April, '12] HERRICK: SHADE TREE PESTS 171 



those from the Library south along each side of Central Avenue. The 

 two machines sprayed 59 of these very large trees. The cost of the 

 men and teams was $17.00, the arsenate of lead $6.61|, the gasoline 

 35c, total $23.96|, which is an average of 40.6c per tree. 



In all, there are about 530 trees on the University Grounds that 

 were sprayed. About 100 of these were scattered over the steep hill- 

 sides west of the buildings and along University and Stewart Avenues. 

 Many of these trees were a mile from our water supply and the major- 

 ity were scattered and not easy to reach. It cost, exclusive of per- 

 manent equipment, $464.90 to spray these trees twice or an average 

 of approximately 88c each. The scattered trees just mentioned 

 raised the average cost of the whole, quite materially. If all of the 

 trees had stood along streets and reasonably near a water supply the 

 average cost would have fallen I think, below 70c. It took the two 

 machines ten days to make the first spraying and eleven days to make 

 the second. The second spraying was done more thoroughly and 

 there was much more leaf surface to cover. On the other hand, experi- 

 ence had made the men more efficient. 



In conclusion of these notes on the elm leaf-beetle, I should like to 

 note the work of Sporotrichum globuliferum in killing scores of the 

 pupae and newly emerged beetles of the first generation in the latter 

 part of July and first part of August, and a great majority of the 

 pupae of the second brood in September. 



The Elm Sawfly Leaf-Miner (Kaliosysphinga ulmi) 



This miner is present at Ithaca and injures the English and Scotch 

 elms very severely. Its life history and habits were investigated by 

 the late Professor Slingerland and described in Bulletin 233 of the 

 Cornell Experiment Station. No adequate method of control, how- 

 ever, had been found up to 1911, so far as I am aware. 



Recalling the penetrating power of certain contact insecticides, it 

 occurred to me that possibly the larvae might be killed in their mines 

 in the leaves before they caused much injury. It was with a forlorn 

 hope, however, that I sprayed a small Scotch elm which had been 

 badly injured. 



The mixture consisted of Black-leaf-40 at the rate of one gallon 

 to 800 gallons of water with four and one-half pounds^ of laundry 

 soap to 50 gallons of water. The application was made in Maj' just 

 as the tiny mines had begun to show in the leaves. The effect was 

 quite surprising. I examined a great many of the sprayed leaves and 

 every larva had apparently been killed within a comparatively short 



» We intended to use but two pounds of soap to 50 gallons but by a mistake 

 in calculation four and one-half pounds were used. 



