The Pecan and its Culture

by H. Harold Hume

CHAPTER XV.

INSECTS ATTACKING THE PECAN.

Some time ago the statement was occasionally made that the pecan had no known enemies. This, to thinking and observing persons, was too good to be true, and fortunately the words, "no known," were inserted, for later investigations, particularly on the part of Profs. Gossard and Herrick, have revealed the fact that the pecan, in common with all other fruit trees, is subject to the attacks of insect and other enemies. But the outlook is hopeful, for we know of the abandonment of no fruit industry because of the attacks of insect pests, and the pecan industry is in no wise in danger of being abandoned because of their inroads.

Feeding Habits of Insects.

If an insect is to be successfully controlled, the grower must know something of its life-history, and particularly of its feeding-habits. Careful observation of the insect, while at its work of destruction, will frequently give a clue to the method of control. Many insects, like the caterpillars of the pecan, bud-moth and case-worm, obtain their food by biting off pieces of the leaves or other parts of the tree and swallowing the solid particles. On the other hand, a number of insects, such as the scales and plant-lice, obtain their food by thrusting their small, bristle-like sucking tubes into the tissues of the leaves and sucking out the juices contained in the cells.

Plate VIII.
The Pecan Bud Moth (Proteopteryx deludana).
1. Winter stage on bud, enlarged. 2. Tube made in leaf. 3. Work of bud destruction. 4. Caterpillar, enlarged about twice. 5. Cocoon, enlarged. 6. Chrysalis, reduced. 7. Moth, enlarged. 8. Moth, about natural size.

It is quite obvious that these two classes of insects cannot be controlled or destroyed in the same way. Those which eat solid particles of food may, in most cases, be destroyed by applying some poisonous substance, such as arsenate of lead or Paris green, to the food which they eat. But those which obtain their food by sucking cannot be killed in this way. They can be destroyed, however, by spraying over their bodies some substance, such as kerosene emulsion, which will penetrate their bodies and so kill them. Or, they may be killed by suffocating them with a gas or by stopping up their breathing pores with some powdered substance, such as pyrethrum. Some insecticides, such as resin wash, act both as a caustic application and a suffocating covering.