ONION INSECTS 245 



can be more easily and satisfactorily controlled by killing them 

 with a sweetened poison spray. The most satisfactory results 

 have been obtained by using the following formula : 



Sodium arsenite i ounce 



Water 1 gallon 



Molasses 1 pint 



This material should be sprinkled over the plants and sur- 

 rounding soil when the flies first appear so that they may be 

 killed before laying their eggs. The application should be 

 repeated at intervals of a week, or oftener during rainy seasons. 



References 



Cornell Agr. Exp. Sta. Bull. 78, pp. 495-496. 1894. 



N. J. Agr. Exp. Sta. Bull. 200. 1907. 



Conn. Agr. Exp. Sta. Kept, for 1911, pp. 286-292. 



Severin and Severin, Jour. Ec. Ent., 8, pp. 342-350. 1915. 



The Onion Thrips 



Thrips tahaci Lindeman 



Onions are subject to injury by a small yellowish thrips 

 which punctures the epidermis of the leaves, sucks out the 

 juices and causes the plants to turn whitish, wilt and fall down. 

 This trouble is known among onion-growers as white blast. 

 The onion thrips is almost cosmopolitan in its distribution, 

 occurring in Europe, North America, South Africa and Aus- 

 tralia. In the United States it has been reported from nearly 

 all parts of the country and is present in southern Canada. 

 In some seasons this insect is the most serious enemy of the 

 onion crop on the muck lands of New York, Ohio and Indiana 

 and in the Bermuda onion regions of Texas. It sometimes 

 seriously infests cabbage and cauliflower and is found on many 

 wild and cultivated plants including cucumber and melon. 

 In Europe it is a serious enemy of tobacco. 



