REPORT OF THE ENTOMOLOGIST.

LAWRENCE BRUNER, Entomologist, State University, Lincoln.

INJURIOUS INSECTS, AND HOW TO FIGHT THEM.

MR. PRESIDENT AND GENTLEMEN: I have been requested to prepare a paper for this meeting, with the privilege of choosing my own subject. Presuming that something relating to insect life will receive your approval fully as much as any other subject upon which I could write, a paper is here offered on "Injurious Insects, and How to Fight Them."

There are many other features in connection with these "bugs" that I might have talked about. But being something of a farmer myself and knowing just what we as farmers are after, the subject of the injurious ones among insects has received my attention here.

It is not my intention to start out, like some entomologists do, with the impression that only entomologists know anything about insects. Neither is it my intention to fill the paper with high-sounding technical terms. Certain of our insects have received common every-day names that are known to all of us, and by which we know them. In treating of them I will, therefore, use these popular names wherever practical. There are a few names, however, in use among entomologists that apply to certain groups of the various insects with which we must deal, and which can hardly be avoided. These are the names of the orders into which the class Insecta is divided, the divisions being based upon certain structural characters. The names are Coleoptera, Hymenoptera, Diptera, Lepidoptera, Neuroptera, Dermaptera, Orthoptera, and Hemiptera. Each of these names, it will be noticed, ends in p-t-e-r-a, meaning wing, preceded by some explanatory part, as for example, in the words Hymenoptera, meaning membrane wings; Orthoptera, meaning straight wings; Diptera, two wings, etc.

In coming before you now it is not for the purpose of saying something original, but to impress upon your minds the necessity for continual vigilance against insect enemies. There is scarcely a plant that grows, or dies either, for that matter, whether cultivated or wild, but that affords food and shelter to one or more kinds of insect life. These insects, when they become numerous, of course do damage to the particular plants upon which they feed; and when very numerous cause them not only to become dwarfed and sickly, but also in many instances to die. While all kinds of vegetation suffer more or less from the ravages of insects, the cultivated forms appear to be especially subject to their attacks. Here it is where they appear to center their strength. To prevent these injuries and thus save the plants in question, is sometimes a matter of much perplexity, and one which causes a vast amount of hard labor, in addition to the expenditure of large sums of money.

When a nation goes to war it first tries to learn the tactics of the opposing forces before engaging in decisive battle. So, also, when we wish to engage in battle with an insect enemy. we too must first learn its mode of attack, life history, etc., in order that weak points may be discovered and taken advantage of. We must learn the effect of various climatic conditions, as heat, cold, humidity, and drouth, upon the species with which we have to deal in order to be most successful. Again, different insects work in different ways, and attack the plant from different points. Some work upon the foliage, some upon the twigs, stem, or main stalks; others again bore into these parts, while still others destroy the roots. Another class attack the blossoms, fruit, and seed. Again, different kinds of insec's attack the same plant during its different stages of growth and during different seasons of the year. In fact, most plants suffer from insect devastation in root, trunk, branch, limb, twig, bud, leaf, blossom, fruit, and seed; and each of them in its various parts.

Since the gardener, the horticulturist, and the farmer, has each to deal with a different class of plants that have their special insect foes, it is quite evident that each of these classes of toilers in the soil must learn something about the particular enemies of the plants that fall to their immediate care. To do this a close observation is necessary, and can be carried forward from day to day. The subjects and their works are never lacking-observation only need be made and the result remembered.

WHAT ARE INJURIOUS INSECTS?

It is not necessary for me to dwell long on the definition of the term injurious insects. Yet, 1 wish to make it plainly understood that not all insects, or, as they are more frequently termed, “bugs," are to be included in this category. Far from it! There are equally many or more of the "nasty things" that are our friends and hence beneficial to us. By injurious ones we mean all such species as directly or indirectly are the cause of loss or injury, or that in any way interfere with our individual comfort and welfare, whether caused by their attacks upon our persons, our beasts, or upon any of the vegetable or animal productions from which we derive the necessities and comforts of life. Beneficial insects, on the other hand, are all such as directly or indirectly work to our good, whether as enemies to the injurious ones, to weeds and other extraneous substances and things, or whether scavengers or the producers of some available article of diet, clothing, or manufacture.

Some insects are of one class during one of their stages of growth, while in others they are to be classed among those of the opposite. The common house fly cannot be called a particularly useful affair; still as a maggot it is a scavenger. Mosquitces also belong to this same class. The silk worm is injurious to the vegetation upon which it feeds, but when ready to transform, spins for itself cocoons the material of which forms an article of commerce as well as of beauty. Blister beetles, while in the larval stage, feed upon the eggs of locusts or grasshoppers, but after maturity are defoliators of trees, shrubs, and herbs. The beetles of some of the kinds are also utilized in medicine - thereby becoming doubly beneficial—before maturity and again when dead.

Butterflies of bright hue benefit us by exciting our better natures, and cause us to forget things gloomy.

By becoming acquainted with a few forms among the myriads of insects about us, we will be better prepared to fight the injurious ones and protect those that are beneficial. This acquaintance can be more readily made by the aid of an entomologist or "bug man" to do the introducing act, because he is supposed to be able to mediate between you and the bugs, on the ground of mutual acquaintance. He knows you and he knows the bugs, or should know them, to a limited extent at least.

Happily, injurious and beneficial insects usually occur in groups, some of which contain hundreds, yes thousands, of distinct species or kinds. If we become familiar with any one representative member of such a group, we can through inference place its allies either among our enemies or friends, as the case may be. It is by this means alone that the bug man has the apparent advantage over his more ignorant (?) fellow mortals-a very modest ground indeed, when any one of us can in the course of a few hours' study make these distinctions for ourselves. The farmer is directly interested in all such insects as attack the various crops raised on a farm. Those of the grains first, then the garden crops, after which come those of fruit, forest, shade, ornamental, and hedge trees, as well as of forage plants. Among the grain insects we have to deal with the Chinch-bug, the Hessian fly, the Wheat Midge, Army Worm, the locusts or grasshoppers, corn-root worms of several kinds, the cut-worms, Boll-worm (or Corn-worm, grain aphides of several kinds, as well as others. Among garden pests the cabbage worms of several species, potato-beetles, white grubs, Wire-worm, Radish fly, Onion fly, tomato worms, (two kinds,) cut worms, sweet potato beetles, bean and pea weevils, squash and melon bugs, etc., etc. Then for the little fruit which a farmer expects to raise he must be prepared to contend with a host of insects that attack his small fruits, his plum, cherry, peach, pear, and apple trees. Among these are the Goose-berry and Currant worms, the Codling-moth, Flat and Roundheaded borers of the apple tree, leaf beetles, caterpillars, bugs, saw-flies, and plant lice, in great variety.

Then again his forest, shade, hedge, and ornamental trees also must be looked after if he would keep them comparatively safe from the depredations of insect foes, such as the Tentcaterpillars, Fall Web-worm, canker worms, leaf beetles, borers, etc., of which there are plenty for each kind of tree grown. His meadows and pastures, too, are subject to the ravages of insect life. Truly there are many bugs!

The injuries caused by the various kinds of insects that attack our fruits, trees, grains, and grasses, must necessarily vary greatly in degree. This depends more on the mode of attack than from the numbers of the foe. A single grub, boring into the root or main stem will often more effectually injure the plant than hundreds or perhaps thousands of others feeding upon the foliage. In other words, internal enemies are far more destructive than those which are external. This rule is general. The foliage of a plant may be entirely destroyed several times

without much apparent injury to the general health of the body and roots. Not so with the roots or trunk, however. If these latter are greatly injured, the whole plant suffers in like

manner.

Nebraska as an agricultural state is comparatively young when compared with its sister states; still, in the number of insect depredators present, she is not far behind. We have here all of the most noted grain pests, as the Chinch-bug, Hessian fly, Army worm, Corn worm, Corn-root worm, cut worms, wire worms, white grubs, etc. Among garden insects, the cabbage butterflies, Cabbage louse, Onion maggot, Colorado Potato beetle, Tomato worm, Squash bug, flea beetles, etc. As fruit pests we have the Codling-moth, Plum curculio, Plum gouger, apple tree borers, grape insects, etc. And among forest and shade tree pests, most of those found in other localities are also found here. We have our own injurious species also. Some of these are the Cottonwood Leaf beetle, Willow Saw-fly, and grasshoppers, which are not among the least of our injurious species.

COMPARATIVE LOSSES CAUSED BY INSECT DEPREDATIONS.

It might be well here to give a few estimates as to the possible magnitude of losses that can ensue from insect depredations. In speaking of Chinch-bug depredations, Mr. Howard, of the Division of Entomology of the United States Department of Agriculture, (Bulletin No. 17,) has the following to say:

"In 1871 great damage was done in Illinois, southern Iowa, in parts of Indiana and Nebraska, in southern Missouri, and Kansas. It was estimated by Dr. Le Baron, in his second Illinois report, that the loss to the wheat, oat, and barley crops during this year amounted to $10,500,000 in Illinois alone, and in the other six states mentioned, including Indiana, the total lo-s was upward of $30,000,000." Again in 1874 the same insect occurred in this region, when Prof. Riley estimated the loss in the state of Missouri alone at $19,000,000. In this estimate he only included the wheat, oat, and corn crops.* As a result of careful investigation at the hands of Mr. J. R. Dodge, upon the subject of Chinch-bug depredations, the result as footed up amounts to $60,000,000 in the states of Kentucky, Ohio, Indiana, Illinois, Wisconsin, Minnesota, Iowa, Missouri, and Kansas. It will be noticed that Nebraska has not been included in this estimate. All who remember anything about that year will remember it to have been one of our worst Chinch-bug years.

The annual loss to the cotton crop in ten of the southern states by the ravages of the Cotton worm (Aletia xylina) is estimated to have been $30,000,000 prior to the year 1879, and from the close of the war. (Bulletin No. 3, U. S. Ent. Com., p. 8.) Since that time it has been less. The Hessian fly is also one of the depredators of the country, from the ravages of which millions of dollars have been lost in a single year.

It is not, however, until we come to foot up the probable losses occasioned by the Grasshopper scourge, that we find the figures climbing into the most startling sums. By referring to the first Report of the United States Entomological Commission, you will find there recorded carefully-prepared statistics upon this subject, (pp. 114-122.) It has been estimated that the total losses for the states of Iowa, Missouri, Kansas, and Nebraska were fully $100,000,000 for the single year of 1874.

With these figures before us, the importance of or at least the magnitude of insect depredations is not difficult to see. And if these figures include only one insect's destructive powers during a single year over a limited area, what would be that of all injurious species combined?

REMEDIES AGAINST THE DEPREDATIONS OF INSECT FOES.

For convenience, these may be divided into two classes, viz., artificial and natural. Under the former will fall the use of insecticides, machines, and hand-picking. Under the latter, meteorological conditions, predaceous insects, parasites, insectivorous birds, reptiles, and mammals, and lastly fungoid and germ diseases.

Usually the natural enemies of any one insect, together with the climatic conditions, are sufficient to keep it within proper bounds. Occasionally, however, through various causes, these fail, and an insect becomes sufficiently numerous to injure the vegetation upon which it feeds. It then becomes necessary for us to adopt some artificial means by which to kill off the superfluous numbers of this particular species. When this is to be done we must be guided by

*Seventh Report State Entomologist of Missouri.

the nature of our enemy, its food-plant or plants, and the comparative numbers of them to be dealt with, in the choosing of a remedy. Where poisons can be used without injury to individual or stock, that remedy can be applied; if not, then we have pyrethrum, kerosene, coal tar, naphthaline, soap-suds, lye, ashes, lime, etc., from which to choose, according to the place and condition of use. Then there are what will be called here the mechanical appliances, as machines for spraying solutions of the various insecticides. These are pumps and sprinklers. Again, bellows for sprinkling on powders, as of hellebore, pyrethrum, etc. Other machines can be made, for crushing; these are either simple drags or rollers, but can be made more complicated to suit the tastes of the operator. Pans for kerosene, either to drag along or to stand still, ditches, trenches, holes, fences, (dry or wet,) smoke, fire, and an almost endless number of contrivances that are to be thought of in connection with these mentioned above can be brought into use when the requirements make it necessary. Deep plowing, cultivating, rotation of crops, the use of fertilizers, burning of rubbish, etc., etc., when added to clean fence corners, hedges, and other nooks about the farm, also count for much.

As before stated, any or all of these remedies just suggested can be resorted to at the will of the operator, and as the nature of the pest to be handled requires. Usually by a little forethought, much later worry and loss can be averted, if we only assist our friends, the predaceous insects, parasites, and birds. This we can do in various ways. Don't kill the birds that you know feed upon noxious insects! But few of these are of such great importance to us as food that we could not do without them. A reckless destruction of birds, and especially of the song birds, and a few others, as the quail and smaller birds of prey, deserves to be repaid in kind by the visitation of insect pests. Predaceous insects should be spared and fostered, while parasites should be carried from one part of the country where numerous, to another where scarce, and set at liberty. In this way we will be aiding our friends, and at the same time fighting our foes. In this latter way the United States Entomologist has caused to be introduced certain parasites from foreign countries and turned them loose to prey upon injurious species that have also been introduced. Even now one of the agents of the United States Department of agriculture is in Australia engaged in the collection of certain parasites that work upon the introduced Cottony Cushion-scale (Icerya purchasi) of California, and shipping them alive to another agent in California, who cares for them after their arrival, and turns them loose among the insects to be destroyed.

These parasites mostly belong to the order which entomologists have named Hymenoptera, meaning parchment wings- the order of bees, hornets, and wasps. There are several families of these little friends, which together embrace many thousands of species. All of them live parasitic, either internally or externally, upon different species of insect life, though not always upon injurious species, for some of these parasites are in turn infested by others. Some of them attack the eggs, others the larvæ, and still others the mature insect. Of course an insect that can live and grow to maturity within the egg of a butterfly or moth must be very small, yet many of them do that very thing, and even these little fellows are not entirely free from enemies. A few of the two-winged flies (Diptera) are also parasitic within the bodies of caterpillars, locusts, and other large insects. These are what we call Tachina, or flesh flies. A few, also, of another class, are parasitic upon plant-lice and their allies.

While I have prepared rather full accounts of a few of the most destructive and wide-spread of our Nebraska insect pests for publication in your annual report, it is not my intention to worry you with it now. An agricultural report has the name of being rather "dry reading." That being the case, it is certainly equally as "dry" when listened to, and especally is this true when it relates to "bugs." Skipping this portion of my paper, I will now call your attention to a few cases in which an attempt has been made to show some of these insects, together with their work.*

Prominent among the vegetable-feeding insects are those known as locusts or grasshoppers. These insects are in fact all of them more or less injurious to the farmer. Here in Nebraska we are quite familiar with them, and one of them in particular, viz., the Rocky Mountain or Migratory species. This insect (Figs. 1, 2, and 3) has at times during the past years visited us from the more elevated and arid regions of the west and northwest. During these invasions or visitations, great and wide-spread have been the devastations and resulting privations caused by their ravages.

* Here an exhibit was made of some cases of injurious insects, arranged with a special view to their economic relations to agriculture. Not only were the insects themselves shown in their various stages of growth, but also amples of their work, together with their parasites and some of their other insect enemies.

In addition to the Rocky Mountain Locust, there are upwards of 100 other species of grasshoppers to be met with here in Nebraska, some of which, also, frequently occur in sufficiently

greatly restricted in their power to do general damage. Of these latter kinds the differential (Fig. 4) and red-legged (Fig. 5) species are the two usually concerned in all local depredations. I shall not, however, dwell any longer, at present, upon the grasshopper, its habits, life history, likes, and dislikes, and other attributes, for there is now a work under way in the experiment station entirely devoted to these insects, together with their allied forms, as crickets, katydids, etc., in which the subject will receive a very liberal attention from the various standpoints. In this bulletin will be described upward of two hundred distinct species, together with chapters on their life history, classification, food habits, parasites, etc., etc. The work will also contain a chapter on remedies against their depredations.

CHINCH-BUG.

FIG. 5.-The 'Red-legged Locust, (Melanoplus femur-rubrum;) female. [After Riley.]

[Blissus leucopterus.- Figs. 6-7.]

The Chinch-bug, which has become one of our most destructive insect pests in the United States, was first noticed in the state of North Carolina, where, like all of our other injurious insects, it acquired its taste for cultivated crops, and began its attack upon these plants in preference to those growing wild, and upon which it had probably fed from times very remote. These new food plants being always at hand during the season when the bug lays its eggs and the young are growing, and occurring in vastly greater quantity, of course gave the insect advan tages for rapid increase. The loose soil about the roots of these cultivated plants, too, more nearly met the requirements necessary for the work of the young than was to be found upon uncultivated grounds.