THE EFFECT OF BODY WEIGHT ON THE RESISTANCE TO INSECTICIDES OF THE LAST-INSTAR LARVA OF DIATARAXIA OLERACEA L., THE TOMATO MOTH

At a constant temperature of 24° C. the final larval instar of Diataraxia oleracea lasts about 10 days, during which its resistance to DDT and γ-BHC as contact insecticides progressively increases up to the 5th or 6th day. It then suddenly decreases, this coinciding with cessation of feeding and the beginning of prepupal formation.
Between the 2nd and the 6th days the gross body weight of the last-instar larva increases from about 0.27 to 0.65g. Under the conditions of the experiments, the LD50 of parathion, as a stomach poison, was linearly related to body weight; on the same basis TEPP was slightly less, and lead arsenate, slightly more, toxic to the larger than to the smaller larvae. However, DDT as a stomach or contact insecticide, and γ-BHC as a stomach poison were notably less toxic to the larger larvae. For example, the increase in LD50 for an increase in larval body weight of × 2 was about × 11 for DDT as a stomach poison and about × 12 as a contact insecticide.
The order of effectiveness of the above insecticides as stomach poisons for the last-instar larva of D. oleracea was parathion > DDT > γ-BHC > TEPP = lead arsenate. Zinc fluoarsenate and rotenone were relatively non-toxic. Larvae of D. oleracea were repelled by food leaf treated with an extract of natural pyrethrins.     

THE TOXICITY OF SOME INSECTICIDES TO FIFTH-INSTAR NYMPHS OF THE DESERT LOCUST

The toxicities of the insecticides γ-BHC, diazinon, dieldrin, DNC, heptachlor and parathion to fifth-instar hoppers of the desert locust were determined. Parathion and dieldrin were the most toxic, followed in descending order by heptachlor, γ-BHC, diazinon and DNC. The resistance of the hoppers to γ-BHC and DNC changed appreciably with age within the instar.
The effects of some factors which might influence the resistance of the insects were examined and are discussed.     

The insecticides; their hazard in industry and in the home

Chemical, pharmacologic and toxicologic properties of the chlorinated hydrocarbon and organic phosphate insecticides have been reviewed. The chlorinated group present problems if there is either acute or chronic exposure, whereas the problems associated with the organic phosphates develop only in event of acute exposure. Chlorinated hydrocarbon insecticides accumulate in body fat depots and cause both liver and kidney damage while being metabolized and excreted. Organic phosphates destroy cholinesterase and produce effects related to overstimulation of the cholinergic branch of the autonomic nervous system. Barbiturates control the convulsions produced by the chlorinated hydrocarbon insecticides. Atropine blocks most of the effects of the organic phosphate insecticides. These compounds may be grouped in the following order of decreasing toxicity: TEPP, HETP, parathion, OMPA, ENP, aldrin, chlorophenothane, toxaphene, gamma benzene hexachloride, malathon and chlordane.     

THE INSECTICIDES—Their Hazard in Industry and in the Home Part I—Chemistry and Pharmacology

Chemical, pharmacologic and toxicologic properties of the chlorinated hydrocarbon and organic phosphate insecticides have been reviewed. The chlorinated group present problems if there is either acute or chronic exposure, whereas the problems associated with the organic phosphates develop only in event of acute exposure.Chlorinated hydrocarbon insecticides accumulate in body fat depots and cause both liver and kidney damage while being metabolized and excreted. Organic phosphates destroy cholinesterase and produce effects related to overstimulation of the cholinergic branch of the autonomic nervous system. Barbiturates control the convulsions produced by the chlorinated hydrocarbon insecticides. Atropine blocks most of the effects of the organic phosphate insecticides. These compounds may be grouped in the following order of decreasing toxicity: TEPP, HETP, parathion, OMPA, ENP, aldrin, chlorophenothane, toxaphene, gamma benzene hexachloride, malathon and chlordane.     

The Systematic Separation and Identification of Pesticides in the First Division

The systematic identification and determination of many kinds of pesticides were tried by a combination of column, thin-layer and gas chromatography. Pesticides in the first division,¹⁾ e.g., aldrin, DMC ethylene, CPAS, DDDS, o,p′-DDT, p,p′-DDT, heptachlor, quintozene, Telodrin and tetrasul, were separated from pesticides in the second division,¹⁾ e.g., α-BHC, β-BHC, γ-BHC, trifluralin, CPA, CNP, nitrofen, endrin, dieldrin, dicofol, etc. by column chromatography. Further, pesticides in the first division were separated from each other and determined approximately by thin-layer and gas chromatography.

The recoveries of these pesticides, except for aldrin and CPAS, were about 100%. The recoveries of aldrin and CPAS were about 70 %, due to decomposition during the procedures, or to adsorption on the adsorbent during the column chromatography. It was presumed from GC-MS data that CPAS was decomposed to DDDS, tetrasul and other compounds during the procedures.     

粉剂防治粘虫Pseudaletia separata (Walker)研究

粘虫Pseudaletia separata(Walker)是粮食作物的毁灭性害虫,也是全国农业发展纲要(修正草案)所规定要消灭的八大害虫之一。粘虫在大发生时为害面积很广,虫体发育迅速,食量很大,过去多采用人工器械捕打办法,但不能澈底解决问题,尤其在作物密植的情况下,捕打也发生了困难,常因捕打时将作物践踏而引起损失,因此要求在发生时应用化学防治方法,以达到迅速消灭为害之目的。     

The effects on soil fauna of insecticides tested against wireworms (Agriotes spp.) in wheat

The organophosphorus insecticides Bayer 38156 (O-ethyl S-p-tolyl ethyl phosphonodithioate), trichloronate, Stauffer N 2790 (O-ethyl S-phenyl ethyl phosphonodithioate), thionazin and fenitrothion were compared with aldrin, dieldrin and γ-BHC for their effects on soil fauna, particularly wire-worms, and on crop yields in 1964 and 1965. At 1·5 lb active ingredient/acre, none of the organophosphates had as great an effect on wireworms as an aldrin spray at 2·25 lb a.i./acre or a dieldrin seed dressing at 2·25 lb a.i./acre. Some treatments significantly increased and some significantly decreased numbers of mites and Collembola. Except for Allolobophora chlorotica in plots treated with Bayer 38156, earthworm numbers were greater in plots sprayed with Bayer 38156 or aldrin, or sown with dieldrin-dressed seeds, than in untreated plots. In May 1964, one month after sowing, untreated plots had significantly fewer plants than plots sprayed with aldrin, trichloronate or Bayer 38156, or sown with γ-BHC or dieldrin-dressed seeds, but yields from untreated plots at harvest were high for such a large wireworm population and did not differ significantly from yields of treated plots in either year. The persistence of thionazin and Bayer 38156 in treated plots was measured by a bioassay using Collembola. Bayer 38156 was detected in plots 1 month after spraying but not after 6 months. Thionazin left detectable residues 1 month after spraying in the two acid plots but not in the two alkaline plots. More frequent samples taken from thionazin-treated plots in 1965 showed a similar pattern of persistence, and laboratory tests, using soil mixed with various amounts of powdered calcium carbonate, confirmed that thionazin persisted longer in more acid soils.     

THE USE OF SEED DRESSINGS CONTAINING γ-BHC IN THE ESTABLISHMENT OF SUGAR-BEET SEEDLINGS

From 1949 to 1952 field trials were made to determine the effect of seed dressings containing γ-BHC, with and without the addition of organic mercurial compounds, upon the establishment of sugar-beet seedlings. Most of the trials were made in fields where no serious pest problems were anticipated. The 1949 trials established the concentration of γ-BHC non-phytocidal to sugar-beet seedlings. Later trials tested the effect on pre- and post-singling plant populations of dressings applied to natural or rubbed seed sown at standardized rates. Parallel tests of dressed seed were made on farms representing a variety of soil types, It was found that the phytotoxiCity of γ-BHC varied with season and soil type, but that a dressing containing 40 % was usually safe. In these trials, the benefits from seed dressing were, as a rule, slight. Generally the combined mercury-γ-BHC seed dressing gave the best pre-singling stand of plants. Most of the improvement was attributable to the organic mercury rather than to the γ-BHC, but where pest attacks occurred, γ-BHC gave marked improvements in stand. Wireworm appeared to be the chief pest controlled: control of pygmy mangold beetle was only partial.     

Isolation of four aquatic streptomycetes strains capable of growth on organochlorine pesticides

Ninety-three wild-type isolates identified as actinomycetes were tested against 11 organochlorine pesticides (OPs): aldrin, chlordane, DDD, DDE, DDT, dieldrin, heptachlor, and heptachlor epoxides, lindane, and methoxychlor. Qualitative screening agar assays displayed 62-78% tolerance of strains to OPs. Four strains designed M4, M7, M9 and M15 were selected based on multi-OP-tolerance, and identified as members of the streptomycetes group. Different growth profiles were observed in cultures of the four selected streptomycetes cultured in synthetic medium containing 5-50 microg x l(-1) aldrin or chlordane or lindane. Increase of aldrin removal by the selected microorganisms was concomitant with the 4.8-36.0 microg x l(-1) pesticide concentration range. After 72 h of streptomycete M7 growth in synthetic medium containing 48.0 microg x l(-1) aldrin, the remaining OP concentration in the supernatant was approximately 10% of the initial concentration. Also, in stationary growth phase less than 2.5 microg x l(-1) aldrin residual concentration was detected in the medium.     

EXPERIMENTS IN THE SUDAN GEZIRA ON CONTROL OF WILT OF DOLICHOS BEAN (DOLICHOS LABLAB) ASSOCIATED WITH ATTACK BY COCKCHAFER GRUBS (SCHIZONYCHA SP.)

Wilt of dolichos bean ( Dolichos lablab ) in the Sudan Gezira appeared to be due primarily to cockchafer grubs ( Schizonycha sp.) in the soil attacking the hypocotyls or roots of plants up to about 6 weeks after sowing. Many wilted plants also showed symptoms of ashy stem blight ( Macrophomina phaseoli ), but in these the fungus was probably a secondary invader rotting roots weakened or damaged by unfavourable soil conditions or insects. Wilt was often severe in dolichos sown on land cropped to sorghum ( Sorghum vulgare ) in the preceding season, sorghum roots in the soil harbouring the grubs. Under moderate grub attack seed dressings containing organomercurial and γ-benzene hexachloride (BHC) gave satisfactory-protection at 0.089%γ-BHC/seed but were inadequate when wilt was severe. Dieldrin and aldrin at 0.044 or 0.089%/seed gave excellent protection in all experiments, but their performance under exceptionally severe wilt conditions has yet to be tested, as also the relative efficiencies of seed treatment and soil treatment under such conditions. Fungicide-insecticide seed treatment also reduced preemergence rotting of germinating seeds due to grub attack.
Wilt rarely occurred in dolichos planted on land fallow in the preceding season, but, even in the apparent absence of wilt, seed treatment often appreciably improved emergence, plant populations, growth and yields. These effects possibly resulted from control of root damage by soil insects, such damage reducing growth and yields but not sufficiently severely to cause wilting. Pending further investigation a powder seed dressing containing organomercurial plus 20% dieldrin, and applied at 1:450 by weight to seed (about 5–6 g./acre of dieldrin), is recommended for dolichos bean in the Gezira.     

STUDIES ON THE MECHANISM OF INSECTICIDAL ACTION OF ORGANO-PHOSPHORUS COMPOUNDS WITH PARTICULAR REFERENCE TO THEIR ANTIESTERASE ACTIVITY

The preparation of an extract of the mealworm larvae, Tenebrio molitor L. which hydrolyses ethyl butyrate and o -nitrophenyl acetate, but not acetylcholine, is described. The inhibition of this esterase by TEPP-containing materials and parathion was determined.
An enzyme that hydrolysed o -nitrophenyl acetate and was inhibited by a TEPP-containing material was demonstrated in the five other insect species used.
The relative toxicities as contact insecticides to adult Tribolium castaneum Hbst. of ten samples of TEPP-containing materials were compared with their relative activities as esterase inhibitors. There was not an exact quantitative correlation between TEPP content estimated chemically, insecticidal activity and anti-esterase activity; but the correlation was sufficient to suggest interdependence of these factors.
Eggs of Diataraxia oleracea L. and Ephestia kühniella Zell, were shown to contain an enzyme that hydrolysed o -nitrophenyl acetate and was inhibited by the TEPP-containing materials. This enzyme was present in eggs less than 24 hr. old, i.e. before there was any visible signs of development. The TEPP was shown to be toxic to these eggs and in high concentrations kills at an early stage of development before differentiation of the nervous system. This, in conjunction with the other evidence, suggests that esterases other than the choline-esterase of the nervous system are important when considering the toxic action of these compounds.
Comparison of the anti-esterase activity and toxicity of parathion and TEPP-containing materials as insecticides showed that although the TEPP materials were the more potent enzyme inhibitors, parathion was the more potent contact insecticide to five species of insects. This appears to be due to the relative instability of TEPP. The study of the rates of action of the two poisons applied at different concentrations supports this view.     

CONTROL OF INSECTICIDE EXPOSURE IN EMPLOYMENT—A Guide to Physicians for Dealing with Organic Phosphates

Increasingly larger amounts of the highly efficient and highly toxic organic phosphate insecticides, particularly parathion, tetraethyl pyrophosphate, and Systox (demeton), are being applied on California''s farms. These insecticides have become an economic necessity to agriculture. They can be used safely when rigid precautions are utilized and when medical supervision is provided for employees regularly working with these chemicals.The demand for the services of physicians prepared to supply this kind of industrial medical supervision is expected to increase in California.The basic procedures through which effective medical supervision can be provided are outlined.     

Updated Mortality Analyses of Pernis Epidemiological Data on Human Exposures to Aldrin and Dieldrin

An extensive clinical and epidemiological study of workers engaged in the manufacturing and formulation of aldrin and dieldrin, the Pernis study, provides occupational hygiene and biological monitoring data on individual exposures over the years of employment and provides the opportunity to investigate dose response relationships for these chemicals. The human epide miological mortality data on these workers, who were exposed to fairly substan tial lifetime average daily doses of aldrin and dieldrin, suggest that low dose exposures do not significantly increase human mortality and may even de crease the human mortality hazard rate. While hormesis from low dose expo sure to aldrin and dieldrin is not statistically significant, it is observed in the raw data and in the best fitting dose response models. The decrease in risk suggests increased survival time at low doses of aldrin and dieldrin. Using an upper bound on cancer potency based on mouse liver tumors, the U.S. Environmental Protection Agency (EPA) estimated that lifetime average daily doses (LADDs) of 0.0000625 and 0.00625?µg/kg body weight/day would correspond to increased cancer risks of 0.000001 and 0.0001, respectively. However, the best estimate from the Pernis epidemiological data is that LADDs of 0.0000625 and 0.00625?µg/kg body weight/day correspond to no increase in cancer risk and a decrease in the probability of mortality from all causes by the age of 70 years. At low doses of aldrin and dieldrin, the estimated decrease in mortality in a reference period of 70 years is more than 1000 times larger than the U.S. EPA's upper bound on the increase in the lifetime probability of cancer.     

Persistence and distribution of insecticidal seed-dressings for control of the wheat bulb fly, Leptohylemyia coarctata

Samples of plants and soil from two experimental sites, one clay loam and one peaty loam, were analysed chemically to try to explain differing results with γ-BHC and dieldrin seed-dressings applied to control wheat bulb fly on different soil types, and to suggest reasons for patchy plant stands and occasional failure to control the pest. Seed dressed with dieldrin yielded more than untreated seed on both sites, whereas seed treated with γ-BHC yielded as much as seed treated with dieldrin on the clay site, but it yielded less than untreated seed on peat. The chemical analyses showed that the poor performance of γ-BHC on the peat site could not be explained by its failure to persist, because the soil still contained considerable quantities of γ-BHC at the time of insect attack. Possible reasons may be sorption of the poison by organic matter making it less available, and deeper sowing, permitting larvae to reach the plants without prolonged contact with the insecticide. Bayer 38156 (O-ethyl S-p-tolyl ethyl phosphonodithioate) and trichloro-nate (O-ethyl O-2,4,5-trichlorophenyl ethyl phosphonothionate) persisted in soil long enough and were sufficiently toxic to wheat bulb fly to suggest that organophosphorus compounds might provide alternatives to chlorinated hydrocarbon insecticides for control of the fly. Analyses made on seeds dressed at the laboratory for the experiment showed that the amounts of insecticide on seeds were smaller than expected and that the amounts on individual seeds differed greatly. Of ten samples of seeds dressed commercially with y-BHC, three carried very little insecticide, and the variations in the other seven samples were greater than with experimentally applied dressings.     

THE CONTROL OF POTATO VIRUS DISEASES BY INSECTICIDES

Replicated trials were carried out in the years 1950, 1951, 1953 and 1954 to see if the spread of leaf-roll virus and virus Y in potato crops could be reduced by applying insecticides. The crops were disease-free, except for small numbers of deliberately introduced infected plants, and were sprayed at intervals of 10 or 14 days, according to the stage of growth of the plants, with a tractor-mounted spraying machine at 1OO gal./acre/application. Disease spread was estimated by growing tubers taken from the five plants on either side of each infector. DDT emulsion, DDT suspension, endrin, schradan, mipafox, malathion, parathion and Systox prevented the spread of leaf-roll virus and decreased the spread of virus Y, although DDT emulsion was the only insecticide used in all the trials. Dieldrin and toxaphene were ineffective. When virus control was successful, aphid control (estimated by counting apterae in the crops) was good.     

Laboratory and field tests in 1966-67 on chemical control of wireworms (Agriotes spp.)

Of sixteen compounds applied to soil in laboratory tests, azinphos-ethyl, P2188 (O,O-diethyl S-chloromethyl phosphorothiolothionate), ‘Dursban’ (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate), P1973 (S-(N-methoxycarbonyl-N-methylcarbamoylmethyl) dimethyl phosphorothiolothionate), B77488 (O,O-diethylphosphorothioate O-esterwith phenylglyoxylonitrile oxime) and R42211 (O,O-diethyl O-(2-diethylamino-6-methyl-pyrimidin-4-yl) phosphorothioate) killed wireworms when first tested, but in second tests with the same soils only ‘Dursban’, P2188 and B77488 did so. Treating seeds with ‘Dyfonate’ (O-ethyl S-phenyl ethyl phosphonodithioate) or with ethion/γ-BHC mixtures killed few wireworms. Three field trials compared the organophosphorus insecticides ‘Dursban’, ‘Dyfonate’ and phorate with organochlorine standards. In trials with barley and potatoes the standard was 3 lb a.i./acre (3·36 kg/ha) of aldrin. The organophosphorus compounds increased plant stands of barley almost as much as aldrin, although they killed fewer wireworms; and they protected fewer potato tubers from wireworm damage. The third trial compared the organophosphorus compounds with 0·5 lb a.i./acre (0·56 kg/ha) γ-BHC sprayed on a site drilled with sugar beet seed dressed with dieldrin. The γ-BHC increased plant stands almost as much as did 3 lb a.i./acre of the organophosphorus insecticides, and killed as many wireworms.     

THE PHYTOTOXIC EFFECTS OF D.D.T., B.H.C., PARATHION AND TOXAPHENE ON TOBACCO

No phytotoxic effect was seen following a pre-sowing spray of tobacco seed-beds with 27 lb./acre technical D.D.T. or after an application of the same material at 75.6 lb./acre to 3-week-old tobacco seedlings.
A pre-sowing application of parathion (diethyl para nitrophenyl thiophosphate) (2 % dust) at 1–8 lb. parathion per acre had no harmful effect. Used on 3-week-old tobacco seedlings at the excessive rate of 22.7 lb./acre it caused serious stunting and many deaths.
Toxaphene (chlorinated camphene: empirical formula C₁₀H₁₀Cl₈), applied as a 25 % wettable powder in a pre-sowing spray at 6-4 lb. toxaphene per acre, did not injure tobacco seedlings.
No residual phytotoxic effects appeared in beds re-sown 4 months after being treated with parathion or toxaphene at the pre-sowing doses given above.
Benzene hexachloride, applied before sowing at doses above 1.6 lb. technical B.H.C. per acre, suppressed root development in newly germinated tobacco seedlings. B.H.C. dusts used on n-day-old seedlings at 2–25 lb. technical B.H.C. per acre caused temporary distortion and stunting. Up to 11 lb./acre these symptoms were transitory: at 37.5 lb./acre many plants were killed and the remainder severely stunted. Resistance to these phytotoxic effects increased with age of plant, but 3-week-old tobacco seedlings showed considerable mortality after the application of 75.6 lb./acre of technical B.H.C.
Beds re-sown 4 months after the application of 6-4 and 12.8 lb. respectively of technical B.H.C. per acre showed no phytotoxic effect, but, as tobacco seed is sown on the soil surface, the effect of the B.H.C. may have been merely masked, and it is not safe to assume that there was no residual effect. The actual persistence of B.H.C. in the soil was not determined.
The possible mechanism of action of the B.H.C. effect is discussed.     

Determination of the resistance of locusts to γ-BHC and diazinon in relation to their age, sex and weight

The relation between body weight and resistance to γ-BHC and diazinon was studied in experiments using the desert locust ( Schistocerca gregaria ) and the African migratory locust ( Locusta migratoria migratorioides) .
In all experiments with Schistocerca , resistance was proportional to weight within any one age and sex group. Resistance to diazinon (per unit body weight) decreased with age, that of the males at a faster rate than that of the females. Against γ-BHC the insects showed a nearly twofold increase in resistance about 1 week after fledging.
Within groups of Locusta the resistance to diazinon was found to be independent of weight, but the resistance to γ-BHC was dependent on weight. Similarly the resistance to diazinon at different ages after fledging was independent of age but resistance to γ-BHC increased with age.     

Reductive transformation of methyl parathion by the cyanobacterium<Emphasis Type="Italic"> Anabaena</Emphasis> sp. strain PCC7120

Organophosphorus compounds are toxic chemicals that are applied worldwide as household pesticides and for crop protection, and they are stockpiled for chemical warfare. As a result, they are routinely detected in air and water. Methods and routes of biodegradation of these compounds are being sought. We report that under aerobic, photosynthetic conditions, the cyanobacterium Anabaena sp. transformed methyl parathion first to o,o-dimethyl o-p-nitrosophenyl thiophosphate and then to o,o-dimethyl o-p-aminophenyl thiophosphate by reducing the nitro group. The process of methyl parathion transformation occurred in the light, but not in the dark. Methyl parathion was toxic to cyanobacteria in the dark but did not affect their viability in the light. Methyl parathion transformation was not affected by mutations in the genes involved in nitrate reduction in cyanobacteria.     

GENETICS OF DIELDRIN AND γ-BHC RESISTANCE IN THE HOUSEFLY

A factor for dieldrin resistance in a -BHC selected strain of Uruguayan origin was located in linkage group 4 (Hiroyoshi's numbering system) and showed approximately 40% crossover to the marker ct in F₁ females. Resistance to -BHC is partly due to the same factor. Factors on other linkage groups play an important part in resistance to -BHC, but when studied separately only the fifth linkage group showed a small effect. It is concluded that several factors on different chromosomes must contribute to the total resistance to -BHC.

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Genetik der dieldrin- und -cyclohexan bei der stubenfliege

Zusammenfassung Ein Faktor für Dieldrin-Resistenz in einem -Cyclohexan-selektierten Stamm uruguayischer Herkunft ist in der Koppelungsgruppe 4 (Hiroyoshi's Zählungssystem) gelegen und zeigt bei F₁-Weibchen annähernd 40% Crossing-over gegenüber dem Markierungsgen ct. Die Resistenz gegenüber -Cyclohexan beruht teilweise auf dem gleichen Faktor. Faktoren in anderen Koppelungsgruppen spielen eine wichtige Rolle bei der -Cyclohexan-Resistenz, aber bei getrennter Untersuchung zeigte nur die 5. Koppelungsgruppe eine schwache Wirkung. Es wird daraus geschlossen, daß an der Gesamtresistenz unterschiedliche Faktoren auf verschiedenen Chromosomen beteiligt sein müssen.