The metabolism of contact insecticides in stored grains. III. 1970–1974

Rowlands, D. G.

doi:10.1007/978-1-4613-9394-8_2

Cited by 9 publications

(4 citation statements)

References 88 publications

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“…A half-life of 43 weeks for piriraiphos-methyl on wheat grain maintained under normal storage conditions has been reported (Bengston et al, 1975). Wheat grain 14 o treated with I C] pirimiphos-methyl and stored at 21 C for 8 months was found to contain 78% of the radioactivity recoverable as parent compound (Rowlands, 1975). In a subsequent study (Rowlands and Wllkin, 1975) it was observed that approximately io% of the radioactivity was bound to wheat and was unextractable except by digesting.…”

Section: Introductionmentioning

confidence: 93%

Bioavailability to rats of bound [¹⁴C] pirimiphos‐methyl in stored wheat

Khan¹,

Kacew

Matthews³

1992

Journal of Environmental Science and Health, Part B

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Stored wheat treated with radiolabelled pirimiphos-methyl (0-2-diethyl-amino-6-methyl-pyrimidin-4-yl 0,0-dimethyl phosphorothioate) formed bound (nonextractable) 14C residues. Supercritical fluid extraction, gas chromatography and mass spectrometric techniques were used to identify and quantitate the 14C bound residues in wheat grains. The amount of bound 14C residues present after 28 weeks of storage was about 9.9% of the applied radioactivity. Pirimiphos-methyl accounted for 80% of the bound residue. Grain-bound residues were fed to rats for 5 days. After a total period of 8 days a substantially large percentage of the administered bound 14C residues (72.9%) was eliminated in urine while feces contained only 17.9%. Bound pirimiphos-methyl in wheat grain was metabolized in rats by processes involving hydrolysis, N-dealkylation and 0-demethylation. The results indicate that wheat-bound residues of pirimiphos-methyl are highly bioavailable to the rat and may possess a toxicological potential as manifested by a significant reduction in body weight gain.

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Section: Introductionmentioning

confidence: 93%

Bioavailability to rats of bound [¹⁴C] pirimiphos‐methyl in stored wheat

Khan¹,

Kacew

Matthews³

1992

Journal of Environmental Science and Health, Part B

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“…5 % MC) can be safely stored for long periods without serious microfloral growth, germination loss, or mite infestation although stored-product insects can thrive at low moisture levels. Most insecticides used on stored cereals break down slowly on dry seed, but rapidly, because of increased enzymic action, on grain that is moist (> 15% MC) or warm (Rowlands 1975). During the year of storage the grain temperatures were highest in July and August and lowest in January and February (Fig.…”

Section: Resultsmentioning

confidence: 99%

Residual Activity of Organophosphorus and Pyrethroid Insecticides Applied to Wheat Stored Under Simulated Western Canadian Conditions

White¹

1984

Can Entomol

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Wheat treated with 2,4, or 8 ppm of insecticide, on a whole-seed basis, was bioassayed with Tribolium castaneum (Herbst) and Cryptolestes ferrugineus (Stephens) adults at 30 °C and 70% RH after 4 days, 2 weeks, and then at eleven 1-month intervals. Malathion was more toxic to C. ferrugineus than to T. castaneum whereas the reverse was true for pirimiphos-methyl; malathion showed little effectiveness after 2 weeks. The pyrethroids, cypermethrin and permethrin, were more toxic to T. castaneum than to C. ferrugineus. For malathion and pirimiphos-methyl, percentage knockdown of the insects following exposure for 24 h was similar to percentage mortality after a 3-day recovery period; for cypermethrin and permethrin under the same conditions, knockdown was consistently greater than mortality. Cypermethrin at 8 ppm on wheat gave 90% knockdown of T. castaneum after 1 year of storage. Pirimiphos-methyl gave nearly 100% control of both species for 9 months at 4 ppm and 11 months at 8 ppm, and of the grain mite Acarus siro (L.) for at least 4 weeks at 8 ppm. Seed germination did not change during 1 year of storage; the levels of Penicillium spp. infection observed were much greater (about 60%) on wheat treated with pirimiphos-methyl (2, 4, 8 ppm) or cypermethrin (2 ppm) than with malathion or permethrin.

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“…Insecticide dégradation in stored cereals results largely from enzymatic activity in the seeds (Rowlands 1975) or by seed-borne fungi (Anderegg and Madisen 1983) when appropriate température and moisture are available . Storage under western Canadian conditions includes cold winter températures (Yaciuk et al 1975) and usually relatively dry grain (Kawamoto et al 1991).…”

Section: Discussionmentioning

confidence: 99%

Impact of pirimiphos-methyl and cold temperatures on arthropod populations in stored wheat

White¹,

Jayas²,

Sinha³

2005

phyto

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The insecticide pirimiphos-methyl applied at a mean concentration of 6.4 mg a.i. kg 1 to 5t of wheat (Triticum aestivum) in a farm granary in southern Manitoba remained active over 24 mo. Most insects and mites in the treated grain could not survive except a psocid, Liposcelis sp., and the mites Tarsonemus granarius and Aeroglyphus robustus, and their populations were sharply reduced relative to those in a bulk of untreated wheat. Insecticide residues at a 1-m depth decreased ca. 52% in 12 mo from 8.1 mg kg-1 to 4.0 mg kg-1, then remained constant until 24 mo. Grain moisture content (MC) at this depth was consistently higher (over 14% MC) than at the top of the wheat bulk where residues remained near 4.5 mg kg-1 over 24 mo. Grain temperatures fluctuated from summer maxima near 23°C to winter minima near -40°C at the bulk surface. Bioassay of treated wheat with adult Tribolium castaneum after 24 mo of storage resulted in about 80% mortality. Populations of T castaneum or Rhyzopertha dominica introduced into 5 t of untreated wheat did not become established; small populations of Cryptolestes ferrugineus were established but were eliminated by winter cold. Populations of Liposcelis sp. and the mites A. robustus, T. granarius, Blattisocius keegani and Cheyletus eruditus were highest in late summer and autumn. Seed germination and microflora were not directly affected by pirimiphos-methyl. The slow rate of degradation of this insecticide in grain would prevent communities of arthropods from developing to the same extent as in an untreated stored-wheat ecosystem over 24 mo.

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The metabolism of contact insecticides in stored grains. III. 1970–1974

Cited by 9 publications

References 88 publications

Bioavailability to rats of bound [¹⁴C] pirimiphos‐methyl in stored wheat

Bioavailability to rats of bound [¹⁴C] pirimiphos‐methyl in stored wheat

Residual Activity of Organophosphorus and Pyrethroid Insecticides Applied to Wheat Stored Under Simulated Western Canadian Conditions

Impact of pirimiphos-methyl and cold temperatures on arthropod populations in stored wheat

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The metabolism of contact insecticides in stored grains. III. 1970–1974

Cited by 9 publications

References 88 publications

Bioavailability to rats of bound [14C] pirimiphos‐methyl in stored wheat

Bioavailability to rats of bound [14C] pirimiphos‐methyl in stored wheat

Residual Activity of Organophosphorus and Pyrethroid Insecticides Applied to Wheat Stored Under Simulated Western Canadian Conditions

Impact of pirimiphos-methyl and cold temperatures on arthropod populations in stored wheat

Contact Info

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Bioavailability to rats of bound [¹⁴C] pirimiphos‐methyl in stored wheat

Bioavailability to rats of bound [¹⁴C] pirimiphos‐methyl in stored wheat