Residues of tetrachlorvinphos and its breakdown products on treated crops. II.—Residues on apples

Apples treated with tetrachlorvinphos (Gardona, trans-isomer of dimethyl 1-(2′,4′,5′-trichloropheny1)-2-chlorovinyl phosphate) insecticide under field conditions in several countries in 1965, 1966 and 1967 have been analysed at intervals after treatment for residues of tetrachlorvinphos itself, its cis-isomer and seven potential breakdown products. Residues of up to 10 ppm of tetrachlorvinphos were detected immediately after the last of three applications of tetrachlorvinphos (diluted to 0.16% active material). The initial half-life of the tetrachlorvinphos was on average about 0.5 weeks under U.K. conditions and only 10% of the tetrachlorvinphos remained unchanged at 2 weeks after application. The overall chemical persistence of the wettable powder formulation was not significantly different from that of the emulsifiable concentrate formulation. Within 8 weeks of the application the residues were mainly of tetrachlorvinphos itself, its cis-isomer and the alcohol 1-(2′,4′-5′-trichlorophenyl)ethan-l-ol, in free and sugar-conjugated forms. The residues of the conjugates of this alcohol (up to 0.92 ppm) were generally present in higher concentration at 6-8 weeks after the application than were the residues of the other components. Whilst residues of other breakdown products were detected on the apples their individual residues were below 0.05 ppm and generally below 0.01 ppm at 6 weeks or more after the last of several applications of tetrachlorvinphos.     

The absorption of cypermethrin in the grasshopper Melanoplus sanguinipes (Fab.): Effects of volatilisation,temperature, age,sex and parasitisation by Malameba locustae (King and Taylor)

The residues from metered doses of cypermethrin were recovered from excised portions of grasshopper cuticle to determine losses by volatilisation. Residues from similar doses were also recovered from the cuticles of intact grasshoppers and from whole body homogenates after rinsing the cuticle, to determine rates of absorption and losses from metabolism. Residues were recovered from males and females one week and three weeks after fledging in grasshoppers infected with Malameba locustae and in uninfected ones. They were maintained at 15 or 30°C and sampled from each combination of factors at 4, 8, 16, 24, 30 and 48 h after treatment. There was no measurable loss of cypermethrin by volatilisation up to 72 h after application to excised portions of cuticle at either 15 or 30°C. In all combinations of factors, more cypermethrin was recovered externally (P <0.05) from grasshoppers held at 15°C than those held at 30°C and more from infected grasshoppers than from those that were uninfected. Significantly more cypermethrin was also recovered externally from males than from females (P <0.05) and more from infected one-week-old grasshoppers than those that were three weeks old. At 15°C there was a gradual trend towards accumulation of cypermethrin internally, but at 30°C an initial trend towards accumulation was followed by one of decline. Residual cypermethrin recovered could in general be related to the negative temperature coefficient of toxicity, to a decreased sensitivity to cypermethrin in infected grasshoppers and to an increased sensitivity in older grasshoppers.     

灭蚊幼球形芽孢杆菌漂浮颗粒剂研制与应用

根据蚊虫的生活习性和球形芽孢杆菌BS-10灭蚊特点,以玉米棒芯颗粒为载体、以球型芽胞杆菌BS-10为杀虫活性物质,加工制成生物灭蚊漂浮颗粒剂新剂型,经试验与示范应用,该颗粒剂具有高效,毒力效价达106.5 IU／mg,每平方米水面使用颗粒剂2 g,对蚊幼虫(孑孓)杀灭效果达95%以上;持效期长,药后12 d,灭蚊效果达96.8%;性质稳定,室内常温储存1 a,药效无变化;生产工艺简单,药剂使用方便,与环境相容性好。     

Studies on granular formulations of Bacillus thuringiensis berliner

Survival of the spores of Bacillus thuringiensis in granular formulations has been tested under storage conditions in the laboratory and also outdoor conditions exposed to weather. The granular formulations were prepared with attapulgite and aqueous and non-aqueous carriers. The virulence of the spore formulation was tested on Bombyx mori larvae. A 0.4% spore concentration, with an initial count of 64 × 10⁶, gave ultimately 0.3 to 0.4 × 10⁶ viable spores/g of the granule after 248 days of storage in the room. The viable count of spores in the granules exposed to outdoor weather conditions fell rapidly within two days; at the end of 65 days, it was maintained at between 3 × 10⁴ and 12 × 10⁴/g of the granules. Optimum concentrations required in granules for 100% mortality of the test insect was found to be 0.4 × 10⁶ spores/g, at the rate of 50 mg of granules per 85 cm² of leaf surface. The granular formulation of B. thuringiensis was found to be more virulent than “Thuricide” formulation on B. mori larva.     

Evaluation of neonicotinoid, organophosphate and avermectin trunk injections for the management of avocado thrips in California avocado groves

BACKGROUND: Trunk injections of systemic insecticides were evaluated for the management of avocado thrips. Insecticide residues were quantified in leaves to determine when after treatment, and for how long, toxic concentrations of the insecticides were present. Residues in fruit were quantified to determine whether trunk injection of insecticides might present a greater risk than traditional application methods for contaminating fruit. RESULTS: Residues of imidacloprid and dinotefuran were at least tenfold higher in leaves when trees were treated via trunk injection compared with soil application. Dinotefuran uptake was more rapid than imidacloprid, and no residues were detected within fruit. Acephate was also mobilized very rapidly and gave good control of thrips in bioassays; however, residues of acephate and its insecticidal metabolite methamidophos were detected in the fruit for up to 4 weeks after injection. Avermectin uptake was very slow, and it was ineffective against avocado thrips. CONCLUSIONS: Trunk injections of acephate and dinotefuran permitted rapid uptake into avocados, and they are strong candidates as control methods for avocado thrips. However, residues of organophosphates in fruit could necessitate increased preharvest intervals. Residues of neonicotinoids were below detection limits in fruit, suggesting that neonicotinoids may be the more suitable control option of the two chemical classes. Copyright © 2012 Society of Chemical Industry     

Biochemical and histochemical studies on the digestive gland of Eobania vermiculata snails treated with carbamate pesticides

In this study the land snail (Eobania vermiculata), one of the most abundant gastropod of Egyptian farms, was investigated to determine the lethal toxic action of methomyl and methiocarb and to identify the biochemical and histochemical changes as a function of sublethal dose or concentration on the digestive gland of this snail under laboratory conditions, using topical application and baiting techniques. The results showed that methomyl exhibited greater efficacy than did methiocarb against the snails in both techniques. However, higher mortality rates were obtained in the topical application technique than in the poison bait experiments. Biochemical and histochemical examinations revealed that treatment of the snails with methomyl and methiocarb either by topical application or toxic baits caused significant decrease in carbohydrate, lipid and protein contents. This decrease was also more obvious after topical application than after baiting technique, and methomyl was found to be more toxic than methiocarb.     

Residues of carbofuran and 2,3-dihydro-3-hydroxy- 2,2-dimethylbenzofuran-7-yl methylcarbamate in the mushroom,agaricus bisporus,cultivated in casing soils treated with the insecticide

Residues of carbofuran ( 1 ) and 2,3-dihydro-3-hydroxy-2,2-dimethylbenzofuran-7-yl methylcarbamate ( 2 ) in and on mushrooms, cultivated on casing soils containing added carbofuran granular insecticide, were determined. The quantitative estimations in cleaned mushroom extracts were done on thin-layer plates using a cholinesterase inhibition method. Samples were analysed, which had been harvested at different times from cultures, to which different amounts of carbofuran were added. Residues in washed and unwashed mushroom samples were compared. Residues did not exceed 0.5 mg (carbofuran) kg^?1 and 0.25 mg (compound 2 ) kg^?1 for fresh unwashed mushrooms grown on casing soil treated with carbofuran granules 1 g (a.i.) m^?2.     

Accumulation of endosulfan residues in fish and their predators after aerial spraying for the control of tsetse fly in Botswana

Residues of endosulfan insecticide (α- and β-isomers, and ‘endosulfan sulphate’) in fish and their predators were measured during and after operations to control tsetse fly in the Okavango Delta, Botswana. Six ultra-low-volume doses of endosulfan 35% e.c. (6–12 g a.i. ha^?1) were applied from the air in a period of 12 weeks over 2500 km². The concentration of residues found in living fish was up to 0.19 mg kg^?1 wet wt in caudal muscle, and usually < 0.8 mg kg^?1 wet wt in pooled viscera (maximum 2.8 mg kg^?1). These values returned to near-normal within 3 months after cessation of spraying, but residues were still detectable after 12 months. By comparison, fish killed by spraying contained a maximum residue level (whole-body) of 1.5 mg kg^?1 wet wt. The residue level in fish was approximately proportional to their fat content. Lean fish were more susceptible to poisoning than fat fish. The proportion of the ‘endosulfan sulphate’ metabolite in fish increased at least six times with respect to the parent isomers (α+β) during the period of spraying, but more advanced stages of metabolic breakdown were not monitored. Residue levels in fish predators (fish-eating birds and crocodiles) were similar to those in their prey, and the risk to them was consequently low.     

Residues of the carbamate acaricide, 3-methyl-5-isopropylphenyl-N(n-butanoyl)-N-methylcarbamate (promacyl) and two metabolites in the tissues and milk of cattle

In order to assess some of the residue characteristics of the experimental carbamate acaricide, 3-methyl-5-isopropylphenyl-N-(n-butanoyl-)-N-methylcarbamate (promacyl) a 0.2 % aqueous emulsion was applied to cattle in a series of five trials and in a sixth, the technical product was added to the feed of stalled cattle. A method of analysis involving the formation of a derivative suitable for gas chromatographic analysis on electron capture detection mode was developed. Separate estimations of levels of the parent compound and the metabolites, 3-methyl-5-isopropylphenyl -N-methylcarbamate and 3-methyl-5- isopropylphenol, were carried out on fatty tissues and butterfat but for non-fatty tissues “total” levels, which were a combined estimate of 3-methyl-5-isopropylphenol itself and all substances hydrolysable to it, were estimated and quoted as Promacyl. The highest group average level of the parent compound was 0.9 part/million in fatty tissues 24 h after the last of 8 applications at 3 day intervals. In a single spray trial the maximum group average of 0.7 part/million in fatty tissues 24 h after treatment fell to 0.2 part/million after 5 days. Residues in butterfat, 7 h after a single dermal application showed a maximum level of 1.2 parts/million and this declined to 0.1 part/million on the seventh day after treatment. “Total” residues in non-fatty tissues were of the order of 1/10 those found in fatty tissues.     

Foliar residues and toxicity to green leafhoppers of the systemic insecticides aldicarb and its isomer butocarboxim in young peach and plum groves

The isomeric systemic carbamoyloximes aldicarb and butocarboxim were applied at two dose rates to the soil in young peach and plum groves to control the green leafhopper Asymmetrasca decedens Paoli. The effectiveness of the treatments was assessed indirectly by measuring the growth rate of shoots, and by determining the adult mortality of leafhoppers that were collected in the field and kept for 24 h on detached peach leaves in the laboratory. Residues of the insecticides and of their sulphoxide and sulphone metabolites, in the leaves of the peach trees, were determined 18 and 31 days after treatment. Only the sulphoxides and sulphones were found; the sulphoxides amounted to 70–80% of the toxic residues after 18 days, and to 50–70% after 31 days. At an identical rate of application, the leaves from aldicarb-treated peach trees contained higher concentrations of the toxic metabolites and were more toxic to leafhoppers than those of trees treated with butocarboxim.     

Evaluation of the bioefficacy and leaching of a controlled–release formulation of chlorsulfuron

A controlled–release formulation of chlorsulfuron (DT26B) and a conventional granular formulation were compared for their initial bioefficacy and leaching in laboratory and field experiments. Three alkaline soil types, representative of farm soils in SE Australia, were used for these experiments. Laboratory tests of initial bioefficacy using a Mallee sand (pH 7.2) were able to detect, within ED_05–95 limits, that approximately 50% of active ingredient remained as a non–available reserve in DT26B immediately after spraying, when compared with the granular formation. There was also an indication that the bioavailable component of active ingredient in DT26B would be sufficient for weed control. This was confirmed at field sites on a Kattyoong sand (pH 7.9) and a Wimmera Grey clay (pH 8.4), after using recommended application rates of chlorsulfuron during the 1994 winter growing season. The formulations produced only marginal differences in control of Lolium rigidum Gaud. The field leaching trials at these sites showed that there can be rapid leaching of chlorsulfuron with only small amounts of rainfall. Under these conditions, there was an overall trend of reduced leaching by DT26B at both trial sites, although these reductions were not significant when compared with the granular formation, A laboratory system designed to measure the mobility of herbicides is described. It was used to impose upon each formulation a greater level of leaching than in the field trials, using Mallee sand columns irrigated with 50 mm day^–1 under –50 kPa suction. This test revealed a negligible reduction in leaching of chlorsulfuron by DT26B as compared with the granular formulation. Therefore, although the controlled–release formulation DT26B demonstrated that it could provide a viable alternative for weed control under conventional spraying conditions in arable farming, the agricultural usage of DT26B for the purpose of reducing leaching could not be warranted at its current stage of development.     

Determination of residues of promecarb and its metabolite, 3-methyl-5-isopropylphenol,in cattle

A procedure is described for the colorimetric determination of promecarb as 3-methyl-5-isopropylphenol in tissues using 2,6-dichlorpbenzoquinone-4-chlorimine as the chromogen. Cattle were exposed to either 1, 3, 5 or 8 spray applications of a 0·2% promecarb emulsion at 3-day intervals or were fed promecarb at 2 ppm or 20 ppm daily in the diet for 20 days. All animals were slaughtered 30 h after final exposure. Of the animals in the spraying trial, residues in omental fat ranged from 0·9 ppm to 1·5 ppm promecarb and 0·4 ppm to 1·9 ppm 3-methyl-5-isopropylphenol. Residues in perirenal fat ranged from 0·8 ppm to 1·9 ppm promecarb and 0·9 ppm to 1·6 ppm 3-methyl-5-isopropylphenol. Residues in diaphragm muscle did not exceed 0·06 ppm. In the feeding trial, the maximum residues induced were 2·2 ppm promecarb and 1·4 ppm 3-methyl-5-isopropylphenol in omental fat of an animal fed for 20 days on a diet containing 20 ppm promecarb.     

Extended summaries pesticides group symposium physicochemical properties as factors affecting the penetration of xenobiotics to the target site

Allyl alcohol esters (propionate, formate, and acetate) and structurally related compounds (3-methylallyl alcohol and vinyl acetate) were evaluated for their fumigation properties vis-a-vis Theba pisana (Mueller) snails. The esters were very effective in exterminating the snails, although less so than the parent alcohol. These results suggest that the esters might first have to undergo hydrolysis, and only thereafter demonstrate their potency. 3-Methylallyl alcohol (four-carbon member) and vinyl acetate (two-carbon member, after hydrolysis) were significantly less potent than the allyl esters. All three esters showed less phytotoxicity towards roses than did allyl alcohol itself. However, only allyl acetate caused no damage whatsoever to the entire plant tested (flower, leaves, sepals, and stem).     

Residues of zeta‐cypermethrin in bovine tissues and milk following pour‐on and spray application

The depletion of zeta‐cypermethrin residues in bovine tissues and milk was studied. Beef cattle were treated three times at 3‐week intervals with 1 ml 10 kg^?1 body weight of a 25 g litre^?1 or 50 g litre^?1 pour‐on formulation (2.5 and 5.0 mg zeta‐cypermethrin kg^?1 body weight) or 100 mg kg^?1 spray to simulate a likely worst‐case treatment regime. Friesian and Jersey dairy cows were treated once with 2.5 mg zeta‐cypermethrin kg^?1 in a pour‐on formulation. Muscle, liver and kidney residue concentrations were generally less than the limit of detection (LOD = 0.01 mg kg^?1). Residues in renal‐fat and back‐fat samples from animals treated with 2.5 mg kg^?1 all exceeded the limit of quantitation (LOQ = 0.05 mg kg^?1), peaking at 10 days after treatment. Only two of five kidney fat samples were above the LOQ after 34 days, but none of the back‐fat samples exceeded the LOQ at 28 days after treatment. Following spray treatments, fat residues were detectable in some animals but were below the LOQ at all sampling intervals. Zeta‐cypermethrin was quantifiable (LOQ = 0.01 mg kg^?1) in only one whole‐milk sample from the Friesian cows (0.015 mg kg^?1, 2 days after treatment). In whole milk from Jersey cows, the mean concentration of zeta‐cypermethrin peaked 1 day after treatment, at 0.015 mg kg^?1, and the highest individual sample concentration was 0.025 mg kg^?1 at 3 days after treatment. Residues in milk were not quantifiable beginning 4 days after treatment. The mean concentrations of zeta‐cypermethrin in milk fat from Friesian and Jersey cows peaked two days after treatment at 0.197 mg kg^?1 and 0.377 mg kg^?1, respectively, and the highest individual sample concentrations were 2 days after treatment at 0.47 mg kg^?1 and 0.98 mg kg^?1, respectively. © 2001 Society of Chemical Industry     

Influence of block and cell size,growing medium and insecticide dose on the behaviour and uptake of phorate by lettuce and uptake of carbofuran and chlorfenvinphos by calabrese

Phorate residues in peat blocks and lettuce were determined following incorporation of the insecticide into different block and ‘Speedling’ cell sizes. Between-block variability was influenced little by block size. Phorate oxidation was most extensive in the largest blocks containing the smallest dose. Total residue concentrations in the lettuce declined from the time of planting to harvest, although accumulation of insecticide continued and was related more to dose than to block or cell size. Residues in the lettuce at harvest exceeded the proposed maximum limit of 0.2 mg kg^?1 in some treatments. Residues at planting comprised mainly the parent sulphoxide and sulphone, but by harvest, the oxygen analogue sulphoxide and sulphone predominated. Lettuce weight was not influenced by dose but was related directly to block size. Carbofuran and chlorfenvinphos residues were determined in calabrese sown into two sizes of blocks. At planting time, carbofuran residue concentrations were 100 times greater than those of chlorfenvinphos but residues of both insecticides in the mature heads were < 0.01 mg kg^?1. Seedling weights in both sowings declined with increasing concentrations of the insecticides. It was concluded that manipulations of block size and the dose of insecticide need to be evaluated for individual insecticide/crop combinations to exploit the technique fully.     

1％阿维·鱼藤新型乳油防治柑橘红蜘蛛田间药效试验

采用1％阿维·鱼藤新型乳油对柑橘红蜘蛛进行田间药效试验。结果表明,1％阿维·鱼藤新型乳油500、1000和1500倍液3个处理对活动螨态均具优异的杀灭效果,药后1d,500倍液处理组防效显著高于对照药剂200阿维·哒3000倍液处理,二者各为99．70%±0．30％和93．64%±2.29％;药后5d,1％阿维·鱼藤新型乳油500、1000和1500倍液3个处理对活动螨态的防效与对照药剂相当,4者防效均高达94．72％以上。此外,1％阿维·鱼藤新型乳油1500、1000和500倍3个处理均对柑橘红蜘蛛螨卵具一定的杀卵效果,其中500倍处理组的杀卵作用较好,校正杀卵率达80．59%±2．51％。     

Evaluation of oil formulations of deltamethrin for use on cotton targets for tsetse fly control

A range of formulations of deltamethrin were prepared, some containing an ultraviolet (UV) absorber compound or a combination of the UV absorber and an oil, and applied to blue cotton tsetse fly target samples which were then exposed to the effect of simulated sunlight and water in the laboratory. The residue of insecticide remaining on the targets and the activity of the latter against tsetse flies was determined. Formulations containing the UV absorber and coconut oil or silicone oil remained the most effective against tsetse flies. A coconut oil formulation of the insecticide was selected for field evaluation in comparison with a commercial deltamethrin formulation, Glossinex 200′ S.C., which contains 10% UV absorber. Target samples treated with these formulations were exposed to natural tsetse fly habitat in Ghana for a period of five months and evaluated for deltamethrin residues and activity against four species of tsetse fly. After five months, 4–13 times more deltamethrin remained on the targets treated with the coconut oil formulation than on those treated with ‘Glossinex’, and consequently the former were more active against tsetse flies than the latter. Target samples sequentially dipped in the coconut oil formulation resulted in uniform insecticide concentration on the targets, whereas those dipped in ‘Glossinex’ contained gradually decreasing deltamethrin concentrations.     

鱼藤酮水基纳米悬浮剂的特性及对松材线虫的杀虫作用

为改善鱼藤酮制剂的分散性,提高其悬浮率、稳定性及生物活性,制备了鱼藤酮纳米悬浮剂。该剂型为水基剂型,环境扫描电子显微镜和高效液相色谱检测结果显示,在鱼藤酮的水基纳米悬浮剂中,鱼藤酮悬浮颗粒的平均粒径为127.1 nm±31.8 nm,鱼藤酮的包封率为81.7%±3.5%,该制剂悬浮率高达99.23%±0.49%,抗光照分解的稳定性增强,36 h紫外光照射后鱼藤酮纳米悬浮剂中残存的鱼藤酮浓度比鱼藤酮丙酮溶液提高68.9%。以LC50表示的24 h对松材线虫的毒力鱼藤酮纳米悬浮剂是鱼藤酮丙酮溶液的7.5倍。     

Comparison of commercial glyphosate formulations for control of prickly sida, purple nutsedge, morningglory and sicklepod

The efficacy of the commercial glyphosate [( N -phosphonomethyl) glycine] formulations Roundup Ultra, Touchdown and Engame were compared for the control of prickly sida ( Sida spinosa L.), morningglory ( Ipomeae hederacea var. integriuscula Gray), sicklepod ( Senna obtusifolia L.) and purple nutsedge ( Cyperus rotundus L.). Engame is a new formulation of glyphosate that contains glyphosate acid and 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS), a proprietary mixture of sulfuric acid and urea, other than glyphosate salt and surfactants. Injury by Engame differed from Roundup Ultra and Touchdown in that necrotic lesions formed on leaves several hours after treatment. Leaves of very susceptible species, such as prickly sida, were rapidly, although incompletely, desiccated and then became chlorotic and died in a manner typical of other glyphosate formulations. Engame was 2–3 times more active to growth inhibition than either the Roundup Ultra or Touchdown formulations, based on GR₅₀ comparisons expressed on an acid equivalent basis. The GR₅₀ estimates did not change over the 3 week evaluation period for prickly sida and purple nutsedge, and after 2 weeks after treatment for morningglory. The GR₅₀ estimates for sicklepod decreased over the 3 week evaluation period indicating a slower response to glyphosate. The application of AMADS alone caused minute necrotic lesions on sicklepod and purple nutsedge, and lesions up to 3 mm in diameter on prickly sida and morningglory. Further injury from AMADS was not noted and plants resumed growth without apparent delay. At glyphosate rates above 1120 g ha⁻¹, greater than 80% control was achieved at 7 days after treatment. These results demonstrate that glyphosate efficacy can be further enhanced by formulations that apparently improve uptake and translocation.     

A scanning electron microscope study of glyphosate deposits in relation to foliar uptake

The effects of several formulations on foliar uptake of glyphosate, and on the morphology of glyphosate deposits on leaves, were examined in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.). [¹⁴C]glyphosate, in the form of the free acid or the isopropylamine salt (IPAS), was applied to foliage alone or with various adjuvants. Uptake of all glyphosate IPAS formulations was greater than that of the corresponding acid formulation. Addition of ‘Tween 20’ enhanced the uptake of glyphosate IPAS compared to glyphosate alone, but had no effect on the uptake of glyphosate acid. Ammonium sulfate and the ‘Roundup’ formulation blank increased the uptake of glyphosate acid and IPAS to 2-3 times that of herbicide alone. Surface deposits, as observed by scanning electron microscopy, varied with the formulation of the herbicide, although there were no differences between the acid and IPAS formulations. Glyphosate alone initially formed a deposit with both crystalline and smooth, amorphous areas. Later in the treatment period (48 and 72 h after application), the deposit was almost entirely crystalline. The addition of ‘Tween 20’ or of formulation blank resulted in the formation of a more amorphous, non-crystalline deposit. Herbicide solutions containing ammonium sulfate dried to form a highly crystalline deposit. However, crystals similar to those of glyphosate alone were not visible in these deposits. The ability of these adjuvants to prevent or delay crystal formation may play a role in their enhancement of herbicide uptake.