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PubMedDate not supplied

[The chemical control of disease vectors. Evaluation of new insecticides. Operational insecticides. New insecticides (author's transl)].

The chemical control of disease vectors which has been very successful during about 15 years is now faced with some difficulties due to the resistance of insects to the insecticides, to the decreasing number of candidate insecticides, to the increase of their price and to the legal restrictions concerning their safe use and their environmental inocuity. Since 1960, W.H.O. has carried out an evaluation programme to define the properties of new insecticides and to access their usefulness for public health. Through this programme several alternative insecticides have been selected and are now used in vector control operations. Although research continues on organophosphorous compounds and carbamates, it also includes the promising groups of pyrethroids and insect growth regulators. The present trend of vector control is to integrate various control techniques and to limit the use of insecticides to the control of the epidemiologically dangerous part of the vector population. This approach might prevent or delay the development of resistance.

Animals↗

PubMed2004

Comparison of efficacy of programs using insecticide and insecticide plus mating disruption for controlling the obliquebanded leafroller in apple (Lepidoptera: Tortricidae).

The relative efficacy of an insecticide program and an insecticide plus mating disruption program using a sprayable pheromone formulation or a hand-applied pheromone dispenser was compared for control of the obliquebanded leafroller, Choristoneura rosaceana (Harris) at three commercial apple farms in a production area along the north shore of Lake Ontario, Canada, during 2000, 2001, and 2002. The average rate of disruption ranged from 50 to 80% in blocks of orchard treated with sprayable pheromone and from 84 to 98% in blocks treated with the hand-applied dispenser. The average proportion of shoots with larval feeding injury ranged from 0.002 to 0.09, 0.001 to 0.09, and 0.005 to 0.13 in the insecticide, insecticide plus sprayable pheromone, and insecticide plus hand-applied dispenser treatments, respectively, during the 3-yr study. The percentage of fruit with damage caused by spring, summer and overwintering larvae ranged from 0.03 to 0.06, 0.01 to 0.02, and 0.01 to 0.03 in the insecticide, insecticide plus sprayable pheromone, and insecticide plus hand-applied dispenser treatments, respectively. The addition of sex pheromone-mediated mating disruption to a conventional, insecticide-based program did not provide additional control of C. rosaceana feeding injury to shoots or fruit. The possible reasons for the failure of mating disruption to provide additional control are discussed.

Animals↗

PubMed2000

Larval susceptibility of an insecticide-resistant western corn rootworm (Coleoptera: Chrysomelidae) population to soil insecticides: laboratory bioassays, assays of detoxification enzymes, and field performance.

Soil insecticides were evaluated in laboratory and field studies against larvae of an insecticide resistant population (Phelps County, NE) of western corn rootworm, Diabrotica virgifera virgifera LeConte. Insecticide toxicity was evaluated by topical application of technical insecticides to 3rd instars from Saunders County, NE (susceptible) and Phelps County populations. Resistance ratios (LD50 Phelps County/LD50 Saunders County) for the insecticides methyl parathion, tefluthrin, carbofuran, terbufos, and chlorpyrifos were 28.0, 9.3, 8.7, 2.6 and 1.3, respectively. Biochemical investigation of suspected enzymatic resistance mechanisms in 3rd instars identified significant elevation of esterase activity (alpha and beta naphthyl acetate hydrolysis [3.8- and 3.9-fold]). Examination of 3rd instar esterases by native PAGE identified increased intensity of several isoenzymes in the resistant population. Assays of cytochrome P450 activity (4-CNMA demethylation and aldrin epoxidation) did not identify elevated activity in resistant 3rd instars. Granular soil insecticides were applied at planting to corn, Zea mays L., in replicated field trials in 1997 and 1998 at the same Phelps County site as the source of resistant rootworms for the laboratory studies. In 1997, planting time applications of Counter 20CR, Counter 15 G (terbufos), and Lorsban 15 G (chlorpyrifos) resulted in the lowest root injury ratings (1-6 Iowa scale); 2.50, 2.55, 2.65, respectively (untreated check root rating of 4.55). In 1998, all insecticides performed similarly against a lower rootworm density (untreated check root rating of 3.72). These studies suggest that resistance previously documented in adults also is present in 3rd instars, esterases are possibly involved as resistance mechanisms, and resistance to methyl parathion in adults is also evident in larvae, but does not confer cross-resistance in larvae to all organophosphate insecticides.

Animals↗

PubMed2004

Combining zooprophylaxis and insecticide spraying: a malaria-control strategy limiting the development of insecticide resistance in vector mosquitoes.

Strategies to eradicate the vector-borne infectious diseases (e.g. malaria and Japanese encephalitis) are often directed at controlling vectors with insecticides. Spraying insecticide, however, opens the way for the development of insecticide resistance in vectors, which may lead to the failure of disease control. In this paper, we examine whether the combined use of insecticide spray and zooprophylaxis can limit the development of insecticide resistance in mosquitoes. Zooprophylaxis refers to the control of vector-borne diseases by attracting vectors to domestic animals in which the pathogen cannot amplify (a dead-end host). The human malaria parasite Plasmodium spp. has a closed transmission cycle between humans and mosquitoes, and hence cattle can serve as a dead-end host. Our model reveals that, by a suitable choice of insecticide spraying rate and cattle density and location, malaria can, in some situations, be controlled without mosquitoes developing insecticide resistance.

Animals↗

PubMed1997

Resistance to insecticides in insect vectors of disease: est alpha 3, a novel amplified esterase associated with amplified est beta 1 from insecticide resistant strains of the mosquito Culex quinquesfasciatus.

Vector control programmes in many countries face the dual problems of parasite drug resistance and insecticide resistance in the insect vectors of the disease. Here we report for the first time a new esterase-based insecticide resistance mechanism in the filariasis vector Culex quinquefasciatus. The field collected COL strain of C. quinquefasciatus from Columbia was heterogeneous for organophosphorus insecticide resistance. On native polyacrylamide gels it had an elevated beta-naphthyl acetate specific esterase with the same Rf as that for the Est beta 1s involved in insecticide resistance in other strains of this mosquito species. After five generations of temephos insecticide selection, both the esterase specific activity with p-nitrophenyl acetate and the temephos LC50 values were increased, suggesting that elevation of esterase activity was the underlying mechanism of resistance. Western blots with antisera raised to Est alpha 2(1) and Est beta 2(1) from C. quinquefasciatus indicated that the COL strain had an elevated Est alpha 3 enzyme which co-migrated on native gels with Est beta 1. Southern blots indicated that an est alpha 3 gene was amplified in the COL strain and a Cuban mosquito strain (MRes), although the restriction digest patterns of the est beta 1 genes in these two strains are different. In contrast, the Californian TEMR strain, with the amplified est beta 1(1) gene, had no associated elevated Est alpha. Restriction digest patterns for COL and TEMR DNA suggest that they contain an identical est beta 1(1) gene, but our data suggest that the est alpha 3 gene occurs on the same amplicon as an est beta 1 gene although the genes are probably > 10 kb apart. Hence, either the COL strain has two est beta 1 genes or the est beta 1(1) amplicon in TEMR has been disrupted at some stage during the long colonisation of this strain and the amplified est alpha has been lost.

Animals↗

PubMed2001

Malaria control--two years' use of insecticide-treated bednets compared with insecticide house spraying in KwaZulu-Natal.

OBJECTIVES: The objective of this study was to produce data indicating whether insecticide-treated bednets should replace insecticide house spraying as a malaria control method in South Africa. We report 2 years of preliminary data on malaria incidence comparing areas receiving insecticide-treated bednets and those subjected to house spraying in northern KwaZulu-Natal. DESIGN, SETTING AND SUBJECTS: In order to measure significant reductions in malaria incidence between the two interventions, a geographical information system (GIS) was used to identify and create seven pairs of geographical blocks (areas) in the malaria high-risk areas of Ndumu and Makanis in Ingwavuma magisterial district, KwaZulu-Natal. Individual blocks were then randomly allocated to either insecticide-treated bednets or house spraying with deltamethrin. Malaria cases were either routinely recorded by surveillance agents at home or were reported to the nearest health facility. RESULTS AND CONCLUSIONS: The results show that 2 years' use of insecticide-treated bednets by communities in Ndumu and Makanis, KwaZulu-Natal, significantly reduced the malaria incidence both in 1997 (rate ratio (RR) = 0.879, 95% confidence interval (CI) 0.80-0.95, P = 0.04) and in 1998 (RR = 0.667, CI 0.61-0.72, P = 0.0001). Using a t-test, these significant reductions were further confirmed by an assessment of the rate of change between 1996 and 1998, showing a 16% reduction in malaria incidence in blocks using treated bednets and an increase of 45% in sprayed areas (t = 2.534, P = 0.026 (12 df)). In order to decide whether bednets should replace house spraying in South Africa, we need more data on the efficacy of treated bednets, their long-term acceptability and the cost of the two interventions.

Aerosols↗

PubMed2001

Identification and cloning of a key insecticide-metabolizing glutathione S-transferase (MdGST-6A) from a hyper insecticide-resistant strain of the housefly Musca domestica.

Strains of the housefly, Musca domestica, highly resistant to organophosphate (OP) and other insecticides are known because they overproduce glutathione S-transferases (GSTs). Previous work has shown that overproduction in these strains involved numerous isozymes with glutathione conjugating activities (Pesticide Biochem. Physiol., 25 (1986) 169; Mol. General Genetics, 227 (1991) 355; J. Biol. Chem., 267 (1992) 1840; Mol. General Genetics, 245 (1994) 236; J. Mol. Evol., 43 (1996) 236). The current work describes the purification and identification of a M. domestica GST isozyme (pI 7.1) broadly specific for substrates from a housefly strain, Cornell-HR, that is highly resistant against OP-insecticides, and the isolation of two new MdGST genes using the antibody made against it. This isozyme, which was identified from amongst more than 20 isoelectric forms of GSTs of the same subunit size, was highly active for conjugating GSH to the model substrate 3,4-dichloronitrobenzne (DCNB). When expressed in Escherichia coli, one of the cloned GSTs, MdGST-6A, produces an enzyme that conjugates glutathione to the insecticides methyl parathion and lindane. On indication that it was the most active isozyme toward several xenobiotics among several MdGSTs tested, we advance the notion that MdGST-6A probably plays an important role in M. domestica Cornell-HR's resistance towards OP-insecticides. MdGST-6A and a second closely related one found in this work, MdGST-6B, are members of the traditional insect class I family (theta-class) and share the greatest homologies with a cluster of Drosophila GSTs on locus 55. In addition to having the unusually broad substrate specificity, the sequence of the new group of enzymes reveals that it has a highly diverged hydrophobic motif in its active site as compared to other class I GSTs from insects.

Amino Acid Sequence↗

PubMed2003

Efficacy of mosquito nets treated with insecticide mixtures or mosaics against insecticide resistant Anopheles gambiae and Culex quinquefasciatus (Diptera: Culicidae) in Côte d'Ivoire.

Only pyrethroid insecticides have so far been recommended for the treatment of mosquito nets for malaria control. Increasing resistance of malaria vectors to pyrethroids threatens to reduce the potency of this important method of vector control. Among the strategies proposed for resistance management is to use a pyrethroid and a non-pyrethroid insecticide in combination on the same mosquito net, either separately or as a mixture. Mixtures are particularly promising if there is potentiation between the two insecticides as this would make it possible to lower the dosage of each, as has been demonstrated under laboratory conditions for a mixture of bifenthrin (pyrethroid) and carbosulfan (carbamate). The effect of these types of treatment were compared in experimental huts on wild populations of Anopheles gambiae Giles and the nuisance mosquito Culex quinquefasciatus Say, both of which are multi-resistant. Four treatments were evaluated in experimental huts over six months: the recommended dosage of 50 mg m(-2) bifenthrin, 300 mg m(-2) carbosulfan, a mosaic of 300 mg m(-2) carbosulfan on the ceiling and 50 mg m(-2) bifenthrin on the sides, and a mixture of 6.25 mg m(-2) carbosulfan and 25 mg m(-2) bifenthrin. The mixture and mosaic treatments did not differ significantly in effectiveness from carbosulfan and bifenthrin alone against anophelines in terms of deterrency, induced exophily, blood feeding inhibition and overall mortality, but were more effective than in earlier tests with deltamethrin. These results are considered encouraging, as the combination of different classes of insecticides might be a potential tool for resistance management. The mixture might have an advantage in terms of lower cost and toxicity.

Animals↗

PubMed1996

Insecticide and Insecticide Metabolite Interactions with Cytochrome P450 Mediated Activities in Maize

In vitro assays were used to determine if organophosphate, carbamate, and synthetic pyrethroid insecticides affected the cytochrome P450 monooxygenase (P450) catalyzed hydroxylation of nicosulfuron, bentazon, cinnamic acid, or lauric acid in maize microsomes. All P450 activities were inhibited approximately 50% by carbaryl, and none were inhibited by permethrin. Hydroxylations of nicosulfuron, bentazon, lauric acid, and cinnamic acid were inhibited by malathion 83, 92, 38, and 0%, respectively. Terbufos was only moderately (36%) inhibitory of in vitro P450 hydroxylation of nicosulfuron. Nicosulfuron hydroxylation was more sensitive than bentazon hydroxylation to inhibition by the insecticides, and both herbicide hydroxylations were more sensitive than lauric acid or cinnamic acid hydroxylations to the insecticides. Since the oxidative metabolites of terbufos were shown to be more potent inhibitors of in vivo nicosulfuron metabolism than terbufos, we examined the effect of terbufos-sulfone on in vivo and in vitro herbicide metabolism. Terbufos-sulfone inhibited metabolism of nicosulfuron and imazethapyr, but not bentazon, in excised corn shoots. Microsomal hydroxylation of nicosulfuron, bentazon, chlorimuron ethyl, and imazethapyr, as well as the desulfuration of malathion, were strongly inhibited (>65%) by terbufos-sulfone. Cinnamic acid hydroxylase appeared to be different from the P450(s) responsible for the pesticide metabolism as it was not inhibited by terbufos-sulfone. However, the data also suggest that malathion, nicosulfuron, bentazon, chlorimuron ethyl, and imazethapyr all share a P450 in common with terbufos-sulfone. Alternatively, there may be separate P450s for the metabolism of the herbicides and malathion, all of which also metabolize terbufos-sulfone. These data show that the inhibition of P450 hydroxylation of nicosulfuron by terbufos-sulfone can explain the injury when maize is exposed to both terbufos and nicosulfuron. However, the insecticides that are the most potent in vitro P450 inhibitors are not necessarily the ones that cause the most herbicide injury in the field.

Journal Article↗

PubMed2000

Seasonal fluctuation in susceptibility to insecticides within natural populations of Drosophila melanogaster: empirical observations of fitness costs of insecticide resistance.

To investigate genetic variation and seasonal fluctuation in susceptibility to insecticides, natural populations of Drosophila melanogaster were collected from Katsunuma in mid summer and late fall for two consecutive years. After isofemale lines of each population collected in each season had been established in a laboratory, the susceptibility of each line to five insecticides, including permethrin, malathion, prothiophos, fenitrothion, and DDT, was examined. Lines of each population exhibited the broad ranges of variation in susceptibility to all chemicals. Comparison between populations in different seasons indicated that genetic variation in susceptibility to organophosphates fluctuated in consistency with the population size, in which the susceptibility increased in fall. In addition, highly significant correlations were observed among responses to organophosphates, and the correlations also fluctuated with seasons. On the other hand, genetic variation in susceptibility to permethrin and DDT was less fluctuated. These results suggest that not only a common resistance factor for organophosphate resistance but also different resistance factor(s) for each insecticide could be involved within a natural population, and that the fluctuation observed in the susceptibility to organophosphates could be associated with fitness costs of organophosphate resistance factor(s).

Animals↗

PubMed1975

[Investigations on the influence of insecticides on autoxidation processes. X. Formation of peroxides from octadecenic acid methylester in the presence of water and chlorinated hydrocarbon insecticides (author's transl)].

According to the range DDT less than DDE less than heptachlor less than heptachlorepoxide, chlorinated hydrocarbon insecticides promote the formation of peroxides from cis- and trans-9-octadecenic acid methylesters within the lipid and the water phase of the investigated model system. Compared with DDT and heptachlor the metabolites DDE and heptachlorepoxide proof as more efficient prooxidants; this may be explained by their higher reactivity. According with these observations the amount of insecticides, especially of heptachlor and heptachlorepoxide, that can be extracted from the model system with petroleumether after 72 hrs of autoxidation is markedly diminished. From that it is concluded, that in the investigated lipid-water-system the insecticides not only have a catalytic effect, but also are in part immediately involved in the formation of peroxides from 9-octadecenic acid methyl ester.

DDT↗

PubMed1975

[Investigations on the influence of insecticides on autoxidation processes. XI. Formation of secondary metabolites from octadecenic acid methyl ester in the presence of water and chlorinated hydrocarbon insecticides (author's transl)].

For determining the influence of chlorinated hydrocarbon insecticides on the formation of secondary metabolites from peroxidized 9-octadecenic acid methylester by autoxidation within 72 hrs, substances reacting with phosphomolybdanic acid have been separated by TLC. Furthermore the increase of metabolites containing carbonyl groups and the variation of the ratio of polar to unpolar OH-groups in the metabolites have been determined by IR-spectrophotometry. All results proved, that the trans-9-octedecenic acid ester is autoxidized more rapidly than the cis-ester. Moreover the insecticides principally favour the formation of secondary metabolites from the lipidperoxide. This effect increases in the range DDT, DDE, heptachlor, heptachlorepoxide. If the increase of metabolites with carbonyl groups is chosen as a measure for the prooxidative effect, the effect appears equally high for the cis- and the trans-ester. But the hydroxyl index is changed depending on the kind of the insecticide added and the steric configuration of the lipid.

Chromatography, Thin Layer↗

PubMed1994

Behavioral response of host-seeking mosquitoes (Diptera: Culicidae) to insecticide-impregnated bed netting: a new approach to insecticide bioassays.

The response of Anopheles gambiae Giles s.s and Culex quinquefasciatus Say to insecticide-treated netting in a wind tunnel permeated with guinea pig odors was recorded on videotape. With no insecticide present, mosquitoes spent 99% of the time on the netting, either at rest or occasionally walking across it. On nylon netting, permethrin at 50, 400, and 1,000 mg m-2 irritated the mosquitoes, causing them to spend significantly more time away from the netting and relatively more time walking than at rest when they were on the netting. These effects increased with dose, but the total contact time was always enough to cause 100% mortality. At the two highest doses, knockdown occurred before the end of the 10-min observation period. A wash-resistant formulation of permethrin (ICI patent) reduced irritancy without affecting mortality or knockdown. A mixture of pirimiphos-methyl and permethrin also was less irritating than permethrin alone. Pirimiphos-methyl at 400 mg m-2 was the least irritating of all treatments tested. Lambda-cyhalothrin at 2.5, 6, and 25 mg m-2 was less irritating than permethrin, even though the doses of lambda-cyhalothrin used were far more toxic than the permethrin doses as measured by LT50. Cotton netting significantly reduced the toxicity and irritancy of the permethrin treatments. Cx. quinquefasciatus was less irritated by permethrin but more irritated by lambda-cyhalothrin, than was An. gambiae. Our study indicated that mosquitoes are so strongly attracted to a host protected by netting, they will tolerate relatively high doses of irritating insecticides long enough to pick up lethal doses.

Animals↗

PubMed1977

Insecticide solvents: interference with insecticidal action.

Several commercial solvent mixtures commonly used as insecticide carriers in spray formulations increase by more than threefold the microsomal N-demethylation of p-chloro N-methylaniline in midgut preparations of southern army-worm (Spodoptera eridania) larvae exposed orally to the test solvents. Under laboratory conditions, the same solvent mixtures exhibit a protective action against the in vivo toxicity of the insecticide carbaryl to the larvae. The data are discussed with respect to possible solvent-insecticide interactions occurring under field conditions and, more broadly, to potential toxicological hazards of these solvents to humans.

Enzyme Induction↗

PubMed2000

Toxicity and residual effectiveness of insecticides on insecticide-treated spheres for controlling females of Rhagoletis pomonella (Diptera: Tephritidae).

This study evaluated the toxicity of five technical-grade insecticides of four different classes to apple maggot females, Rhagoletis pomonella (Walsh), following a 10-min exposure period in insecticide-coated glass jars, with or without a feeding stimulant (sucrose) present. According to LC90 values for toxicity by ingestion and tarsal contact, imidacloprid was 1.5 times more toxic than dimethoate or abamectin, diazinon was less toxic, and phloxine B (a phototoxic dye) least toxic. Based on LC90 values for tarsal contact alone, dimethoate was 2.3, 4.0, and 18.4 times more toxic than imidacloprid, abamectin, and diazinon, respectively. Contact alone with phloxine B caused no mortality. When exposure was assessed using spheres coated with a latex paint mixture containing sucrose and formulated dimethoate (Digon 400 EC) or imidacloprid (Provado 1.6 F) at concentrations ranging from 5 to 70 g (AI)/cm2, both insecticides showed reduced effectiveness compared with toxicities from glass jar tests, with Digon two times more toxic than Provado. After exposure to artificial rainfall and retreatment with sucrose, Digon- and Provado-treated spheres exhibited greatest residual effectiveness, with diazinon-treated spheres less effective. Spheres treated with formulated abamectin (Agri-Mek 0.15 EC) at 1.0% (AI) performed only slightly better than phloxine B-treated spheres, which completely lost effectiveness after exposure to rainfall. Spheres treated with formulated imidacloprid (Merit 75 WP) at 1.5% (AI) showed equal or better residual efficacy in killing apple maggot flies (> 80% mortality, shorter lethal duration of feeding) over a 12-wk exposure period to outdoor weather than spheres treated with Digon at 1.0% (AI) after both types were retreated with sucrose. Our results indicate that imidacloprid is a promising safe substitute for dimethoate as a fly killing agent on lure-kill spheres. Imidacloprid formulated as Merit 75 WP had greater residual efficacy than imidacloprid formulated as Provado 1.6 F.

Animals↗

PubMed2002

Insecticidal 2-hydroxy-3-alkyl-1,4-naphthoquinones: correlation of inhibition of ubiquinol cytochrome c oxidoreductase (complex III) with insecticidal activity.

The insecticidal and in vitro activities of four homologous series of 2-hydroxy and acetoxy-3-substituted-1,4-naphthoquinones have been measured and correlated with their (Log) octanol/water partition coefficients (Log Ko/w). In vitro activity against mitochondrial complex III was only exhibited by 2-hydroxy-3-alkyl-1,4-naphthoquinones, indicating that the 2-acetoxy compounds act as proinsecticides. Good correlation was observed between in vivo activity against the two-spotted spider mite, Tetranychus urticae and inhibition of complex III isolated from blowfly flight muscle. Both hydroxy and acetoxy analogues of individual compounds exhibited similar levels of in vivo activity with optimum activity for analogues with Log Ko/w values of 7-8. In contrast, the acetoxy derivatives showed superior in vivo activity against the tobacco whitefly, Bemisia tabaci. Complex III isolated from whitefly was optimally inhibited by hydroxy analogues with lower Log Ko/w values (6.0-6.5) and was also more sensitive than the blowfly enzyme to all the compounds tested.

Algorithms↗

PubMed1999

Chemical models of cytochrome P450 catalyzed insecticide metabolism. Application to the oxidative metabolism of carbamate insecticides.

Cytochrome P450 (CP450) catalyzed oxidative metabolism of carbofuran (1), carbaryl (2), and pirimicarb (3) has been modeled using biomimetic oxidations catalyzed by iron(III) tetraarylporphyrins. Oxidation products of 1 were identified by comparison of HPLC retention times measured under standardized conditions for metabolites synthesized and characterized by (1)H and (13)C NMR spectroscopy. Comparison of product distributions to in vivo metabolic profiles revealed that the H(2)O(2)/meso-tetrakis(pentafluorophenyl)porphyrin iron(III) chloride [Fe(TF(20)PP)] system mimics the action of insect CP450s against carbofuran. The effectiveness of this system was further demonstrated by the biomimetic oxidation of other carbamate insecticides (2 and 3) monitored by HPLC/electrospray MS. The predictive power of this biomimetic model was compared to that of knowledge-based expert systems. Although similar models were recently applied in pharmaceutical research, the usefulness of this approach has first been demonstrated for the prediction of metabolic profiles of agrochemicals.

Animals↗

PubMed1983

Insecticide fingerprinting technique for detection and location of organochlorine insecticide residues in foods.

Insecticide fingerprinting technique enables the detection and location of DDT and HCH residues in vegetables through the development of green and prussian blue colors respectively. Cut vegetables are pressed against o-tolidine impregnated paper and exposed to sunlight where colored spots appear instantly. The studies on 18 vegetable varieties revealed the pesticide residues and their distribution in different tissues. This direct method is sensitive (0.3/micrograms for HCH & 0.5/micrograms for DDT) and has special applications in quality control laboratories and food industry.

DDT↗