Food Pest Research Articles

EFFICIENCY OF HERBICIDES APPLICATION AFTER SPROUTS OF THE MAIZE CORN SOWING

In Ryazan region edaphoclimatic conditions allow to obtain stable yield of corn more than 19841,6 pounds of grain per hectare. Investigators consider that increasing of corn yield by 50% depends on availability of plant food compounds and pest, disease and weeds protection, by 25% from soil tillage quality and by 25% from varietal features of cultivated crop and hybrids. Weeds in the wide-row planting during the active vegetation period compete with crop for nutrients and moisture reserve in the soil. As a result of the institute multi-year research the average loss of corn yield from weeds without protection measurements is 30-50 %. The results of two-year field tests on the study of the herbicide usage effectiveness after corn germination are presented, to reduce the weed infestation of sowing and increase yields. The researches were carried out in the OOO “Svet”, Ryazhskiy district, Ryazan region. The soil is leached chernozem, the content of the humus is 5.2%, potassium and phosphorus- average, pH-6.0. The area of cultivated plot is 10.0 ha, control plot –0.2 ha, record plot – 107.64 sq. ft, number of replication – 4. The corn variety is Klarissa, sowing rate is 55.12 pounds per hectare, forecrop is winter wheat. Agricultural practices in the experience is application of 220.46 nitrophoska pound per hectare, 440.93 pounds per hectare of the ammonia nitrate, harrowing of the autumn plowing, cultivation, seeding with precision seeder. For weed protection of the corn seedlings in 2016 was applied herbicides tank mixture; Egida-48%, VDG (AVG – 0193)– 0.55 pound/ha + Dublon – 4%, SK – 0.26 gal/ha and factory product Elyumis – 10.5%, MD – 1.32 hal/hа, in 2017 – Egida tank mixture, VDG – 0.44 pound/ha + Dublon, SK – 0.26hal/ha and Elyumis, MD – 0.26 hal/ha. It was found that the studied herbicides effectively reduced the weed infestation of crops and increased the yield of grain maize by 7936.64-12786.8 pound / ha.

Studies of Behavior of the Tribolium Flour Beetles. I. Contrasting Responses of T. castaneum and T. confusum to Fresh and Conditioned Flours

The studies set out in Part Fi of this series contrast the behavioral responses of Tribolium castaneum Herbst., and T. confusum Duval, to two markedly differing conditions of the flour medium: fresh whole-wheat flour, and whole-wheat flour of the same origin that has become heavily conditioned by supporting the growth of high populations of Tribolium in stock rearings. The conditioning of a flour medium by beetles living within it is a process involving at least 3 factors: depletion of the nutritive value of the medium; accumulation of cast larval skins, dead imagoes, and similar debris; and finally and most markedly, accumulation of the quinones given off by Tribolium imagoes and taken up by the flour. Conditioning is a progressive, cumulative process, so that a flour is more, or is less, conditioned depending on its occupancy by larger, or smaller, numbers of beetles for longer, or shorter, periods. Interest in the behavior of these 2 Tribolium species arises primarily from their use by Dr. Thomas Park, of the University of Chicago, in a biologic model of interspecies competition (Park 1954). The model is meaningful in view of the close relation between these species and their ability to survive indefinitely as single-species control populations under identical conditions of husbandry. As Park (1954) has pointed out, these are species exhibiting marked ecological similarity, between which the struggle for survival in competition might be presumed to be severe. In confirmation, Park has found that under 6 different combinations of temperature and humidity, elimination of one or the other species follows invariably when they are placed in competition. Study of their behavior offers one important route by which we may now assess the degree to which these species are, in fact, ecologically similar. The results of competition between these beetles are better known and better documented than they are for any other species, so that by assessing their ecological similarity we may also hope to assess the importance of ecological similarity itself as a factor in competitive elimination. A substantial literature of Tribolium studies has arisen partly because these insects are admirably suited to laboratory investigation of ecological problems, and also partly because they have been of considerable economic importance as pests of stored food. Economic interest has led to a number of studies of the gaseous secretion that is the principal cause of the conditioning of the flour medium. Roth and Howland (1941) found that last instar larvae and prepupae exposed to the gas gave rise to variously aberrant adult beetles. Roth (1943) found that there was no detectable secretion of the gas in larvae of all instars or in prepupae, but that tests for gas were positive among some very late pupae and in all adults an hour after emergence. In this same year Alexander and Barton (1943) identified the main part of the volatile secretion of T. castaneum as ethylquinone and noted that the same substance could be obtained from T. confusum. A decade later, Loconti and Roth (1953) provided the presently most exact determination of the composition of the secretion of T. castaneurn. They found that 3 quinones were present in the odorous secretion: 80-90% 2-ethyl-1, 4-benzoquinone; 10-20% 2methyl-1, 4-benzoquinone; and a trace of 2methoxy1, 4-benzoquinone. Loconti and Roth introduced a new approach to the study of this gaseous secretion by performing qualitative repellency tests with the 3 quinones isolated from adult beetles, using T. castaneum as the test animal. Their test method was based on the strong attraction of starved beetles to flour. The introduction of the ethyland methyl-quinones into the flour repelled starved beetles, whereas the methoxyquinone did not. It may be supposed that, had they also performed these repellency tests with T. confusurn as the test animal, they would have noted the single most striking observation from the present studies-that, unlike T. castaneum, T. confusum is strongly attracted to conditioned flour. This emerges in the present study as a major facet of behavioral dissimilarity affecting the ecological relations of these species. 1 These studies have been aided by fellowships from the University of Chicago and currently by P.H.S. Grant M-5561 (A).

The persistent Toxicity under standardised field Conditions of Pyrethrum, DDT and “Gammexane” against Pests of stored Food

The persistent toxicity of films of pyrethrum in P31 oil may endure on suitable surfaces under warehouse conditions for much longer periods than hitherto supposed, but unexplained fluctuations in toxicity may occur.Within the range 0·8 per cent. to 1·3 per cent. total pyrethrins, the pyrethrum content appears to be only a minor factor in determining the persistent toxicity of such films.The nature of the surface sprayed is of great importance in determining the persistent toxicity of pyrethrum films in P31 oil, which is negligible on concrete and increases steadily through the following list of surfaces—brick, heavy hessian, light hessian, jute, cotton, and wood; the last-mentioned two being particularly good substrates.Residual deposits of DDT or “ Gammexane ” derived from kerosene sprays are of little use on concrete, but appear otherwise little affected by the nature of the surface treated; they give a uniform degree of persistent toxicity on the various surfaces listed.

Insect Pests of Flour

UNDER the title of "Insect Pests of Food : The Control of Insects in Flour Mills" (London : H.M. Stationery Office. 7s. 6d. net), the Ministry of Food has recently issued a useful 84-page practical bulletin by J. A. Freeman and E. E. Turtle. The authors are, respectively, chief entomologist and chief chemist of the Infestation Control Division of the Ministry. The bulletin deals with those insects and mites that affect the flour miller : it describes the measures that can be adopted in order to prevent infestation and how to control such insects should they manage to establish themselves. It is divided into three main sections, namely, methods of prevention and control ; life-histories of insects and mites ; and infestation in the mill. The losses which these creatures inflict on the industry may be assessed as damage to wheat ; interference with productive processes ; contamination and spoiling of finished products and loss of goodwill and trade. reputation. The methods of control that are described are only those which have been examined by the Ministry and thoroughly proved in practice. It should not be inferred, however, that these methods are in any sense static. New work is continually going on, and, as examples, may be mentioned that which is being done in assessing the value of D.D.T. and of benzene hexachloride (‘Gammexane') in this connexion. The bulletin is very well illustrated by numerous half-tone plates and text-figures.

Pests of Stored Foods Food and Agriculture Organisation Conference

A MEETING of scientific workers concerned with pests of stored food was held in London in the of August 4. The meeting was opened by Sir John Boyd Orr, director-general of the Food and Agriculture Organisation, who urged the delegates to propose methods which would enable Governments to preserve the 1947 harvest.

Insect Pests of Food, and the Consumer, by R. V. WADSWORTH, F.R.I.C., F.R.E.S., Chief Chemist, Cadbury Brothers, Ltd

Insect Pests of Food, and the Consumer, by R. V. WADSWORTH, F.R.I.C., F.R.E.S., Chief Chemist, Cadbury Brothers, Ltd

Insect Pests of Food

THE Ministry of Food has published, under the title of "Insect Pests of Food" (London: H.M. Stationery Office, 5s. net), two important papers on moths and their larvæ affecting stored products. They are designed to provide a reliable and up-to-date guide to the identification of the insects referred to. Although the two papers are primarily for the use of the Ministry's inspectors, they will be valuable to anyone concerned with the pests in question. The paper on lepidopterous larvæ affecting stored products is by Dr. H. E. Hinton and was originally published in the Bulletin of Entomological Research (34), and that on the moths by Dr. A. S. Corbett and Mr. W. H. T. Tarns is reprinted from the Proceedings of the Zoological Society of London (113 B).

Animals and Plants of Use to Man

THE British Museum (Natural History) is now open to the public on Saturdays and Sundays from 1 p.m. until 4 p.m. A special exhibition has been arranged in the Shell Gallery to show the animal and plant sources from which some useful commodities come. This is too vast a field for the exhibition to be an exhaustive one, consequently only selected exhibits, illustrating commodities which lend themselves to attractive demonstration, are shown. These include the sources of certain textiles like linen, cotton, silk and rayon; plant and animal dyes used in commerce; the colouring matter and ingredients of cosmetics; the sources of leathers and of bristles for brushes; the plants and animals which produce oil in large enough quantities for it to be valuable to mankind; and some of the uses of moulds and mushrooms. Several of the cases have a war-time interest; for example, animals of use in war, margarine, bacon pigs, pests of stored food. The object of the exhibition is to show the sources of certain commodities, and not to give a detailed explanation with examples of how the raw materials are worked up into the finished products.