WESTERN NEW YORK HORTICULTURAL SOCIETY. 475 



The insect is so small that it is overlooked unless especial pains be taken. (Every fruit- 

 grower should have a small pocket magnilier or lense, and make frequent use of it on 

 his trees.) The nymphs which hatch from the eggs become full grown— (it would take 

 twenty of them to measure an inch) — in about a month, and change to the adult jump- 

 ing forms, which lay eggs on the leaves for another brood. There are four or five 

 broods during the summer, all working in the same manner mostly in the axis of the 

 leaves and fruit stems. A very curious and characteristic feature of an attack of this 

 pest is the immense quantities of a sweet, sticky fluid called honey dew, which is 

 secreted by the nymphs, and which covers the leaves, fruit and branches of the tree, or 

 even drops off onto the vegetation beneath. Within this honey dew there grows a 

 black fungus which causes the tree, especially after the leaves have fallen, to look as 

 though it had been thinly painted with black, or as though soot had been sifted on it. 

 Most of the damage is done before June 15, by which time the fruit and many leaves 

 are so much weakened that they almost cease to grow and soon drop off. The pest 

 prefers the Bartlett, but works extensively on most of the other varieties. A long 

 series of experiments showed that we cannot kill the pest in the egg without injuring 

 the tree also. As the pest obtains its food by sucking and not by chewing, the arsenites 

 or other poisons will have no effect upon it. In kerosene emulsion, however, we have 

 a very effective agent for the destruction of this serious pest. To make emulsion, 

 thoroughly dissolve one-half pound hard or soft soap in one gallon boiling water. 

 While this solution is still very hot add two gallons of kerosene and quickly begin to 

 agitate the whole mass through a syringe or force pump, drawing the liquid into the 

 pump and forcing it back into the dish. Continue this for five minutes or until the 

 whole mass assumes a creamy color and consistency will adhere to the sides of the ves- 

 sel, and not glide of like oil. It may now be readily diluted with cold rain water, or 

 the whole mass may be allowed to cool when it has a semi-solid form, not unlike lop- 

 pered milk. This standard emulsion if covered and placed in a cool dark place will 

 keep for a long time. In making a dilution from this cold emulsion, it is necessary to 

 dissolve the amount required in three or four parts of boiling water, after which cold rain 

 water may be added in the required quantities. I found that by spraying trees once, 

 just after the leaves had expanded in the spring, with this emulsion diluted with fifteen 

 parts of water that I killed from seventy-five to ninety per cent of the nymphs. This 

 emulsion must come in contact with the inject, and thus the spraying should be very 

 thorough; but the nymphs die within a few seconds after being hit so that 

 a rain storm soon after spraying does no harm. It is better to make the application 

 just after a rain, when the leaves have dried off, for the rain will wash 

 off much of the honey dew which often so covers the nymphs as to render 

 it impossible to hit them with the emulsion. A second application a few days 

 later will doubtless be advisable in a serious attack by the pest. Do not 

 wait until after June Ist to do the spraying, for most of the damage is done by the 

 first spring brood of npmphs. It has been found impracticable to spray the adults 

 as they are too active, flying away from the tree in clouds when the spray strikes it, 

 and they are also not so susceptible to the emulsion. In some orchards the birds seem 

 to have picked a good many of the hibernatmgadultsout from the crevices of the bark. 

 So far as now known the pest has no other natural enemies. Watch your trees in the 

 spring, and spray before June 1st with the emulsion, and if it is thoroughly done this 

 pest can be kept within bounds. For full discussion of this pest refer to bulletin 44 of 

 the Cornell Experiment Station. 



Mr. WiLLARD asked what effect the pear psylla had on the fruit'.' 



Mr. Slingerland: So far as I know there are no external visible indications of the 

 work of the insect on the fruit itself. Of course the fruit is stunted in its growth 

 from the loss of sap taken from its stem by the nymphs; and finally the fruits are 

 so weakened that they drop off when about half grown in mid-summer. Often the 

 honey dew runs down on to the fruit and renders it somewhat unsightly. The pest 

 has no jaws by which it could mar the fruit in any manner, as does the plum curcnlio 

 or codlin moth. 



Mr. Pease, of Oswego: Can you mix the arsenites and Bordeaux mixture with the 

 emulsion? 



Mr. Slingerland: Yes; Paris green, Bordeaux mixture, and kerosene emulsion can 

 be mixed together, and the mixture would then contain all the elements to make it 

 almost a panacea for all the insect and fungous ills of the fruit grower. But unfortu- 

 nately the combination is not easily secured; the Bordeaux must be in a neutral con- 

 dition or the emulsion will not mix with it satisfactory; and some other minor factors 

 enter in so that one cannot depend on getting a good staple mixture although all the 

 conditions are fulfilled. Again, when the combination, or Cornell mixture as it was 

 •dubbed, was applied to trees, it was found that the liquid did not spread over the 



