518 ANKUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



INVESTIGATIONS IN TIDEWATER VIRGINIA. 



The work in tidewater Virginia, mentioned in the last report, was 

 continued through the year. Several species of plant-lice were ex- 

 perimented with, especially the cabbage aphis, the pea aphis, and tiie 

 spinach aphis, and it was found after experimentation with various 

 substances that nicotine sulphate, 1 part to 900 of water, with the 

 addition of a little wlialc-oil soap, brought about the most eti'ective 

 results. Whale-oil soap at the rate of 5 pounds to 50 gallons of water 

 gave practically the same results, but was injurious to the plants. 



In the course of experiments to stop the injury of grasshoppers to 

 kale, it was found that an application of whale-oil soap, 4 pounds to . 

 50 gallons of water, completely checked the invasion of this pest, 

 making the plants so distasteful that the grasshoppers soon left the 

 field. 



An interesting experiment was made with the use of a plumber's 

 gasoline torch against the harlequin cabbage bug, and it was found 

 that upon horse-radish 95 per cent could be destroyed by the torch 

 without injury to the plants. 



A lengthy series of experiments was made against the Colorado 

 potato beetle with arsenite of zinc and lead chromate in comparison 

 with better-known poisons. The lead chromate had little effect, 

 whereas the arsenite of zinc at the rate of 1^ pounds to 50 gallons of 

 water was fairly effective. 



An interesting series of experiments against earthworms on lawns 

 was carried on, and the best results seemed to follow the use of kero- 

 sene emulsion, together with a proprietary compound composed of a 

 mixture of 24 per cent soda soap and 20.50 per cent of fatty matter, 

 combined with some less active ingredient. 



INVESTIGATIONS IN SOUTHERN TEXAS. 



In Texas much work was done on the onion thrips, an insect which 

 damaged 25 per cent of the onion crop of Texas during the season 

 1910-11. When spraying was begun sufficiently early — that is to say, 

 before the plants had begun to curl and before the ends of the leaves 

 had begun to die — good results were gained. The insecticides which 

 have given the most favorable results are nicotine solutions combined 

 with whale-oil soap, strong turpentine soap, lye-sulphur, and the 

 lime-sulphur solutions. Kerosene emulsion was used to some extent, 

 but, owing to the hardness of the water in southern Texas, it was 

 very difficult to secure an emulsion that would remain stable long 

 enough to be applied. More work must be done in order to devise 

 some method of spraying that will lessen the number of applications 

 and to perfect a machine which will cover more than one row at a 

 time without injuring the onions. 



The seed-corn maggot caused damage to onions and other truck, 

 especially beans, in the lower Rio Grande Valley, and the injury was 

 greatest where cottonseed meal or other decaying organic matter 

 was used as a fertilizer. The damage was almost entirely to the 

 first planting, and where this approximated 50 per cent the entire 

 crop was plowed up and destroyed by fire. The soil was cultivated 

 in some form daily for about a week, and then a second planting 

 was made of the field. This second planting did not suffer. 



