12 MASS. EXPERIMENT STATION BULLETIN 409 



Oil Emulsion. — Oil emulsion reduced the Infestation about 80 percent when 

 diluted to contain 3 percent actual oil. There was no significant difference 

 between the commercial emulsions, Kleenup and Spra-Cream, and any emul- 

 sion of this type should be satisfactory. In 1941 when it was applied with a 

 low volume pump, the oil emulsion was slightly less effective. It was evident 

 that the oil spread with difficulty Into the crevices among the loose bark where 

 the eggs are laid and that a heavy, thorough application Is necessary to give 

 complete wetting on old grape canes. Although the tests in which nicotine 

 sulfate, dinltro cresol powder, and dinltro phenol powder were added to the oil 

 emulsion were limited to one experiment and therefore the results are not con- 

 clusive, the increased control did not seem great enough to warrant the addi- 

 tional cost. The addition of the dinltro powders appeared to aid the wetting of 

 the spray, and this apparently contributed to the slightly better control as much 

 as the added toxicity". 



Sodium dinitro cresylate. — Elgetol was the most effective material used and 

 was the only material which gave 85 percent or more control in the field experi- 

 ments. When diluted to 1 percent it was most satisfactory. A J^ percent dilu- 

 tion lacked sufficient toxicity and a IJ^ percent dilution was not significantly 

 superior. Elgetol wet the rough bark of the canes very easily and thoroughly. 

 It discolors paint badly and should not be used near buildings or on arbors which 

 are painted with light colors. 



SUMMARY AND CONCLUSIONS 



Although the grape plume moth has not become a serious pest in commercial 

 vineyards. It is an abundant and annoying pest in home vineyards, which include 

 the great majority of grapevines in eastern Massachusetts. 



The common varieties of cultivated grapes In New England, such as Concord, 

 Delaware, and Niagara, are favorite hosts of this Insect. 



This bulletin, and a preliminary report on the same studies, give the first pub- 

 lished description of the eggs of the grape plume moth as well as of the other life 

 stages in detail. 



This insect has one generation annually in Massachusetts. The moths, which 

 are weak fliers, lay eggs In the pubescence of the canes at the axils of one- or 

 two-year-old shoots. Incubation takes place soon after oviposltlon, but the larva 

 does not leave the eggshell until the following year. The larva feeds for about 5 

 weeks and the average pupation period was 12.64 days, making the average time 

 from the hatching of the caterpillar to the emergence of the moth about 7 weeks. 



The grape plume moth lives as an egg or as a small larva In the eggshell from 

 late June until the following May, a period of about 320 days. Hatching occurs 

 about May 10 to 15 when the grape buds are breaking open, and the larva 

 feeds and grows until mid-June. Pupation occurs in late June and the moths 

 emerge and lay eggs in early July. 



Injury to the vine Is caused entirely by the feeding of the larva or caterpillar 

 In the opening bud and at the tip of the new shoots where they tasten a few leaves 

 into a nest. Only a few blossom buds are damaged, and the loss of fruit is slight. 



Five species of parasitic insects have been reared from the larva of the grape 

 plume moth, but in Massachusetts these and other natural enemies have been 

 unimportant. Careful annual pruning by one of the recommended pruning 

 systems removes 70 percent or more of the eggs, and is an important factor m 



