90 FIFTH ANNUAL REPOKT 



This little parasite, which works for the most part unseen but 

 none the less effectually, and which so materially aids man in pro- 

 tecting his apple-trees, is, fortunately, easily introduced into sections 

 of the country not yet favored with it, and may, no doubt, be colo- 

 nized wherever its natural prey flourishes. The second brood sleeps 

 away the winter in the larva state, sheltered by the scale intended to 

 protect the bark-louse eggs ; and twigs thus freighted with our little 

 sheltered friends may easily be carried from one part of the country 

 to another, or even to a foreign land. The torpid condition of the 

 larva will insure its safe transportation in winter, and its presence 

 may not only be surmised by the smooth holes in the deserted scales 

 which are found in orchards where this ApJielinus abounds, but may 

 be positively ascertained by careful lifting of a few parasitized scales. 

 To colonize the parasite, all that is necessary is to tie such parasitized 

 twigs on to trees which it is required to protect, and the microscopic 

 flies will issue at the proper season and carry on their good work, 

 unconscious of the carrying process which man had submitted them 

 to during their larval dormancy. Dr. LeBaron has already made some 

 efibrts to introduce this parasite around Galena, Ills., where, as he 

 ascertained, it did not previously occur ; and I shall take steps the 

 coming season to introduce it into Clark and Wright counties in our 

 own State. 



remp:dies. 



I have little to add to the advice given in 1868. The importance 

 of critical examination, before planting, of all young trees and scions, 

 or of applying some simple remedy when the young lice are hatching, 

 can not be too strongly urged ; and, as a rule which will hold very 

 generally true, it may be stated that the young begin to hatch just 

 about the time the blossom falls and the fruit begins to set. Let those 

 who prefer to work toward eradicating the pest in winter time (as 

 many no doubt will, on account of the leafless state of the trees and 

 the greater leisure which most fruit-growers have at that season) vig- 

 orously prune and scrape the infested trees ; and afterward apply 

 some of the oily applications previously recommended. As a remedy 

 not previously named, I would mention linseed oil, which has. been 

 used with marked and beneficial results in Grundy county, Ills. 

 Many persons have been deterred from using greasy or oily sub- 

 stances on their trees from a fear of evil consequences resulting to 

 the trees ; but there is nothing more certain than that, judiciously 

 applied in early spring after the sap begins to flow, these applications 

 do not injure trees; while they are effectual, more especially when 

 applied at such season or during thawing weather, in killing the eggs 

 under the scales — the oily particles being absorbed through and under 

 the scales, and destroying the eggs as soon as touched. The follow- 

 ing experiment, performed by Dr. LeBaron, and which I quote from 

 his second Report, will give confidence to the hesitant : 



