Predaceous Insects Research Articles

Effect of Time of Day on Surveys of Predaceous Insects in Field Crops

Effect of Time of Day on Surveys of Predaceous Insects in Field Crops

LEY DETERIORATION AND SOIL INSECTS

Two insecticides were applied to a 5‐year‐old ley and their effects on yield and soil fauna were studied a year later. Aldrin (2 lb. actual toxicant per acre) or dieldrin (1 lb. actual toxicant per acre) was incorporated in a standard dressing of compound fertilizer.One year after treatment the yield of dry matter was significantly higher on dieldrin plots than on plots receiving fertilizer alone. The soil fauna was examined in dieldrin and control plots. The wireworm (Agriotes spp.) populations were 80,000 and 400,000 per acre respectively. The increase in herbage yield was ascribed to the reduction in the number of wireworms. Mite and Collembola populations were very significantly reduced by dieldrin: the effect of this reduction on the breakdown of soil organic matter is discussed. A reduction in numbers of predaceous insects also followed insecticidal treatment, but it is thought that the resurgence rate of these insects would keep pace with that of wireworms.

Evaluation of Insecticides for Lygus Bug Control and Their Effect on Predators and Pollinators

A laboratory method involving the use of caged carrot seed heads was evolved to study the effectiveness of new insecticides and insecticidal combinations for lygus bug control. These laboratory tests showed that DDT or toxaphene combined with Dipterex or malathion resulted in quicker lygus bug mortality and lasted for a longer period of time than each insecticide did when used alone. Malathion and Dipterex alone resulted in satisfactory lygus bug control, but they were not as long lasting as DDT. Bayer 19639, Thiodan, demeton, endrin, and a combination of DDT-Trithion were identified as new treatments of potential value against this pest by means of the laboratory tests. Replicated plots and aircraft applications in fields of seed carrots showed that DDT was satisfactory for lygus bug control in this area. DDT did not appreciably reduce numbers of honeybees or cause a buildup of red spiders. Dipterex and malathion resulted in satisfactory lygus bug control, caused no spider mite buildup, but did not last as long as DDT and were of no ad- vantage for use on the carrot seed crop. Under the conditions of these experiments, DDT-Dipterex was the only new treatment indicated as a possible substitute for DDT or toxaphene for lygus bug control. This combination treatment significantly increased mortality over that of DDT, did not induce a buildup of spider mites, or reduce numbers of honeybees. The toxaphene-Dipterex combination was also significantly more toxic to lygus bugs than DDT. However, this combination, as well as toxaphene-malathion and DDT-malathion combinations, caused a spider mite buildup; and they were highly toxic to the predaceous insects present in carrots grown for seed. Data from field trials on carrot seed crops showed that it was advisable to evaluate new treatments in terms of their effect on beneficial insects as well as on the lygus bugs.

The Mating Activities of Balloon Flies

IN 1875, while visiting in the Swiss Alps, Baron Osten-Sacken made the first recorded observations on what we now call balloon flies. On sunny days, between the hours of about 9 and 10 o'clock, he noticed brilliant, silvery flashes among the sunbeams which penetrated the shadows of the fir forest. When he concentrated his attention on the flashes he concluded that they must be produced by insects, so he determined to catch some and added an extension to his net handle. The white flashing objects seemed to dodge with agility and it was only after several swings that he was certain he had netted one of them. However, when he looked into the net, he was at first astonished to see only an inconspicuous dull-colored fly, much smaller than he had anticipated. He assumed that this one had been captured by accident, along with the one he had tried for. So he examined his net carefully and it was only then that he noticed the white, filmlike packet of sparkling material on the gauze. He tried to pick it up, but it was so light that his breath carried it away. He pursued it and finally eased it into a vial. This was the first of the so-called fly-balloons to be taken. To make certain that the balloons actually were associated with the flies, OstenSacken caught one specimen after another, always with the same results. Each time there was the balloon in the net along with the fly. And examining the flies with his hand lens, he observed that invariably they were males. (See Fig. 1.) It was Becker (1888) who described this fly that Osten-Sacken had discovered, and he named it Hilara sartor. Hilara is a genus of the family Empididae which is made up of the dance flies, so called because of the habit indulged in by many species of dancing on the wing in assemblages which sometimes reach huge proportions. All of the balloon-making flies belong to the Empididae. Becker was interested in natural history as well as taxonomy, so he joined Osten-Sacken in speculation as to what the significance of the balloon might be. In fact he went to observe the flies in their home environment, but they flew too high for him to get close enough to make accurate observations. As a result he reached the erroneous conclusion that the males carry the white structures on their backs. He also supposed that these structures serve as decorations which attract the attention of the females, and of course in this he was not far wrong. That same year Mik (1888) also went to see these flies in action, and apparently he had either better eyesight or a taller stepladder than Becker because he was correct in insisting that the flies carry the balloons below their bodies, where they are suspended by the legs. He observed, moreover, that these structures are considerably flattened, this flattening being much more pronounced than in any of the later-discovered species. This observation led him to propose the fantastic theory that the male hilaras use the flattened objects as aeronautical surfboards on which to cavort among the sunbeams. The next entomologist to speculate on the significance of the balloons was Verhoff (1894). He concluded that they must serve as warning signals to birds and predaceous insects. There is no evidence that these flies are distasteful to birds; on the contrary I have seen birds attack swarms of related species of empidids. In regard to the second part of Verhoff's

Toxicity of Insecticides to Some Predaceous Insects on Cotton1

Journal Article Toxicity of Insecticides to Some Predaceous Insects on Cotton Get access William V. Campbell, William V. Campbell Mississippi State College Search for other works by this author on: Oxford Academic PubMed Google Scholar Ross E. Hutchins Ross E. Hutchins Mississippi State College Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 45, Issue 5, 1 October 1952, Pages 786–789, https://doi.org/10.1093/jee/45.5.786 Published: 01 October 1952

Toxicity of Insecticides to Some Predaceous Insects on Cotton1

Toxicity of Insecticides to Some Predaceous Insects on Cotton1

Studies on searching capacity of the larvae of three predators of the citrus red mite

Abstract does not appear. First page follows. The citrus red mite, Paratetranychus citri (McGregor), probably native to China, was originally recorded from orange in Florida in 1885. It now occurs in all states in which citrus is grown, with the possible exception of Arizona. There are no known parasites of this pest, but it is attacked by a number of predaceous insects and mites. A comprehensive account of the life histories and habits of the citrus red mite and its natural enemies in California has been given by (Quayle (1912)).4 Three predators of the citrus red mite commonly found in California are the red mite destroyer, Stetborus picipes Casey; the green lacewing, Chrysopa californica Coquillett; and the dusty wing, Conwentzia hageni Banks. The laboratory studies reported here were undertaken to gain a better understanding of various interesting factors which determine the searching capacity of the larval stages of these predaceous species. Procedure Experiments were carried on in a basement room at the University of California Citrus Experiment Station, Riverside. This room was maintained at a constant temperature of 80° ± 2° F, and at a relative humidity of 50 ± 2 per cent. Illumination was entirely artificial. The Experimental Universes The prey and each species of predator were tested separately in four types of experimental universe: Type-I, characterized by conditions of uniform light and topography; Type-II, varied light and uniform topography; Type-III, uniform light and varied topography; and Type-IV, varied light and topography. The predators were then tested in each environment with prey present in its preferred locations, and again with the prey present in its least-preferred locations.

Addition of Dinitro Compounds to D.D.T. to Prevent Outbreak of Spider Mites

IT is frequently observed that the use of sprays containing D.D.T. on fruit trees leads to a severe outbreak of Tetranychid mites or red spiders. In the United States, for example, Tetranychus pacificus McG., Paratetranychus pilosus C. & F. and P. citri McG. have all been found to increase very considerably after D.D.T.-spraying has killed the predaceous insects which normally keep them under control. Research workers who have obtained excellent control of codling moth (Cydia pomonella L.) or other pests with D.D.T. have felt unable to recommend its general use owing to the risk of producing a severe mite infestation. It may therefore be of interest to record a method by which this difficulty was overcome by the addition of dinitro-ortho-cyclo hexylphenol to the spray. The successful use of this material in the United States has been recorded, but does not appear to be widely known even there ; and it has never previously been tested on Bryobia mite, the prevailing 'red spider' of South African and Australian fruit crops.

THE PARASITE CATALOGUE OF THE IMPERIAL PARASITE SERVICE

The rapid development of scientific and practical work on parasitice and predaceous insects during recent years has created a need for a work of reference indicating the host relations of the entomophagous and providing in a convenient form a bibliography of the subject.

Living Parasitic and Predaceous Insects for Classroom Use

Living Parasitic and Predaceous Insects for Classroom Use

Notes on the Natural Enemies of the Iris Borer, Macronoctua Onusta Grote (Lepidoptera)

Little is known concerning the natural enemies of the Iris borer, Macronoctua onusta Grote. Dietz (1) records two species of Hymenoptera that were found to be parasitic on the larvae of this pest, and his record seems to be the only one that has been made. As several entomologists and the Iris growers themselves are interested in the biological control of the borer, the writer has been urged to record some observations he has made on its natural enemies. An unusually heavy infestation of the Iris borer of several years standing was under observation. Evidence is at hand to show that the caterpillars are attacked by a number of predaceous and parasitic insects, and that they are further reduced in numbers by insectivorous birds and rodents. The relations between the habits of this insect and its enemies will be more clearly understood if a brief resume of its seasonal activities is presented.

Contribution to the Knowledge of the Interrelations of the Bumblebees of Illinois with Their Animate Environment.*

Tho bumblebees are well endowed by nature with the means of a certain type of defense, this does not make them invulnerable to the attacks of parasites nor secure to their sedentary nests an immunity from inquilines, scavengers, and the like. Even adult bumblebees occasionally fall victims to predaceous insects and other animals, in spite of the fact that they possess a formidable sting and know how to use it to very good advantage.

The Natural Enemies of the Citrus Aphid, Aphis Spiraecola (Patch)

This is a preliminary report on the natural enemies of Aphis spiraecola in Florida. The citrus area of the state was injured by the aphid to the extent of about four million dollars during 1924. No true parasites were observed by the writer, but several predaceous insects are of some value in checking the aphid. In colonies on the native host plant, Spiraea spp. only two small predators were noted, a coccincllid beetle and an agromyzid fly.

Natural Enemies of Beet Leafhopper (Eutettix TenellaBaker)

Among the natural enemies of the beet leafhopper (Eulettix tenella Baker) are a large number of predaceous insects which prey upon the nymphs and adults. Seven species of egg parasites, two species of Pipunculus flies, a Dryinid and a hair-worm were bred by various entomologists in California. The percentage of parasitized hoppers gradually increases during the summer months and reaches its height during August (35.1 per cent). The weak point in the parasitism of the leafhoppers occurs on the plains and foothills where 4.4 to 8.2 per cent were parasitized during the winter and 1 to 1.5 per cent during the spring.

Societies and Academies

LONDON.Entomological Society, March 2 —Mr. C. O. Waterhouse president, in the chair.—Exhibits.—Commander J. J Walker: Living specimens of the heteromerous beetle Sitaris muralas firsfi re-discovered at Oxford in 1903 by Mr. A. Hamm on old stone walls in the vicinity, of Oxford inhabited by the mason bee, Podalirius (Anthophora) pilipes, on which it is parasitic in its early stages. —G. T. Porritt. Black specimens of both sexes, of Fidonia atomaria from the Harden Moss Moors, Huddersfield, illustrating the melanic tendency of Lepidoptera in the district.—H. St. J. Donisthorpe: Apion semivittatum, taken at Deal; Magdalis duplicata from Nethy Bridge, the first record of the species for Scotland; Formica sanguinea from Aviemore and Nethy Bridge, the first record for Scotland; and Piezostethus formicetorum, taken with Formica rufa at Rannoch, a species not recorded since 1874.—A. H. Jones: A case of butterflies taken this year from Herculesbad, South Hungary, including specimens of Erebia melas from the Domogled, which bore a remarkable resemblance to Erebia alecto, var. nicholli, Oberth., from Campiglio, and Erebia lefebvrei, Oberth., also shown for comparison by Mr. H. Rowland-Brown. Mr. Jones also exhibited examples of Chrosophanus dispar, var. rutilus, and C. alciphron, from the neighbourhood of Budapest, both species of great size and brilliant colouring.—Dr. F. A. Dixey: Specimens from Uganda of the African Pierine genus Mylothris, showing an almost complete gradation between Mylothris chloris, Fabr., and M. agathina, Cram.—M. Jacoby: Several fine forms of the ab. ceronus of L. bellargus taken this autumn at Folkestone, and one example of the ab. cinnides, Stgr.—Norman Joy: A specimen of the rare beetle, Cryptophagus subdepressus, Gyll., taken near Garva, Ross, on August 4 last.—W. J. Lucas: Two specimens of Deilephila euphorbiae bred by Mr. Nicholson and Mr. Summers from larvæ found in Kew Gardens. Mr. Lucas also exhibited several examples of predaceous insects with their prey in situ.—H. M. Edelsten: Specimens of Sesia andraeniformis, bred from pupæ taken in Bedfordshire and Kent, and ova of Nonagria cannae, giving an account of its remarkable methods of oviposition.—A. Harrison and H.Main: Four broods from females of Pieris napi, var. bryoniae, captured on the Kleine Scheidegg Pass, Switzerland, in July, 1906, showing a wide range of variation.—Prof. T. Hudson Beare: A specimen of the rare bug Lygaeus equestris, Linn., from St. Margaret's Bay, also specimens of Hypera tigrina, Boh., taken in some numbers on the wild carrot at the same locality, Apion semivittatum, Gyll., off plants of Mercurialis annua, all taken during the same period at St. Margaret's Bay.—Papers;.—The species of Hesperidæ from the Indo-Malayan and African regions, described by Herr Plotz, with some new Species: Colonel Charles Swinhoe.—The butterflies of Mauritius and Bourbon: Lieut. Colonel Neville Manders,—The hibernating habit of the lepidopterous genus Marasmarcha: Dr. T. A. Chapman.

XVI. Predaceous Insects and their Prey

XVI. Predaceous Insects and their Prey

6. The Attacks of Predaceous Insects other than Mantidæ upon conspicuous specially‐defended Lepidoptera, etc. (E. B. P.)

6. The Attacks of Predaceous Insects other than Mantidæ upon conspicuous specially‐defended Lepidoptera, etc. (E. B. P.)