Better Butternuts, Please

S. H. Graham, Ithaca, N. Y.

"As to palatability, there are many persons who would be disposed to place the butternut at the very head of edible nuts." This is the opinion of Luther Burbank in Vol. XI, page 32, of "Luther Burbank, His Methods and Discoveries."

The butternut tree is noteworthy as being at home in a greater variety of soils than the blackwalnut as well as being hardier than the black walnut or the hickory. It ripens so early that the nuts always have plenty of time to mature while the richly flavored kernels are rarely shrunken and never astringent. Despite these good qualities, a search through the publications of the Northern Nut Growers' Association for the past thirty years proves that comparatively little interest has been manifested in it. It would seem quite in order to inquire into the reasons for this neglect. Five of them come to mind: 1. Too early blooming. 2. Difficulty of propagation. 3. Curculios. 4. Melanconis disease. 5. Lack of sufficiently good varieties.

The butternut too often blooms so early that its blossoms are caught by frost. The filbert has the same fault and so, to a less extent, has the Persian walnut. Late blooming varieties of each have already been selected. It does not seem too much to hope that late blooming varieties of butternut may also be found. I know of one butternut that has had good crops every year but one for the last ten years but have never visited it at the right time to observe its blooming habit. President Weschcke reports that butternuts on black walnut stocks have their blooming retarded for a few days.

Many experienced nut tree propagators have little success in grafting the butternut. But Mr. Harry Burgart of Michigan, has found that nursery trees may be successfully grafted if the operation is performed at a point three or four feet from the ground, while the late Dr. G. A. Zimmerman of Pennsylvania, found that very early grafting gave him the best results. He reported that his best catch was from grafts set March tenth. Some moderately successful propagators do not pay careful attention to outside temperatures when they cut their scions. In contrast to this let us see what Mr. J. F. Jones thought about it. He was undoubtedly the most successful nut tree propagator in the East and he was always as generous in sharing his hard earned knowledge as he was skillful in its application in his own commercial nursery. Note this from his paper in the 1920 annual report. "In the case of trees that bleed freely when cut, we must guard against taking scions after hard freezing weather and before the tree has fully recuperated. This semi-sappy conditions following low temperatures that freeze the wood seems to be a provision of nature to restore the sap lost by evaporation. We always try to avoid taking scions of any kind soon after hard freezing weather. I have found scions of English and Japanese walnuts, cut from trees in this condition, to be practically worthless for propagation, although they may have been cut in late winter long before the sap gets up in the tree naturally." This warning would undoubtedly apply to the butternut as it bleeds freely when cut. Another pitfall for the inexperienced propagator lies in storing scions in packing material that is too moist. Sphagnum is commonly used. It should be no more than slightly moist to the touch.

If left to run wild, the butternut curculios are a serious menace to the butternut, the Japanese walnut and the Persian walnut. Their life history as described at length in U.S.D.A. bulletin 1066, is briefly as follows: The beetles (called elephant bugs by some because the side view resembles the elephant) spend the winter in the ground. As soon as new growth appears on the host tree they begin feeding on the tender leaves and stems. Soon they begin laying their eggs in crescent shaped punctures which they cut in the new shoots and nutlets. The larvae hatch in a few days and tunnel through the pith of the shoots seriously injuring and stunting their growth while the infested nuts soon fall from the tree. The eggs may be laid from late May to early August. They hatch in a few days. The larvae complete their growth in four or five weeks when they enter the ground to pupate. In about a month they emerge as adult beetles and begin feeding on leaves and leaf stems as their parents did in the spring, but they will do no egg laying until the following spring. Poison spray applied in early spring and again in late August and September should so reduce their numbers that they will not become a serious pest. Our State Experiment Station suggests the use of a cryolite spray as it is more effective against curculios than arsenical sprays and less likely to injure tender walnut foliage. The Mitchell hybrid, (butternut x heartnut) with us, appears to have natural immunity to the curculio. This brings to mind a secondary but very important reason for finding better butternuts,—namely that they may be used as a starting point for the super variety that someone should give the world from his long rows of crosses between the best butternuts and the best heartnuts.

The nut growers of this country are indebted to Dr. Arthur H. Graves of the Brooklyn Botanic Garden for a complete study of the Melanconis disease of the butternut. This study was begun in New York City but has since been widely extended. He thinks that the disease is probably present throughout the entire range of the butternut and is usually responsible for the dead limbs that are so often seen in butternut trees. The Japanese walnut is also susceptible. The disease usually enters the tree through twigs that have been injured in some way. His conclusions, after thorough scientific laboratory and field work covering a period of over twenty years, is that it is caused by a weak parasitic fungus attacking rapidly only when the host tree is in a weakened condition; that it may lie practically dormant in vigorous trees and that it may be successfully combatted by fertilizing, mulching, providing necessary water in time of drought and avoidance of any condition that might weaken the tree. All dead twigs and all twigs showing fruiting bodies of the fungus should be pruned off some distance below the apparent infection as soon as discovered and the pruning wounds painted. Dr. Graves thinks it possible that butternuts grafted on black walnut stocks may have their vigor increased sufficiently to help in warding off the disease. Mr. Weschcke says that, although the Melanconis disease is prevalent in his locality, there has never been the slightest indication of it on the butternut trees which he has growing on black walnut stocks. If kept free of disease the butternut may reach great size. Dr. Robert T. Morris has stated that when he was a boy there were magnificent butternut trees over the greater part of Connecticut.

There still remains the stumbling block of lack of really outstanding varieties bearing nuts of good size, large percentage of kernel and perfect shelling quality with heavy and regular bearing. This is a large order to fill but it is a fair guess that somewhere there are wild trees better than any thus far brought to light. Trying to locate them should be an exciting assignment for a nut tree enthusiast. Do not think lightly of a butternut tree just because it looks small and unthrifty. It may be that the fault lies in an unfavorable location. Only an appraisal of the nut will establish its value.

The butternut is fairly abundant throughout its range which extends well up into Canada. In central New York there are uncounted thousands of butternut trees along fence rows, in the large and small valleys and along little streams. One person with limited time can hardly hope to examine more than a small proportion of them during the period when the nuts are ripe. The scout for better nuts should lose no opportunity to tell his errand to the people that he meets. I have found the average stranger interested and cooperative. He may direct you to a superior tree that you would never otherwise find. For this work one must be able, like the successful inventor, to hold his enthusiasm after many disappointments. If the coveted variety is not found, one at least has been out in the woods and fields during a wonderful time of year.