642 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



whicli. however, has not yet become seriously abundant. There are 

 also several species of thrips, as well as an undescribed mite, which 

 attack alfalfa, and another mite attacks barley in Arizona. Upon 

 all of these si:)ecies studies have been begun. 



WORK ON INSECTS AFFECTING VEGETABLE CROPS. 



The work on insects injurious to vegetable crops, which includes 

 truck crops and some of the smaller berries, and some other work 

 which can not otherwise be classified, such as the investigation of hop 

 insects, has been carried on under the direct supervision of Dr. F. it. 

 Chittenden, as in previous years. Several stations, established at 

 first in a tentative way, are now nearly under full swing, as follows: 

 In tidewater Virginia, where general work has been done for several 

 years; in southern Texas, where a somewhat different line of work 

 has been carried on; in southern California; at Rockyford, Colo.; in 

 Indiana; on Long Island, and in Maryland. The life hi-tories and 

 habits of quite a number of species not hitherto investigated have 

 been nearly completed, and some insects comparatively new as pests 

 ha"\'e been studied. New insecticides, especially in combination with 

 others, have been tested at all the stations, and some eminent suc- 

 cei^^ses have been achieved in demonstration. 



INVESTIGATIONS IN TIDEWATER VIRGINIA. 



Series of arsenical spraying tests against the Colorado potato 

 beetle in tidewater Virginia, begun toward the end of the laSt fiscal 

 year, have been continued with different strengths of arsenite of zinc 

 in comparison with arsenate of lead and Paris green and in combina- 

 tion with or in comparison with Bordeaux mixture, lime-sulphur, and 

 other sprays. The results will be available when the potato crop is 

 dug. 



While observations were bemg contmued on the seed-corn maggot, 

 a general pest in vegetable fields, a field comparatively free from 

 these insects became seriouslj^ infested after the application of fish 

 scrap or tankage. This attracted the flies, which laid their eggs, and 

 tlie field was soon found alive with maggots. This fish scrap is much 

 used in tidewater Virginia, both as a fertilizer and as an insect de- 

 terrent, but it is obvious that in this case at least its use was detri- 

 mental rather than beneficial. 



Lady-beetles obtained from California were liberated in the vicinity 

 of Norfolk and Portsmouth, Va., to the number of more than 100,000. 



Experiments against Fuller's rose beetle were carried on at this 

 station, but nothing more efficient than hand picking was found. 



INVESTIGATIONS IN TEXAS. 



While many of the truck-crop insects have been studied in Texas, 

 and reports upon them will soon be available, the onion thrips, as 

 during the previous year, was the principal project. Damage by 

 this insect during 1911 w^as very considerable, but it has not been so 

 pronounced during the first part of 1912. Clean cultivation has been 

 practiced with favorable results, and the spraying solutions which 



