INSECTS INJURIOUS TO THE APPLE AND PEAR 569 



stems and young fruit, feeding at the same time on growing parts 

 of the plant. Injury by the adults is generally to the fruit buds 

 before blossoming. The young forms feed on foliage and fruit 

 and cause the defacement of fruit called fruit scab which greatly 

 reduces the quality, especially of prunes which are the greatest 

 sufferers. They remain inactive as fully grown nymphs from 

 early summer until the following spring when the adults again 

 appear. 



Control. Since the insect spends a large part of the year in 

 the soil in immature stages thorough cultivation throughout the 

 summer may be expected to destroy large numbers. Spraying 

 has not given entire satisfaction, but distillate oil emulsions are 

 largely used in California. These are made by mixing 30 pounds 

 fish oil soap, twenty gallons distillate oil and twelve gallons of hot 

 water, by pumping them together under high pressure through a 

 spray outfit into the tank. This is stock solution and should be 

 diluted at the rate of one to twenty. To this should be added 

 Black-leaf 40, about one-half pint to 100 gallons of the spray. 

 This is applied at the time the buds are bursting and may be 

 repeated after the petals fall. Spraying with thick whitewash 

 gives some control but the first solution is preferred. Any spray- 

 ing treatment should be supplemented by liberal fertilization. 



The Pear Slug * 



Not infrequently the foliage of pear and cherry, and occasion- 

 ally of plum trees turns brown in midsummer, which is found to be 

 due to small, slimy, slug-like larva? which have eaten off the surfaces 

 of the leaves. The Pear Slug is a common pest throughout the 

 country, having been known here for over a century. It is an 

 old European pest and has become distributed to many of the 

 British colonies in various parts of the world. The parent insect 

 is a small saw-fly, about one-fifth inch long, glossy black, with 

 four wings which are iridescent, with a smoky band across the 

 middle, and which are folded over the back when at rest. 



Life History. The flies are abroad by the time the foliage is 

 well out, by the middle of April in Maryland and late May or early 

 June in New England. Like most of the saw-flies the female is 



* Caliroa cerasi Linnaeus. Family Tenthredinidce. See C. L. Marlatt, 

 Circular 26, Div. Ent., U. S. Dept. Agr., and R. L. Webster, Bulletin 130, Iowa 

 Agr. Expt. Station. 



