We usually advise putting scions in cold storage where convenient, especially if they are for use in late May or June, but this is not at all necessary if the scions are packed in moss only slightly damp. In fact scions kept in an ordinary cellar at a temperature around 50 degrees have given us better results on the average the past two years than have those from cold storage.
The association adjourned until 2 p. m.
Afternoon Session, Friday, October 8, 1920, 2 p. m.
The President: We very fortunately have with us a gentleman from the Bureau of Entomology, Mr. F. E. Brooks, who will talk to us about nut insects for a time and we will be very glad to listen to him.
Mr. Brooks: I believe your program is full for this afternoon and I shall keep you but a few minutes.
A little more than a year ago the problem of insects affecting the nut crop of Northern United States was assigned to me by the Bureau of Entomology. I wish to say the work has been very delightful to me from several standpoints. In the first place, it has brought me into association with a delightful group of workers. I want to express to you the pleasure I have had in meeting the various nut growers of the northern part of this country and noting the hearty way in which they are ready to co-operate in solving the nut insect problems. The field of work is interesting because there appear to be in sight no insect pests that promise to embarrass or overwhelm the nut grower. We have a few quite serious insect problems, perhaps none more serious than that occasioned by our old acquaintance, the "chestnut worm." That problem, however, is being solved rapidly in many localities by the chestnut blight.
Thus far in the work, I have devoted most of my time to a study of the species attacking the fruit of nut trees, and I may mention three groups that have been given special consideration. First, the group to which the chestnut worm, or chestnut weevil, belongs. There are two very similar species of these weevils which attack chestnuts, one which attacks hickory nuts and pecans, one which attacks hazel nuts and numerous species which attack acorns. The adults of these weevils are medium-sized beetles, yellow, brown or gray in color, and all have enormously long snouts. The mouth is located at the point of the snout and the beetles use these snouts to bore through the covering of the nuts after the kernel is partially or fully formed. When the puncture into the nut is completed one or more eggs are inserted by means of an extensile, thread-like tube, or ovipositor, of the same length as the snout. The eggs hatch into the familiar worms found in ripe chestnuts, hickory-nuts and hazel nuts. The large hole in the shell of the nut is made by the full grown worm as it escapes to enter the ground, where it completes its transformation into a beetle. An interesting thing in connection with these weevils is that each species confine its attacks to one particular kind of nut. Even those species that attack acorns show a decided tendency to distinguish between oak species and confine themselves as groups very largely to particular species or botanical groups of oaks. There is, therefore, no danger that any of these weevils will multiply, for example in an oak forest, and then migrate into nearby plantations of chestnut, hickory or hazel. Hazels might be used for interplanting among chestnut or hickory trees with no danger that the hazel nuts would become infested by the weevils that develop in the chestnuts or hickory nuts. This habit of the weevils is greatly to the advantage of the person who would plant a particular kind of nut outside its natural range, or at a considerable distance from any other trees of its kind. He could do so with reasonable assurance that the weevil attacking his species of nut would not occur upon his trees until brought into the locality by artificial means.
There is another group of weevils, nearly related to the common plum curculio, the species of which attack immature nuts. In this group the snout is much shorter than in the group just described, and the insects are considerably smaller. There is one species, Conotrachelus juglandis, that confines its attacks to the young fruits and shoots of walnuts of the butternut group, another, Conotrachelus retentus, that seems to attack exclusively the black walnut fruits from the time they set until they are half grown, still another, Conotrachelus affinis, that appears to attack only half-grown hickory nuts. Another species, Conotrachelus aratus, feeds abundantly in some localities within the leaf petioles of hickory. At least two other species of the group commonly attack acorns. Those injuring walnuts lay their eggs on the concave side of crescent-shaped punctures which they eat in the husks of the young nuts. The larvae developing from the eggs cause the nuts to drop within a few weeks and the larvae enter the ground to complete their transformation. There is a divided tendency with some of these species to attack the young wood and leaf stems of the introduced species of walnut. Dr. Morris states that he has had young Japanese walnut trees killed by C. juglandis feeding in the grub stage within the branches. He has, however, found that the pest succumbs to an arsenate of lead spray.