The young louse is an active, crawling creature, very minute and yellowish in color. (Fig. 2a). The young spread out upon the new b а FIG. 2.-Young larvæ, and development of scale; a, ventral view of larvæ, showing sucking beak with the bristles separated; b, dorsal view of same, somewhat contracted, with first waxy filaments appearing; c, dorsal and lateral views] of same still more contracted, illustrating farther development of wax secretion; d, later stage of the young scale-all greatly enlarged. (From Ent. U. S. Dept. Agriculture). growth of the tree, settle down, and each begins to secrete a scale,as shown in fig. 2. During its traveling stage it possesses the characters shown in the illustrations. The male is an active, two-winged insect, shown in figure 3. The full-grown female loses her legs FIG. 3.-Male of the San Josè Scale. (From Div. Ent. U. S. Dept. Agriculture. and antennæ, and bears a very slight resemblance to a living insect. It is shown in fig. 4a. Fig. 4b, shows the spinnerets. α FIG. 4.—a, Adult female, ventral view; b, spinnerets of the same. (From Div. Ent., U. S. Dept. Agriculture.) The insect affects not only the young twigs and limbs, but is also found upon the leaves and upon the fruit. When abundant the fruit is destroyed. One of the most characteristic points in the appearance of the insect upon the fruit is the purple discoloration around the edge of each scale. So far as we know this result is confined to this one scale insect. Upon the leaves the insects have a tendency to collect along the midrib on the upper side of the leaf, in one or more quite regular rows, and also to some extent along the side ribs. The infested leaves turn brown, but do not have a tendency to fall as a result of the damage. How the insect spreads. This scale insect can be carried upon fruit sent to market. Large numbers are thus sent long distances, and almost invariably reach their destination in good health. But as most of such fruit is eaten in the cities or away from orchards, there is not so much danger on that account, and only where peelings of fruit are thrown about in a careless and filthy manner among grow. ing bushes and trees can the young lice find a new home. These young lice are decidedly active for a brief time, two or three days at most, and they crawl with considerable rapidity and great persistence, so that they might possible descend from one tree and crawl for a number of yards to another; but the spread in this manner is insignificant. Where trees are close together they may pass from the branches of one to the branches of another. They rarely crawl long in one direction, however, but rather move rapidly around, irregularly and at random. Usually they do not go farther than is necessary to find a good place to settle and at once begin to form a scale. This very interesting process is shown in figure 2. As soon as the young louse has inserted its beak into the plant, and has begun to feed, a change comes over it, and within a few hours it is entirely covered with a fine, white, waxy film. This turns to yellow and then gray or even black, and the creature is a fixture, absolutely incapable thereafter of shifting its position under any possible circumstances. Strong winds may carry the young bodily from one tree to another, but the principle method of spread is by means of other insects which are winged and by birds. The active young lice will soon crawl upon any small winged insect, particularly if the latter is of a dark color, and they may be carried by it to a considerable distance. They also crawl upon the feet of birds which visit the trees and may thus be carried for miles. They are often found upon ants, and ants, as every one knows,are great travellers. The difficulty in moving from one place to another, and the dependence upon external agency for their distribution, will account for the fact that trees here and there in an orchard newly set out may be very badly infested, while not a trace will be seen on the trees on either side. Few birds or insects visit a young orchard that is at all well kept, and the distance between the trees, especially if the land is cultivated, is altogether too great to be covered by the young lice, even did they know enough to make a bee line for the nearest point. The result is that everything fixes upon the tree upon which it was hatched, killing it more rapidly than would otherwise be the case, but at all events confining and preventing its spread to points not before infested. This also explains why nursery stock is so evenly troubled: here the trees are grown just as closely together as is possible in rows, and there is no hindrance to crawling from one to the other. As the insects must feed for a time in the spring before attaining their full growth, it follows that only such as are fixed to the tree itself have any chance of reproducing their kind. Those that fix to the leaves fall with them, and as these dry or decay the insect dies for want of food before attaining maturity. Those on the fruit are removed when this is ripe. We have thus to consider only the wood, free of all leaves and fruit, when attempting the destruction of the insect. All our deciduous fruit trees and many forest trees are attacked by this insect in varying degrees. Smaller plants, like currants, gooseberries, raspberries, roses, etc., are also to its taste. In fact, nearly all bushes and trees will support it. Like most other insects this scale insect has a number of parasites that kill some of them. Large numbers are also eaten by such insects as the lady-bugs, and chiefly the smaller kinds do not despise such a little creature. They are, all combined, but a slight check to the FIG. 5.-a, b, c, Different stages of a minute black lady-bug; d, larvae and adult of the same in the act of devouring the scale insect. (From Div. Ent. U. S. Dept. Agriculture.) increase of an insect that is so prolific and has so many generations in the course of a single summer. The figures given of the number of offspring in one season are almost past belief, but they are based upon actual observation. Remedies.-A large number of remedies have been tried, with more or less good results. As the writer has no experience with them as regards the scale, and as so much has been written about the insect and the remedies in pamphlets that are accessible to all interested in this matter, it is not necessary to mention them at this time, especially as the insect can still be prevented to spread in our state. By all means the best, and in the end the cheapest way, is to destroy the trees that harbor such insect. Quite recently Profs. Smith and Webster have sent out circulars in which they state that pure kerosene oil, sprayed upon the bare trees during a day with sufficient wind to evaporate this oil very rapidly, would kill the insects without injury to the trees. Perhaps it will, and it would be a sort of patriotic action on the part of some of you to sacrifice a few trees, or rather to run the risk of doing so to try the remedy. Soaking the bark of an infested tree with such oil and burning it is also recommended; I suppose on the principle that burning a house will kill all bedbugs. Recommendations.-1. Every orchard that has been set out within the last six years should be thoroughly examined to ascertain whether or not the San Josè scale is present. 2. If the insect is found to be confined to a few trees these had better be taken out and destroyed, unless the infection is so slight that all scales can actually be removed with a stiff brush. No half way measures will suffice. 3. No fruit grower should admit a single young fruit tree or a single cutting or a single bud from a distance into his orchard without first carefully examining it and satisfying himself absolutely that it does not carry a single specimen of this scale. 4. Buy trees only from responsible nurserymen, best from your own state, and only when you feel quite certain that they sell plants not infested by this scale. 5. Infested stock is most likely to come from eastern or southern states where the scale abounds. 6. Avoid nurserymen that do not grow themselves the plants they sell. The scales that found their way into Minnesota were all bought outside the state, not from nurserymen but from dealers in nursery stock. 7. Have quarantine regulations established by the state. As showing the existence of the San Jose scale in Minnesota the following letter from Mr. Thos. Miller, of Heron Lake, Minn., was read by the secretary: Mr. Dewain Cook, HERON LAKE, MINN., Nov. 7th 1897. MY DEAR SIR:-Your letter of the 6th inst. at hand. It is true that the "San Josè scale" was found here in my orchard by Prof. Otto Lugger, State Entomologist. I will relate how it came to be discovered as briefly as possible. In 1893 I entertained the idea that nearly all the hardy fruits could be grown in Minnesota, especially apples and plums. My brother and I had about fifty acres that were suitable for fruit culture, and we proposed to plant it all with fruit. mostly apples and native plums. Before planting such a large tract, it was nec essary to experiment with the different varieties to see which were hardiest and thrifty. Since '93 our orcharding has been mostly experimental, embracing some twenty six varieties of apples, eleven varieties of plums, seven varieties of pears, seven varieties of cherries, with strawberries, blackberries, etc. We have planted trees from five nurseries, your own included. Last spring among others planted were six Wolf River apple trees. I planted them just as I had done all my others. Two failed to make any start, another lingered along for a month and then died, leaving three. These were the first apples I ever failed to make grow the first year. Sometime during the summer I had been reading some notes on the "San Josè scale," and as I have had a taste for entomology since I was very young it proved interesting reading. About the first of August I was walking through the orchard looking out for aphis on the plum trees. In my walk I pass. ed the Wolf River apples, and on one I thought the bark looked funny just at the crotch. I went up to it and found it covered with grayish white spots about the size of a pin head or smaller. By rubbing with the fingers the bark had a greasy feel, and the whitish spots rubbed off, leaving the bark its natural color. I saw it was a parasitic disease, and from what I had read knew it was the dreaded San Josè scale. As soon as I was reasonably sure in my own mind it was the scale. I looked all my other trees over but could not locate any more. The two remaining Wolf River apples that came in the same shipment, I examined carefully but could find no scale. The infested tree I kept watch on daily. The scale increased until the bark seemed covered with a whitish mould, and on October 1st I notified Prof S. B. Green and at his request sent some twigs for inspection, which Prof. Otto Lugger pronounced "San Josè scale." On October 25th, Prof. Lugger visited the orchard, saw the infected tree and pronounced it the San Josè Scale, sure. The other trees were examined, but no more were found. These are the facts in the case. I was not aware a petition went from here to the last legislature against the San Josè scale bill. Would like the name of the party who sent it. Yours truly, |