BUREAU OP ENTOMOLOGY. 231 



Insects affecting cucurbits. — The principal enemies of cucum- 

 ber, melon, squash, and other cucurbits have been studied at various 

 stations. The melon aphis, as formerly, has been the subject of con- 

 tinuous investigation, and the cucumber beetles have been the subject 

 of special work from the standpoint of their action as carriers of the 

 virus of cucurbit diseases, especially of the mosaics, this work being 

 conducted in cooperation with the Bureau of Plant Industry and 

 scientific growers. Special attention has been given to this project 

 in new stations established in Michigan, Wisconsin, and Indiana, 

 the work requiring three experts and three temporary assistants. 

 This work, although preliminary in character, will serve as a founda- 

 tion for more extensive work during the coming year. The results, 

 while satisfactory in the main, have not entirely reached expectations 

 in the community demonstration work conducted at the field stations 

 mentioned. The lateness of the season and the consequent lateness 

 in the appearance of the beetles and the limited funds for the prose- 

 cution of this work at the time when it was necessary to conduct in- 

 vestigations are responsible for this condition. At the Virginia sta- 

 tion similar experiments have been conducted on the striped cucum- 

 ber beetle and the tarnished plant-bug as transmitters of cucumber 

 diseases. A publication on an insect closely related to the common 

 squash bug, which has occurred in injurious numbers in Louisiana, 

 has been prepared. The western and southern cucumber beetles, 

 especially the western striped and the western twelve-spotted and the 

 belted cucumber beetles, have been the subject of considerable study, 

 this work being conducted with a view to more complete publications 

 on these pests. 



Control of the spinach aphis and other aphbos by ladybirds in 

 tidewater Virginia. — Research work on the control of the spinach 

 aphis and other aphids by lady-beetles in tidewater Virginia was 

 begun in 1909 and is practically completed. Both the convergent 

 ladybird and the spotted ladjHbird have proved, under normal condi- 

 tions, to be almost complete checks on the ravages of these pests, 

 which formerly were a serious menace to the cultivation of spinach, 

 cabbage, and various other truck crops in southeastern Virginia. 

 Prior to the introduction and establishment of these ladybirds it was 

 found impossible to control the spinach aphis because of inability to 

 reach the plants, even with an underspray. This investigation has 

 given the most gratifying results in practically every instance. Con- 

 ditions in tidewater Virginia are peculiar. The extensive cutting 

 down of trees and removal of underbrush for planting truck crops 

 left no available places for the ladybirds to hibernate, with the 

 result that when work by the Bureau of Entomology was begun it 

 was found that the ladybirds were so scarce as to be absolutely useless 

 as controllers of the aphids. Such conditions have not been reported 

 in any other region, and where the trap-crop method of protection 

 of ladybirds as a means of lessening injury to the main crop has been 

 carried out, it has always met with indifferent results. 



In practically all of the stations special attention has been given to 

 the effects of arsenicals and contact poisons, both on the different 

 insect pests and on different plants, and similar attention has been 

 given to the types of sprayers and spraying apparatus most suitable 

 in each case. 



