To me, the filberts are fascinating at all times of the year. When the snow is deep and the cold bites deep, their tight little catkins always hold forth the comfortable promise of spring. When spring does come the thrill of the tiny red blossoms and lumbering catkins is as real and enduring as the promise of a crop of the shiny nuts is fickle. Then, of course, after the last tiny blossom has faded and the last catkin has withered, the leaves push forth. To me, these tiny leaves are a sight comparable to the opening and unfurling of the various varieties of the grape. Then enters the element of suspense, between the time of leafing out and the time when the little nut clusters appear.
My bushes are all growing together on a rise of ground near an old barn foundation. The ground is rich and they love it. Each bush is individual and distinctive as are their nuts—some tucked far in the husk, some bulging out in a precarious fashion, some fat and round, others long and narrow. They're interesting. I can let the butternuts, bitternuts and hickories pass, the heartnuts, chestnuts, and pecans can wait until I am sure they will bear here. The walnut will grow up along with the other trees—blending into the landscape, but the filberts, like Zombie, call attention to themselves every day of the year.
Somebody said recently that the emphasis in England is in being, and in our country in becoming. I imagine our land stopped being with the disappearance of the Indian and the primeval forest and is now in the process of becoming something else. What that something else is we don't know, and each generation carries a new set of values, but we all know that to become something better, trees must and will figure in the plans of all generations—better and more useful and more disease resistant trees. It is significant that nut trees lead in these requirements.
Biology, Distribution and Control of the Walnut Husk Maggot
DR. F. L. GAMBRELL, New York State Agricultural Experiment Station,
Geneva, N. Y.
DR. GAMBRELL: Mr. Chairman, ladies and gentlemen, some 22 years ago, I believe it was, I attended one of your meetings at the Experiment Station in Geneva, and at that time I gave a little talk on the walnut husk maggot. Perhaps some of you are old enough to have been there and remembered something about it, or maybe you are old enough so that you have forgotten as much as I have, so it would be worth talking over again. At any rate, when the chairman of your program committee wrote Dr. Chapman, asking him if he might talk, he came to me and said, "Would you be willing to do this?" I said I'd be willing but I didn't know whether I'd be able. But finally, the pressure was so great that I said yes, and I am here.
After I accepted the invitation, I made up my mind that I would like to bring myself up to date as much as possible on recent developments on walnuts, so I took the liberty of writing to a lot of our entomological colleagues and talking to one of your members, Mr. Slate, in the hope that I might get some more recent information on the maggots, or, particularly, the control of this walnut husk maggot. I wrote to some 10 or 15 entomologists in 15 states, as well as the United States Department of Agriculture in Washington and to our neighbors on the north in Ottawa. I must say that I have had a very fine response from everybody. They were all very willing to help, but practically all of them had the same answer: while they knew there was such a bug, they didn't know too much about it as an economic pest. So that left us all right in the same boat, with about two exceptions, as when we began. Our friends to the north in Canada sent some very nice information. We also had some information from the U. S. Bureau of Entomology and Plant Quarantine, Washington, D. C., together with some illustrated material. Also our good friend, Dr. Boyce, at the Citrus Experiment Station, in Riverside, California, with whom I have discussed the walnut husk maggot problem quite a few years ago, had a very nice bit of information and illustrative material which he provided. Incidentally, he is the man who has been mainly responsible for the development of the walnut husk fly control program for the nut industry in California. I would certainly like to take this opportunity to acknowledge any contributions he or the other people have made towards this discussion.
In New York State we have in our official list of insects about 30 species of fruit flies that are catalogued, but only about five of these can be classified as of economic importance. Two of these occur on the cherries, both sweets and sours, and are called the cherry maggots. Another one on apples, known as apple maggot, and a related form on blueberry. And then, of course, the walnut husk maggot, and one other which occasionally occurs on currants, but this one, of course, is of less importance than the others.
The fruit industry, of course, in New York is quite large, both apples and cherries, so that there is a considerable problem there as far as control is concerned. The growers spend thousands of dollars every year in combatting the various species of fruit flies. The interesting thing in this connection is that throughout the last 25 years with which I am familiar with the cherry fruit flies—in fact, that was one of the first projects I worked on in cooperation with Dr. Hugh Glasgow when I came to the Experiment Station in 1925—the control measures which we developed in 1925 to 1927 are essentially the ones which we are still using today; that is, for the most part. There have been various attempts to change the control program through the introduction of these newer insecticides, and some progress has been made, but in every case they have been wrought with some difficulties. At the present time the official state recommendations for the control of apple maggot and cherry maggot still include the use of arsenate of lead under some conditions. I mention that at this point because it is of some significance in the overall control. I am going to discuss that later on.
As far as the host plants and distribution of the walnut husk maggot is concerned, according to the original description which was published almost a hundred years ago, it was listed as occurring in and to the Middle States. That is a little bit indefinite, but at least it occurs all over the Eastern United States and as far west as Kansas. Then the one which occurs in California, which has since been called Rhagoletis completus (?) looks very similar to the one that we have here, but there are slight taxonomic differences, so at least it is considered a different species. At any rate, it is very similar to the one we have here, and this whole group of fruit flies that we have been talking about have a lot of similarity in their wing patterns and things of that sort.