230 ANNUAL REPORTS OP DEPARTMENT OF AGRICULTURE. 



thrips has been investigated, and a bulletin on the same has been 

 prepared. 



Onion insects. — An investigation of the onion thrips conducted 

 at various stations, more especially in recent years in Indiana and to 

 a greater extent in southern Texas, as the principal onion-growing 

 regions of this country, is practically completed, and a bul- 

 letin dealing with the insect has been prepared. An investigation 

 of the lesser onion thrips has been started in southern Texas. The 

 onion maggot, with other root-maggots, has been studied in Wiscon- 

 sin. The major portion of this work is devoted to measures of con- 

 trol. The use of tarred-felt pads or disks in Wisconsin continues to 

 be the best remedy, and such growers as have been using them con- 

 tinually since the nineties agree that nothing better could be desired. 

 A great number of other measures have been the subject of experi- 

 ment against root-maggots, but many of these have proved un- 

 satisfactory. 



Bean and pea insects — The wireworms which are troublesome to 

 sugar beets also affect beans in California, and they have been 

 studied there from the standpoint of bean pests also. The bean 

 ladybird, an important insect enemy of beans in the southwestern 

 region, has received considerable study in southern Colorado. The 

 bean leaf-beetle has also been studied. The pea aphis has not been 

 so destructive as in the past, and, as a consequence, it has not been 

 possible to give it the study which was intended. Nicotine sulphate 

 at the rate of 1 part to 1,800 parts of water combined with soap at . 

 the rate of 21 pounds to 50 gallons of water has given very satis- 

 factory results. If growers could be induced to plant in rows in- 

 stead of sowing broadcast it would be possible to control this pest 

 in the principal pea-growing regions, such as Virginia, Michigan, 

 California, and other States. 



Insects injurious to cruciferous crops. — The principal insects 

 injurious to cabbage, cauliflower, turnip, and horse radish have been 

 given continued study. A bulletin on the common cabbage worm 

 has been prepared. The cabbage looper and related forms have been 

 kept under observation with a view to complete reports on all of 

 these insects which have somewhat similar life histories and food 

 habits. '■ The cabbage maggot has been studied in connection with the 

 onion maggot, especially in Wisconsin and Michigan. A general 

 article on the horse radish flea-beetle is available. A root aphis 

 which attacks cultivated cruciferous crops in Louisiana has been 

 studied with relation to alternate food plants and methods of control 

 by contact poisons. The diamond-back moth, a well-known enemy 

 of cabbage and turnip, has been studied, especially in Colorado, and 

 the false turnip aphis has been studied in Texas, Louisiana, and 

 Kansas, results proving that it can be readily controlled by spraying 

 with nicotine sulphate in combination with soap under strong pres- 

 sure. Constant complaints are made in regard to the harlequin 

 cabbage bug, and it is gradually working its way northward. A 

 report covering the general topic with special attention to remedies 

 for combating and controlling this pest is in course of preparation. 

 Such remedies as trap-crop planting and the destruction of the bugs 

 with special burners are among the most successful. 



