Application Of DDT Research Articles

The accumulation and loss of organochlorine insecticide residues by beetles, worms and slugs in sprayed fields

Analyses of samples of ground-beetles, worms and slugs at four sites showed large differences in uptake, retention and metabolism by these groups. Live beetles caught in pitfall traps after field applications of DDT did not contain more than about 4 ppm pp′-DDT, but beetles artificially exposed during spraying acquired up to 70 ppm on their body surfaces. Metabolism to pp′-DDE was rapid and in one species resulted in residues of 58–75 ppm which declined to about 5 ppm after four months. Worms and slugs acquired much higher levels of DDT and these were more persistent. Breakdown in worms was chiefly to DDE and in slugs to TDE. Worms from an aldrin-treated site contained both dieldrin and aldrin, the proportions of each changing with time. The aldrin was probably from the soil within their guts. It was concluded that higher residues were picked up by invertebrates which fed at the soil surface after a foliage application of pesticide than by subterranean species after a soil application followed by rotovation. Acute poisoning of birds could result from the consumption of insects exposed to DDT spraying.

Persistence of DDT in wild populations of small mammals.

THE protracted persistence of DDT and some other organochlorine insecticides in soils is well documented1,2. While it has also been shown that these persistent residues can contaminate a resident fauna3, there has been little indication of the duration of this relationship once treatment ceases, except for observations covering a year or two4,5. We now present data of pesticide residues from small mammals covering a period of 9 years after single applications of DDT applied to forests at a rate of 0.89 kg/hectare (1 pound/acre). These treatments were for control of the spruce budworm, Choristoneura fumiferana (Clem.), in northern Maine, United States.

Toxicological Studies on Cutworms. II. Field Studies on the Control of the Dark-Sided Cutworm with Soil Insecticides1

Small-scale field trials using microplots were conducted to assess effectiveness of soil treatments of DDT, Dursban® (O, O-diethyl 0-3,5,6-trichloro-2-pyridyl phosphorothioate), and Bayer 37289 (O-ethyl O-2,4,5-trichlorophenyl ethylphosphonothioate) against larvae of the dark-sided cutworm, Euxoa messoria (Harris), attacking flue-cured tobacco. DDT emulsifiable concentrate (EC) at 4 Ib per acre applied either as a soil surface application or incorporated to a depth of 2 in. in the soil provided excellent control of the early instars. DDT-bran bait applied to the soil surface at 1 Ib per acre did not provide effective control. Dursban EC did not provide adequate control as a Soil surface application at 1 or 1.5 Ib per acre, but provided good control at 1 Ib per acre when incorporated into the soil. Bayer 37289 EC showed promise as a soil surface application at 1.5 Ib per acre. None of the materials tested provided adequate control of late-instar larvae. Residue studies indicated that DDT was highly persistent in soil, slightly less so on the soil surface. Dursban disappeared rapidly, particularly on the soil surface. Dursban residues were not detected in the tobacco plants at harvest. Residues of DDT and its metabolites were present in the tobacco, but were attributed to drift from adjacent fields treated with DDT. Large-scale field trials using soil surface applications of DDT at 4 Ib per acre provided excellent cutworm control.

DDT residues and declining reproduction in the Bermuda petrel.

Residues of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] averaging 6.44 parts per million in eggs and chicks of the carnivorous Bermuda petrel indicate widespread contamination of an oceanic food chain that is remote from applications of DDT. Reproduction by the petrel has declined during the last 10 years at the annual rate of 3.25 percent; if the decline continues, reproduction will fail completely by 1978. Concentrations of residues are similar to those in certain terrestrial carnivorous birds whose productivity is also declining. Various considerations implicate contamination by insecticides as a probable major cause of the decline.

Minimum Number of Insecticide Applications for the Control of the European Corn Borer on Sweet Corn in Quebec1

Field experiments were conducted at St. Luc, Quebec, from 1963 to 1965, to determine the relative effectiveness of 1, 2, 3, or 4 applications of DDT or carbaryl (Sevin®) in 2 commercial sweet corn fields. In all cases, the 1st application was made 5 days after the beginning of egg laying period and the others at weekly intervals, except for the single application of DDT or carbaryl, which was made 15 days after the 1st eggs were observed. In general, results were similar for the 3 years: the early variety was more infested than the late variety, DDT was slightly superior to carbaryl, the peak of egg laying always occurred between the 2nd and 3rd insecticide applications, and the date on which the single application was made varied each year from only 2 to 4 days from the date of maximum oviposition. The results of this 3-year study indicate that under the conditions of heavy infestations of the European corn borer, Ostrinia nubilalis (Hubner), in southwestern Quebec, 3 applications of either DDT or carbaryl would be recommendable for an early variety of sweet corn and 1 application for a late variety to obtain economical commercial control.

Effect of DDT on Control of Corn Earworms in Sweet Corn Entries Selected for Varying Resistance1234

Sweet corn entries selected for varying degrees of resistance to the corn earworm,. Heliothis zea (Boddie), were treated with DDT in 1963 and 1964. Resistant entries showed minimum improvement in control and susceptible entries showed maximum improvement. Such possible influences on control with DDT as the infestation level, the system of grading damage, and the efficiency of application and fate of DDT on the com plant are discussed.

Populations of Arthropod Predators and Heliothis Spp. After Applications of Systemic Insecticides to Cotton123

populations of arthropod predators, certain groups of hymenopterous insects, and Heliothis spp. including the bollworm, Heliothis zea (Boddie), and the tobacco budworm, Heliothis virescens (F.), were sampled in experiments following in-furrow applications of disulfoton and Temik®, a 10% formulation of UC-21149 (2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoyl)oxime); sidedress soil applications of phorate, American Cyanamid CL-47031 (cyclic ethylene (diethoxyphosphinyl)dithioimidocarbonate), and Temik; stem applications of Azodrin® (3-hydroxy-N-methyl-cis-crotonamide dimethyl phosphate) and CL-47031; and foliar applications of toxaphene plus DDT. Results indicated that populations of certain predators, particularly those belonging to the order Hemiptera, may be reduced by applications of systemic insecticides. Spiders (order Araneida and certain groups of hymenopterous insects (families Braconidae and lchneumonidae) Were less affected. In 2 experiments, the number of eggs and larvae of Heliothis spp. increased as the population of predators decreased. These results demonstrated the importance of natural populations of predators in regulating populations of Heliothis spp.

Fish Losses After Forest Sprayings with Insecticides in New Brunswick, 1952–62, as Shown by Caged Specimens and other Observations

The survival of young Atlantic salmon and eastern brook trout, held in cages and free-living, was observed in New Brunswick streams inside and outside forested areas sprayed operationally and experimentally from aircraft with DDT and other insecticides for budworm control. DDT-in-oil in a single application at [Formula: see text] caused heavy loss of underyearling salmon and parr within 3 weeks. DDT-in-oil at [Formula: see text] had no apparent short-term effects on salmon parr, but killed many underyearlings; two applications 10 days apart were about as harmful as a single application at [Formula: see text]. DDD at [Formula: see text] and [Formula: see text], and malathion at [Formula: see text], were no more harmful to young salmon than DDT at [Formula: see text]. Replacing Stearman airplanes with larger aircraft in operational spraying and associated changes in spraying procedure sometimes caused heavy fish losses even for single applications of DDT at [Formula: see text]. Experimental spraying of phosphamidon-in-water at 1 lb/acre had no apparent harmful effects on young salmon and trout.Observations at a counting fence across the Northwest Miramichi 12 miles below the lower boundary of the forested area sprayed with DDT at [Formula: see text] in 1954 showed extensive killing of suckers and cyprinids; also, the numbers of these species moving through the fence were abnormally low for several years after spraying.Wild young salmon were found dead in streams when autumn water temperatures approached freezing after June sprayings of watersheds with DDT.

Recent Developments in the Control of Some Arthropods of Public Health and Veterinary Importance: Mosquitoes

In the field of mosquito control, considerable interest has been created in developing chemical and biological agents that would be effective against disease-carrying mosquitoes, such as the various species of Anopheles , Aedes aegypti (L.), and Culex pipiells quinquefasciatus Say. The two last-mentioned species are being looked at with renewed emphasis because of (1) an increase in the significance of disease problems associated with them ( i.e. , hemorrhagic fever and filariasis, respectively); (2) the establishment of an A. aegypti eradication program in the United States, Virgin Islands, Hawaii, and Puerto Rico; (3) evidence that areas freed of A. aegypti have suffered reinfestation by the same species; and (4) the failure of DDT applications to eradicate A. aegypti in the Caribbean and other areas. Specific indication of the global interest in the problem of A. aegypti control was the convening of the recent Seminar on the Ecology, Biology, Control and Eradication of Aedes aegypti by the World Health Organization in Geneva, Switzerland, in August 1965.

The replacement of Culex nebulosus Theo. by Culex pipiens fatigans Wied. (Diptera, Culicidae) in towns in Nigeria.

An account is given of the disappearance in Kaduna, Northern Nigeria, of Culex nebulosus Theo. from the town streams and drains and other polluted collections of water, habitats in which until comparatively recently it appears to have been the dominant species, and its replacement by C. pipiens fatigans Wied., which was formerly rarely recorded in these sites. Similarly, the latter species has replaced the former as the commonest Culicine mosquito resting in houses. Increased urbanisation and the widespread use of residual organo-chlorine insecticides within recent years have both been advanced as possible explanations for this change.A laboratory experiment with larvae of C. p. fatigans from Kaduna and of C. nebulosus from villages on its perimeter showed the latter species to have a slightly, but significantly, quicker rate of larval development than C. p. fatigans; this would possibly confer an advantage on it in circumstances where the two species are in competition for the same larval habitats. Field and laboratory observations showed that both species can tolerate high organic pollution in their larval habitats. There appeared to be little evidence in Kaduna, or in other towns in Nigeria, to support the theory that urbanisation has been responsible for the replacement of C. nebulosus by C. p. fatigans. Laboratory and field trials demonstrated that larvae of C. nebulosus were extremely sensitive to DDT, and although resistance was not found in C. p. fatigans, this species showed tolerance of the insecticide. It is believed that, in Kaduna and most probably in other towns, the application of DDT as a larvicide to streams and drains has been responsible for the eradication of C. nebulosus there, and in the absence of competition from C. nebulosus and because of the greater tolerance of DDT shown by C. p. fatigans the latter has been able to establish itself as the dominant species.

Differential Reaction of Lolium perenne Genotypes to Certain Herbicides

THE rapid progress in weed destruction made possible simply by introducing new chemicals has resulted in a concentration on obvious and gross effects. Examples of the selective toxicity of various chemicals between different plant genera and between different species of the same genus1 have been widely reported. Much less frequently cited are differential responses between varieties of one species. In potatoes, variation in varietal reaction to pre-planting application of trichloroacetic acid (TCA) has been noted2 and large differences in varietal susceptibility to 2 : 4-dichlorophenoxyacetic acid (2,4D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA)3 have been found. Hayes4 has demonstrated the differential response of barley to DDT, susceptible varieties being killed by DDT application. Commercial varieties of sugar-cane differ in physiological tolerance to dalapon5. Fiddian6 gave evidence of differential susceptibility of cereal varieties to some commonly used herbicides, variation occurring in amount of leaf scorch, growth deformity, ripening retardation, ear malformation and spikelet sterility.

Concentrations of DDT in Landlocked Salmon (Salmo salar) at Sebago Lake, Maine

Abstract A decline of the sport fishery for salmon has been associated with the application of DDT to control human insect pests around the shores of Sebago Lake. The average DDT contents of 10-salmon samples collected in 1962, 1963, and 1964 were 1.1, 3.2, and 1.8 ppm by total wet weight. Salmon belonging to age group III had average DDT contents of 1.2 ppm; age group IV, 8.0 ppm; and age group V, 8.8 ppm. Ovaries of III-year-old salmon had 0.87 ppm of DDT, while ovaries from IV- and V-year-olds had 6.0 ppm DDT. Data also include results of DDE assays and calculated DDT concentrations in the fat. DDT concentrations found in small samples of lake chubs, common shiners, smallmouth bass, American smelt, lake white-fish, and brook trout are also reported.

Systates exaptus Mshl. (Col., Curculionidae) and related species as soil pests of maize in Rhodesia

A description is given of the damage caused by the larvae of two weevils, Systates exaptus Mshl. and Mesoleurus dentipes (Mshl.), which are soil pests of germinating maize and other crops in Rhodesia. Information is given on their life-cycles and some features of their biology. The larvae are nearly full grown at the beginning of the dry season, which is passed in an inactive state in the soil. Activity is resumed with the onset of the main rains, and it is at this time that the larvae may cause serious damage by attacking seedlings of maize or other crops growing in infested soil. Factors that encourage local increase of field populations are examined. It is shown that sunn hemp, soya bean and groundnut, all crops with high plant populations, favour the presence of large numbers of weevil larvae in the soil at the beginning of the following season. Growing closely planted maize year after year on the same land has been found to be one of the main causes of serious infestations in farm fields.Results of soil-insecticide trials are given, and these show that larvae are very difficult to control. In the discussion, attention is drawn to similar weevil larvae indigenous to other parts of Africa, which are tolerant of soil insecticides and are also pests under conditions of intensive crop production.Ways are suggested for reducing infestation in the following season. It is shown that properly timed applications of DDT to the maize crop will kill adults and prevent oviposition. Otherwise, infested fields may be left fallow, planted to grass or planted very late in the season.No method of protecting germinating seedlings has been found, but reference is made to a soil-sampling technique that is useful for detecting infested fields before crops are planted.

Evidence of DDT Resistance in Populations of Spruce Budworm, Choristoneura fumiferana (Clem.), From DDT-sprayed Areas of New Brunswick

AbstractA series of laboratory toxicological experiments using various concentrations of oil formulated DDT solutions (AR-50/fuel oil (2:7 V/V)) was carried out on 5th and 6th instar spruce budworm larvae collected in the field from DDT-sprayed and untreated areas of New Brunswick, Canada, and Maine, U.S.A.Results obtained in 1959, 1961, and 1962 with larvae collected from isolated, unsprayed areas in New Brunswick showed a consistent, straight log-dosage probit mortality curve. Larvae collected in 1962 and 1963 from infestation centres previously subjected to three, four, and five applications of non-consecutive large-scale aerial sprays of DDT showed a significant departure from the straight log-dosage probit curve previously obtained. The departure occurs as a change in the shape of the curve as well as a shift to the higher concentration range of DDT. The magnitude of change appears to be correlated with the number of sprays to which the population was exposed. Results obtained in 1962 and 1963, from untreated control and inter-spray areas, bounded by DDT-sprayed forest lands, showed a small but significant departure from the normal straight probit line of a susceptible population. These changes are indicative of a progressive development of DDT resistance in wild populations of spruce budworm.Studies on the effect of the tolerance of spruce budworm larvae within instar classes to the action of DDT showed that the early phase of instar development immediately after moulting is more susceptible to the action of DDT, whereas the latter phase of instar development immediately prior to moulting is more tolerant to topical application of DDT than the average for the instar. This effect is evident in both susceptible and resistant populations.The data interpretation assumes that a deviation from the straight line probit dosage – mortality curve is indicative of a difference in the DDT-susceptibility factor of the budworm population and that in the course of the tests, the amount of toxicant causing mortality was not proportional to the dosage.

Comparisons of residues in milk resulting from two types of spray applications of DDT, Shell Compound 4072, and ronnel.

In tests to compare residues in milk resulting from application of insecticide sprays to dairy cows, the animals were covered completely with a spray of a concentration sufficient to leave a residue for 1 to 4 weeks or with a mist-spray applied by an automatic device. The mist-spray dispersed approximately the minimum required to control horn flies, Haematobia irritans (L.), for 1 day, thus avoiding any heavy deposits on the animal. The insecticides tested were DDT, ronnel, and Shell Compound 4072 (2-chloro-1-(2,4-dichlorophenyl) vinyl diethyl phosphate). Residues of each insecticide present in the milk after the sprays were applied were determined by gasliquid chromatography. Results showed that residues of insecticides in milk can be greatly reduced by proper use. When minimum amounts for horn fly control were applied to dairy cows in small daily doses, residues from all 3 insecticides were extremely low.

THE GENETIC RESPONSE OF BARLEY TO DDT AND BARBAN AND ITS SIGNIFICANCE IN CROP PROTECTION

Summary. The response of eleven barley varieties to DDT and barban was assessed in field and glasshouse trials. Chlorosis following the application of DDT and minimal doses of barban is an all‐or‐nothing effect, whereas in apical inhibition there are several degrees of resistance. The criteria used to assess the eflect of barban on apical inhibition were fresh weight of seedlings, fertile tiller production at maturity and visual estimates of damage at the seedling stage and at maturity. Inheritance studies showed that resistance to the chlorosis reaction of both DDT and barban is controlled by single recessive genes independently inherited.Resistance to apical inhibition, on the other hand, appears to be quantitatively inherited. When F2 and F3 segregating populations in the field were sprayed with barban, the proportion of resistant plants in successive generations was markedly increased.The authors conclude that collaboration between plant breeder and pest control specialists could lead to a far more efficient control of weed, pest and pathogen by the development of varieties of crop plants with a high degree of tolerance to the chemical employed, especially under conditions where selectivity is narrow and delicate, such as in the control of other monocotyledonous plants in cereals.

RESIDUES IN SWEET CORN FROM DDT AND CARBARYL APPLIED FOR CONTROL OF THE EUROPEAN CORN BORER

Control of the European corn borer by sprays of DDT and carbaryl, alone and in combined schedules, was assessed. One application of DDT at 1.12 kg toxicant per hectare (1.0 lb/acre) applied before tassellmg plus two weekly applications of carbaryl at 1.68 kg toxicant per hectare (1.5 lb/acre) applied during ear formation gave excellent control. Residue studies suggest that following this treatment the husks could be safely fed to milch cattle and the entire plant to beef cattle. Pesticide residues are becoming increasingly important, and this combination of two insecticides for corn borer control might well be considered when corn is fed. DDT used alone at the low rate of 1.12 kg toxicant per hectare (1.0 lb/acre) cannot be recommended because it results in undesirable residues and ineffective control. The Ontario recommendation for DD1 is 1.68 kg toxicant per hectare (1.5 lb/acre) provided the treated corn is not fed to livestock.

Aster Yellows Control in Head Lettuce and Carrots in Prince Edward Island1

Weekly applications of DDT, 1 lb toxicant/acre, plus malathion, 1.25 lb, resulted in a significantly lower incidence of aster yellows in head lettuce, a virus disease transmitted in nature largely by the six-spotted leafhopper, Macrosteles fascifrons (Stål). Twice-weekly applications were more effective than weekly applications. Granular phorate applied to the soil with the seed at planting time at 1 lb toxicant/acre was as effective as either Di-Syston® (O,O-diethyl 5-[2- (ethylthio) ethyl] phosphorodithioate) or E.I. 43064 (2- (diethoxyphosphinothioylimino)-1-3-dithiolane) at 2 lb. Control of lettuce and carrot yellows with phorate was equal to that obtained with regular sprays of malathion or carbaryl. E.I. 47031 (2- (diethoxyphosphinylimine) 1-3-dithiolane) was not effective in reducing the incidence of lettuce yellows, although some control of carrot yellows was evident. Spraying barriers of sweet corn plants that completely surrounded lettuce and carrot plots, rather than the lettuce and carrots, was not effective in reducing the incidence of lettuce or carrot yellows.

Response to insecticides inCostelytra zealandica(White) in relation to sex and weight

Adults of Costelytra zealandica (White), treated by topical application of DDT in olive oil solution, showed differences in susceptibility between two collections taken from untreated paddocks and one from a paddock that had received applications of DDT, the latter containing 60–70 per cent of individuals surviving dosages that produced complete mortality in the first two. In the susceptible collections, males were two-three times as susceptible as females, at the LC50 level; in the tolerant one males were also more susceptible than females. In males, the LC50 of the susceptible samples was about one-sixth that of the most tolerant fraction of the tolerant sample. The difference in live weight between the sexes was insufficient to account for their difference in susceptibility; the dry weight of females was nearly double that of males, however, although there was little difference in their fat content. Observations on the seasonal increase in weight and susceptibility to DDT and fenthion in samples of lar...

Granulated Insecticides for Control of Some Corn Pests1

From 1961 through 1963, 4 experiments were conducted using granulated insecticides for control of various corn pests. In 1961 granules were applied to corn in the pretassel stage for control of second-generation European corn borer, Ostrinia nubilalis (Hubner). Applications of DDT, Zinophos ( O,O -diethyl O -2-pyrazinyl phosphorothioate), Kepone® (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one), and carbophenothion were effective in reducing stalk infestation at harvest. While these same insecticides did not produce a statistically significant reduction of ear infestation, there did appear to be a reduction of ear infestation by European corn borer. In 1961, 1962, and 1963 granulated systemic insecticides were distributed in the furrow with the seed at planting time. In 1961 Di-Syston® ( O-O -diethyl S-[2- (cthylthio) ethyl] phosphorodithioate) increased stand as a result of seed-corn maggot ( Hylemya cilicrura (Rondani)) control. In 1962 Zinophos and phorate were apparently phytotoxic, but phorate did reduce infestation of first-generation European corn borer in the plants in the whorl stage. In the 1963 experiment the significant observations were that phorate apparently was phytotoxic in that it reduced stand. Bayer 25141 ( O,O -diethyl O-p- (methylsulfinyl) -phenyl phosphorothioate) also caused a reduction in stand, which was significantly reflected in a reduction in yield.