11 



The average increase thus estimated is 4.5 tons per acre. The average 

 Avholesale price of winter squashes during the sales-from-harvest period, Sep- 

 tember 1 to November 15, appears to be $.03 per pound or $60 per ton.^ 

 The value of the expected average increase of 4.5 tons per acre is therefore 

 $270. Subtracting from this figure the cost of treatment leaves an estimated 

 average net profit of fi'om $241.65 to $243.45 per acre. 



Summary. 



The squash vine borer is a serious native enemy of winter squashes and related 

 plants, for Avhich no adequate remedy has previously been devised. The 

 adult insect is on the wing during July, laying its tiny, reddish eggs upon the 

 squash plants. The borers developing from these eggs cause the vines to 

 droop and die by tunneling in the stem and girdling the plant, throwing masses 

 of yellow frass out through holes in the stem, and causing the stem to rot. 

 These larvae leave the vines in the fall, and spin cocoons in the soil. A 

 number of cultural practises, such as fall plowing of infested fields, adequate 

 fertilization to promote growth and to aid the secondary roots, and covering 

 the runners with earth, have been recommended, as has the practise of cutting 

 the borers from infested vines. 



Experiments at this Station indicate that nicotine sulfate (Black-leaf " 40 "), 

 at the strength of 1 part in 100 parts of water, kills over 97 per cent of the eggs, 

 and, at the strength of 1 part in 250 parts of water, kills over 90 per cen^ of 

 the eggs. Spraying should be done four times, at weekly intervals beginning the 

 first week in July, using the stronger dosage with compressed air sprayers 

 or similar machinery, and the weaker dosage with barrel pumps or poAver 

 sprayers. When thoroughly done, spraying will largely eliminate borers from 

 the fields. Complete extermination is then possible by cutting out the remain- 

 ing borers during the middle of August. 



The treatment is estimated to cost between $25. and $30. per thousand plants. 

 Thus intensive methods of culture and careful, economical spraying must be 

 the rule where the treatment is to be found practicable on a commercial scale. 

 However, estimates of various squash growers regarding the expected increase 

 in yield from borer-free plants indicate an average net profit of over $200. per 

 acre from the use of this treatment. For the home gardener, to whom cost of 

 production is a small item, it offers a ready means of successfully figbtiho- 

 this most troublesome enemy of squashes. * 



» Computed from the Boston Produce Market Reports, 1920-1923. 



