APPENDIX. 331 



species of Chiijsopa or lace-wing fly, a very small Dipteron which was not 

 bred, two species of parasitic wasps which have not been determined, and, 

 most effective of all, a fungous disease. Yet this entire force of natural 

 enemies failed to keep down to harmless numbers, the plant lice on even a 

 small tree. I would expect that in a favorable season the disease noted 

 would tend to become epidemic ; but this is the only one of the checks that 

 is likely to be of any practical benefit. Unfortunately we cannot always 

 secure the co-operation of weather conditions to favor the development of 

 the disease ; hence, we must depend upon our own efforts to lessen or pre- 

 vent injury. 



REMEDIAL MEASURES. 



The number of plant lice on a tree can be materially lessened at any time 

 during the season by a thorough spraying with even a comparatively weak 

 ^mixture of any good contact poison. Arsenical sprays or other stomach 

 poisons are worse than useless. 



Kerosene emulsion one part, water twelve parts; or five per cent, of ker- 

 osene in a mechanical mixture with ninety-five per cent, water; or fiish-oil 

 soap one pound in six gallons of water ; or a tobacco decoction equal to an 

 extract from one pound of tobacco in two gallons of water — any of these will 

 answer, and all of them will fail to eradicate, partly because of the diflSculty 

 of hitting all the examples when the tree is full of foliage. 



Young leaves and shoots of apple are not easily wet by a watery spray, 

 because some varieties are densely clothed with hair which sheds or repels 

 water. Therefore, we may find, after an application, that the tips of these 

 hairs are studded with globules of our spraying mixtures, while the aphid.s 

 are digging deep in the pile, protected from injury by the very plant which 

 they are feeding upon ! Of course, oily or soapy mixtures penetrate better : 

 but even these are repelled to some extent unless forcibly applied. 



The period when our applications are likely to be most effective, and 

 when the check to the insects is likely to be most severe, is that following 

 immediately after they hatch from the eggs. The material best adapted for 

 use at that time is a tobacco soap. Mr. James Good, of Philadelphia, has of 

 late added tobacco to his potash soap No. 3, and this, at the rate of one pound 

 in six gallons of water, applied just as the buds are opening and again a 

 week thereafter, should be an almost complete remedy. At that time the 

 insects are not protected by foliage, all parts of the tree can be easily 

 reached by the spray and the insects themselves are very susceptible to the 

 poison. A tobacco extract, like that prepared by Hammond or by the Ken- 

 tucky Tobacco Product Comijauy, will answer as well, when reduced by 

 from ten to twenty parts of water. 



A five-per-cent. mechanical mixture of kerosene and water may be equally 

 good and is certainly less expensive. It can be thoroughly applied at this 

 time without danger to the tree. 



It is important for the fruitgrower to know that he has just fifteen days 

 from the time when his trees first begin to show a tinge of green, to destroy 

 the specimens that come from the winter eggs, before they can reproduce. 

 He has at the outside ten days thereafter to prevent the development of 



