THE MONTHLY BULLETIN. 



281 



Infested leaves have the characteristic pale, spotted appearance. Mr. 

 J. A. Prizer of San Diego has found tliat flowers of snlphnr. applied 

 with a blower on the citrus trees during a night when the dew is plenti- 

 ful, followed by hot days, will produce excellent results. Lime-sulphur 

 solution, diluted to 2 per cent or 2| per cent strength and applied at 

 a pressure of from 150 to 200 pounds, will also be of great value in 

 keeping down the infestation. The atomic and milled sulphurs may 

 also be used, and have the advantage of being less liable to burn the 

 foliage than the lime-sulphur solution. Spray when the mites become 

 numerous enough to i)roduce injury. In very hot weather it is not 

 advisable to spray, unless the seriousness of the situation demands it. 



Fig. 60. — The citrus thrips. Greatly enlarged. Photomicrograph of 

 adult female. (Photo by Arizona Agricultural Experiment Station.) 



Diabrotica Soror. 



The Biabrotica soror is one of the plant feeding beetles which destroys 

 the foliage of a large variety of plants, and is often injurious to the 

 citrus tree. The beetles are recognized by the greenish color and the 

 twelve l)lack spots on the wing covers. They are quite resistant to 

 poison sprays, but numbers of them may be killed by spraying the 

 foliage with arsenate of lead, 4 pounds to 50 gallons of water. 



