316 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



isfactory progress is being made in I'earl Kiver, Hancock, and Har- 

 rison Counties. New infestations, however, have developed in Jack- 

 son and George Counties. The hearty and thorough cooperation of 

 the plant boards of Alabama, Mississippi, Gedrgia, and Florida has 

 materially facilitated the progress of the eradication campaign. 



Insects destructive to cabbage and bei^ted crops. — Lead arse- 

 nate and Paris green sprays and laundry soap added as a spreader or 

 "sticker'" for the control of the common cabbage worm have proved 

 eifective. Preliminary experiments were made witli nicotine dust 

 for the flea-beetles which are specific enemies of cruciferous plants 

 in Louisiana, with encouraging results. Nicotine dust was also 

 applied effectively in the District of Columbia and vicinity and 

 in New Jersey for cabbage flea-beetles, with the result that it killed 

 all with which it came in contact, but, since these insects are ex- 

 tremely active and hop and fly readily, it is difficult to give a definite 

 statement as to results. The various plant-lice or aphids which at- 

 tack cole crops, including the cabbage aphis, turnip aphis, and spinach 

 aphis, have been found to yield to dusting by nicotine, which kills 

 a very high percentage. 



Insp:cts injurious to potato and related crops. — Experiments on 

 the potato leafhopper, the cause of potato " hopperburn^" have been 

 continued under abnormal weather conditions, and a clear-cut in- 

 fluence of the treatment upon foliage conditions and yield was less 

 evident than in former years. Three types of experiments, cover- 

 ing effective planting dates, effective number of sprayings, and re- 

 sistant seed selection, were carried on, and commercial experiments on 

 a large scale in several northern counties of Wisconsin are now 

 under way, with a view to ascertaining the variations m treatment 

 necessary on different soil types and under various climatic con- 

 ditions. ' Farmers' Bulletin No. 1225, entitled " The potato leaf- 

 hopper and its control," has been issued and covers the .subject in a 

 practical way to date. Work on the potato aphis is nearing com- 

 pletion, and additional facts have been learned in regard to the 

 life history and control of the spinach aphis, the tarnished plant-bug. 

 and flea-beetles on potatoes and related crops. 



The striped cucumber beetle. — The control of the striped cucum- 

 ber beetle from a practical standpoint has been brought near comple- 

 tion through the excellent results obtained by nicotine dusts. A 

 preliminary report has been published showing how this, our most 

 destructive pest of seedling cucumbers, can be controlled by the use 

 of a dust containing 1.6 per cent nicotine. In Wisconsin a com- 

 bination of nicotine-Bordeaux dust, prepared by spraying nicotine 

 sulphate on powdered monohydrated copper sulphate and lime, 

 secured even better killing than did the nicotine-kaolin and lime 

 mixture, apparently evolving nicotine more slowly and hence acting 

 over a longer period than the usual mixture. The method of appli- 

 cation is of the greatest importance to obtain the best results. A 

 good volume of dust thrown quickly and with force to drive the 

 beetles from cracks in the soil about the plants and to reach active 

 individuals which escape by flight has been found necessary. 



Strawberry and blackberry insects. — Work on the strawberry 

 leaf-roller in New Jersey has been completed during the fiscal year. 

 It embraces a thorough study of the insect's biolo^ in its occurrence 

 in that State and methods for its control. Certain parasites reared 



