208 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



beetles and ants feed on the larvte. Dissections, beginning with 

 beetles collected in June and extending to the time the beetles left the 

 plants, show first a great increase and then a decrease of parasitism, 

 as the following per cents will indicate. Beetles collected during the 

 first two-thirds of June showed 3% containing parasites; those on 

 June 28th, 7% ; those on July 30th, 7^% ; those on August 5th, 

 18%; those on August 8th, 421/0%; those on August 13th, 50%; 

 those on August 14th, 50% ; those on August 22d, 24% : those on 

 August 31st, 12% ; those on September 7th, 0% ; those on September 

 12th, 0% ; those on September 18th, 0%. 



Some idea of the mortality that may well occur in nature may be 

 gathered from the fact that in soil regularly watered and kept con- 

 stantly producing young plants, out of 329 larvae introduced into the 

 soil at hatching, only 34 reached maturity. 



Methods of Combating 



In the study of artificial methods we experimented with several 

 substances as preventatives, as the solution of this problem appears 

 to lie in prevention rather than in cure. One-half of an acre of 

 cucumber plants and two and one-half acres of squash were used in 

 the experiment. These were livided into plats and treated with Bor- 

 deaux (3 pounds Copper Sulphate, 4 pounds lime, to 50 gallons of 

 water), Bordeaux plus Paris green, air-slaked lime plus sulphur, sul- 

 phur, "Bug Death." Hammond's "Slug-Shot," tobacco dust, road 

 dust, arsenate of lead (3 pounds to 50 gallons), and arsenate of lead 

 (6 pounds to 50 gallons). The Bordeaux plats were further pro- 

 tected by plantings of squash as trap crops, according to Sirrine's 

 suggestion. 



The beetles were serious enough to destroy only about one-fourth of 

 the plants in the check plats, but the effect of their work was well 

 shown in the setback these plats experienced. Bordeaux mixture 

 alone or with Paris green, sulphur, and "Slug-Shot" appeared to 

 stunt the plants. Road dust afforded but little protection, "Bug 

 Death" and tobacco dust when used carefully enough seemed to be 

 fairly efficient, but the air-slaked lime and sulphur mixture seemed 

 just as successful and was certainly much cheaper. Arsenate of lead, 

 however, gave the most efficient protection and injured the plants 

 least of any mixture used. Three pounds seemed almost as successful 

 as six pounds. Our experiments would lead us to advise the following 

 treatment where fungus enemies are a serious problem: Plant trap 

 squash for either cucumber or squash between the hills of every other 

 row, or if the piece be small, about the edge a week or ten days before 



