植物源农药的研究

植物源农药就其低毒、低残留、与环境和谐、对非靶标生物相对安全等优点,符合现代环保和人们健康的要求而越来越引起人们的高度重视。本文综述植物源农药的资源、植物源农药杀虫剂、杀菌剂和除草剂等的研究进展。     

十种常用农药与球孢白僵菌的生物学相容性

球孢白僵菌孢子粉与10种常用农药相容性的测定结果显示,随着孢子浓度上升,所试农药对孢子的抑制作用均有不同程度的增强。在1/10田间常规使用浓度下,百菌清和代森锰锌均能抑制或杀死孢子(萌发率<1％)。除阿维菌素外,所有杀虫剂均与白僵菌孢子相容,在常规使用浓度的10倍稀释液中孢子萌发率达90％以上。吡虫啉、蚜虱灵、灭多威和氟虫腈与孢子的相容性最好,其中吡虫啉和蚜虱灵对孢子萌发率的影响不明显随药剂浓度的变化而变化,即使在田间常规使用浓度下孢子萌发率也在95％以上,而阿维菌素与白僵菌的相容性极差。因此,应用白僵菌制剂防治害虫,选择生物学相容性好的农药以低剂量与白僵菌制剂混用,既可使菌剂增效,又可大幅度降低化学药剂用量。     

多杀菌素等新杀虫剂对粘虫的杀虫活性

浸叶法证明，多杀菌素(spinosad)、乙酰氨基阿维菌素和虫螨腈比阿维菌素对粘虫表现出更高的杀虫活性。其杀虫活性分别比阿维菌素高5倍、8倍和3．7倍。     

磷酸、膦酸酯类农药的质谱裂解规律研究

在对23种磷酸、膦酸酯类农药及其氧化物的质谱数据进行归纳整理的基础上,明确了这类农药质谱裂解规律。结果表明:电子轰击离子化条件下,磷酸、膦酸酯类农药分子极易裂解,且分子离子峰较弱。发现C_2H_6O_3P~+(m/z109)是其最具代表性的特征碎片离子。磷酸酯类农药裂解规律是二甲氧基磷酸酯P-0键易发生a断裂,生成m/z 109特征碎片离子。二乙氧基磷酸酯易脱去中性碎片C_2H_4,形成m/z81的特征离子。R'含有烯烃结构,易产生m/z127的特征碎片离子。膦酸酯类农药裂解规律与磷酸酯类似,特征性弱,膦键容易发生a断裂。选定了磷酸、膦酸酯类农药在质谱分析中常见的碎片离子,为农药残留筛查、确证分析提供参考。     

Being exposed to low concentrations of pirimiphos-methyl and chlorfenapyr has detrimental effects on the mobility of Trogoderma granarium

BACKGROUND

Sublethal effects of insecticides may negatively affect several biological and behavioral traits of insects. The lethal effects of pirimiphos-methyl and chlorfenapyr have been previously showed on Trogoderma granarium, but little knowledge is available about their sublethal effects at low concentrations on both sexes. Herein, the sublethal effects of pirimiphos-methyl and chlorfenapyr on the mobility of T. granarium males and females were investigated.

RESULTS

Lethal concentration (LC) values of pirimiphos-methyl and chlorfenapyr were lower for T. granarium females than males. LC values on males were LC₁₀ = 0.000788 and 0.00139 mg active ingredient (a.i.) cm⁻², LC₃₀ = 0.00350 and 0.00535 mg a.i. cm⁻², and LC₅₀ = 0.00986 and 0.0136 mg a.i. cm⁻² for pirimiphos-methyl and chlorfenapyr respectively. LC on females were LC₁₀ = 0.000704 and 0.00110 mg a.i. cm⁻², LC₃₀ = 0.00323 and 0.00428 mg a.i. cm⁻², and LC₅₀ = 0.00925 and 0.0110 mg a.i. cm⁻² for pirimiphos-methyl and chlorfenapyr respectively. The walking duration of beetles exposed to LC₃₀ of pirimiphos-methyl was significantly lower than the individuals exposed to LC₁₀ and LC₃₀ of both insecticides and control ones. Pirimiphos-methyl LC₃₀-exposed males remained more time on their back (101.7 s) than females (46.9 s), while the latter stayed immobile longer than males (381.7 s versus 371.9 s). The highest speed was recorded for control beetles (14.17 mm s⁻¹ females vs. 12.44 mm s⁻¹ males), while the lowest speed was observed in pirimiphos-methyl LC₃₀-treated males (8.36 mm s⁻¹) and females (9.66 mm s⁻¹).

CONCLUSIONS

Overall, males and females exposed to low concentrations of pirimiphos-methyl and chlorfenapyr showed reduced motility. This knowledge can be exploited further to unlock behavioral effects of insecticides for effective pest management programs in warehouses. © 2023 Society of Chemical Industry.     

4种不同杀虫剂防治淮山斜纹夜蛾药效试验

通过选用4种不同的杀虫剂防治淮山斜纹夜蛾试验，结果表明：药后10d，10亿PIB／mL银纹夜蛾多角体病毒悬浮剂（奥绿一号）处理的防效达100％，0．15％甲氨阿维·1000万PIB／mL苜银夜核悬浮剂（攻蛾）防效达92．8％，15％杜邦安打悬浮剂防效达91．7％，这3种药剂值得在生产上推广应用。     

Integration of soil applied neonicotinoid insecticides and acibenzolar-S-methyl for systemic acquired resistance (SAR) control of citrus canker on young citrus trees

Soil application of systemic neonicotinoid insecticides for control of psyllid vectors of Huanglongbing disease on young citrus trees also produces season-long SAR control of citrus canker caused by Xanthomonas citri subsp. citri Schaad et al. The neonicotinoids imidacloprid (IMID) and thiamethoxam (THIA) were compared with soil or sprinkler applications of the commercial SAR inducer acibenzolar-S-methyl (ASM) and foliar sprays of copper hydroxide (CH) and/or streptomycin (STREP) to evaluate their effects on the percentage of canker-infected leaves on 2-yr-old ‘Vernia’ orange and 3-yr-old ‘Ray Ruby’ grapefruit trees in Southeast Florida. All treatments significantly reduced the incidence of foliar canker compared to the untreated check. Soil drenches of ASM and season long rotations with IMID and THIA were highly effective for suppressing foliar canker on young grapefruit and orange trees under weather conditions absent of high intensity rains or tropical storms. Sprinkler application of ASM was less effective than soil drench. The level of control for SAR treatments was comparable to eleven 21-day interval sprays of CH and/or STREP. SAR induced by soil-applied insecticides provides substantial benefits for canker disease management on young citrus trees that may be augmented with ASM.     

The use of entomopathogenic fungi for the control of stored-grain insects

The present contribution discusses the recent advances in the biological control of stored-grain insects with entomopathogenic fungi (EF). Thus, the effect of formulated vs. unformulated strains of EF and the effect of combinations of EF with other components, i.e. diatomaceous earths (DEs), chemical insecticides, natural products and natural enemies against stored-product insects are reviewed. Very few formulations of EF strains have been developed and used, of which invert emulsion formulation (water-in-oil type) is considered the most important. A synergistic effect of EF is produced by combining them with DEs, chemical insecticides and natural products but not with natural enemies belonging to arthropods. Moreover, since the action of EF against insect pests in general, and stored-grain insects in particular, is compatible with the food safety and environmental regulations, a good perspective for these biocontrol agents is expected as alternatives to synthetic insecticides. The potential areas of future research on the effective use of EF as biocontrol agents of stored-grain insects and the constraints that are associated with the registration and commercialization of EF as biopesticides under storage conditions are also discussed. Suggestions for the possible ways for implementation of this technology in storage systems are also provided in the present study.