308 STATE HORTICULTURAL SOCIETY. 



during wet seasons, it becomes very conspicuous in the orchards of 

 Missouri, clustering upon the suckers from the base of the tree, about 

 the axils of twigs and leaves and upon the scars where pruning has 

 been done. Everywhere its punctures are not only exhausting to the 

 tree, but possess a poisonous property which causes gall-like growths, 

 those above ground appearing like small kernels or seeds. 



As with most aphids, a true sexed generation is produced in the 

 autumn, the females of which lay their microscopic, shining black eggs 

 in crevices of the bark near the base of the tree, and a large propor- 

 tion of the young lice, hatching from these eggs, find their way to the 

 roots while, under certain circumstances, the remainder start small 

 colonies above ground. 



Orchards on gravely or porous soils are peculiarly liable to suffer 

 from the apple-root aphis, and every precaution should be taken to 

 have the roots of the trees when planted, absolutely free from the in- 

 sect, and also to make strict examination of the soil for fibres of roots 

 that might be infected. 



Where the presence of the insect in the nursery is suspected the 

 roots of the young trees should be immersed for a couple of hours in 

 soap-suds or in water heated to not more than 130°. This will kill the 

 lice without injury to the roots. 



When it is designed to plant newly cleared timber land to apple- 

 trees it should be first cultivated for one or two seasons to corn or 

 some other crop requiring repeated plowing or hoeing. This to make 

 sure that all the roots of wild crabs, thorns, etc., on w^hich the lice are 

 often found, have been thoroughly cleared from the soil. It is also 

 hazardous to replant an orchard in the position occupied by old trees^^ 

 but sometimes it seems desirable to replace a few trees that have died 

 out, to preserve the symmetry of the rows. In order to do this with 

 safely the soil should be repeatedly worked over and fertilized heavily^ 

 with fresh wood ashes. 



There area number of natural checks upon the multiplication of 

 both the root feeding and the aerial forms of this insect. Among these 

 are a small chalcid tly (Aphilinus malij, the root-louse syrphus fly 

 fPipiza radicum, Riley), a lace-wing fly and several of the lady-bird 

 beetles. These have never, however, been found in sufficient numbers 

 to locally exterminate the pest, though, no doubt, at times greatly re- 

 ducing its numbers. 



To apply artificial remedies for the root inhabiting form, it is an 

 excellent plan to first mulch the trees, and by this means bring the 

 insect as near to the surface of the ground as possible. The roots. 



