4 percent and in the row trapped by the bulb and pan 

 traps, 1.35 percent. In one row adjoining the first-named traps injury was 2.9 

 percent; in the third row adjoining, 7.5 percent. Band catches of codling moth 

 larvae furnished a definite indication of the value of light trapping. In the electro- 

 cutor trapped row 21 larvae were caught in the bands, whereas 19 were caught in 

 the bulb and pan trapped row. A ring of 12 trees in a circle one row outside the 

 two light rows contained 160 larvae, while the circle formed by 22 trees in the 

 third row outside the lighted rows contained 537 larvae. In the 44 banded trees, 

 737 larvae were present, even after the regular spray and dust schedule. 



As an aid in the supplementary control of orchard pests when combined with 

 the regular spray program, as a means of timing the spray schedule according 

 to the emergence of the different orchard pests, and as a means of securing a 

 record of the occurrence of the various insects both harmful and beneficial, insect 

 light traps seem to have a value to the comniercial fruit grower. 



Apple Leaf-Curling Midge. (W. D. Whit comb, Waltham.) The early infesta- 

 tion by the apple leaf-curling midge (Dasyneura malt Kieffer) in 1934 was heavy, 

 but midsummer drought and decreased leaf growth reduced the abundance of the 

 later generations below that of 1933. No new infestations were discovered outside 

 the area established last year. 



At Ipswich, emergence and oviposition by the first generation began about 

 May 25 and continued to June 8, the first larvae hatching about June 1. Maggots 

 emerged from rolled leaves from June 19 to about July 1, and adults of the second 

 generation were present from July 3 to 15, laying eggs from which mature maggots 

 developed July 27 to August 3. After this date no regular cycle was noticeable but 

 scattering infestations developed irregularly until October. 



Population counts on representative infested trees showed an average of 345.7 

 eggs per bud, an average of 277.4 maggots per bud in rolled leaves, an average of 

 484 infested tips per small tree, and an average of 174.66 to 361.8 maggots per 

 square foot collected under the tree. Since most of the trees spread 80 to 100 

 square feet, the estimated number of maggots is 15,000 to 25,000 per tree. 



For the first time it was observed that some of the maggots crawled down the 



