402 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



selected by inspectors are taken from farms under supervision and 

 planted in approved fields. This method is preferred by the farmers,, 

 since they are not dependent upon outside sources. The final success 

 of this method will be of great importance in proving the direct value 

 of cultural efforts on the part of individual groAvers. In Alabama a. 

 small new infested area was discovered in a fishing settlement on 

 the Gulf of Mexico. This infestation, the only one known in the 

 State, does not immediately threaten the commercial sweet-potato- 

 growing areas, but repressive measures are being applied. The num- 

 ber of infestations in Mississippi has increased to some extent during 

 the past year, and insufficient personnel, coupled with high winter 

 temperatures which favor the growth of volunteer sweet potato, is. 

 responsible for the increased infestations. In Pearl River County, 

 Miss., the planting of " outlaw " slips is responsible for the extension 

 of the infested area. An interesting occurrence of the year was th& 

 discovery of an infestation in Stephens County, Okla. The close 

 cooperation of the State plant boards of Mississippi, Florida, Ala- 

 bama, and Georgia has continued to facilitate the eradication cam- 

 paign. 



Insects injurious to potato, tomato, and related crops. — Tests 

 for determining the minimum application of various arsenicals for 

 the control of the Colorado potato beetle are being conducted in. 

 Louisiana. Attempts to control the tomato suckfly, Dicyplius sepa- 

 ratus Uhl., in Texas have led to the conclusion that from 3 to 5 appli- 

 cations of a 3 per cent nicotine sulphate dust are required. Further 

 work with improved dusts is planned. Plantings' of trap crops of 

 sweet corn for the tomato fruitworm were found to be ineffective 

 in Louisiana. The only promising remedy for this insect consisted 

 in keeping the tomato foliage well covered with arsenicals during 

 the fruiting period, a difficult operation in regions of frequent rains. 

 The Australian tomato weevil, which was recently discovered in: 

 southern Mississippi, has been found to be more widely distributed 

 over the Gulf Coast region than had been anticipated. It has been 

 determined to be, in restricted localities, a severe pest on turnips and 

 tomatoes. Investigations are still under way on the potato leaf- 

 hopper and potato aphis. 



Cucurbit insects. — Studies on the striped cucumber beetle are- 

 being continued in Wisconsin and Virginia. The value of nicotine 

 dust for the control of this pest has been proved by additional ex- 

 periments, and at the present time improved dusts are being tested 

 against it in the hope that various combination treatments may be 

 developed. Nicotine dust has also been tested against the melon aphis 

 in Maryland and Texas and it has been found to give a much more 

 satisfactory control than the nicotine soap sprays. The belted cucum- 

 ber beetle, Diabrotica talteata Lee, has been studied in Louisiana,, 

 where this insect within the past few years has developed into an 

 important and threatening enemy of beans, cucurbits, and other 

 vegetables. 



Insects injurious to cabbage and other cole crops. — Experi- 

 ments in the control of various insects affecting cabbage and related 

 crops have been conducted in South Carolina and Louisiana. Nico- 

 tine dust has been found to control effectively the turnip aphis, Rho- 

 pcdosiphuTTi pseudohrassicae. Insecticide tests are also being con- 

 ducted against the cabbage aphis and the harlequin cabbage bug. 



