THE APPLE-TREE FLEA-BEETLE.

Graptodera foliacea Lec.

Here in the west, where the nursery business is an extensive one, we are very much interested in the matter of insect depredators. Especially are we occupied in our studies of those that in one way or another affect the apple tree. This being the case, I shall endeavor to pay particular attention to these insects.

Professor J. A. Lintner, in his first annual report as Entomologist of the State of New York, gives a list of all such insects as were then [1883] known to attack in any way the apple tree

and its fruit. Since the writing of that report, several additional species have been ascertained to attack this tree. Among these latter is the Graptedera foliacea or Apple-tree Flea-beetle as I will call it. This insect has recently become quite destructive to nursery stock in portions of this state, Kansas, and Colorado.

We are indebted to Prof. E. A. Popenoe for a pretty full life history of this beetle,* and in treating of it here I will quote his language largely.

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"Throughout its range, so far as noted, it usually occurs upon plants of the evening primrose family (Onangracea), being especially partial to the silky gaurus (Gaura parviflora), and others, the leaves of which are often riddled by it. * "For several years past the beetle in question has attracted attention on the college grounds [at Manhattan, Kas.] by its attacks during May and June upon the apple tree, the leaves being the portions injured. In orchard trees the lower branches only, near the ground, have suffered, and these but slightly. The greatest injury has been done in the nursery, where the beetle has often completely defoliated the spring-set root-grafts, and the yearling trees, and has seriously injured even two-year-old trees. The insects are most active in bright, warm weather, and are then attracted to the trees in great abundance, where they feed upon the parenchyma [green pulp between the veins] of the leaf (Fig. 18), avoiding the veins and midrib, these being sometimes all that remains after a few days' presence of the beetle. It is on the young shoots of the root-grafts that their work is the most injurious. In these they keep the new growth cut so close that the graft sometimes fails to recover. While the injury to yearlings is considerable yet the trees, though denuded, usually recover, and throw out new leaves after the season of attack is past.

*Bulletin No. 3 of the Experimental Station of Kansas Agricultural College, pp. 37-39.

"Like its near ally, the Steel-blue Grape-beetle, this species is easily alarmed, and on being approached, springs off the leaf, afterward seeking safety in flight, but only to return and again occupy its feeding ground, after the danger is past."

This insect, which is represented in Fig. 19, magnified, can be readily recognized from the following description: In size it is somewhat variable, ranging from four to five millimeters in length; it is oval in its outline, and of a highly polished brassy-green color. Antennæ dull brownish black beyond the three basal joints, which are somewhat obscured by a coating of short fine hairs or gray pubescence. The feet are dull brownish, or reddish brown, and, with the legs and under parts generally, are also somewhat pubescent.

In No. 3 of the periodical bulletin of the U. S. Department of Agriculture, Division of Entomology, known as "Insect Life," is a communication from the pen of Miss Mary E. Murtfeldt, also on the life history of this insect, together with notes on its habits. We take the liberty of quoting from this article as follows:

"About the 1st of June of the present year [1888] a correspondent sent me, from Colorado, a package containing a dozen specimens of a flea-beetle, closely resembling in size and form the Grape-vine Flea-beetle (Grapto iera chalybea Illig.), but differing in color, being of a highlypolished metallic green instead of blue. The apple leaves inclosed with these specimens were riddled with small, irregular perforations, and I was informed that these leaves correctly represented the condition of the foliage of most of the young trees in an extensive nursery - that of Stark Bros., near Denver, Colorado.

"As the species was unknown to me, I inclosed specimens to Professor Riley, who kindly determined them for me as the species under consideration. Professor Riley informed me that he had observed the work of the beetle and its larvæ in Missouri in 1872, feeding upon the hawthorn; also in 1877, in Colorado, and had published a brief account of it and its life history, with a description of its larvæ, in the Scientific American for June 16, 1887, and in the Gardner's Monthly for July 19, 1887 (Vol. 29, p. 216), under the name of G. punctipennis, which is a synonym of foliacea.

"I placed my beetles on fresh apple leaves and awaited developments.

"More than a mouth elapsed before I found eggs in the jar. On the 9th of July I found several clusters attached to the stems and bases of the midribs of the leaves. They are generally in twos and threes, ranged side by side. They are about one millimeter in length, slender, oblong rather than oval, of a pale, dull orange color, somewhat translucent, and Professor Popenoe, who has also obtained them, says that 'under a high magnifying power the shells are seen to be minutely granulated.'

"By the 17th of July a number of larvæ had hatched. They are nearly cylindrical, of a dull black color, and rather more elongate in proportion to their diameter than the larvæ of G. chalybea. When grown they feed on the parenchyma of the leaf, indifferently on either surface, but later they gnaw holes in it similar to those made by the perfect insects. The first molt took place in eight days, and two or three of the small larvæ perished in the process, being unable to entirely withdraw themselves from the outgrown skins. The second molt occurred one week later, and in this also one larva perished. During these periods there are no changes of color or maculation. August 2d one larva had completed its growth, and as it was making its way into the earth I put a stop to its further development by transferring it to the alcohol bottle. The following characters were noted: Length of mature larva, from six to seven millimeters; diameter, one and one-half millimeters; form, cylindrical, tapering somewhat posteriorly; general color, varying from dull black to dark fucous; piliferous plates inconspicuous, of the same shape, number and arrangement as those of G. ch lybea, black in color and slightly polished, each giving rise to from one to three minute hairs; head rounded, cordate, deep black, but not brilliantly polished; prolegs well developed, faintly annulate at the joints with dingy white.

"The larvæ move about considerably, but in a slow and rather clumsy fashion, with the tip of the abdomen appressed to the surface of the leaf or stem to assist in keeping them in position.

"The pupa is inclosed in a frail earthen cocoon or cell, just beneath the surface of the ground."

She (Miss Murtfeldt) further states that the pupal stage is less than two weeks in duration, some of the larvæ having entered the ground just fourteen days before emerging as beetles.

This beetle is double-brooded, the last brood remaining in the pupal stage over winter. It is also long-lived, many of the beetles of early summer remaining active and voracious throughout the summer into the fall.

While this new apple-tree pest has thus far done more damage in the states of Colorado and Kansas than elsewhere, it is by no means entirely absent from this state. On the contrary, its work has been observed for several years past in different parts of the state. This year [1888] especially has its presence been noted by various observers with whom I have recently been speaking upon the subject of apple-tree pests. Like all other injurious species, a change of habit in its food-plants from wild to those that are cultivated, has been the means for its rapid increase, and is liable to continue in the future as it has in the past few years, if some decisive measures are not taken at an early day to check its depredations.

REMEDIES.

Professor Popenoe, in speaking of remedies against the injuries of this insect, says: “Upon the college grounds we have checked the advances of this beetle without much trouble, by timely application by spraying of the arsenical poison (Paris green or London purple) in water, as used against the Coddling moth. As the beetles fly well, and as they may come in, from time to time through three weeks or more, from other localities, it may be necessary to repeat the application, the more if heavy rains have fallen. Our use of these poisons so far has been with the purpose of saving the trees, and we have not made trial to find the minimum effective strength of the mixture. In the strength employed, about six ounces of London purple to the barrel of water, we found that some injury to the tender leaf-growth followed, the plants suffering less from this, however, than they would have suffered from the unchecked attacks of the flea-beetle."

Miss Murtfeldt states that "the gentleman from whom I obtained the specimens wrote me that he had tried in vain to check its ravages with pyrethrum, kerosene emulsions, Paris green, etc., in the proportions and by the methods usually recommended, but that he succeeded in destroying it without injury to the trees by the use of white arsenic, one pound to 200 gallons of water, the arsenic being first boiled in a small quantity of water and then diluted to the proportions given above."

My experience with these different poisons as insecticides is, that the white arsenic, while perhaps a little more dangerous to handle than those which are colored, is by far the cheapest and at the same time most effective in its results. The proportions in which this latter can be used of course varies somewhat according to the vigor of the plant upon which it is used, the mode and time of application, and the nature of the insects to be destroyed. As a general rule, three ounces of the poison to the barrel of water (45 to 50 gallons) is sufficient, provided it is applied with force in the form of a very fine spray. A larger proportion than this of the arsenic will blister the foliage of most trees and other vegetation, and a lesser quantity will not be efficacious in destroying the insects. The mature insects, if beetles, will be more difficult to kill than the larvæ, and the mature larvæ than those just hatched. Mixing a little bicarbonate of soda or saleratus with the arsenic when boiling it will materially add to its virtue by dissolving more of it, and a little molasses added to the water in the barrel or tank before spraying upon the injured plant will also prove of value by causing the mixture to adhere to the vegetation.

In the use of any of these poisons for insecticides, great care is necessary to avoid accident to stock, as well as to individuals. More especially is this necessary where the white arsenic is used, and the vegetable sprayed is of a kind used for food or fodder.

THE APPLE-TWIG BORER.
Amphicerus bicaudatus Say.

The Apple-twig borer, which is herewith represented in all its stages of growth (Fig. 20), is one of the fruit tree and vine pests that is familiar to all who have paid the least attention to fruit raising, whether here in Nebraska or in other states. It is also one of the few insects most frequently recieved by entomologists, with an accompanying request to know what it is, to give a statement of its life, history, habits, etc., and how to get rid of it.

As the name indicates, this beetle, for such it is, attacks the apple-tree, in the twigs of which it works, its mode of attack being to gnaw into the twig or limb at the axil of two twigs or of a bud and twig, and bore downward or upward a short distance-never more than an inch or two, resulting in the death of the part beyond the injury. The pear, peach and sumac are also attacked in a similar manner by the mature beetles during the fall of the year. Both sexes work alike, and presumably for finding winter quarters and food only. It does not breed here.

Notwithstanding all these years of inquiry and study, the life history of this insect remained a sort of mystery until the past summer; at any rate there was no definite published account of it. In June, however, Professor E. A. Popenoe published a full account of its life history, together with the descriptions of two Hymenopterous parasites that attack its larvæ.* As his ac

FIG. 20.-The Apple-twig Borer (Amphicerus bicaudatus); a, female beetle from above; b, outline side view of male; c, antenna; d, full-grown larva; e, head and antenna of do.; f, right legs of do.; g, front view of pupa, in outline; h, twig, showing above the larval burrow packed with castings, and below, the pupa in its cell. The figures, excepting h, which is natural size, are enlarged, the hair-lines at the side showing natural size. [After Popenoe, drawings by C. L. Marlatt.]

count of the insect is the most complete of any reviewed by me up to date, I take the liberty of quoting from it,

"September 8th, 1887, an examination of the dead stems of Tamarix, a flowering shrub of strong growth, but in this locality killing to the ground in severe winters, revealed the work of two beetle larvæ unknown to us. The burrows extended lengthwise through the stems, for the most part through the center, following the line of the tender pith. The larger of the two larvæ proved to be the young of the twig-borer under consideration. These burrows in which the larvæ remained, or in which the pupa were found, were as shown in our Fig. 20, h, nearly of the same diameter throughout, packed closely with the sawdust-like castings of the larvæ, and usually about three and one-half or four inches in extent. The pupa was found in a cell at one end of the burrow; and in one case the adult, alive, was found in the same situation, before the outward passage had been made. Many of the burrows had already been deserted by the beetles, and, in such cases, an opening had been made outward, near the upper end of the pupal cell. This must have been done by the beetle itself, and not by the larva, as the cells containing pupæ had no such openings. The usual relation of this opening to the empty pupal cell is indicated by the dotted lines just above the base of the side shoot [Fig. 20, ]. These openings may be found upon any part of the infested stem, and the position in the figured burrow, at the base of the twig, is, of course, accidental.

"In the twigs examined at this time, the place of the egg and the beginning of the larval bur

* Bulletin No. 3 of the Experiment Station of the Kansas State Agricultural College, pp. 27-36.

row were not made out to a certainty. Indeed, the larval track, to all appearance, had doubled upon itself, and the whole length had been traversed anew by the nearly full-grown larva, the width of the burrow being thus left nearly uniform. This interpretation is strengthened by the finding, in one case, of a partial overlapping of earlier and later-made portions of the same burrow.

"Certain old vines in the college vineyard, nearly dead from the effects of the summer and winter of 186-87, were allowed to remain through the summer of 1887, but in most cases failed to recover. On pruning the vineyard these vines were found, January 26th, 1888, to be literally riddled by beetle larvæ of several kinds. An examination showed among them three specimens of the larvæ of Amphicerus. The beetles were found alive in the same vines. Later, during the warm and bright days of early spring, beetles of this species were frequently taken flying. During April and May many specimens were brought in by neighboring grape growers whose vines they were also attacking. As late as the twenty-first of June they were found alive in grape-canes.

"On the twenty-third of June, examination of the dead stems of Tamarix showed the larvæ, about one-fifth grown, in narrow burrows, some of which had reached the pith, but others being still in the outer layers of the wood. These burrows could be traced backward to their initial point in the bark, but nothing could be discovered as to the probable situation of the egg. From the size and position of the larvæ, it is probable that the eggs from which they hatched were deposited early the last spring."

DESCRIPTIVE.

LARVA. "The larvæ, found in connection with pupa and numerous living beetles in the dead stems of Tamarix, may be described as follows: Fleshy, curved, whitish grubs (Fig. 20, d), measuring in length about nine to ten millimeters (0.4 inch. Head 1.5 mm. in width. Thoracic region much thickened. Lateral breathing pores minute, and with difficulty seen. Mandibles black, other mouth parts reddish-brown; labrum, labium, and maxillæ thickly set with brownish hairs; maxillary and labial palpi apparently three jointed [basal tubercle two joints?] Antennæ reddish brown, four jointed, basal joint [or basal tubercle?] stout, second joint small, and when (as in Fig. 20, e) not fully extended, projecting about one-half the length of the third joint, which is darker colored, and furnished at tip with a long bristle; the last joint short, onehalf the diameter of the third.

PUPA. "The pupa (Fig. 20, g), of which three perfect and several parasitized specimens were found, all unmistakably referable by form and details of structure to the present species, meas

FIG. 21. The Magnificent Charitopus, (Charitopus magnificus), a parasite of twig borer. [After Popenoe, drawing by C. L. M.]