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This article discusses the results of two years' work, in Presidio, Texas, on the effects of plowing and of irrigation as measures of pink boll worm ( Pectinophora gossypiella Saunders) control. The best control was obtained by thorough plowing followed as soon as practicable by irrigation.

From 1922 to 1926, an average of 3.27 per cent of cotton boll weevils survived the winter in various types of protective shelters at Florence, South Carolina. Practically all weevils issuing from hibernation before cotton was available as a food plant died, the average longevity at this time being 5.64 days. Of weevils emerging from winter quarters after cotton came up, and placed in field cages on young cotton plants, a great majority died before these started to square, their average longevity under these conditions being 8.12 days. Weevils emerging at or after the time when squares were developed on cotton plants were longer lived in these same field cages than those emerging prior to this time, the average longevity for males being 16.28 and for females, 13.42 days. The maximum longevity at this time was 66 days for males and 46 for females. According to trap crop records and field counts, weevils continued to enter the cotton fields for three to four weeks after the first squares formed, or until about the time the first blooms appeared. In 1925, 90.01 per cent of the surviving. weevils had emerged in all cages at the time cotton began to square, 73.04 in those in the woods, 90.37 in those in the field, and 47.01 per cent in the trap crops. That year emergence in the hibernation cages located in the woods corresponded very closely with that in the two trap crops after May 14. In 1926, 98.03 per cent of the weevils had emerged in all the hibernation cages when cotton began to square, all in those in the woods, 97.91 per cent in those in the field, and none had been collected in the trap crops. The emergence of the weevils in the hibernation cages is called the “total emergence,” and that in the trap crops the “effective emergence,” since the latter represents those weevils that emerge late enough to find cotton. Trapcrop records and field counts for the two years indicate that there may be a considerable migration of weevils to cotton fields after first square production, although this may actually represent a small percentage of the total survival for that year. The use of the trap crop in determining the rate of “effective emergence” of the weevil from hibernation is more reliable and more representative of field conditions than is that of the hibernation cage.

The biological control of insects as related to host resistance is a relatively new field of study in which recent development has been rapid. Many insects, especially species that attack field crops which are produced on marginal land, cannot be economically controlled by the use of insecticides. Therefore it is necessary to seek other means. In many cases the most feasible method of control seems to lie in the development of resistant varieties of plants.

Tests conducted with home-made Bordeaux: Mixture, 4–4–50 formula and also with three proprietary preparations of this compound, indicate that these spray materials are toxic to the nymphs of at least one common and injurious cicadellid, namely: Empoasca mali Le B. They also are apparently toxic to the nymphs of three other species of leafhoppers, namely: Empoa rosae Linn, Erythroneura comes Say, and E. tricincta Fitch. The young nymphs are more susceptible to the action of the Bordeaux than the older ones, while the adults, although they are repelled from plants sprayed with this preparation, are not affected when forced to feed from treated leaves. Bordeaux mixture should therefore be classed as a specific insecticide for certain species of leafhoppers.

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The results of three years studies on the hibernation of the pink bollworm are presented. It was found that in the cotton field the greatest number of the over-wintering stages were in bolls on the stalks, although a considerable number were in shed forms or cocoons in trash on the surface of the ground. A comparatively small percentage were in the soil. Averages for three years show that the final survival in bolls buried 4 inches but not irrigated was greater than in bolls on the surface of the soil when not irrigated, though this ratio was reversed in sandy-loam soil or when bolls were buried in the month of March. An irrigation of surface bolls increased the survival. March burial of 4 inches produced greater mortality than December burial at the same depth, without irrigation in either case. Immediate irrigation of bolls buried 4 inches caused much greater mortality under certain conditions than occurred in bolls buried the same depth but not irrigated, but three-year averages under such irrigation in all soil types studied and for all months show very little difference. Delaying irrigation three months after burial greatly increased survival over that in bolls buried 4 inches but not irrigated or in bolls buried 4 inches and irrigated at once. The survival in bolls in sandy loam was much lower than in bolls in silty-clay soil.

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In 1954 a study was undertaken to determine the effects of several insecticides on the insect, spider, and mite populations in an alfalfa field. One of the first problems was to develop a standard method of sampling which would have a minimum amount of experimental error. A review of literature showed that several methods had been used by other workers. Five methods were tested and some were modified. This paper is a report on these tests, most of which were made in 1955.

On the basis of these tests, if lead arsenate is to be used as a spray for killing the adults it should be applied at the rate of 6 pounds per 50 gallons of water. The practicability of controlling the adults with a stomach poison is not proved, however. Field studies show the beetles to be exceedingly active in running about over the branches and main trunks of trees and in flying from tree to tree. Even if all the trees in an orchard were sprayed it would not prevent beetles from flying in and ovipositing on the trees.

The period of emergence of either the fall or spring brood of Hessian flies, Phytophaga destructor Say, varies from year to year with bioclimatic conditions. On this account "fixed" or "approved" dates are unreliable and the seeding date each year should be correlated with the season and with the fall brood of flies. In Iowa, the flaxseed count has been the only constant and reliable factor to use in predicting accurately the actual f1y-free-date. One hundred or more flaxseeds were collected at each station each day (average about 1,000 per day at Monona county station) from old stubble dug up at random in heavily infested fields. These flaxseeds were then classified as parasitized, empty and viable. The viable flaxseeds were then dissected to determine the per cent of larvae, of pupae and of parasitized larvae. Hence, the flaxseed count gave the daily rate of transformation from the larva to the pupa and to the adult state, as well as the rate of approach of the fly-free-date. When this count yields very few pupae and only a small per cent of larvae in contrast to a large number of empty flaxseeds, it ;s proof that the actual fly-free-date is at hand and that the few remaining pupae will immediately issue as flies, lay their eggs and perish before wheat drilled at this time will come up. Thus it is possible to predict the f1y-free-date so that farmers can begin drilling wheat six or seven days before the end of the egg laying period of the fall brood of flies. The records of the Iowa Observation Stations for 1922 and 1923 are given in the form of a summary.

Two of the most common wet land wireworms in Iowa are Melanotus Communis Gyll. and M. pilosus Blatch. They have a six year life cycle, the adults laying eggs chiefly in June of the first year, the larvae hatching mostly by July. The second, third, fourth and fifth years are spent in the larval stage. Pupation takes place usually in August of the sixth year and the adults emerge on an average of from 14 to 18 days later. These adults hibernate in protected situations above the ground, issuing from hibernation next year in May and June. The food of the adults is chiefly pollen.

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In May, 1933, my attention was drawn to a peculiar leaf injury to young cotton plants at Presidio, Texas. The leaves showed a striking reddish brown spotting from the upper side that at first glance resembled red-spider injury. The damaged plants were quite localized in one section of a large cotton field. Examinaion revealed the presence of large numbers of lace bugs present on the lower surface of the leaves. This species was identified as Gargaphia iridescens Champion by H. G Barber of the U. S. National Museum. Gibson, 1919, records the food plants as Ambrosia, Solanum, Malva, and sand nettle. According to records in the U. S. National Museum, this species has been collected by McMillan at Brownsville, Texas, on Solanum, string beans, and Ambrosia; on egg plant at Olmito, Texas, by McMillan; on Croton texanus at Tucson, Arizona, by W. D. Pierce.