Chemical control of vine weevil larvae on container-grown hardy ornamental nursery stock 1986–1989

In a search for alternatives to the former standard aldrin compost incorporation treatment for control of vine weevil (Otiorhynchus sulcatus) larvae on container-grown hardy ornamental nursery stock, a series of 87 tests of insecticides were done at four experimental centres of the ADAS (Leeds, Reading, Wolverhampton and Wye) from 1986 to 1989. Insecticidally-treated plants and untreated controls were artificially infested with vine weevil eggs at varying intervals before and after treatment, and the survival of the pest was assessed. Aldrin treatment gave consistent and excellent preventive control of vine weevil larvae for over 2 years. Of the candidate materials tested, a slow-release granular formulation of chlorpyrifos incorporated into compost at a dose rate of 100 g a.i. m^-3 of compost gave good control for up to 34 wk after treatment (the longest period evaluated) and a micro-encapsulated slow release formulation of fonofos incorporated at a dose rate of 43.3 g a.i. m^-3 usually gave good control for up to two years (the longest period evaluated). Surface applications of these two organophosphates or of carbofuran granules, though sometimes effective, were unreliable as either preventive or remedial treatments even for short term control.     

Variation Characteristics of Chlorpyrifos in Nonsterile Wetland Plant Hydroponic System

Six wetland plants were investigated for their effect on the degradation characteristics of chlorpyrifos in nonsterile hydroponic system at constant temperature of 28°C. The results showed that the removal rates of chlorpyrifos in the water of plant systems were 1.26–5.56% higher than that in the control without plants. Scirpus validus and Typha angustifolia were better than other hygrophytes in elimination of chlorpyrifos. The removal rates of the two systems were up to 88%. Plants of acaulescent group had an advantage over caulescent group in removing chlorpyrifos. Phytoaccumulation of chlorpyrifos was observed, and the order of chlorpyrifos concentration in different plant tissues was root > stem > leaf. It was also found that chlorpyrifos and its metabolite TCP decreased rapidly at the initial step of the experiment.     

亚致死浓度溴虫腈和毒死蜱对等钳蠊螨生长繁殖和解毒酶的影响

【目的】害虫综合治理中,化学防治对天敌资源也具有一定的杀伤力。为缓解这一矛盾,本研究旨在探究溴虫腈和毒死蜱亚致死浓度处理对等钳蠊螨Blattisocius dentriticus生长繁殖及解毒酶活性和基因表达量的影响。【方法】利用药膜法处理2-3日龄等钳蠊螨成螨24 h,测定溴虫腈和毒死蜱的亚致死剂量;测定和比较LC_(10)和LC_(30)剂量这两种药剂处理后F_0和F_1代的产卵量、产卵期、卵孵化率和雌成螨寿命等生物学特性的变化;通过酶活力分析和RT-PCR分别测定LC_(10), LC_(30)和LC_(50)剂量下这两种药剂处理后钳蠊螨成螨体内谷胱甘肽-S-转移酶(glutathione S-transferase, GST)、细胞色素P450(cytochrome P450, CYP450)、羧酸酯酶(carboxylesterase,CarE)酶活力及其基因表达量变化。【结果】溴虫腈和毒死蜱处理24 h对等钳蠊螨成螨的LC_(50)分别为42.56 mg/L和72.42 mg/L。溴虫腈和毒死蜱LC_(10)和LC_(30)剂量处理等钳蠊螨雌成螨后,与对照(清水处理)相比,仅F_0代雌成螨寿命和产卵期显著缩短(P0.05),而产卵量和卵孵化率无明变化。酶活力测定结果发现,GST, CYP450和CarE的活力在溴虫腈和毒死蜱LC_(10)和LC_(30)剂量处理后无明显变化,而LC_(50)剂量下,上述3种酶的活力均显著增加(P0.05)。基因表达结果表明,溴虫腈LC_(10), LC_(30)和LC_(50)剂量处理下2个GST基因(BdGST3和BdGST6)、3个CYP450基因(BdCYP2-4)和5个CarE基因(BdCarE1-5)表达均显著上调;在毒死蜱这3个剂量处理下3个GST基因(BdGST1,BdGST3和BdGST4)、3个CYP450基因(BdCYP2,BdCYP5和BdCYP6)和2个CarE基因(BdCarE1和BdCarE2)表达量均显著上调。【结论】结果表明,LC_(10)和LC_(30)剂量的溴虫腈和毒死蜱亚致死剂量会抑制F_0代雌成螨的生长繁殖;LC_(10), LC_(30)和LC_(50)剂量下这两种药剂可诱导等钳蠊螨GST, CarE和CYP450基因表达;LC_(50)剂量能明显诱导等钳蠊螨体内GST, CarE和CYP450活性上升。该研究为等钳蠊螨抗性品系的筛选及田间应用提供了理论依据。     

Biochemical effects of chlorpyrifos organophosphorous insecticide,camphor plant oil and their mixture on Spodoptera littoralis (Boisd.)

The biochemical effects of the chlorpyrifos organophosphate insecticide and camphor plant oil in addition to their combination were studied and compared against the fourth larval instars of the cotton leaf worm Spodoptera littoralis under laboratory condition. Biochemical analysis showed that the total protein content of the cotton leaf worm larval instars was decreased at 31, 26 and 13.5% by using a camphor extract, chlorpyrifos and combination, respectively. In addition, the activity of acid phosphatase, α-esterase was significantly declined. Biochemical analysis also showed that the alkaline phosphatase activity was increased comparing with control in another side. Acetylcholinesterase enzyme amount and activity were increased with the treatment of camphor extract followed by chlorpyrifos, even though the mixture of them nearly showed the same amount in control trail. In contrast, chitinase enzyme showed a negative effect of both camphor and chlorpyrifos with nearly about the same lowering in the amount and activity of chitinase, while the mixture of them revealed a high positive increasing in the amount and activity of chitinase. On the opposite trend, phenoloxidase enzyme of treated larvae increased by action of chlorpyrifos, followed by camphor, while the mixture of them showed a negative decrease when comparing with the control.     

Multi-biomarker responses after exposure to organophosphates chlorpyrifos in the freshwater mussels Unio tigridis and snails Viviparous benglensis

Effects of chlorpyrifos (CPF) on soft tissues of mollusks, Unio tigridis and Viviparous benglensis, have not been studied for biochemical and molecular traits. Therefore, the changes of antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)), malondialdehyde (MDA), acetylcholinesterase (AChE), and DNA damage in these mollusks were assessed during 21-day exposure to three concentrations of CPF. The results showed that SOD and CAT enzymes in the two mollusk species decreased with highest CPF concentration, while MDA significantly increased with highest CPF concentration. AChE concentrations also showed a clear reduction in soft tissues of both mollusks. DNA damage parameters showed significant differences between controls and three CPF concentrations for each parameter measured in the digestive gland of U. tigridis; and for V. bengalensis significant differences were observed between controls and highest two concentrations of CPF for comet length and tail length. CPF has the ability to prevent reproduction status for the snail V. bengalensis compared to the controls. In this study, we can conclude from the significant changes occurring in the concentrations of CAT, SOD, MDA, AChE, and DNA damage that the concentrations of these biomolecules in the soft tissues of the mussel and snail can be considered suitable biomarkers for a sublethal exposure and/or effects of CPF at the tested concentrations, and we can then use it in biomonitoring of water bodies.     

Trade‐off between thermal tolerance and insecticide resistance in Plutella xylostella

Fitness costs associated with resistance to insecticides have been well documented, usually at normal temperature conditions, in many insect species. In this study, using chlorpyrifos‐resistant homozygote (R_R) and chlorpyrifos‐susceptible homozygote (S_S) of resistance ace1 allele of Plutella xylostella (DBM), we confirmed firstly that high temperature experience in pupal stage influenced phenotype of wing venation in insecticide‐resistant and insecticide‐susceptible Plutella xylostella, and S_S DBM showed significantly higher thermal tolerance and lower damages of wing veins under heat stress than R_R DBM. As compared to S_S DBM, R_R DBM displayed significantly lower AChE sensitivity to chlorpyrifos, higher basal GSTs activity and P450 production at 25°C, but higher inhibitions on the enzyme activities and P450 production as well as reduced resistance to chlorpyrifos under heat stress. Furthermore, R_R DBM displayed significantly higher basal expressions of hsp69s, hsp72s, hsp20, hsp90, Apaf‐1, and caspase‐7 at 25°C, but lower induced expressions of hsps and higher induced expressions of Apaf‐1, caspase‐9, and caspase‐7 under heat stress. These results suggest that fitness costs of chlorpyrifos resistance in DBM may partly attribute to excess consumption of energy caused by over production of detoxification enzymes and hsps when the proteins are less demanded at conducive environments but reduced expressions when they are highly demanded by the insects to combat environmental stresses, or to excess expressions of apoptotic genes under heat stress, which results in higher apoptosis. The evolutionary and ecological implications of these findings at global warming are discussed.     

螺旋粉虱的田间抗药性监测及其对毒死蜱的抗性风险评估

【背景】螺旋粉虱是新入侵中国海南的一种危险性害虫,化学防治是目前最主要的防治手段和应急措施。【方法】采用POTTER喷雾法监测了海南各地理种群螺旋粉虱对毒死蜱、丙溴磷、高效氯氰菊酯、高效氯氟氰菊酯、吡虫啉、啶虫脒和阿维菌素等7种药剂的抗性水平,并运用Tabashnik域性状分析法估算了螺旋粉虱对毒死蜱的抗性现实遗传力。【结果】螺旋粉虱对各药剂均处于抗性敏感阶段,抗性倍数为1.03~4.29倍。螺旋粉虱对毒死蜱的抗性现实遗传力h2=0.2405;预测结果表明,当田间使用毒死蜱对螺旋粉虱的防治效果达90%时,螺旋粉虱对毒死蜱的抗性提高10倍所需代数为7.09代。田间试验表明,螺旋粉虱对毒死蜱的抗性发展速率要比模型预测缓慢。【结论与意义】本研究可为螺旋粉虱的化学防治及抗药性治理提供参考。     

Laboratory Efficacy of Chemical Repellents for Reducing Blackbird Damage in Rice and Sunflower Crops

Abstract: Nonlethal alternatives are needed to manage blackbird (Icterids) damage to rice and sunflower production in the United States. We evaluated 4 registered fungicides on rice seeds (i.e., Allegiance® FL, Thiram 42-S, Trilex®, and Vitavax® 200 preplant seed treatments) and 2 foliar pesticides on sunflower seeds (Cobalt™ insecticide and Flock Buster bird repellent) as candidate blackbird repellents. Red-winged blackbirds (Agelaius phoeniceus) preferred untreated rice relative to rice treated with Thiram (P < 0.001) and Vitavax (P < 0.001), and untreated sunflower relative to sunflower treated with Cobalt (P < 0.001). Blackbirds preferred untreated sunflower relative to sunflower treated with Flock Buster repellent on day 1 of a 4-day preference test (P < 0.001). We observed no difference in consumption of treated versus untreated rice during the Allegiance preference test (P = 0.928), and blackbirds preferred rice treated with Trilex relative to untreated rice (P = 0.003). Although repellency was positively related to tested concentrations of Thiram (P = 0.010), Trilex (P = 0.026), and Vitavax (P < 0.001), maximum repellency was < 50% during our concentration-response tests of these seed treatments. Repellency was also positively related to tested concentrations of Cobalt (P < 0.001), and we observed >80% repellency of sunflower treated with Cobalt at ≥50% of the label rate. We observed no concentration-response relationship for the Allegiance seed treatment (P = 0.341) and Flock Buster repellent (P = 0.952). We recommend implementation of supplemental field studies to compare laboratory efficacy, repellency, and chemical residues of effective avian repellents throughout periods of needed crop protection.     

毒死蜱和高效氯氰菊酯防治荔枝蝽的田间试验效果

采用害虫种群动态、虫口减退率和校正虫口减退率3个指标评价了毒死蜱及高效氯氰菊酯单独使用和复配使用对荔枝蝽的野外防治效果。结果表明:4.5%高效氯氰菊酯乳油1500倍和9%毒死蜱.高效氯氰菊酯乳油1000倍液是防治荔枝蝽象的有效配比,防治效果较好,药效持续时间较长。2种杀虫剂复配使用无增效作用,但能够降低害虫产生抗药性的风险,在荔枝蝽虫口密度较低时可考虑使用。