520 ANNUAL KEl'ORTS OF DErARTMENT OF AGItlCULTURE. 



WORK IN INDIANA. 



Although the onion thrips has been the subject of investigation for 

 the past four years in Florida, Colorado, California, and especially in 

 southern Texas, an outbreak of this insect in the vicinity of Knox, 

 Ind., covered an entirely new region where conditions are quite diU'er- 

 ent. Damage from the thrips in that region during 1910 was esti- 

 mated at $54,000 and undoubtedly will prove much greater in 1911, 

 as the acreage devoted to this crop has been doubled. Here the mis- 

 take has been that the growers do not begin work upon the thrips in 

 time. Experiments are now going on and new adjustments are being 

 made on sprayers which will undoubtedly give excellent results. 



Cutworms damaged onions in this region during May and early 

 June, and about 400 acres were treated with the usual bran-mash 

 remedy with excellent results. 



OTHEB WORK. 



Investigation of insects injurious to late cauliflower and related 

 crops on Long Island has been begun. 



Work upon asparagus insects has been taken up in Maryland, and 

 the egg parasite of the asparagus beetle has been imported from 

 Massachusetts. 



Although the sprays tested have been found to be effective against 

 plant-lice on the various truck crops in tidewater Virginia, it has 

 been deemed worth while to import ladybird beetles in the effort to 

 hold the plant-lice distinctly in check. The spotted ladybird has 

 been introduced from New Jersey and liberated at Warrenton, Va., 

 with promising results. In cooperation with the California State 

 Horticultural Commission 60,000 beetles were sent from California 

 for liberation near Norfolk. The species was the so-called converg- 

 ent ladybird. The main object of this last introduction was to en- 

 deavor to keep the spinach aphis under control in this way, since the 

 growth of the spinach plant is such that it is very difficult to reach 

 the plant-lice with a spray. 



Work on hop insects has been taken up in California, and the hop 

 flea-beetle, the red spider of the hop, and the hop aphis have been 

 studied. Excellent reports of progress in the control of these insects 

 have been made. 



WORK ON INSECTS AFFECTING CITRUS FRUITS. 



The work on insects affecting citrus and other subtropical fruits 

 is carried on under the direct supervision of the assistant entomolo- 

 gist, Mr. C. L. Marlatt. The principal subjects under investigation 

 have been the white fly in Florida and the orange thrips in Califor- 

 nia, together with certain minor or newW introduced insect pests, 

 chiefly in Florida. The hydrocyanic-acid gas fumigation investiga- 

 tion was completed July, 1910, and was discontinued during the last 

 fiscal year. 



WORK ON THE WHITE FLY IN FLORIDA. 



It was indicated in the report of last year that the main features 

 of the Florida white-fly investigation were approaching completion. 

 The life-history studies, fumigation experiments, and control by 



