INSECTS INJURIOUS TO CITRUS FRUITS 629 



Diabrotica soror * 



The most common of the leaf-beetles on citrus fruits on the 

 Pacific coast are the members of this species which is almost 

 identical with the twelve-spotted cucumber beetle or Southern 

 corn-root worm. It attacks the tender foli- 

 age of the orange but rarely damages the 

 lemon. The larva, like that of the cu- 

 cumber beetles, feeds on the roots of plants 

 where it is little noticed. 



Control. On small trees the beetles 

 may be jarred off into tar or oil on screens 

 while they are sluggish in the early morn- 

 ing. On larger trees they must be poi- 

 soned. Lead arsenate paste at the rate FlQ - 540. Diabrotica 



soror. After Quayle, 

 of two pounds to fifty gallons water is Cal. Agr. Exp. Sta. 



effective. The powdered form, applied as a dust with sulphur, 

 might kill these beetles and the mites at the same time. 



The Melon Aphis f 



The Melon-aphis is occasionally injurious to the young shoots 

 of citrus trees in the spring. They are of no special importance 

 to the citrus trees, but as these serve as an alternate host they 

 should be destroyed when present in considerable numbers, for 

 the protection of the other host plants, such as melons, cotton 

 and other plants. 



Black-leaf 40, 1 to 1000, with soap as a spreader, is effective 

 here as elsewhere. 



The Orange Dog t 



This conspicuous caterpillar is the larva of an equally con- 

 spicuous large, swallow-tail butterfly, black, with broad, yellow 

 bands running diagonally across the fore wings and just inside 

 the margins of both wings. 



The larva feeds on foliage but may easily be destroyed by hand- 

 picking or by the use of any arsenical. This is a Florida species. 



* Family Chrysomelidce. 



t Aphis gossypii Glover. See same, Chapter XVIII. 



j Papilio cresphontes Cramer. Family Papilionidce. 



