GRAPE-BERRY MOTH IN NORTHERN OHIO. 37 



were parasitized. The parasite was not determined but was thought 

 to.be the same as recorded by Johnson and Hammar 1 at North East, 

 Pa., in 1906, Trichogramma pretiosa Riley. 



SUMMARY. 



The present account of the life history of the grape-berry moth in 

 northern Ohio is based upon a series of studies made in 1916, 1917, 

 and 1918. 



In the course of a year the grape-berry moth in northern Ohio 

 produces one full brood and a partial second, the second brood of 

 larvae being much larger and more destructive than the first. 



The grape-berry moth passes the winter in the pupal stage in 

 cocoons in old grape leaves under the grape trellis. Under a leaf 

 blanket approximating conditions in a protected part of a vineyard 

 the mortality among the pupae was 80 per cent during the winter of 

 1916-17 and 76 per cent during the winter of 1917-18. 



The first moths emerge in the spring about 10 days before grapes 

 begin to bloom but emerge in greatest numbers during and imme- 

 diately following the period of grape bloom. In 1917 but 4 per 

 cent emerged previous to bloom, 50 per cent during grape bloom, 25 

 per cent in the 10-day period following bloom, and the remaining 21 

 per cent later in the season. Moths begin ovipositing about 4 days 

 after emergence and the eggs hatch in from 3 to 10 days, with 5 days 

 as the average length of the egg stage. 



The first-brood larvae feed in the young grapes for a period of from 

 14 to 37 days, and the average length, of the feeding period was 20.6 

 days in 1917. At the end of the feeding period the larvae leave the 

 grapes and go to tender grape leaves on the vines in which they spin 

 their cocoons. The prepupal period lasted for from 1 to 3 days and 

 averaged 1.77 days with the first brood in 1917, and lasted for from 

 3 to 7 days and averaged 4.15 days with the second brood in 1916. 

 The pupal period varied from 11 to 16 days and averaged 13 days 

 for first-brood pupae in 1917. The total period in the cocoon varied 

 from 6 to 32 days with an average period of 15 days. 



The life cycle of the first generation in 1917, taken as a total of the 

 average length of the separate stages, was 39.79 days. The total of 

 the maximums was 76 days and of the minimums 23 days. 



The incubation period of second-brood eggs varied from 4 to 10 

 days with 5.1 days as the average period. The feeding period of 

 second-brood larvae was from 16 to 36 days and averaged 24.18 days 

 in 1916. All other records have given this period as about 40 days 

 which is probably nearer the average condition than the figures 

 presented here. 



i Johnson, Fred, and Hammar, A. G. The grape-berry moth. U. S. Dept. Agr., Bur. Ent. Bui. 116.. 

 pt. II, p. 39. 1912. 



