GRAPE-BERRY MOTH IN NORTHERN OHIO. 33 



MATING. 



Mating was observed but once, this in the insectary on July 19, 



1917, at 2.45 p. m. The moths emerged the day previous and the 



jar contained 4 males and 10 females with a sprig from a grapevine 



bearing a grape leaf and cluster. The moths were on the bottom of 



the jar, not mounted, but with their bodies in opposite directions, the 



posterior parts touching. 



OVIPOSITION. 



The following observations on oviposition were made in a heavily 

 infested part of a large vineyard on June 30, 1917. Oviposition 

 began about sundown or 6.30 p. m. When the moths first appeared 

 they fluttered nervously about the vines, alighting seemingly at 

 random, generally upon clusters, though often upon stems or leaves. 

 Upon finding a cluster a moth would walk rapidly about upon a 

 grape berry, covering practically the entire surf ace. Finally becom- 

 ing quiet she would flex the abdomen until its tip touched the berry. 

 During the process the abdomen twitched or shook slightly but the 

 tip was at no time lifted and then replaced. The deposition of the 

 egg required less than a minute's time but was not instantaneous. 

 Upon completion of the deposition of a single egg the moth usually 

 flew nervously away from the cluster. The following exception 

 occurred among four depositions observed. A moth alighted upon a 

 grape and oviposited immediately without any preliminary inspec- 

 tion and upon completion walked directly onto the next grape in the 

 same cluster and repeated the operation. 



The spring brood of moths deposits a considerable percentage of 

 the eggs near the attachment of the grape to the cluster, and the 

 first-brood moths seem frequently to select a place on the underside 

 of the cluster, away from the light. 



Repeated observation has shown that the moths discriminate 

 between sprayed and unsprayed grapes as places for oviposition. 

 This was most marked in one experimental vineyard in 1916. Four 

 rows had been left unsprayed and the adjoining rows sprayed, with 

 the exception of the side of one row next to the checks. This row was 

 thoroughly sprayed from one side by the trailer method and the grape 

 clusters well covered on that side. About a third of the surface of the 

 clusters remained unsprayed and deposition by first-brood moths 

 was apparently as heavy on this unsprayed surface as on the adjoin- 

 ing check rows, whereas practically no eggs were deposited on the 

 sprayed side of the same clusters. This observation led to continued 

 study on the same point and it was substantiated repeatedly during 

 the investigations. That eggs are deposited to some extent on the 

 sprayed surface has been shown by infestation of sprayed plats. 



That early blooming varieties of grapes are more heavily infested 

 than mid-season varieties has been known generally among grape 



