THE MONTHLY BULLETIN. 



43 



Control.— A spray containing .02 of one per. cent nicotine has proven 

 to be the most effective contact insecticide for this pest. This must 

 be applied when the nymphs begin to appear about the first of June, 

 and great care fallen to drench the under sides of the leaves. High 

 pressure is necessary for good work. 



Screen cages have been used very successfully in many localities in 

 the State. Plowing and cultivating close to the vines and practicing 

 clean culture aid in reducing the numbers. 



Natural Enemies. — So far no internal parasites of this pest are 

 known. The larva of the California green lacewing {Chrysopa cali- 

 fornica Coq.). devour the young nymphs. Ladybird beetles also prey 

 upon the young, but are of little consequence in the matter of control. 



PSYLLID^ (Family). 



JUMPING PLANT LICE. 



The adults of the members of this family greatly resemble minute 

 cicadas and are exceedingly like the large Avinged plant lice. They 

 differ from the former in having the proboscis rising from the middle 

 of the sternum and being much smaller, and from the latter in having 

 the hind femora greatly developed, enabling them to .jump freely. 

 The pupffi are also characterized by the large and conspicuous wing 

 pads. These insects, like plant lice, feed upon the tender foliage and 

 bark of various plants. The most important member of this family 

 in California is the pear psylla. 



THE PEAR PSYLLA, 



Psylla pjjricola Foerst. 

 (Fig. 37.) 



General Appearance.— Adults are small, orange yellow, jumping 

 insects, not unlike miniature cicadas. More common than the adults 

 are the nymphs, which are queer looking creatures with wide flat 

 bodies and large heads. The general color is orange with dark striped 



Fig. 37. — The pear psylla (Psylla vyricola Foerst). Young, nymph and adult. 



(U. S. Dept. Agrcl.) 



