THE MONTHLY BULLETIN. 



281 



THE PEAR OR CHERRY SLUG. 



Ciilirod cerasi Linn. ( T'lunily 'i'cnthrcdiniclae) . 



( /'Jriixd III i)i)iil<s lliiiiiciiKi Itetz. I 



(Fig. 283.) 



General Appearance. — The adult is a glossy, black, four-winged 

 insect about one fifth of an inch in length. The larvte are dark olive 

 green, slimy and from three eighths to nearly half an inch in length. 

 Their work is very uoticeable and consists in the removal of all of the 

 upper green surface of the leaf, causing the injured areas to turn 

 brown. Badly infested trees appear scorched as if by fire. 



Life History. — The eggs are oval, slightly flattened on one side and 

 deposited under the epidermis of the leaves, 

 usually on the under sides, by the sharp 

 ovipositor of the female. They hatch in about 

 two weeks. The young larva^ cut a semi-circular 

 hole in the upper surface of the leaf and begin 

 to feed. They are first white and later become 

 dark green, because of the slimy secretion. The 

 entire green upper surface of the leaves is removed 

 by the larva^ until only skeletons are left. The 

 remaining under-surface turns brown. When 

 full grown the larvfe crawl an inch or .so into 

 the ground and spin a cocoon in which to jnipate 

 and hibernate throughout the winter. The 

 adults appear in the early spring. 



Distribution. — Generally distriliutcd through- 

 out the State. 



Fig. 283. — The 

 pear or cherry slug 

 { C a I ir o a cerasi 

 Linn. ) and its worlv 

 upon the leaf. (After 

 Ewing. ) 



Food Plants. — Pear, cherry, plum, quince, button-bush, thorn, moun- 

 tain-ash, Amdancliier canadensis. 



Control. — This is one of the easiest pests to control. The larvae 

 readily suceuml) to the ordinary soap or emulsion sprays and may be 

 effectually destroyed by l)lo\viiig dust upon the infested leaves. 



Natural Enemies. — Without doul)t the reason for this pest not becom- 

 ing more serious in California is due to the natural enemies which hold 

 it in check. In this State these enemies have never been recorded but 

 in the Middle States the egg parasites, Pentarthron minulnn) Riley and 

 Closterocerus cinctipeunis Ash., are quite common. 



There are probably also para-ites working on the larva^. This, 

 however, has never been definitely ascertained. The predaceous bug, 

 Podisus niaculiveiitris Say, and the Reduviid, Sinea diadema Fab., are 

 active enemies of the larvtv and adults. The larva' of the green lace- 

 wing also devour many of the young. 



