REMEDIES FOR THE STRIPED CUCUMBER BEETLE. 



There are probably few injurious insects for which 

 more remedies and preventives have been recom- 

 mended than for the striped cucumber beetle (Dia- 

 brotica vittata), the everywhere abundant yellow 

 "bug" with black stripes along its back, which 

 attacks squashes, cucumbers, melons, and in fact 

 nearly all cucurbitaceous plants. A large propor- 

 tion of these remedies are doubtless worthless, if, 

 indeed, not positively injurious. 



In order to get at a more definite knowledge of the 

 value of these various substances, the writer undertook, 

 last season, at the Ohio Agricultural Experiment Station, 

 a series of experiments, in which it was designed to give 

 each a field test, and to arrive, if possible, at some relia- 

 ble conclusions for the guidance of the interested public. 



The methods that have been proposed for preventing 

 the injuries of this insect may be divided into four classes : 

 I. Keeping away by strong odors supposed to be offen- 

 sive to the insects. 2. Coating the plant with substances 

 so as to make a mechanical barrier to the insect. 3 . Coat- 

 ing the plants with poisonous substances. 4. Fencing out 

 the insects. 



Four experiments with the first class of preventives 

 were conducted, the substances used being hen manure, 

 cow manure, kerosene and crude carbolic acid. The lat- 

 ter was the most effective of the four, having an evident 

 effect in keeping away the beetles ; but even it was not 

 a complete success. The three other substances were 

 practically worthless. 



Two substances of the second class were tried — 

 saltpeter and gypsum. The former proved worse 

 than useless, while the latter had quite a decided 

 effect in saving the plants ; not sufficient, however, 

 to make it reliable where the beetles are as thick 

 as they often are in many parts of Ohio. 



The same may be said of substances of the third 

 class — the diluted poisons. We tried both slug 

 shot and peroxide of silicates. The former proved 

 directly injurious to many of the young leaves to 

 which it was applied, perhaps because it had been 

 on hand for some time. The peroxide had a de- 

 cided saving effect, and where the beetles were 

 not very thick, would probably bring the plants 

 through in good condition. But the trouble with 

 all these substances is that the beetles burrow 

 down in the earth about the stem, and devour it, 

 often cutting it completely off Very often they _ " ■ 

 burrow down in the soil long before the plants 

 have appeared above ground, and eat the stem 

 and seed-leaves so that the plants never come up. 



Obviously the only way to prevent this sort of injury 

 is to fence out the insects. Of the various forms of ap- 

 paratus for this purpose, some are shown in the figures. 



Perhaps the simplest method, and one which I am told 

 in largely practiced in some of the great melon growing 

 sections of the state, is that of laying a piece of thin 

 cloth over the hills before the plants are up, covering 

 the edges of it with loose earth. We tried this quite ex- 

 tensively and found that it worked very well while the 

 plants were young, but was liable to cripple them if left 

 on too long. To obviate this difficulty, we tried various 

 methods of holding the cloth up in the middle. One of 

 the simplest and perhaps most satisfactory method is to 

 take two pieces 

 of wire and put 

 their ends in the 

 ground so as to 

 form a double 

 arch, like the 

 center arch of a 

 croquet ground. 

 Over this the 

 cloth is laid, the 

 edges being held 

 down b y loose 

 earth as before, 

 and as shown in 

 Fig. 7. Or the 

 wires may be 

 twisted around 

 each other, as 

 shown in Fig. 3 ; 



l."ia. 3. 



F!s. 5. 



Fig. 6. 



Fig. 7. 



or a single long wire may be bent as shown in Fig. 2. 

 A half barrel hoop makes a very good substitute for the 

 wire, as may be seen in Fig. 5. 



The best cloth we found for the purpose is the lightest 



