Plant diseases are damaging to crop production in a temperate and humid climate like that of Japan, which has resulted in the development of many excellent fungicides, but wide-spread use of site-specific fungicides can cause pathogens to develop resistance in the field. While all modern fungicides have been developed through extensive safety evaluation, there is deep public concern about their side effects on non-target organisms. Thus there is a growing interest in non-fungicidal disease-controlling agents since they are supposedly specific to target organisms and less likely to cause resistance. Two groups of non-fungicidal rice blast chemicals are currently on the market; melanin biosynthesis inhibitors (MBIs) and plant defense activators or priming effectors which induce host resistance against the pathogen's attack. Recently, field isolates resistant to MBI-D have emerged and molecular mechanisms of action/resistance are attracting interest. Complex III in the electron transport system of fungal mitochondria which contains a cytochrome b with two ubiquinone binding sites, Qo and Qi, is another novel target of fungicides. Methoxyacrylate fungicides are known to block electron flow by binding to the Qo site. Resistance to Qo inhibitors has been observed in field isolates with a point mutation in the cytochrome b gene (G143A). While dicarboximide fungicides have been applied to protect various crops and vegetables against gray mold and other diseases, their mechanisms of action have remained unclear for many years; recent study revealed that dicarboximides interfere with the osmotic signal transduction pathway consisting of histidine kinase and MAP kinase cascades. The mutations conferring dicarboximide resistance in the field have been identified within the histidine kinase genes in Botrytis cinerea and Alternaria alternata. Thus management strategies for fungicide resistance may become a part of registration requirements worldwide. © Pesticide Science Society of Japan

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Carboxylesterases hydrolyze numerous endogenous and exogenous ester-containing compounds. They play a role in the detoxification of many agrochemicals including pyrethroids, organophosphates, and carbamates. Research on these enzymes is still developing and there are several topics that should be addressed to further investigations in this area. This paper focuses on a number of these issues including enzyme nomenclature, catalytic mechanism, substrate specificity, agrochemical metabolism, role in insecticide resistance and environmental significance. It is expected that carboxylesterase research will increase with specific emphasis on isozyme and substrate identification. Future research directions are discussed and the current state of the field is evaluated. © Pesticide Science Society of Japan

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The aim of this study is to observe the adulticidal activity of five essential oils against the mosquito Culex pipiens quinquefasciatus. Fumigating adulticidal activity was investigated by airtight fumigation in conical flasks. The result showed that the toxic effect of the five essential oils varied with the period of fumigation. Rutaceae oil was the most toxic of the five. Carvacryl oil had the shortest adulticidal time (6.087 min). The chemical components of rutaceae oil were analyzed by GC/MS. The major components were α-citral (33.50%) and citral (35.77%). Citral showed marked adulticidal activity in a short-term fumigation. All five essential oils had considerable adulticidal effects on Cx. pipiens quinquefasciatus. © Pesticide Science Society of Japan

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The excretion, tissue distribution and metabolic fate of simeconazole [(RS)-2-(4-fluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-3-trimethylsilyl propane-2-ol] in rats were studied by administering ¹⁴C-labeled simeconazole orally to male and female rats at 5 mg/kg b.w. (low dose) and 70 mg/kg b.w. (high dose). The simeconazole was readily absorbed and most of the radioactivity was excreted in the urine and feces within three days. The blood radioactivity level reached a maximum at 4–8 hr and 1–2 hr post-dosing in male and female rats, respectively. The radioactivity in the tissues and organs rapidly decreased with time. Simeconazole was initially metabolized to M1, the hydroxymethyl metabolite. M1 was further metabolized to glucuronide, sulfate, silanols and various dessiloxane compounds. © Pesticide Science Society of Japan

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Fumigation toxicity of hydrogen cyanide (HCN) was compared to very potent natural and synthetic cyanohydrins against the house fly and the lesser grain borer. The concentration of cyanide ion was much higher in the house flies exposed to HCN fumigation than in the flies that were exposed to cyanohydrin fumigation or to topical application of cyanohydrins. The results indicate that the toxic action of cyanohydrins in insects is due to the combined effects of cyanide ion, the aldehyde or ketone produced by the decomposition of the cyanohydrin, and possibly the intact cyanohydrin molecule. © Presticide Science Society of Japan

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Biomimetic oxidation mediated by three types of iron porphyrins was examined for five organophosphrus pesticides, fenitrothion (I), cyanophos (II), tolclofos-methyl (III), butamifos (IV) and fenthion (V). The major products from I–IV were the corresponding phenols and each oxon formed via a phosphoxathiirane intermediate by oxidation at the P=S moiety similarly as reported for their mammalian metabolism by cytochrome P450 enzymes. Stepwise oxidation of the methylthio sulfur via sulfoxide to sulfone, and ester cleavage and oxidative desulfuration primarily proceeded for V. Both the electron distribution of the highest occupied molecular orbital and its energy level of the pesticides calculated by MNDO-PM3 were shown to control the reaction site and rate of oxidation at sulfur atoms. © Pesticide Science Society of Japan

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Insecticidal thiamethoxam and related heterocyclic compounds were examined using American cockroaches to see if they decayed to the acyclic neonicotinoid clothianidin and what was responsible for activity. The minimum insecticidal dose was 1.4 nmol for thiamethoxam, and 2.0 mmol for clothianidin, while the doses for triazine and thiadiazine analogues were evidently larger than that for clothianidin. In a physiological salt solution of thiamethoxam for 7 days, the appearance of clothianidin could not be confirmed, while the related compound triazine partly decayed to clothianidin. From these results, the prodrug concept does not necessarily apply to thiamethoxam but does to the triazine in the present experiment. Insecticidal and neuroblocking tests were also conducted for three chloronicotinyl derivatives of thiamethoxam, triazine and thiadiazine analogues, six N-desmethyl derivatives and three acyclic clothianidin analogues. © Pesticide Science Society of Japan

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To evaluate the efficacy of the novel fungicide cyazofamid against potato late blight, 5 field tests were carried out in 1998–2000. Cyazofamid provided excellent control of late blight in the field. In preventative scheduled application tests, the efficacy of cyazofamid at dose rates of 67 and 100 μg active ingredient (a.i.)/ml with 10-day and 14-day intervals, respectively was superior to that of mancozeb at 1875 μg a.i./ml with a 7-day interval. The spray program that included cyazofamid was equal or superior to the standard spray program in Hokkaido, Japan. In the curative application test, cyazofamid suppressed the development of late blight. Cyazofamid will be useful in spray programs for the control of late blight in potato cultivation. © Pesticide Science Society of Japan

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The active conformation of antimycin A, a specific inhibitor of mitochondrial complex-III, expected from structure–activity studies is consistent with that come from X-ray crystallography of the enzyme. The structure–activity studies of acetogenins, potent inhibitors of complex-I, indicate that these inhibitors elicit potent activities only when the γ-lactone ring and hydroxylated THF ring moieties are directly linked by an alkyl spacer. Δlac-Acetogenins that are acetogenin mimics possessing two alkyl tails without a γ-lactone ring appeared to be a novel type of complex-I inhibitor, the binding site of which differs from that of ordinary complex-I inhibitors. © Pesticide Science Society of Japan

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Dinotefuran is a new neonicotinoid developed by Mitsui Chemicals and first registered in Japan in 2002 under the trade name of Starkle^® and Albarin^®. It has a characteristic tetrahydro-3-furylmethyl group instead of the aromatic heterocyclic ring that was previously considered indispensable for insecticidal activity of neonicotinoids. Dinotefuran was discovered by research using acetylcholine as the lead compound by way of a 3-methoxypropyl compound and its cyclization. It has excellent insecticidal properties and offers excellent control of a wide variety of pests in many kinds of crops. © Pesticide Science Society of Japan

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Pyriproxyfen yellow tape formulation is a novel pesticide delivery system utilizing the whitefly's attraction to yellow color and pyriproxyfen's excellent transovarial ovicidal activity against whiteflies. The tape formulation attracts whiteflies by its yellow color causing the whiteflies to come into contact with pyriproxyfen, which initiates the transovarial ovicidal activity against whiteflies. The formulation has an excellent efficacy against whiteflies when the tape is applied horizontally along ridges as a preventive measure. The tape formulation has great advantages in reducing the grower's exposure to the toxicological effects of pesticides as well as reducing the environmental impact because this method offers whitefly control without spraying. This technology is also useful as a tool for integrated pest management (IPM). © Pesticide Science Society of Japan

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Cucumber, bitter gourd and zucchini sprayed once with a mixture of acephate, metalaxyl, imidacloprid and thiacloprid were harvested at 1–14 days after application. Samples from each harvest were analyzed for pesticide residues by GC and HPLC. No differences in the initial residues or the rate of disappearance were observed between cucumber, bitter gourd and zucchini. Individual pesticide residues were low enough compared with the MRLs of cucumber (acephate 5<ppm, methamidophos 1 ppm, metalaxyl 2 ppm, imidacloprid 1 ppm, thiacloprid 1 ppm). A cucumber would be a suitable representative crop in the cucurbit vegetables group for evaluating pesticide residue levels.

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The effects of ethephon applications on growth were studied in cultivation of shoots in Taranoki (Aralia elata Seem.). The growths of stem and internode after spraying with 50–200 mg/l ethephon were shorter than those without ethephon application. Internode growths after spraying with 50–200 mg/l ethephon were shorter than those without application. Stem diameters increased after spraying with 50–200 mg/l ethephon spray. Stem growths and sucker formations were promoted by spraying with 50 mg/l gibberellin. Lateral bud growth was promoted by spraying with 200 mg/l of gibberellin. The results, show that stem diameters increased after spraying of ethephon, and stem growth and vegetative growth were promoted by spraying of gibberellin in Taranoki.

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