portions of the nursery in which the work is being carried on were planted in breeding cages here at the Experiment Station and in no case were we able to rear leaf-hoppers from these trees. As a further evidence that in Missouri the pest is not carried over in the egg condition, one block which came under the writer's observation consisted of forty or fifty acres of one-year-old apples which had been severely injured two years ago by this pest. The winter of 1911 and 1912 was so severe that these trees were cut back to the ground before spring opened with a view of securing strong, healthy one-year-old trees on two-year roots. In the early spring of 1912 the writer examined this block when the pest first became noticeable throughout the nursery and while this block was several miles from apple orchards and in fact no fruit trees at all were within a mile of the ground, still it was found that these young trees, before they became half a foot tall were badly infested with very young nymphs and mature leaf-hoppers. The block under consideration was surrounded in part by woods and creek bottom land where an abundance of rubbish and leaves were collected in which the pest evidently passed the winter in great abundance and in the spring the adults simply moved back to the young growing trees and started the first colony of young.

The writer finds that in the early spring the first forms to appear are a few scattered adults. Following these is to be found usually a rather heavy brood of the young which are sufficiently abundant to seriously curl the first leaves. In a month to six weeks following this a second colony arrives and in a like period a third and so on until shortly before the leaves begin to fall. The later broods increase in numbers where measures are not taken to check them.

The writer has not been able to determine definitely with reference to the actual number of summer broods, but those which he has followed through seem to require from four to six weeks to complete their growth. In a nursery where the pest is uninterrupted one can usually determine from a single infested tree the number of times at which the heavy broods arrive from the fact that beginning near the ground is to be found a circle of curled leaves followed by fairly healthy foliage, succeeded in turn by another badly curled portion, and so on to the top of the tree.

From observations made before and after the first killing frosts this fall, it has been found that the adults leave the trees and collect along fence rows and in other protected places for the winter. The writer believes this will be found to be true throughout this state at least.

In reference to remedies for the pest it has been found impossible to control it entirely by the application of sprays. After a number of years of experience with spraying operations, the foreman of the

nursery in which the work is being carried on finds that while he has been able, at great expense, to prevent serious injury from the pest, he has not been able to control it completely. In view of the fact that the pest seems to pass the winter in the adult stage and arrives in the nursery to deposit eggs soon after the trees begin to grow, it occurred to the writer that a very thorough application of a contact. wash in the spring to destroy the first brood of young might have a far-reaching effect upon the pest later in the season. With this in view a series of experiments with different washes was undertaken and from a comparative test of some eight or ten of these, it was found that the young nymphs could be readily destroyed with an oil wash. One of the commercial brands of miscible oils gave the best results. Probably the same results could be obtained by the use of a homemade kerosene emulsion, but this wash was not included in the comparative test this past spring. The kerosene emulsion has been the standard wash with this nursery firm for a number of years and the foreman found that it did not seem to be quite as effective as the miscible oil.

In order to control this first brood it is necessary to make three or four applications at intervals of from three to six days since the nymphs of the first brood do not appear at the same time. The first brood seems to be drawn out over two or three weeks. After carefully applying contact washes for this brood, spraying operations should be discontinued. The washes under consideration had little or no effect upon the stray adults which were found in the nursery during the application and spraying operations are too expensive to repeat throughout the summer at the necessary intervals to catch the nymphs before they become winged.

Following the early spraying this year a machine was run at intervals of three or four days with a view of catching as many of the winged adults as possible. This trap is built on the sticky shield plan, mounted on wheels and so adjusted as to enclose two rows of trees. The sticky shields extended forward to a point slightly in advance of the horse and are roofed over behind and sufficiently high on either side to prevent the escape of many of the insects. In this way the horse acts as an agitator and the back part of the machine is closed by suspending gunny sacks thereby preventing the escape of any great number of insects in that direction.

In the experiment carried on during the summer it was found that so many of the hoppers, tarnished plant bugs, and other insects of this type were caught upon the sticky surface of the machine that it was usually necessary to scrape and re-paint the machine twice each day

and during each cleaning of the machine from one to two or three gallons of insects would be removed.

This sort of machine can be run at very slight expense and in those blocks where it was run regularly during the summer it was impossible to find any signs of curled leaves due to the injury of the pest. The writer is of the opinion that if three or four applications of contact washes of the oil type are made at intervals of three or four days in the early spring when the first young nymphs appear and then follow this up during the summer with a machine for catching the adults, this pest can be controlled in any nursery at a very reasonable expense.

FALL SPRAYING FOR THE PEAR PSYLLA

By H. E. HODGKISS, Geneva, N. Y.

Life history studies on the pear psylla were continued by the station during the past year for the purpose of determining more efficient methods for the control of this pest, and special attention has been given to the habits of the hibernating adults or "flies." Our investigations have shown that these individuals remain on the fruit spurs and young growth of the trees until the first severe cold weather occurs in November, when they seek the protection of the loose bark of the trunks and larger branches of the trees or hide under leaves or other débris which may be in the orchard. The roughened bark on adjacent trees of other kinds of fruits is often sought by them. If there is a warm spell during the late autumn and winter the "flies" become restive and abandon their sheltered places to gather on the lower branches of the trees, especially on the newer wood and fruit spurs. Whenever the weather moderates to a marked extent few of them remain in hiding, and where severe infestations exist myriads of the tiny insects cluster in the center of the trees. At such times the adults walk, but are sluggish in their movements and rarely attempt to jump or fly. The short duration of sunshine and the daily increasing cold cause a continual lessening of the activities of the insects, which become numbed and cling to the wood for considerable periods of time without exhibiting signs of movement.

The behavior of the hibernating psyllas in the spring is quite different from the habits of the insects in the fall. With the conclusion of winter the temperatures are constantly increasing and the daily effectiveness of sunlight is correspondingly longer. Coincident with moderation in the weather thousands of them leave their places of concealment and often a few hours of time are sufficient to effect great activity among the pests. It is not uncommon for them to jump and fly directly after emergence from their winter retreats.

The destruction of the hibernating "flies" is an important measure for the protection of pear orchards from psylla attacks. Careful spraying in the spring greatly reduces the numbers of the individuals and in some instances has completely freed plantings from the insects. The activity of the adults at that time has, however, prevented some growers from obtaining full control of this pest. It appears from the work that we have done that, on account of the difference in the behavior of the "flies" to gradually lessening temperatures, more favorable conditions exist in the late autumn for effective spraying.

During 1911 unprecedented numbers of psyllas entered hibernation, which afforded an excellent opportunity for demonstrating the value of fall treatments for the "flies." The experiments commenced on December 6 and continued until December 18, during which period thousands of the insects were clustered on the branches of the trees. The sprays applied were nicotine, fish-oil soap and lime-sulphur solution, used either separately or in combination: Nicotine preparations and soapy solutions were very effective. The lime-sulphur solution at dormant strength did not cause a marked reduction in the numbers of the psyllas, but with the addition of nicotine, the results from the combination compared favorably with the soapy sprays. Less than five per cent of the original infestation remained in the orchard at the completion of the work and in the following spring only scattering "flies" appeared upon the trees. In 1912 orchardists who were usually unable to control them by spring treatments found little difficulty in ridding their orchard of the insects through late fall applications of these sprays.

The success attending the fall spraying of pear orchards for the psylla is dependent upon,- (1) an understanding of weather influences upon the activities of the hibernating adults; (2) the complete wetting of each tree as the work proceeds; (3) thorough work in spraying.

THE 1912 OUTBREAK OF ALABAMA ARGILLACEA IN PERU By CHARLES H. T. TOWNSEND, Lima, Peru

During the first few months of 1912 the cotton leaf-caterpillar multiplied in extraordinary numbers in the cotton districts of the Peruvian coast region from about 9° to nearly 12° south latitude, and more or less unusually and generally to the northward as far as Piura Department. Complete defoliation occurred over the greater part of the districts from Chancay to Casma, reaching the latter valley on March 5. Much interest attaches to this outbreak from the fact that the meteorological conditions of the warm season of 1911-1912 in the coast region of Peru were very unusual.

The ordinary climatic conditions of the central Peruvian coast region from Chancay to Casma, in the low-lying cotton districts just back from the shore line, are as follows: June to November, very humid atmosphere, mist during nights and mornings, more or less continuous cloud-blanket, cool temperature; December to May, less atmospheric humidity in general with an approach to aridity during days, no mist, generally clear sky, warm but not oppressively hot temperature, cool ocean wind from south decreasing largely or dying out during the hottest part of the season.

The season of 1911-1912 showed the following abnormal conditions in this region: Very cloudy weather in general from November to March; an almost constant cloud-blanket from February 14 to 22, practically no sun, great atmospheric humidity with intensely oppressive heat, an unusually strong and very hot south wind continuing throughout the hottest season. This wind was evidently not the usual cool south wind from off the Humboldt ocean current, but a hot land wind from a general southeast direction that had followed up the coast line and whose origin was probably due to extra-local causes. It seems to have been strong enough to divert the south ocean wind from its usual course, or was perhaps itself a diversion of that wind, and was probably therefore responsible for the piling up of the unusual banks of humidity hanging over the coast line in this region.

It seems quite certain that the abnormal degree of humidity, with no sun, that prevailed during the last half of February, stagnated the soil of the irrigated fields by practically preventing the usual evaporation, while the abnormal heat caused a soil fermentation to set in, whereby neither the cotton plants nor the herbage in the fields showed any growth whatever from February 15 to March 21. The cotton plant was thus physiologically inactive for over a month during its usual period of greatest seasonal growth, and therefore still less prepared than ordinarily to withstand the attack of the caterpillar which was at its period of greatest activity. Irrigation during this period had no effect on the cotton plant, but rather made conditions worse.

The nights of March 21 and 22 were cold, with a sea-fog, and immediately after this sudden change in the meteorological conditions the cotton plants began to show signs of renewed activity. The herbage did not appear to resume growth till about March 30.

It seems indicated that the abnormal degrees of both heat and humidity which prevailed especially during February were most favorable to the rapid development of the caterpillar, resulting in an accelerated development of the stages of the insect, whose life-cycle seems to have averaged shorter than usual in North America, being reduced to about four weeks or even somewhat less. Three well-marked generations