Ninth Report of the State Entomologist 363 



of the various preventive and remedial methods that have been proposed 

 against the beetle, Diabrotica vittata. The methods experimented with 

 were divided into these four classes: 1. The use of offensive odors; 2. 

 Mechanical coating of the leaves; 3. Poisonous coating of the leaves; 

 4. Inclosing plants under tents or gauze-covered frames. 



The results of the above, made when the beetles were exceedingly- 

 abundant, were as follows: 



Of class one, five substances were tested, viz.: hen manure, cow 

 manure, carbolic acid, and bisulpliide of carbon. None of these proved 

 practically successful. 



Of class two, three substances were tried, viz. : coal soot, g3^psum, and 

 saltpetre. Of these, gypsum only showed some beneficial effect, while 

 the other two were Avorthless. 



Of class three, were pyrethrum, slug-shot and peroxide of silicates. 

 Pyrethrum killed the beetles with which it came in contact, but soon 

 lost its efficacy. Slug-shot injured the plants. Peroxide of silicates 

 was beneficial, and saved such plants as had been well started. 



Class four, or fencing out the insects, was hj far the most satisfactory. 

 It was best accomplished by covering the plants with a piece of cheese- 

 cloth about two feet square, held up by a bent hoop or wire, or two 

 crossing at right angles, and fastened at the edges by loose earth or 

 stones. 



It would seem from the above that safety from the cucumber beetle 

 is to be found only by excluding the insect from the plant. This method 

 would, of course, be effectual if all attack from above and below ground 

 could thus be prevented; but unfortunately it is not proof against the 

 operations of the larva in the stalk, or the beetles that may develop 

 from the ground beneath the plants. 



It will be observed, however, that only a few substances were tested, 

 and while these proved inefficient, it is not improbable that others, had 

 they been tried, might have given better results. Paris green and 

 London purple were not experimented with. Possibly they would not 

 have been as injurious as slug-shot. 



A writer in one of our journals {Garden and Forest, for March 12th,. 

 1890), has stated that he annually saves his cucumber plants by sprink- 

 ling a handful of bone dust over each hill as soon as the seed-leaves 

 appear, and rarely has to repeat the operation, unless washed off by rain. 



A correspondent of the Rural New- Yorker claims as a cheap, simple, 

 and effective preventive, spirits of turpentine mixed with common land 

 plaster — about a tablespoonful of the turpentine to two or three gal- 

 lons of plaster. " In the morning after the plants have shown up nicely. 



