INSECTS AFFECTING THE STRAWBERRY.

BY PROF. S. A. FORBES, OF ILLINOIS.

At least two dozen species of insects are on record as enemies of the strawberry in the Eastern United States and Canada, and how many more may infest it whose injuries have never got into print, of course no one can tell. Every part of the plant is attacked by them, some limiting themselves to a single structure, and others devouring two or three indifferently. The fibrous roots are eaten by the root-worm, the white grub, and the larva of the goldsmith beetle; the stem or crown (as it is commonly called) is gnawed and pierced by the root-worm, and excavated by the crown-borer and the crown miner. At least a dozen enemies attack the leaf, either biting and gnawing its tissues or sucking its juices, and one of these, the strawberry plant-louse, also sucks the sap of the crown and even of the peduncle of the flower. The blossom itself is destroyed by two or three; and finally, the ripened fruit is likewise occasionally injured.

Some find their more usual food in other plants, taking the strawberry only when it comes in their way; still others, limiting themselves to the strawberry field, are doubtless the native enemies of the wild plant, whose multiplication has been immensely facilitated by the enormous increase of the food; and still a few others are believed to be of European origin, imported to this country by accident.

I have herein summarized what is known to me with regard to the most important of these insects, thinking it might be worth while to bring the essential facts together in one place for reference. I have included those found injurious eastward as well as in the limited region covered by the membership of this Society, in order that you of the Mississippi valley may be on the lookout for the invasion of eastern enemies; but I have not noticed especially the strawberry pests of the Old World or of the Pacific Slope. I have drawn freely upon the writings of Thomas, Riley, Packard and Saunders in the preparation of this paper, my own contributions to the subject relating chiefly to the crown-borer, the root-worm and the crown-miner.

It is proposed to treat separately the insects injurious to the root, to the stem or crown, and to the foliage, flower and fruit, taking them up under each head in the order of the classification. Under this arrangement the first to be treated will be those attacking the exposed parts of the plant, namely, the foliage, blossom and berry.

INSECTS INJURING THE LEAVES, FLOWER AND FRUIT.

The Strawberry Worm. Emphytus mrculatus, Norton.

Order Hymenoptera, Family Tenthredinidæ.

This insect is one of the most destructive enemies of the strawberry in localities where it secures a footing, but is not as widespread and continuous

in its ravages as the leaf-roller and some of the various beetle larvæ affecting the root and crown. It is, however, to be placed among strawberry insects of the first class. It has occurred in great numbers throughout Central and Northern Illinois, Missouri and Iowa, and as far east as Ontario, Canada. Prof. Riley's terse description, given in his ninth report as State Entomolo

Fig. 1. STRAWBERRY WORM (Emphytus maculatus, Norton): 1. Ventral view of pupa: 2. Side view of same; 3, Enlarged sketch of perfect fly, the wings on one side detached; 4, Larva crawling, natural size; 5. Perfect fly, natural size; 6. Larva at rest; 7. Cocoon; 8. Enlarged antenna, showing joints; 9. Enlarged egg. After Riley.

gist of Missouri, can scarcely be improved upon, and I quote the substance of it in his own words:

"Early in spring numerous flies may be seen hanging to and flying about the vines, in fields which have been previously infested. They are dull and inactive in the cool of the evening and at these hours are seldom noticed. They are of a pitchy black color, with two rows of large, transverse, dull whitish spots upon the abdomen. The female, with the saw-like instrument peculiar to the insects of this family, deposits her eggs by a most curious and interesting process, in the stems of the plant, clinging the while to the hairy substance by which these stems are covered. The eggs are white, opaque, and .03 of an inch long, and may be readily perceived upon splitting the stalk, though the outside orifice at which they were introduced is scarcely visible. They soon increase somewhat in bulk, causing a swelling of the stalk, and hatch in two weeks-more or less according to the temperature -and during the early part of May the worms attract attention by the innumerable small holes they make in the leaves. Their colors are dirty yellow and gray-green, and when not feeding they rest on the under side of the leaf, curled up in a spiral manner, the tail occupying the center, and fall to the ground at the slightest disturbance. After changing their skin four times they become fully grown, when they measure about three-fourths of an inch. At this season they descend into the ground, and form a very weak cocoon of earth, the

inside being made smooth by a sort of gum. In this they soon change to pupae, from which are produced a second brood of flies by the end of June and beginning of July. Under the influence of July weather the whole process of egg-depositing, etc., is rapidly repeated, and the second brood of worms descend into the earth during the forepart of August, and form their cocoons, in which they remain in the caterpillar state through the fall, winter, and spring months, till the middle of April following, when they become pupa and flies again, as related."

As the second brood of the larvæ appear upon the leaves in July, after the fruit is picked, and feed entirely upon the foliage of the plant, they may doubtless be destroyed without difficulty by the use of the ordinary poisons. Paris green, London purple, or powdered hellebore may be safely recommended for this purpose. It is also not unlikely that fire as applied for the leaf-roller, would be found efficient for the destruction of this pest likewise, if used at the time when the eggs and larvæ are exposed upon the foliage. It should be noticed that plowing up the field in autumn will not actually destroy this insect, unless the ground be planted for a year to another crop, and that even then it is possible that the adult saw-flies, escaping from the field, will secure a lodgment in other strawberry vines

Mason Bee. Osmia canadensis, Cresson.

Order Hymenoptera, Family Apida.

I notice this insect here on the strength of a paragraph by Mr. Wm. A. Saunders, contained in the report of the Entomological Society of Ontario, for 1872.

"This," he says, "is the name of a small hymenopterous insect, a sort of wild bee, which has proved destructive to the foliage of some strawberry plants during the past season, in the township of Oxford. It was observed by Mr. Johnson Pettit, of Grimsby, who kindly furnished me with specimens of the insect. In both sexes, the head, thorax, and abdomen is green and more or less densely covered with whitish down or short hairs, those on the thorax being longest. The wings are nearly transparent, with blackish veins. The female is larger than the male." The length is .35 inch, and the spread of the extended wings about half an inch.

"Mr. Pettit says: The insects were taken in East Oxford, July 2d, on a few strawberry plants in a garden. The plants, perhaps nearly one hundred in number, had been nearly all denuded of their leaves, and a search in the evening having failed to reveal the authors of the mischief, I examined them again in the heat of the day, and found the little culprits actively engaged in nibbling away the remaining shreds of the leaves. They appeared to chew the fragments into a pulp and carry it away, but the little time I spent in observing them was insufficient to determine anything further respecting their habits.' Doubtless in this instance the leaves so consumed were used in the construction of suitable nests, in which to deposit the eggs and rear the young of those insects."

If this species should ever become seriously destructive (as is very unlikely), its injuries could probably be checked by the use of insect poison, since the time when it made the attack above described was after the fruiting of the plant.

The Strawberry Span Worm. Nematocampa filamentaria, Guenée.

Order Lepidoptera, Family Phalanidæ.

In June, or earlier to the southward, a wood-colored measuring-worm, seven-tenths of an inch in length, with two unequal pairs of long, slender, fleshy filaments, situated on the third and fifth abdominal rings, the posterior pair shorter than the others, curled at the end, and finely tuberculated, may be found feeding on the strawberry and currant. The head is pale rust-red, with some spots of same hue on the body. Half way between the metathoracic legs and the first pair of filaments are two sub-acute tubercles, which are rust-red. When the four filaments are uncurled, they are as long as from the head to the tubercles. The anterior pair of filaments are pale rustred beneath at base, brown above, but tipped with white. An oval dark spot occurs behind the last pair of tubercles, and extending into the anal plate. This curious worm produces a little pale ochre-colored moth, measuring about an inch across the wings, with brown lines crossing the wings, and an outer border of dull brown that is continuous across both wings except the apical portion of the anterior pair. They are never sufficiently numerous to cause much injury.

This, like the preceding, if it ever becomes destructive, can doubtless be met with insect poison sprayed or sprinkled upon the leaves.

The Green Strawberry Span Worm. Angerona crocataria, Guenée.

Order Lepidoptera, Family Phalanidæ.

This is another of the measuring worms which has been reported injurious to the strawberry; but as it has not been anywhere a serious enemy, as far as I can learn, I mention it here only for the purpose of putting fruit-growers on their guard against it. The larva, which appears on the foliage in May or June, is about an inch and a half long, gradually increasing in size from the head to the first pair of prolegs. The general color is a yellowish green. There is an indistinct dorsal line, and a rather broad whitish line on each side just below the spiracles, bordered above with faint purple, which increases in depth of color towards the posterior rings. This becomes a purple stripe on the anal prolegs, and forms a mark like an inverted A. Beneath, same color as above, but with faint, interrupted longitudinal lines. Spiracles white, bordered with purple. Above, on each segment, from second to seventh inclusive, are five minute black dots (four in a square, and one in front towards the head) and all the rings have a yellowish band on the swelled part, where the succeeding segment is inserted; legs pale green. The pupa is 5 to 6 inch in length, and of a dark olive-green color, with the exception of the abdomen, which is pale greenish yellow, and has a row

of black dots on each side, and another dorsal row. The wing-cases are very prominent, and, from their strong contrast with the abdomen in color, make the chrysalis a pretty object. They are fastened by the tail, and rest in a slight net-work of silken threads, with which the caterpillar draws together the edges of the leaf so as to form a kind of cradle.

The moth appears in June or July, and may be found at twilight until September. It expands about an inch and a half; the wings and body are bright yellow, the first spotted with pale reddish brown, and crossed by a broad, broken band of the same color a little beyond the middle. On the forewings, midway between this band and the body, is another band more broken than the outer one, and the spots of which it is composed are smaller. It is one of the brightest colored of the geometrid moths.

The insect is a very prolific one, a single female depositing over two hundred eggs. These are laid soon after the appearance of the moth, in patches or clusters. They are of an oval shape, about one thirty-third of an inch long and one-fiftieth wide. When first laid they are yellow, but in a day or two change to bright red, and afterwards to grayish-brown. They hatch in one or two weeks. The young caterpillar is about a tenth of an inch long, with a large brown head and yellowish green body, with a dark brown stripe along each side. Below this the body is pale, with a whitish bloom on its surface, and a few short, brownish hairs, which are most numerous on the last segment.

If this insect should ever become sufficiently numerous in the strawberry fields to require especial attention, it can probably be destroyed by the same measures which have been found efficient for the leaf-roller.

The Smeared Dagger. Acronycta oblinita, Sin. & Abb.

Order Lepidoptera, Family Noctuidae.

Fig. 2. SMEARED DAGGER (Acronyeta oblinita, Sm. & Abb.): a. Larva; b. Pupa; c. Moth.