THE CONTROL OF THE SQUASH YL\E BORER IN MASSACHUSETTS. 



by haelan n. worthley. 



Distribution and Importance. 



The squash vine borer ^ is a native of the New World, and apparently is of 

 tropical origin. It has spread northward over that j^ortion of the United States 

 east of the Rocky Mountains, and into Southern Canada. It is found as far 

 south as Argentina. 



In many localities the squash vine borer is the most serious enemy of winter 

 squashes. Pumpkins and summer squashes are also alfected, and more rarely 

 melons and cucumjjers. 



Description. 



Egg. — The egg of the squash vine borer is shown in Plate I, figure 1 and 

 Plate II, figure 2. It is about one-twenty-fifth of an inch in length, and is of 

 a dark reddish brown color. As may be seen in Figure 1, the eggs are not laid 

 in clusters, as in the case of the squash bug eggs, but singly. Magnification, 

 as in Plate II, figure 2, shows the chorion to be finely reticulated into tiny 

 hexagonal figures. 



Larva.- — ^ The larva, or "borer" (Plate I, figure 1 & Plate II, figure 3) as 

 it is commonly called, is a fleshy, white, nearly hairless caterpillar with a black 

 head and a dark brown to black thoracic shield. When full grown it measures 

 about an inch in length. Newlj'-hatched larvae, which are commonly not 

 detected in the field, are about one-sixteenth of an inch long, sparsely covered 

 with hairs, and with a broad black head, from which the white body tapers 

 away to the anal extremity. In appearance the borer is quite distinct from the 

 larva of the striped cucumber beetle, with which, however, it is often con- 

 fused. The latter is but three-tenths of an inch long and is very slender, 

 with the head and anal plate dark brown. 



Pupa. — The pupa (Plate I, figure 1) is contained in an earth-covered 

 cocoon of very tough, black silk about three-fourths of an inch long. The 

 pupa itself is about five-eighths of an inch leng, and is of a dark shining brown 

 color. The head bears a horn-like process between the eyes, and the abdomen 

 bears circles of hook-like spines. 



Adult. — The adult moth (Plate T, figure 1) is five-eighths of an inch or more 

 in length, with a wing spi'ead of an inch to an inch and a half. It is strik- 

 ingly beautiful, Avith long narrow olive green fore wings, bearing a fringe 

 of blackish hairs at the tips. The hind wings are transparent, bearing scales 

 only along the veins. The al)domen is covered with red or orange scales, and is 

 marked with transverse white lines and a longitudinal row of black or bronze- 

 colored spots. The tarsi are banded with white, and the hind legs are covered 

 with long black, white, and orange-colored hairs. The sexes are quite similar, 

 the male being more brilliantly marked than the female, and with a narrower 

 abdomen. 



Life History and Habits. 

 The squash vine borer passes the winter as a full-grown larva. It is en- 

 closed in the tough silken cocoon which it spins in the soil of squash fields, at a 

 depth of from one to six inches below the surface of the ground. Pupation 

 occurs Avithin this cocoon in the spring, and lasts about three weeks. At the 

 end of this time the pupa cuts through one end of the cocoon by means of 

 the horn-like process on its head, and Avriggles to the surface of the ground, 

 being aided in this endeavor by the circles of spines around its abdomen. 

 When it projects above the ground about three-fourths its length, motion ceases, 

 and very shortly the pupal skin splits back from the head and the adult moth 

 slowly drags itself forth. The emergence occupies in the neighborhood of five 

 minutes, Avhen the freed moth climbs vipon some nearby oljject to expand and dry 

 its wings in readiness for flight, Avhich can be accomj^Iished in a matter of 

 fifteen minutes folloAving emergence. 



Plate I, figure 1, is a record of continuous observations from 1920 to 1923, 



^ Melitta satyr iniformis Hiibner (Lepidoptera, jEgeriidse). 



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