MR. GILBERT SMITH: Plenty of them.
DR. ADAMS: You will also observe the damage at Mr. Smith's place. You will see that it is strictly a matter of skeletonization of the leaves.
A MEMBER: They eat the fruit, too.
DR. MacDANIELS: You have damage on fruit.
A MEMBER: They eat berries.
DR. ADAMS: Yes, but on nut plants the damage above ground is confined to leaf skeletonization. It varies widely, depending on the kind of nut plant. Before visiting Mr. Bernath's planting, I sought out the botanical names of the commoner nut plants in Dr. MacDaniels' Cornell Extension Bulletin No. 701, on "Nut Growing." Of the ~Juglans~ species, the black walnut, ~J. nigra~, is sometimes heavily attacked. There are large black walnut trees near one of our peach orchards. I have seen hordes of beetles gather in these trees in July and August, skeletonizing the leaves until the defoliation reached 40% or more. Late in August the beetles seemed to leave the walnut foliage and descend upon the ripening peaches. The heart nut, ~J. sieboldiana~ var. ~cordiformis~, was moderately fed upon at Mr. Bernath's nursery. The butternut, ~J. cinerea~, is only lightly attacked, as a rule.
The hickories and pecans are not attacked to any appreciable extent, but at least some of the chestnuts are very attractive to this pest. I have seen shoots of ~Castanea dentata~ with their foliage reduced to lace. Some of the small Chinese chestnuts, ~C. mollissima~, at Mr. Bernath's place, were about one-fourth defoliated in mid-August.
The hazels seem to be attractive to these beetles. When the Japanese beetle spreads to Prof. Slate's plantings of ~Corylus~ at Geneva, we may get more information on varietal preferences. I find that exposed foliage of ~C. americana~, the common wild hazel here, is sometimes fairly heavily fed upon. I am holding up to the window a portion of a hazel bush; you can see that the leaves along one side are skeletonized. It is probable that the species, hybrids, and varieties of ~Corylus~ will show the same marked variation in susceptibility that is shown in so many other genera of plants.
Among the oaks, the pin oak, ~Quercus Palustris~, and the English oak, ~Q. robur~, are commonly one-third defoliated while the common white and red oaks are almost immune. Among the maples—to go farther afield from nuts—the Norway, ~Acer platanoides~, and the Japanese, ~A. palmatum~, are often severely injured, where the sugar maple, ~A. saccharum~, is only lightly injured and the delicate-leaved red maple and silver maple, ~A. rubrum~ and ~A. saccharinum~, remain untouched.
Since the Japanese beetle is here to stay, and to spread, these differences are worth considering where plant materials are being selected for new ornamental plantings. In our bulletin on Japanese beetle (Cornell Extension Bulletin 770) we have to warn the reader that planting chestnuts may bring him trouble with the Japanese beetle, trouble which he would not have with flowering dogwood, ~Cornus florida~, or the common lilacs, ~Syringa vulgaris~, which are immune to this pest.