CHAPTER XXXII 

 INSECTS INJURIOUS TO ORCHARD TREES 



It is estimated by careful and expert observers that insect 

 pests take, each year, about one-fifth of the American fruit 

 crop. This is an annual money loss to the growers, and to the 

 nation, of about sixty million dollars. A large part of this 

 loss can be prevented. 



The orchard pests include insects of many kinds, repre- 

 senting different orders, and varying greatly in life history, 

 habits and structure. The injury to the trees may be to the 

 roots, the trunk, the leaves, the flower buds, or the fruit. 

 Apple trees, for example, have their roots attacked by the 

 woolly-aphis, their trunks mined by the round-headed and 

 flat-headed borers, their leaves eaten by tent-caterpillars, the 

 buds attacked by the larvae of the bud-moth, and the fruit 

 burrowed into by the codling-moth grub. 



The insects attacking a particular part of the tree, as the 

 leaves, may effect their injury in different ways. They may 

 eat the leaves, as caterpillars, beetles and other insects with 

 biting mouth-parts do; or suck the plant juices from them, as 

 the aphids, scale-insects and other insects with sucking mouth- 

 parts do. Similarly with the fruits. Some insect pests bite 

 holes in them, some suck juice from them, and some bore un- 

 sightly tunnels in them, the insects feeding and developing in 

 the very heart of the fruit. 



Even in the case of two different insects that attack the same 

 parts of the same kind of orchard trees in much the same way, 

 as with two biting insects that eat the leaves, there may yet be 

 such differences in their life history and habits that the best 

 remedies for them may be radically different. The remedy for 

 one, which may be a wingless insect, might be an easy means of 

 preventing its access to the leaves; for the other, a winged 



421 



