13 OHIO EXPERIMENT STATION: BULLETIN 197 



these being published in Vol. I, p. 181, Journal of Economic Ento- 

 mology. In Bulletin 194, p. 193, Ohio Experiment Station, Mr. J. S. 

 Houser devotes a few paragraphs to it. 



NATURAL ENEMIES. 

 I have observed lacewing larvae feeding with great avidity on 

 the leaf-feeding larvae of the midge. In July, 1905, and also 1906, 

 Mr. Houser so frequently obtained a chalcid from the damaged tips 

 that, for awhile, we were uncertain whether it was not itself 

 responsible for some form of damage to the branches. Subsequent 

 observations led to the conclusion that, in all probability, it subsist- 

 ed on the midge larvae, but this supposition has never been 

 definitely proved. Mr. J. C, Crawford, of the U. S. Department of 

 Agriculture, has described this chalcid as Zatrofis catalfae* 

 Adults were obtained July 14, 20, 23, 24, 25 and August 14th. 



REMEDIES. 



Cultivation: Young cultivated groves do hot suffer so much as 

 older uncultivated ones. The larvae fling themselves to the ground 

 when full grown and pupate very near to the surface. The fragile 

 adult flies cannot make their way to the surface, if plowing has 

 buried the immature stages under several inches of earth. Plowing 

 in late fall or early spring will accomplish most, but cultivation 

 throughout the summer will help. 



Fertilizing: Three or four pounds of kainit scattered under a 

 tree over a circle approximating that of the spread of the limbs 

 will in all probability destroy the larvae in the soil as well as 

 stimulate tjbe tree. Small trees will not need more than half this 

 amount. It may be applied in May to prevent the first brood from 

 issuing and if necessary can be repeated in late June to catch the 

 large July hatching. Stir lightly into the soil with a garden rake. 

 Sulphocarbonate of potash, applied at the rate of thirty kegs per 

 acre, has been found effective against the pear midge in the soil by 

 Dr. Marchal of France. 



Drenching ground with insecticides: If, in early spring, the 

 leaves, grass and trash beneath the trees are raked together from a 

 wide circle around the trunks and burned, and these cleared circles 

 are then drenched with kerosene emulsion diluted with eight to ten 

 parts of water, the hibernating stages of the insect will be 

 destroyed. 



Close planting: While methods of planting probably have 

 little or no effect on the multiplication of the midge, it seems to 

 have a direct relation to correction of injuries caused by the midge.' 

 If the trees are planted not more than four to eight feet apart each 



*Proc. Ent. Soc. Wash. Vol. IX Nos. W. 



