PEAR LEAF-BLISTER MITES, REMEDIES FOR. 91 



After various experiments at Cornell University Agricultural 

 Station, two trees were chosen, of which one was treated with 

 Kerosine Emulsion diluted with two and one-third parts of water, the 

 other tree left untreated as a check. " In the spring the Mites 

 appeared in force on the check tree, but upon the treated trees ^' not 

 more than a dozen galls appeared during the season, the pest having 

 thus been nearly exterminated ! " 



This was looked on only as a guiding experiment, and carried on 

 in the following year on a larger scale, as follows : — " In September " 

 (of the first year of observation, 1892) " we found sixteen quite badly 

 infested trees in the Horticultural Orchard here at the Station. These 

 were then labelled, and on March 10th, 1893, all but two (which were 

 left for a check) were sprayed with Kerosine Emulsion diluted with 

 from three to ten parts of water. The trees were standards varying 

 from six to fifteen feet in height ; but it was found that it required 

 only about one and a half quarts of the diluted Emulsion, and about 

 two minutes of time, to spray a tree thoroughly from all sides with a 

 Knapsack Sprayer. 



" July 10th, 1893, the trees were examined, and it was found that 

 the four sprayed with the Emulsion diluted with three parts of water 

 were practically free from the disease. 



"The four trees sprayed with the Emulsion diluted five times, and 

 the four on which the Emulsion diluted with eight parts of water was 

 used, showed a very few galls, — not one per cent, of the number on 

 the trees the preceding year. 



" Two trees which had been sprayed with the Emulsion diluted 

 with ten parts of water showed nearly as many galls as before. 



" The two check trees were as badly infested as they were the 

 year before." f 



From these experiments it appears, as summarized by Mr. Slinger- 

 land, that the Pear Leaf-blister Mite can be nearly exterminated by 

 one spraying of the Pear-trees (at any time after the leaves have 

 fallen off in autumn, and before the buds have begun to swell in the 

 spring) with Kerosine Emulsion diluted with not more than five to 

 seven parts of water, — the tree being sprayed thoroughly from every 

 side, taking especial care to hit every terminal bud, for this is where 

 most of the Mites congregate. — (M. V. S.) 



* " Trees,"— two trees were dressed with undiluted Kerosine, and nearly 

 killed, thus showing the necessity of being very careful in the use of Kerosine ; but 

 as the dozen leaf-galls mentioned above were all to be found on the three trees, the 

 modified strength given in the Emulsion answered well. " The only apparent effect 

 upon the trees treated with the Emulsion was a slight retardation in the unfolding 

 of the leaves in the spring." — (M. V. S.) 



t See Bulletin of Cornell University, before referred to. 



