Uniform egg deposition among available host azuki beans by Callosobruchus chinensis and C. maculatus is expressed by their behavior that the females prefer to oviposit on the beans less conditioned by eggs and a biological conditioning substance (BCS). BCS is excreted by both males and females, but that from females plays a major role. BSC from one species affects another and is supposed to be a similar substance. The weevils discriminate more BCS-conditioned beans from less conditioned beans, but BCS has no deterring activity for oviposition. Thus BCS from both weevils can be defined as an oviposition marking pheromone.

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Acaricidal activities of cyano-(6-phenoxy-2-pyridyl)methyl traps-3-aryl-2, 2-dimethylcy-clopropanecarboxylates were analyzed quantitatively. An analysis of para-substituents of phenyl ring in the acid moiety by Hansch-Fujita method revealed that substituents having an appropriate hydrophobicity with branches at α-position, such as tert-butyl group, were preferable to the acaricidal activity. In addition to the acaricidal activity, some compounds suppressed phytophagous insects.

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Four optically active isomers of cyano-(6-phenoxy-2-pyridyl)methyl trans-3-(4-t-butylphenyl)-2, 2-dimethylcyclopropanecarboxylate were prepared. Their acaricidal and insecticidal activities were found to depend largely on the absolute configuration of the acid moiety but not on that of the alcohol moiety. cis-Isomer of the ester did not have any acaricidal activity.

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The photodegradation of naproanilide [2-(2-naphthoxy) propionanilide] and 2-(2-naphthoxy) propionic acid (NOP) in aqueous solution and in surface water of flooded soil under sunlight and ultraviolet light was investigated under laboratory conditions using ¹⁴C-labeled (uniformly labeled at the naphthalene-ring) compounds. Naproanilide and NOP in aqueous solution were rapidly degraded under sunlight and ultraviolet light. The irradiation resulted in formation of degradation products such as NOP, 2-naphthol, naphthalenediols, 2-hydroxyl, 4-napthoquinone and several unidentified compounds. The adsorption on the soil retarded the photodegradation of naproanilide and its degradation products. The disappearance of naproanilide in paddy fields was largely attributed to the photochemical degradation in the surface water.

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When either topically applied or mixed in the diet, CME-134, 1-(3, 5-dichloro-2, 4-difluorophenyl)-3-(2, 6-difluorobenzoyl) urea, prevented pupation in last instar larvae of Mamestra. CME-134 was about 5 times as effective as diflubenzuron by topical application, with its LD₅₀ value being 0.016μg/insect. By dietary administration, the LD₅₀ values of both insecticides were almost same (0.02ppm) but CME-134 was about twice as effective as diflubenzuron when the LD₁₀₀ values were compared. After application of the same doses of both CME-134 and diflubenzuron to last instar larvae, chitin synthesis was studied by measuring ¹⁴C-GA incorporation into cuticle and midguts. CME-134 inhibited chitin synthesis in vivo. The inhibition by CME-134 progressed faster than by diflubenzuron, although CME-134 was a less potent inhibitor than diflubenzuron for chitin synthesis in vitro using cuticle and midguts. The results suggest that the insecticidal activity of CME-134 is based on strong inhibition of chitin synthesis as so is that of diflubenzuron. CME-134 did not inhibit chitin synthetase that was prepared from the midguts of last instar Mamestra larvae even at a concentration of 1.0×10^-4M.

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The metabolic fate of the herbicide naproanilide, 2-(2-naphthoxy) propionanilide, was investigated in rice plants (Oryza sativa L.) and Sagittaria pygmaea MIQ. ¹⁴C-Naproanilide, uniformly labelled at the naphthalene-ring, was metabolized to phytotoxic 2-(2-naphthoxy)-propionic acid (NOP) in both plant species. In rice plants, NOP subsequently underwent hydroxylation and then rapid conjugation with glucose; considerable radioactivity was found in the water-soluble compounds and the aqueous methanol-insoluble residue. Phytotoxic methyl 2-(2-naphthoxy) propionate (NOPM) was produced only in small amounts. In S. pygmaea, the rates of NOP and NOPM were significantly greater than in rice plants. 2-Naphthol and 2-hydroxy-1, 4-naphthoquinone were also produced but only in small amounts. The difference in the metabolic products of naproanilide between the two plant species showed a possible mechanism of their herbicidal selectivity.

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Condensation of 4-unsubstituted and substituted thiosemicarbazines with α-alkylacetoacetic esters and with amides gave the corresponding thiosemicarbazones and their cyclized products, 3, 4-disubstituted 1-thiocarbamoyl-2H-pyrazolin-5-ones. These products were tested for their preventive and curative activities against rice blast, and 4-hexyl-3-methyl-1-(N-methylthiocarbamoyl)pyrazolin-5-one was found most effective for controlling rice blast.

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A new soil fungicide with plant growth-regulating activity, S-(4-methylsulfonyloxyphenyl) N-methylthiocarbamate(methasulfocarb, Kayabest^®, NK-191), promoted the elongation of rice seedling roots in water culture. Especially at a rate from 3.2 ppm to 12.8ppm the root elongation was remarkably accelerated. α-Naphthylamine oxidation of the rice seelding roots increased with an soil application of methasulfocarb 10% dust at a rate from 9mg to 720mg a. i. per 500ml soil before seeding. In the experiment using the rice seedlings exposed to a temperature of 5°C for 2 days, α-naphthylamine oxidation activity was stronger in the seedlings in methasulfocarb treated soil at a rate of 80mg a. i. before seeding than in those in untreated soil. The chlorophyll in the 2nd and 3rd leaves increased as methasulfocarb was applied at a rate from 160mg to 400mg a. i. The degradation of chlorophyll in the 3rd leaves reduced with the application of methasulfocarb at a rate of 80mg a. i. Water loss of the detached 3rd leaf increased with application of methasulfocarb at a rate of 80mg a. i. The results suggested that stomatal aperture of the leaves from the soil treated with methasulfocarb was wider than that of the leaves from the soil untreated.

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A pyrethroid resistant colony of the housefly collected from a hog farm in Mashiko was further selected with resmethrin for 10 generations in laboratory, and its LD₅₀ values for various insecticides were determined in comparison with those of a susceptible strain. The flies selected showed cross resistance to all the synthetic as well as natural pyrethroids tested. The flies were also highly resistant to the organochlorine insecticide p, p′-DDT, implying the involvement of a common mechanism of resistance for both types of insecticides, i. e. decreased nerve sensitivity due to the gene kdr. Resistance to the other organochlorine insecticide γ-BHC, however, was nominal. In general the flies showed a moderate level of resistance to organophosphorus insecticides, while their resistance to propoxur, a carbamate, was fairly high.

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The degradation of the urea herbicide isouron [3-(5-tert-butyl-3-isoxazolyl)-1, 1-dimethylurea] was studied using 6 kinds of soils under upland conditions. Isouron was stable in soils in general, but in volcanic ash Kanuma and Nasu soils the rapid degradation of isouron occurred after 3 and 6 months of incubation, respectively. Isouron was hardly degraded in loamy sand Toyohama and light clay Kohnan soils during 7 months of incubation. In sandy clay Ryuoh and sandy loam Aburahi soils isouron was easily degraded at the initial stage of incubation with the half-life of 2.1 and 2.5 months, respectively. The populations of bacteria and actinomycetes were larger in Ryuoh and Aburahi soils than in the others, but isourondegrading organisms could not be detected in any of these soils by the most probable numbers method. No correlation was found between the degradation rate and the absorption of isouron. When Kanuma or Toyohama soil was adjusted to neutral pH, isouron was rapidly degraded. Particularly in Kanuma soil adjusted to pH 7.0, the half-life of isouron shortened to 1 month. The degradation product of isouron in the soils was identified as 3-(5-tert-butyl-3-isoxazolyl)-1-methylurea formed through demethylation of the dimethylurea side chain.

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Apparent deuterium and tritium kinetic isotope effects were measured on the O-demethylation of methoxychlor in uninduced and β-naphthoflavone-induced rat liver microsomes. From the apparent values, the magnitudes of the intrinsic deuterium isotope effect values were calculated by Northrop's method as 15.2 for uninduced and 19.2 for naphthoflavone-induced rat liver microsomes. The large values for the intrinsic isotope effect suggest that the C-H bond cleavage reaction in the O-demethylation catalyzed by microsomal cytochromes P-450 has a linear transition state in which there is no bonding between the carbon and hydrogen atoms. A comparison of the intrinsic isotope effect values with the apparent isotope effect values showed the presence of several partially rate-limiting steps in the O-demethylation of methoxychlor catalyzed by cytochromes P-450.

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The crystal structure of a new grass herbicide, ethyl 2-[4-(6-chloro-2-quinoxalinyloxy)-phenoxy]propanoate (I) was investigated by the X-ray crystallographic technique. The solidstate structure and the conformation of I were confirmed and compared with those of methyl 2-[4-(2, 4-dichlorophenoxy)phenoxy]propanoate (II), (2, 4-dichlorophenoxy)acetic acid (IIIa) and 2-(2, 4, 5-trichlorophenoxy)propanoic acid (IIIb). The phenoxy propanoic acid moiety of I was similar to the equivalent moiety of II, IIIa and IIIb in preferred conformation and shape, whereas its 6-chloro-2-quinoxalinyloxy moiety was different from 2, 4-dichlorophenoxy moiety of II in preferred conformation, shape and size.

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Metabolic pathways of the herbicide molinate (S-ethyl perhydroazepine-1-carbothioate) in four strains of microorganisms isolated from a soil; Mycobacterium sp. (B-1), Flavobacterium sp. (B-2), Streptomyces sp. (A-1), and Fusarium sp. (F-1) were studied using ¹⁴C-molinate. In the cultures of both B-1 and B-2, S-β-hydroxyethyl and S-carboxymethyl derivatives were accumulated significantly. The oxidation of S-ethyl moiety was considered to be the main metabolic pathway in these bacteria. Azepine ring-hydroxy- and -oxo-derivatives were also detected in small amounts. In the culture of A-1, azepine ring-4-OH- and -4-oxo-derivatives were detected in substantial amounts. The oxidation of 4-positional carbon on azepine ring was regarded as the main metabolic pathway in this strain. Azepine ring-2-oxo-derivative, sulfoxide and hexamethyleneimine were detected simultaneously, though in small amounts. In F-1, the oxidation of azepine ring-carbon, yielding 3-OH-, 3-oxo-, 4-OH-, and 4-oxo-derivatives seemed to be the main metabolic pathways. In A-1 and F-1, these intermediates seemed to be further metabolized to microbial cell constituents or CO₂.

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Metabolism in cabbage plants of (1R)-cis- and (1R)-trans-isomers of cypermethrin [(RS)-α-cyano-3-phenoxybenzyl (1RS)-cis, trans-3-(2, 2-dichlorovinyl)-2, 2-dimethylcyclopropanecarboxylate] was investigated with ¹⁴C preparations labeled separately in the benzylphenyl ring and cyclopropyl ring. The half-life of disappearance was about 4-5 days and 7-8 days for trans- and cis-cypermethrin, respectively. Both isomers of cypermethrin underwent epimerization to (1S)-isomers, cis/trans isomerization, ester bond cleavage, hydroxylation of the phenoxy group in the alcohol moiety or the geminal methyl group in the acid moiety, hydration of the CN group to the CONH₂ group with subsequent hydrolysis to the COOH group, and conjugation of the resultant carboxylic acids and alcohols with sugars. The major metabolites from the alcohol moiety were glycoside conjugates of 3-(4-hydroxyphenoxy) benzoic acid and 3-phenoxybenzoic acid, and glycoside conjugates of 3-(2, 2-dichlorovinyl)-2, 2-dimethylcyclopropanecarboxylic acid from the acid moiety. Cypermethrin and its metabolites hardly translocated from the treated leaves to other parts of the plants.

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Susceptibility to several insecticides of housefly populations collected from hog and chicken farms as well as garbage dumping land-fill sites in Chiba-ken, Tochigi-ken, Ibaraki-ken and Tokyo was determined by the topical application method and compared with that of CSMA, a susceptible strain. A significant level of resmethrin resistance, i. e. 5.2μg/_??_ in LD₅₀ and 179 fold in resistance factor, was detected only with the colony collected from the same hog farm in Mashiko, Tochigi-ken as where the first case of pyrethroid resistance was found in 1983. All other colonies were highly susceptible to resmethrin except one from the garbage dumping land-fill site of Yachiyo, Chiba-ken, which showed a slight decrease in susceptibility to the pyrethroid. All the colonies except CSMA strain were highly resistant to p, p′-DDT. The flies were also found retaining resistance reported in 1970s to organophosphorus insecticides such as diazinon and fenitrothion to varying degrees.

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[in Japanese]

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[in Japanese]

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The mechanism of diazinon resistance in the Hokota strain, which was the first organophosphorus (OP) insecticide resistant houseflies reported in Japan in 1961, was investigated using ³²P-diazinon and -diazoxon in vitro and in vivo. It was demonstrated that this strain has three resistant mechanisms: slow penetration of diazinon through the cuticle, high microsomal mixed function oxidase activity and high activity of phosphatase which hydrolyzes diazoxon, or an active metabolite of diazinon. About five years after the use of insecticide for housefly control had been completely stopped in order to sericulture, houseflies were collected from the same farm where the diazinon resistant Hokota fly had been found. Single pair culture of captured flies and a diazinon susceptibility test of the offspring showed that a high frequency of diazinon resistant genes was still present. The Akita-f was a strain subjected to selection with fenitrothion for 17 generations. Subsequent evaluation showed the resistance ratio of this then established fenitrothion resistant strain to susceptible SRS strain was about 4000. Crossing between Akita-f and SRS strains showed the fenitrothion resistance almost completely dominant. Linkage group analyses for the dominant factor were carried out using two multi-chromosomal marker strains by the F₁ male backcross method, and the dominant resistant factor(s) was found to be associated only with the 2nd chromosome. The Wakamatsu-m strain, highly resistant to malathion, was established from a colony collected in Kitakyushu after more than 10 generations of selection with this chemical. The dominant factor(s) for malathion resistance was also located only on the 2nd chromosome. This strain possesses as its mechanisms of resistance high malathion carboxylesterase activity, high glutathione S-transferase activity and insensitive acetylcholinesterase. The linkage group of the dominant factor controlling high malathion carboxylesterase was analyzed. Results of the crossing experiments clearly showed that only the 2nd chromosome was associated with the dominant factor controlling high malathion carboxylesterase. Forty-two insect metabolites of trans- and cis-permethrin were identified in in vivo studies with American cockroaches, houseflies and cabbage loopers. The permethrin isomers were metabolized by hydrolysis and hydroxylation at the geminal-dimethyl group and the phenoxybenzyl group. The alcoholic and phenolic metabolites are excreted as glucosides, and carboxylic acid is excreted as glucosides and amino conjugates. The microsomal system was used for the metabolism of permethrin isomers by housefly and cabbage looper preparations. Esteric cleavage is more extensive for trans-permethrin than for cis-permethrin, while the relative extent of oxidative metabolism of the two isomers depends on the enzyme source. The Danish pyrethroid resistant housefly strain, 228e2b, showed cross resistance to all pyrethroid insecticides tested. Genetic study revealed that the factor resistant to permethrin was almost completely recessive and was located on the 3rd chromosome. A strain termed PyR which showed extreme resistance to pyrethroid insecticides was obtained after mating the 228e2b strain and Japanese OP resistant Wakamatsu-m strain, and after selections of their offspring by permethrin for 16 generations. In addition to nerve insensitivity, the PyR strain possessed, as a mechanism of resistance, high enzyme activity of microsomal oxidase which contributed to the detoxication of pyrethroids. Major pyrethroid resistance genes in PyR houseflies were located on the 2nd and 3rd chromosomes.

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Buprofezin (2-tert-butylimino-3-isopropyl-5-phenylperhydro-1, 3, 5-thiadiazin-4-one) exhibits an effect regulating the growth of homopterous insect pests. In the steps to buprofezin, we synthesized a variety of dithiazines and thiadiazines to investigate their biological activities by the long-term observation. Some perhydrothiadiazines were first found to show the nymphicidal activity during the molting on Nilaparvata lugens STÅL. From the structure-activity relationships, the 2-imino group was seemed to be crucial for high nymphicidal activity. Introduction of an aromatic substituent onto the 5-position, especially non-substituted phenyl group, was most effective for the activity. The action of finally selected buprofezin on N. lugens were characteristic: (1) species specificity; (2) the high molt-inhibiting action through chitin biosynthesis inhibition; (3) the short longevity of adults; (4) the suppressive oviposition, and (5) the deposition of unhatchable eggs. Thus, buprofezin is considered to be an insect growth regulator rather than an insecticide.

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Bialaphos, L-2-amino-4-[(hydroxy) (methyl)phosphinoyl] butyryl-L-alanyl-L-alanine, is a metabolite of Streptomyces hygroscopicus and the first herbicide produced by fermentation. Bialaphos acted on foliage and was effective against a wide range of weeds including perennials. Bialaphos was slower acting than paraquat, but faster than glyphosate. It controlled the regrowth of weeds longer than paraquat but shorter than glyphosate. Translocation of radioactivity in Rumex obtusifolius treated with ¹⁴C-bialaphos was observed autoradiographically. Bialaphos did not affect emergence nor growth of crops through soil. Therefore, bialaphos is expected to be used widely for arable land including nontillage cultivation. Growth inhibition of pollen tube of Camellia japonica was recovered by the addition of glutamine. The result suggested that glutamine synthetase (L-glutamine: ammonia ligase (ADP), EC 6.3. 1.2, GS) was inhibited in the pollen. Decrease of GS activity was observed in shoots of Echinochloa utilis OHWI treated with bialaphos. Decrease in glutamine content was observed in plant leaf treated with bialaphos, but it did not appear that the decrease was a main factor for the herbicidal activity. Ammonia content in plant leaf was observed to increase in four hr after the treatment and reached about 30 to 100 times higher than the control in 24 to 48hr. The accumulation was not momentary, but maintained until the death of the plant. The high correlation between free ammonia content and herbicidal activity indicated that the toxicity of accumulated ammonia is the primary factor of herbicidal activity of bialaphos. The ammonia accumulation is considered to be a particular action of bialaphos in plants. More extensive use of microbial metabolites is expected by the fact that bialaphos was developed as a herbicide.

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[in Japanese]

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