166 Report of State Board of Horticulture. 



Fourth Lot of Trees. Oregon Wash. 



This lot is essentially a duplicate of Lot 2 except with respect to the 

 insecticide treatment, which was identical with that of Lot 3, and also 

 with respect to the number of trees made use of, which was eight in this 

 lot and nine in Lot 2. All variations of experiments with Lot 2 are repre- 

 sented in Lot 4 with the exception of that for No. 29. 



Tj'ee No. 18. — A sixteen-foot apple tree, with a nine-inch trunk and a 

 twenty-foot top; in fair general condition, but badly infested by the 

 scale. Treated, like No. 4 of Lot 2, with a single application of fifteen 

 gallons of water on the second day after the experiment, coinciding with 

 the first shower of rain. Forty-seven per cent of the scales alive when 

 the insecticide was applied; fifteen per cent of these dead on the second 

 day, and eighty-three per cent on the fifth, with a final average destruc- 

 tion of eighty-eight per cent. The corresponding ratio for the companion 

 tree. No. 4, was eighty per cent. 



Tree No. 21. — A fifteen-foot peach tree, with an eight-inch trunk and 

 an eighteen-foot top; in good condition, and but moderately infested. This 

 received the same water treatment as No. 27 of Lot 3, namely, one ap- 

 plication of fifteen gallons of water on the fifth day after the insecticide. 

 Thirty-one per cent of the scales were alive in the beginning. None of 

 them appeared to have been killed on the second day thereafter, but 

 ninety per cent of these were dead on the fifth day, and ninety-eight per 

 cent, according to the count made, five days thereafter. The general final 

 average was ninety-seven per cent destroyed. The corresponding ratio 

 for the companion tree, treated with the California wash, is eighty-two 

 per cent. 



Tree No. 22. — A peach tree, thirteen feet high, with a six-inch trunk and 

 a twelve-foot spread; in poor condition, though but moderately in- 

 fested. Treated but once, and that on the tenth day after the insecticide 

 application, fifteen gallons of water being used. The corresponding tree 

 of the second lot was No. 35. Forty-four per cent of the scales alive in 

 the beginning; eighty-eight per cent of these dead on the fifth day, and 

 ninety per cent on the thirteenth, with a final average ratio of ninety- 

 five per cent destroyed; this to be compared with a ninety-four per cent 

 average of the companion tree. 



Tree No. 23. — A fifteen-foot apple tree, with an eight-inch trunk and 

 a fifteen-foot top; in poor condition, moderately infested. This, like 32, 

 treated with three daily water sprays of fifteen gallons each on three 

 days immediately following the insecticide treatment — a duplicate in this 

 respect of No. 32 of the second lot. Forty-nine per cent of the scales alive 

 in the beginning; sixty-five per cent of these dead on the fourth day, and 

 eighty-eight per cent on the thirteenth, with a final average destruction 

 of eighty-nine per cent, that of the companion tree, treated with the 

 California wash, being eighty-five per cent. 



Tree No. 24. — A sixteen-foot peach tree, with a six-inch trunk and a 

 nine-foot top; in fair condition, moderately infested. Treated on two 



