136 PROTECTION OF PLANTS. 1916 17 



In the latter part of June the percentage of infestation was calculated 

 and it was found that on the check trees 42.2 per cent of the buds were 

 infested and on the sprayed trees only 8.3 per cent. So that the reduction 

 in bud moth injury brought about by these two sprays was 80.0 per cent, 

 almost exactly the same as in the preceding year. 



Spraying Experiments in the Summer. — During the summers of 1914 and 

 1915 the writer conducted experiments to determine the practicability of 

 applying a spray, while the eggs are on the leaf, in order to poison the newly 

 hatched larvae as soon as they begin to feed. Owing to the large number 

 of egg parasites which destroyed three quarters of the eggs, no attempt 

 was made to spray in the orchard and the figures are the results of laboratory 

 experiments only. Fortunately several rather large apple seedlings growing 

 in tubs were obtainable for this work. 



In order to ensure the laying of a large number of eggs the branches of 

 these trees were covered with cheese cloth bags into which several bud moths 

 were introduced. After the bags were removed the plants were sprayed 

 with a suspension of lead arsenate in water at the rate oi 2}/2 lbs. (powder) 

 per 100 gallons of water. 



In 1914 no accurate record of the number of eggs laid was kept, but it 

 was estimated that at least 80 to 85 per cent were destroyed. 



The record for 1915 is as follows: — 



June 28th. A. 110 eggs laid. 

 B. 240 eggs laid. 

 June 29th. C 162 eggs laid. 

 June 30th. Sprayed A. and B. Left C. as check. 

 July 8th. Eggs on A. and B. hatching and caterpillars beginning to 



feed. 

 July 9th. Eggs on C. hatching. Many dead larvae on A. and B. 

 July 11th. A count of the three seedlings gave the following results:— 



A. 2 living caterpillars in their tubes. 



B. 6 living caterpillars in their tubes. 



C. 155 living caterpillars in their tubes. 



On A. and B. there were a few larvae dead in their tubes 

 but the majority had died before having an opportunity 

 to construct their tubes. 

 July 14th. A. No living larvae. 



B. One living larva. 



C. All healthy, feeding. 



