5%氯虫苯甲酰胺超低容量液剂防治二化螟田间药效试验

为明确5%氯虫苯甲酰胺UL对水稻二化螟的防治效果和使用技术,本文开展了田间药效试验。结果表明,在二化螟卵孵化高峰期喷施5%氯虫苯甲酰胺UL进行防治,施药后20 d,5%氯虫苯甲酰胺UL 15 g a.i/ha、22.5 g a.i/ha和30 g a.i/ha对二化螟的防效分别为74.18%、88.45%和91.32%,与对照药剂对比,22.5 g a.i/ha处理与30 g a.i/ha处理的防效极显著优于20%氯虫苯甲酰胺SC的防效。试验药剂5%氯虫苯甲酰胺UL对二化螟具有良好的防治效果,掌握在二化螟卵孵化盛期至幼虫1～3龄期使用超低容量喷雾器喷施,用水量为0.6 L/667m2,推荐使用剂量为22.5～30 g a.i/ha,但在使用中,要注意和其他药剂轮换使用,以避免抗药性的产生。     

10%溴氰虫酰胺可分散油悬浮剂防治甘蔗螟虫田间药效试验

为明确10%溴氰虫酰胺OF对甘蔗螟虫的防治效果,进行了田间药效试验。试验以不同剂量的10%溴氰虫酰胺OF作为处理,并以目前对甘蔗螟虫具有较好防治效果的200g/L氯虫苯甲酰胺SC作为对照药剂。结果表明,10%溴氰虫酰胺OF 1000倍对甘蔗螟虫的防效极显著高于对照药剂200g/L氯虫苯甲酰胺SC 3000倍,10%溴氰虫酰胺OF 1500倍与对照药剂200g/L氯虫苯甲酰胺SC 3000倍的防效相当,10%溴氰虫酰胺OF 2000倍对甘蔗螟虫的防效则极显著低于对照药剂200g/L氯虫苯甲酰胺SC 3000倍。建议生产上防治甘蔗螟虫时,推荐使用10%溴氰虫酰胺OF 1000~1 500倍液,在幼虫孵化高峰期喷雾防治。     

5％环虫酰肼悬浮剂防治二化螟田间药效试验

为明确5%环虫酰肼SC对水稻二化螟的防治效果和使用技术,开展了本田间药效试验。结果表明,在二化螟孵化高峰期喷施5%环虫酰肼SC防治二化螟,施药后当空白对照区为害状明显时调查,75 g/ha剂量的处理防效达到88.51%,显著高于对照药剂5%甲氨基阿维菌素苯甲酸盐WG和20%氯虫苯甲酰胺SC的防效,对二化螟有较好的防治效果。     

200g/L氯虫苯甲酰胺SC防除水稻二化螟试验

为验证200g/L氯虫苯甲酰胺SC(康宽)对水稻二化螟的防治效果,为今后大面积推广应用提供科学依据进行了防治二化螟的药效试验,现将试验结果报道如下:     

氯虫苯甲酰胺对草地贪夜蛾防效试验

通过使用200g/L氯虫苯甲酰胺SC15mL/667m²和5%甲氨基阿维菌素苯甲酸盐ME20mL/667m²,在草地贪夜蛾低龄幼虫高峰期进行施药,单次施药对草地贪夜蛾防效可达80%以上,施药2次防效可达90%。200g/L氯虫苯甲酰胺SC和5%甲氨基阿维菌素苯甲酸盐ME均可作为防治草地贪夜蛾的理想药剂进行推荐和推广应用。     

140g/L氯虫·高氯氟微囊悬浮剂防治甘蔗螟虫药效试验

以200g/L氯虫苯甲酰胺SC和50%杀螟丹WP为对照药剂,进行140g/L氯虫·高氯氟CS防治甘蔗螟虫田间药效试验。结果表明:140g/L氯虫.高氯氟CS对甘蔗螟虫有良好的防效,其中3000倍液防效最高、速效性最好、持效期最长,药后7～35d防效达82.58%以上,明显高于200g/L氯虫苯甲酰胺SC和50%杀螟丹WP;其次是4500倍液,药后7～35d,防效为79.46%以上,且对甘蔗安全,值得推广应用。     

200g/L氯虫苯甲酰胺悬浮剂防治柑橘潜叶蛾的药效试验

在砂糖橘秋梢抽出5 cm前喷施200 g/L氯虫苯甲酰胺SC能有效防治柑橘潜叶蛾;药后7 d再喷施1次200 g/L氯虫苯甲酰胺SC,保梢效果在93%以上。试验表明,喷药28 d后,灭虫保梢效果显著,建议防治柑橘潜叶蛾使用200 g/L氯虫苯甲酰胺SC 3 000~4 000倍液。     

4种农药对草地贪夜蛾的田间防治效果

本文研究了60 g/L乙基多杀菌素SC 50 mL/666.7m~2、200 g/L氯虫苯甲酰胺SC 15 mL/666.7m~2、5%甲维盐WG40 g/666.7m~2和5%啶虫咪EC 45 m L/666.7m~2对玉米草地贪夜蛾的田间防治效果。结果表明,药后3 d乙基多杀菌素、氯虫苯甲酰胺和甲维盐防效达90%以上,啶虫咪平均防效略低,仅为84.7%±2.18%;药后7～10 d,4种农药防效均达90%以上,乙基多杀菌素、氯虫苯甲酰胺和甲维盐防效优于啶虫咪;药后14 d,各处理区药剂防效有所下降。试验结果表明,60 g/L乙基多杀菌素、氯虫苯甲酰胺、5%甲氨基阿维菌素苯甲酸盐对草地贪夜蛾幼虫均较好的防治效果。在草地贪夜蛾低龄幼虫高峰期,使用60 g/L乙基多杀菌素50 mL/666.7m~2、200 g/L氯虫苯甲酰胺15 mL/666.7m~2、5%甲维盐40 g/666.7m~2,兑水40 L对玉米叶面喷雾,可收到较好的防治效果。     

几种药剂防治水稻二化螟田间药效试验

选用氯虫苯甲酰胺·噻虫嗪40%水分散粒剂10g/667m2,杀单·苏云63.1%可湿性粉剂50g/667m2,阿维·三唑磷15%乳油100m L/667m2处理二化螟,进行药效对比试验。试验结果表明:氯虫苯甲酰胺·噻虫嗪40%水分散粒剂10g/667m2,杀单·苏云63.1%可湿性粉剂50g/667m2对二化螟有较好的防效,两者药后14d防效分别为92.61%、90.46%,且对水稻生长安全,对其他有益生物未见药害。建议使用时,每667m2用氯虫苯甲酰胺·噻虫嗪40%水分散粒剂10g或杀单·苏云63.1%可湿性粉剂50g于二化螟卵孵盛期至二龄幼虫高峰期兑水40kg于水稻叶面均匀喷雾。     

崇阳县水稻二化螟及稻蓟马高效防治技术研究

研究结果表明,18％噻虫胺悬浮种衣剂700mL/100kg种子处理对水稻苗期稻蓟马具有持久防效,药后20d平均防效保持在78％以上.使用200g/L氯虫苯甲酰胺悬浮剂0.5mL/盘或1％氯虫苯甲酰胺颗粒剂20g/盘均对一代二化螟有良好防效,药后20d防效可以达到75％以上,药后50d防效能保持在30％以上.第二代二化螟...     

Isomerization and Beckmann rearrangement reactions in the metabolism of methomyl in rats

Methomyl {S-methyl-N-[(methylcarbamoyl)oxy]thioacetimidate}, also known as Lannate, may exist in two geometric configurations but the more stable syn isomer is the form applied as an insecticide. In the rat, syn[¹⁴CN]methomyl [CH₃S(CH₃)CNOC(O)NHCH₃] was metabolized to respiratory ¹⁴CO₂ and $\text{CH}{}_3{}^{14}\text{CN}$ in a ratio of about 2 to 1. Studies with the anti isomer showed that it was metabolized predominately to $\text{CH}{}_3{}^{14}\text{CN}$. These and other data are presented supporting the contention that syn methomyl is partially isomerized to the anti isomer in the animal prior to the hydrolysis of the ester linkage. After hydrolysis, the syn oxime [CH₃S(CH₃)¹⁴CNOH] is further metabolized to ¹⁴CO₂ while the anti oxime is metabolized to $\text{CH}{}_3{}^{14}\text{CN}$. Proposed immediate precursors to the carbon dioxide and acetonitrile, formed by Beckmann rearrangement of the syn and anti oximes, are CH₃S¹⁴C(O)NHCH₃ and $\text{[}\text{CH}{}_3{}^{\mathrm{14\oplus }}\text{CNSCH}{}_3\text{]x}{}^{\mathrm{?}}$, respectively.     

Early survival of Quercus ilex subspecies from different populations after infections and co‐infections by multiple Phytophthora species

Forests in Europe are threatened by increased diversity of Phytophthora species, but effects on trees of simultaneous infections by Phytophthora and ecological consequences of their coexistence are unknown. This study explored variation in early survival of Quercus ilex to Phytophthora infections and assessed interactions between Phytophthora species when trees were co‐infected. Three Phytophthora species (P. cinnamomi, P. gonapodyides and P. quercina), seeds from 16 populations of Q. ilex (ballota and ilex subspecies) and two infection times were used as sources of variation in two experiments. The influence of Phytophthora species, Q. ilex subspecies and populations on plant germination and survival were analysed using generalized linear mixed models and survival analysis techniques. Germination rates were not influenced by Phytophthora spp. (P = 0.194) but by the subspecies and populations of Q. ilex (P < 0.001). In Phytophthora‐infested soils, Q. ilex subsp. ilex germinated at higher rates than Q. ilex subsp. ballota. Plant survival was strongly influenced by Phytophthora species (P < 0.001), not by the subspecies and populations of Q. ilex. Seedling mortality was reduced and delayed if a less virulent Phytophthora species infected plants prior to infection by a more virulent Phytophthora species. The results help to explain oak decline syndrome and the lack of natural and artificial regeneration of Q. ilex forests. Lack of interspecific variability of early survival to Phytophthora spp. discourages direct sowing for artificial reforestation programmes. Large, thick seeds, giving plants rapid growth, are advantageous traits when soils are infested with Phytophthora spp.     

Trichoderma species associated with green mould disease of Pleurotus ostreatus and their sensitivity to prochloraz

Green mould disease causes serious economic losses in Pleurotus ostreatus crops worldwide, including in Italy, where prochloraz is the only chemical fungicide allowed to control the disease. The effectiveness of the doses 0.01, 0.05, 0.25 and 1.25 μL L⁻¹ (field dose) of prochloraz (Sponix Flow, 450 g L⁻¹), against colony growth rate and spore germination of Trichoderma pleuroti, T. pleuroticola and T. guizhouense strains on wheat straw extract agar plates were evaluated. Complete inhibition of Trichoderma pleuroti and T. pleuroticola growth was shown by the field dose of prochloraz, and also by the 0.25 μL L⁻¹ dose for T. pleuroti. Complete inhibition of spore germination occurred for all Trichoderma strains at field dose, and at 0.25 μL L⁻¹ for T. pleuroti strains. In in vivo assays, the effect of prochloraz doses 0.05, 0.25 and 1.25 μL L⁻¹ on colonization of straw substrate by T. pleuroti, T. pleuroticola and T. guizhouense inoculated at two spore densities (10² and 10⁵ spores mL⁻¹) immediately after P. ostreatus spawn was studied. Trichoderma pleuroti and T. pleuroticola were both responsible for green mould disease, whereas T. guizhouense was not pathogenic. Trichoderma pleuroti was more aggressive than T. pleuroticola. Prochloraz was effective against T. pleuroti at the field dose, and against T. pleuroticola at 0.25 and 1.25 μL L⁻¹. The study on Trichoderma × Pleurotus interaction type showed that Trichoderma species were active against the mycelial growth of P. ostreatus by competition for space and nutrients, and neither hyphal interaction nor effect by volatile or nonvolatile metabolites occurred.     

Binding of phenthoate to bovine serum albumin and reduced inhibition on acetylcholinesterase

Organophosphorus pesticides (OPs) are of environmental significance due to their high toxicity to animals. Binding to plasma proteins may effective influence the toxicological properties of xenobiotics. In an attempt to evaluate the affinity of phenthoate (PTA) to bovine serum albumin (BSA) and inhibitory ability of bound PTA to acetylcholinesterase (AChE), we investigated the interactions between phenthoate (PTA) and bovine serum albumin (BSA) using tryptophan fluorescence quenching and subsequent inhibition on AChE activity by PTA. The results showed that PTA caused the fluorescence quenching of BSA because of the formation of a PTA-BSA complex. Quenching constants (K_sv), determined using the Sterns-Volmer equation to provide a measure of the binding affinity between PTA and BSA at 303, 306, 310 and 313 K were (3.4295 ± 0.0763) × 10⁻⁴, (3.2446 ± 0.0635) × 10⁻⁴, (3.0434 ± 0.0856) × 10⁻⁴ and (2.8262 ± 0.0569) × 10⁻⁴ M⁻¹, respectively. The thermodynamic parameters, ΔH and ΔS were −25.04 kJ mol⁻¹ and 168.94 J mol⁻¹ K⁻¹, respectively, which indicated that the electrostatic interactions played a major role in PTA-BSA association. The presence of BSA consistently reduced the inhibitory ability of PTA on AChE, with the relative activity being increased from 46.98 to 61.71% for the concentration range of BSA between 0 and 4.0 g L⁻¹.     

Effectiveness of Coniothyrium minitans and Trichoderma atroviride in suppression of sclerotinia blossom blight of alfalfa

The effects of the mycoparasites Coniothyrium minitans and Trichoderma atroviride on the suppression of alfalfa blossom blight caused by Sclerotinia sclerotiorum were evaluated under indoor and field conditions. When T. atroviride (9·0 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) or C. minitans (9·0 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) were applied to detached young alfalfa florets, T. atroviride effectively inhibited saprophytic growth of S. sclerotiorum, whereas C. minitans showed no inhibition under the same conditions. When T. atroviride (6·9 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) or C. minitans (6·9 × 10⁴ conidia/floret) + S. sclerotiorum (6·0 × 10³ ascospores/floret) was applied to young alfalfa petals in vivo just after pollination, the percentage of pod formation was higher for T. atroviride+S. sclerotiorum than that for C. minitans+S. sclerotiorum, and the percentage of pod rot was lower for T. atroviride+S. sclerotiorum than that for C. minitans+S. sclerotiorum. However, when they were applied to senescent petals attached to developing pods of alfalfa at 9·2 × 10⁴ conidia/floret together with S. sclerotiorum at 4·5 × 10³ ascospores/floret at 14 days after pollination, C. minitans was more effective than T. atroviride in suppressing sclerotinia pod rot and seed rot of alfalfa. Field experiments showed that three applications of C. minitans (5·4 × 10⁶ conidia mL⁻¹) or T. atroviride (5·4 × 10⁶ conidia mL⁻¹) at a 7-day interval to blossoms of alfalfa effectively suppressed sclerotinia pod rot in two out of three annual trials. Coniothyrium minitans effectively suppressed sclerotinia seed rot in all three years, whereas T. atroviride was not effective against seed rot in any of the trial years. The efficacy of C. minitans was not significantly different (P > 0·05) from benomyl (250 µg ai mL⁻¹). This study suggests that C. minitans has potential as a biocontrol agent to control blossom blight of alfalfa caused by S. sclerotiorum.     

Concentrations of constitutive alk(en)ylresorcinols in peel of commercial mango varieties and resistance to postharvest anthracnose

Mature green mango fruits of commercially important varieties were screened to investigate the levels of constitutive antifungal compounds in peel and to assess anthracnose disease after inoculation with Colletotrichum gloeosporioides. High-pressure liquid chromatography was used to quantify the levels of 5-n-heptadecenylresorcinol and 5-n-pentadecylresorcinol in the peel extracts. The fruit peel of the varieties ‘Kensington Pride’ and ‘Keitt’ were observed to have the highest levels of both 5-n-heptadecenylresorcinol (107.3–123.7 and 49.9–61.4 μg/g FW, respectively) and 5-n-pentadecylresorcinol (6.32–7.99 and 3.30–6.05 μg/g FW, respectively), and the fruits of the two varieties were found to have some resistance to postharvest anthracnose. The varieties ‘Kent’, ‘R2E2’, ‘Nam Doc Mai’, ‘Calypso’ and ‘Honey Gold’ contained much lower concentrations of resorcinols in their peel and three of these varieties were found to be more susceptible to anthracnose. Concentrations of 5-n-heptadecenylresorcinol were significantly lower at the ‘sprung’ and ‘eating ripe’ stages of ripening compared to levels at harvest. Concentrations of 5-n-pentadecylresorcinol did not differ significantly across the three stages of ripening. The levels of these two resorcinols were found to be strongly inter-correlated (P<0.01, r²=0.71), with concentrations of 5-n-heptadecenylresorcinol being an average 18 times higher than those of 5-n-pentadecylresorcinol. At the ‘eating ripe’ stage, significant relationships were observed between the concentrations of each type of alk(en)ylresorcinol and anthracnose lesion areas following postharvest inoculation, P<0.001, r²= 0.69 for 5-n-pentadecylresorcinol, and P<0.001, r²= 0.44 for 5-n-heptadecenylresorcinol.     

Selection,characterization and genetic analysis of laboratory mutants of <Emphasis Type="Italic">Botryotinia fuckeliana</Emphasis> (<Emphasis Type="Italic">Botrytis cinerea</Emphasis>) resistant to the fungicide boscalid

Resistance to the fungicide boscalid in laboratory mutants of Botryotinia fuckeliana (Botrytis cinerea) was investigated. The baseline sensitivity to boscalid was evaluated in terms of colony growth (EC₅₀ = 0.3–3 μg ml⁻¹; MIC = 10–30 μg ml⁻¹) and conidial germination (EC₅₀ = 0.03–0.1 μg ml⁻¹; MIC = 1–3 μg ml⁻¹) tests. Mutants were selected in vitro from wild-type strains of the fungus on a fungicide-amended medium containing acetate as a carbon source. Mutants showed two different levels of resistance to boscalid, distinguishable through the conidial germination tests: low (EC₅₀ ∼ 0.3 μg ml⁻¹, ranging from 0.03 to 1 μg ml⁻¹; MIC > 100 μg ml⁻¹) and high (EC₅₀ > 100 μg ml⁻¹) resistance. Analysis of meiotic progeny from crosses between resistant mutants and sensitive reference strains showed that resistant phenotypes were due to mutations in single major gene(s) inherited in a Mendelian fashion, and linked with both the Daf1 and Mbc1 genes, responsible for resistance to dicarboximide and benzimidazole fungicides, respectively. Gene sequence analysis of the four sub-units of the boscalid-target protein, the succinate dehydrogenase enzyme, revealed that single or double point mutations in the highly conserved regions of the iron-sulphur protein (Ip) gene were associated with resistance. Mutations resulted in proline to leucine or phenylalanine replacements at position 225 (P225L or P225F) in high resistant mutants, and in a histidine to tyrosine replacement at position 272 (H272Y) in low resistant mutants. Sequences of the flavoprotein and the two transmembrane sub-units of succinate dehydrogenase were never affected.     

Effect of cropping systems and crop successions on fumonisin levels in corn from Northern Paraná State,Brazil

In this study the effect of different cropping systems and crop successions was evaluated on natural Fusarium sp. contamination and fumonisin levels in corn. The cropping systems consisted of a conventional and no-tillage area cultivated with corn in the summer following either oats or fallow in the winter (2006 and 2007 growing seasons). In addition, the effect of applying nitrogen fertilizer (0, 22.5, 45.0, 90.0 and 90.0 kg ha⁻¹ nitrogen supplemented with potassium oxide) on fumonisin contamination was evaluated in the 2006 growing season. Fusarium sp. was detected in 90% samples in 2006 and in 100% samples in 2007. In both growing seasons, no-till corn following oats showed the highest mean fumonisin levels and differed significantly (P < 0.05) from all the others (2006) and from conventional till corn following either oats or fallow in the winter (2007). Fumonisin levels ranged from 0.13 to 19.52 μg g⁻¹ (mean 6.97 μg g⁻¹) and from 3.70 to 7.75 μg g⁻¹ (mean 6.29 μg g⁻¹) in no-till corn following oats from the 2006 and 2007 growing seasons, respectively. Plots treated with 0 kg ha⁻¹ and 22.5 kg ha⁻¹ nitrogen showed the highest mean fumonisin levels and differed significantly from those with 45.0 and 90 kg ha⁻¹ nitrogen. Fumonisin levels correlated negatively (P < 0.05) with the nitrogen fertilization rates. Although no-till is advantageous from a soil conservation standpoint, it may enhance the potential for fumonisin contamination in corn.     

Structure—activity relationships of organotin biocides and Ceratocystis ulmi

The effect of organotin compounds on the growth of Ceratocystis ulmi, the causative agent of Dutch elm disease, was studied in shake culture. Triphenyltin, (C₆H₅)₃SnX, tricyclohexyltin, (C₆H₁₁)₃SnX, and tributyltin, (C₄H₉)₃SnX, compounds were all effective in the inhibition of C. ulmi in vitro. The anionic group, X, did not play a major role in the inhibitory activities of these compounds, suggesting that the species involved in the inhibition is R₃Sn⁺ or the hydrated cation.