40 INSECTS INJURIOUS TO GARDEN AND ORCHARD CROPS. 



August, and is probably the product of the second brood of larvae pro- 

 duced during the previous year. The third lot, which forms the normal 

 second brood, appears late in August and probably later. This pecul- 

 iarity in reproduction and the subsequent appearance of the parent 

 moths is of course, somewhat hypothetical and evidently a survival of 

 the times when this species lived in the Tropics, where breeding was 

 almost continuous except during rainy seasons. The instinct of the 

 insects is still to appear early and remain late, provided the appropriate 

 plants are available for their food. 



ECON03IIC STATUS. 



in the District of Columbia and in nearby localities in Maryland the 

 squash-vine borer has been during the past two years the species most 

 to be feared as an enemy to the culture of squashes. Of its status in 

 other regions Dr. Smith, writing in 1891, says that it is "the most dan- 

 gerous enemy to squash culture in New Jersey." In New England, 

 according to another writer, it is "the most obstinate enemy to this 

 crop in the settled sections." In other localities this species has to 

 yield the first place as a cucurbit pest to the striped cucumber beetle, 

 particularly where cucumbers are the staple crop; and in others, where 

 melons are the chief product, the melon louse is the principal pest. 



PREVENTIVES AND REIVIEDIES. 



Ordinary insecticides are of no value against this insect when once 

 it has entered the vines, and repellents are also practically useless. 

 The measures that have been found of greatest value are, in brief: Not 

 to plant in or near infested ground; to plant early varieties for the 

 protection of "late squashes; to harrow infested fields late in fall and 

 plow deeply in spring, or reverse the process, to prevent the moths 

 from issuing; to encourage the growth of secondary roots by covering 

 the vines at the joints with earth; to destroy dead vines and old plants 

 as soon as the crop is made; to keep the plants in vigorous condition, 

 free from other insects and diseases; to cut out such borers as may suc- 

 ceed in entering the vines, which they will sometimes do in spite of the 

 observance of precautionary measures; and to capture the moths early 

 in the morning or toward dusk when they are less active than in the 

 heat of the day. The employment of all the methods of control men- 

 tioned is not necessary, but if the grower would make certain of secur- 

 ing a good crop in localities where this and other enemies of the squash 

 occur in their most troublesome numbers it will be wise to observe most 

 of these precautions, and if possible it will be well to secure the coopera- 

 tion of neighboring farmers in their observance. 



