The Oak Pruner, Circular 130, Bureau of Entomology.
Insects Injurious to Pecans, Bulletin 86, Mississippi Agricultural Experiment Station.
Insects of the Pecan, Bulletin 79, Florida Agricultural Experiment Station.
The Walnut Weevil or Curculio, Twelfth Report, State Entomologist of Connecticut, page 240.
The Walnut Bud-Moth, Twelfth Report, State Entomologist of Connecticut, page 253.
The above list will furnish information on most of the important nut insects thus far known. Inasmuch, however, as the walnut, pecan, etc., are native trees, it is probable that when these nuts are cultivated they will be attacked by many of the insects which prey upon them in nature. This we have found to be true to a considerable extent in the case of the pecan. Many of the pests of hickory, for instance, are becoming important enemies of the pecan.
We have few requests for information as to the insect enemies of the hazelnut or filbert, practically none as to the almond. I surmise that there is comparatively little injury to the two former crops in the United States, and that in the case of the almond it is largely free from insect pests. The secretary has suggested that I make reference particularly to the insect enemies of the walnut. We have had complaints of severe injury to walnuts in California from the codling moth and walnut aphids. In this state and in the arid sections where walnuts are commercially grown, the codling moth, the well-known apple pest, has turned its attention to the walnut, and under some conditions does serious injury. If walnuts are growing adjacent to pears, the marketing of the crop, which occurs about the time the second brood of larvæ is at its height, deprives these insects of further food and they turn their attention to the walnut. The walnut plant lice in California have just been investigated by an agent of the Bureau of Entomology and we now have a paper in press on these insects. We think it probable that spraying will be a satisfactory remedy where the trees are not too large.
In the East injury is confined largely to certain caterpillars infesting the foliage, as the white-marked tussock moth, the fall webworm, a species of Datana, and occasionally reports of severe injury from red spider are received. Rather recently a good deal of interest has been aroused in the so-called walnut curculio by reason of its attacking the shoots and leaf petioles of the Japanese walnut. It attacks also other species of walnut, including the English walnut and the butternut. This pest has been well treated by Doctor Britton in his report as State Entomologist of Connecticut for 1912.
While pecans are perhaps not of particular interest to growers of nuts in the Northern States, yet brief reference will be made to some of the insect enemies of the pecan. There are two excellent publications on this subject, as indicated in the list of titles above. I should urge all interested in nut culture to obtain these papers, since some of the insects treated are quite general feeders and may be expected to occur on most all varieties of nuts.
The secretary also has asked that reference be made to the hickory bark beetle. This is essentially a forest insect and has been treated by Doctor Hopkins in Circular 144 of the Bureau of Entomology.