Development of nanoalumina dust as insecticide against Sitophilus oryzae and Rhyzopertha dominica

This study aims to characterize and improve the insecticidal activity of nanostructured alumina dusts. To accomplish these goals, multiple solution based synthesis routes utilizing standard aluminum salt precursors were utilized to synthesize three unique types of alumina dust. These were compared with regards to morphology, particle size and surface area using electron microscopy and dynamic light scattering particle size analysis. Insect toxicity of the various dusts was assessed using two insect species that are pests of stored grain, Sitophilus oryzae and Rhyzopertha dominica. The dust synthesized using a modified glycine-nitrate combustion process consistently yielded greater mortality rates, and all dust types were more effective on S. oryzae than on R. dominica, although the difference varied across dust types. The data show that insecticidal activity is dependent on particle size, particle morphology and surface area but also indicated that minimizing particle size and maximizing surface area are not the sole dominant factors influencing efficacy. This study does however suggest that pesticide dusts can be engineered through modified synthesis to better target different insect species.     

Silica aerogel and boric acid against cockroaches: External and internal action

American cockroaches, Periplaneta americana (L.), and German cockroaches, Blattella germanica (L.), ingested large quantities of powder (silica aerogel and boric acid) in the process of preening their appendages. Their crops were greatly distended by the powder, but the denticles of the armarium of the proventriculus permitted the movement of only very small quantities of silica aerogel into the remainder of the alimentary tract. Boric acid likewise passed the armarium in very small quantities and apparently only in solution.There was no significant difference in the rate of mortality of both species of cockroaches confined with deposits of silica aerogel SG-68, whether their mouthparts were sealed with paraffin wax or left unsealed. Ingested powder did not increase the rate of water loss. Cockroaches with unsealed mouthparts died more rapidly on deposits of boric acid than those with sealed mouthparts, as might be expected of a toxic compound. However, cockroaches with sealed mouthparts were strikingly affected by boric acid, indicating cuticular penetration by that compound. Penetration within the integument, in the gross body contents, in the alimentary tract, and in the feces was confirmed by a boric acid flame test.     

Novel use of nanostructured alumina as an insecticide

BACKGROUND: The worldwide need to produce an inexpensive and abundant food supply for a growing population is a great challenge that is further complicated by concerns about risks to environmental stability and human health triggered by the use of pesticides. The result is the ongoing development of alternative pest control strategies, and new, lower‐risk insecticidal molecules. Among the recent technological advances in agricultural science, nanotechnology shows considerable promise, although its development for use in crop protection is in its initial stages. RESULTS: This study reports for the first time the insecticidal effect of nanostructured alumina. Two species were used as model organisms, Sitophilus oryzae L. and Rhyzopertha dominica (F.), which are major insect pests in stored food supplies throughout the world. Both species experienced significant mortality after 3 days of continuous exposure to treated wheat. Nine days after treatment, the median lethal doses (LD₅₀) observed ranged from 127 to 235 mg kg^?1. CONCLUSION: Comparison of these results with recommended rates for commercial insecticidal dusts suggests that inorganic nanostructured alumina may provide a cheap and reliable alternative for control of insect pests. This study expands the frontiers for nanoparticle‐based technologies in pest management. Further research is needed to identify its mode of action and its non‐target toxicity, and to determine the potential of other nanostructured materials as pest control options for insects. Copyright © 2010 Society of Chemical Industry     

Bioresidual and integrated pest management status of a biorational agent and a novel insecticide against whitefly and its key parasitoids

The effects of continuous exposure of the adult and crawler stages of the whitefly, Trialeurodes vaporariorum, and adult of the parasitoids Encarsia formosa and Eretmocerus eremicus to spray deposits of potassium salts of a fatty acid and diafenthiuron applied at recommended rates were evaluated. French bean, Phaseolus vulgaris Prince, plants were sprayed and the adults confined on them using modified 5 cm Petri dishes. Fresh (4 - 5-h-old) deposits of fatty acids resulted in a 10.7% mortality rate of whitefly adults and 8.0 and 10.7% mortality rates of E. formosa and E. eremicus adults respectively, while fresh deposits of diafenthiuron resulted in a 62.7% mortality rate of whitefly adults and 12.0 and 14.7% mortality rates of E. formosa and E. eremicus respectively. The mortality rate (6.9 and 69.7%) of whitefly crawlers was recorded when exposed to 24-h-old deposits of fatty acids and diafenthiuron respectively. The mortality rate declined as the deposits aged. Adult parasitoid emergence from the treated pupae was unaffected. Spray deposits of diafenthiuron were effective against whitefly for up to 2-3 weeks in comparison with fatty acids, which were effective only when sprayed. Both products were harmless to adults as well as pupae of both parasitoids irrespective of the exposure period (age of deposits) tested (IOBC Class 1). These insecticides can be included in integrated pest management strategies against whitefly with the fatty acids used on horticultural crops.     

新化合物ZJ3265对5种鳞翅目害虫的毒力及田间防效

ZJ3265{(E+Z)-2-[2-(4-氰基苯)-1-(3-三氟甲基苯)亚乙基]-N-(4-二氟甲氧基苯)联氨酰胺}是由浙江省化工研究院有限公司自主开发的缩氨基脲类新型杀虫剂。采用浸渍法测定了ZJ3265对粘虫Mythimna separata、小菜蛾Plutella xylostella和斜纹夜蛾Prodenia litura的室内杀虫毒力。结果表明,ZJ3265对粘虫、小菜蛾和斜纹夜蛾的LC50值分别为1.37(1.16~1.62)、18.53(15.13~22.10 )和15.40(11.98~18.85) mg/L。在田间用24% ZJ3265 悬浮剂处理3 d(有效剂量120 g/hm2),其对小菜蛾、斜纹夜蛾、甜菜夜蛾Spodoptera exigua和菜青虫Pieris rapae的防效分别达74.9%、76.7%、70.3%和84.4%;在试验剂量下,未观察到对作物产生药害。     

新型杀虫剂氯氟氰虫酰胺对不同鳞翅目害虫的毒力和田间防效

氯氟氰虫酰胺(ZJ4042){3-氯-N1-(2-甲基-4-七氟异丙基苯基)-N2-(1-甲基-1-氰基乙基)邻苯二甲酰胺}是由浙江省化工研究院有限公司自主开发的邻苯二甲酰胺类新型杀虫剂。采用浸渍法测定了氯氟氰虫酰胺对小菜蛾Plutella xylostella、甜菜夜蛾Spodoptera exigua、斜纹夜蛾Prodenia litura和二化螟Chilo suppressalis的室内杀虫毒力,并进行了田间药效试验。结果表明:氯氟氰虫酰胺对小菜蛾、甜菜夜蛾、斜纹夜蛾和二化螟的LC50值分别为0.046、0.072、0.071和1.95 mg/L,与氟虫双酰胺和氯虫苯甲酰胺的杀虫毒力相当。在田间用20%氯氟氰虫酰胺悬浮剂处理(有效剂量30 g/hm2),对小菜蛾、斜纹夜蛾、甜菜夜蛾及菜青虫Pieris rapae药后7 d的防效为90.1%～96.3%;对二化螟和稻纵卷叶螟Cnaphalocrocis medinalis药后15 d的防效为82.9%～90.5%;在试验剂量下,未观察到其对作物产生药害。     

Bio-efficacy of bacterial insecticide,Bacillus thuringiensis Berl. as biological control agent against snails vectors of Schistosomiasis in Egypt

The molluscicidal activity of Thuricide used as bacterial insecticide,Bacillus thuringiensis, againstBiomphalaria alexandrina andBulunus truncatus was tested.The obtained results indicate that Thuricide possess a mollus-cicidal activity against both snails species.B. truncatus was more sensitive to the action of Thuricide. However the slope function of the LC₅₀ forB. alexandrina was significantly higher than that forB. truncatus. The mortality rate of exposedB. alexandrina increased by increasing the exposure time.     

新杀虫剂HNPC-A9908对几种鳞翅目昆虫的杀虫活性

采用农药生测标准操作程序 (SOP)测定了HNPC-A9908对几种鳞翅目昆虫的毒力及其作用方式。室内生测结果表明 ,HNPC-A990 8对粘虫具有良好的杀虫活性 ,其综合毒力LC₅₀、触杀毒力LD₅₀和胃毒毒力LC₅₀分别为7 71mg/L、400×10^-3μg/头和82.34mg/L ;对斜纹夜蛾的综合毒力为 280.57mg/L。田间小区试验结果表明 ,HNPC-A9908对菜青虫表现出良好的防治效果 ,有效用药量为 10、30、50g/667m² 时 ,药后 1、3、7、10d的防治效果分别为 88.18%～98.39%、100%、96.79%～100%和 88.16%～100%。此外 ,HNPC-A9908对甜菜夜蛾和棉铃虫也具有一定的防治效果     

Esterase inhibitors as synergists for (+)-trans-chrysanthemate insecticide chemicals

Four synergists are used to evaluate the relative contribution of esterases and oxidases in the metabolism of four pyrethroids, the (+)-trans- and (+)-cis-isomers of resmethrin and tetramethrin, by five insect species and by mice. Three of these compounds are known pyrethroid synergists, S,S,S-tributyl phosphorotrithioate acting as an esterase inhibitor and piperonyl butoxide and O-(2-methylpropyl) O-(2-propynyl) phenylphosphonate acting as oxidase inhibitors. The fourth synergist, 1-naphthyl N-propylcarbamate, is an esterase inhibitor selected by screening 65 candidate esterase and oxidase inhibitors for maximal potency in synergizing the toxicity of trans-resmethrin to milkweed bugs. Naphthyl propylcarbamate synergizes the toxicity of trans-resmethrin and -tetramethrin to milkweed bugs, cockroaches, houseflies, cabbage loopers, and mealworms but not to mice. The persistence of trans-resmethrin in milkweed bugs treated by injection is increased by the esterase inhibitors while that of cis-resmethrin is increased by the oxidase inhibitors. The optimal synergist varies with the species and the pyrethoid, being related to both the nature of the pyrethroid alcohol moiety and the trans- or cis-configuration of the acid moiety. This probably results from species variations in the relative significance of esterases and oxidases in pyrethroid detoxification.     

Adipokinetic hormone (Pyrap‐AKH) enhances the effect of a pyrethroid insecticide against the firebug Pyrrhocoris apterus

BACKGROUND: Adipokinetic hormones (AKHs) are insect neuropetides controlling stress situations including those elicited by insecticide treatment. The effect of Pyrap‐AKH on the mortality of the firebug Pyrrhocoris apterus (L.) treated with the insecticide permethrin (Ambush 25 EC) was studied. RESULTS: Coinjection of 50 ng permethrin with 80 pmol Pyrap‐AKH induced a significant 2.3‐fold increase in bug mortality compared with the insecticide alone. The results were confirmed by topical coapplication of both agents (400 ng and 80 pmol respectively). Injections of 50 and 100 ng permethrin elicited a significant increase in the AKH level in CNS and the haemolymph. The results indicate an involvement of AKH in stress response to permethrin. The enhanced effect of insecticide by AKH treatments probably results from the stimulatory role in bug metabolism: carbon dioxide production was increased 3.5‐ and 2.5‐fold respectively 1 and 3 h after permethrin treatment, and 4.3‐ and 3.4‐fold after the permethrin plus AKH cotreatment, compared with the control. CONCLUSION: The elevation of metabolism could intensify the permethrin action by its faster penetration into tissues and by stimulation of biochemically active cells, and could be a reason for enhanced action of permethrin after its cotreatment with Pyrap‐AKH. Copyright © 2009 Society of Chemical Industry     

Biological characterization of sulfoxaflor, a novel insecticide

BACKGROUND: The commercialization of new insecticides is important for ensuring that multiple effective product choices are available. In particular, new insecticides that exhibit high potency and lack insecticidal cross‐resistance are particularly useful in insecticide resistance management (IRM) programs. Sulfoxaflor possesses these characteristics and is the first compound under development from the novel sulfoxamine class of insecticides. RESULTS: In the laboratory, sulfoxaflor demonstrated high levels of insecticidal potency against a broad range of sap‐feeding insect species. The potency of sulfoxaflor was comparable with that of commercial products, including neonicotinoids, for the control of a wide range of aphids, whiteflies (Homoptera) and true bugs (Heteroptera). Sulfoxaflor performed equally well in the laboratory against both insecticide‐susceptible and insecticide‐resistant populations of sweetpotato whitefly, Bemisia tabaci Gennadius, and brown planthopper, Nilaparvata lugens (Stål), including populations resistant to the neonicotinoid insecticide imidacloprid. These laboratory efficacy trends were confirmed in field trials from multiple geographies and crops, and in populations of insects with histories of repeated exposure to insecticides. In particular, a sulfoxaflor use rate of 25 g ha^?1 against cotton aphid (Aphis gossypii Glover) outperformed acetamiprid (25 g ha^?1) and dicrotophos (560 g ha^?1). Sulfoxaflor (50 g ha^?1) provided a control of sweetpotato whitefly equivalent to that of acetamiprid (75 g ha^?1) and imidacloprid (50 g ha^?1) and better than that of thiamethoxam (50 g ha^?1). CONCLUSION: The novel chemistry of sulfoxaflor, its unique biological spectrum of activity and its lack of cross‐resistance highlight the potential of sulfoxaflor as an important new tool for the control of sap‐feeding insect pests. Copyright © 2010 Society of Chemical Industry     

Canola oil as a kairomonal attractant of rangeland grasshoppers: An economical liquid bait for insecticide formulation

Laboratory experiments and field trials demonstrated that canola oil, which is rich in fatty acids that are kairomonal cues in cannibalism, is an effective attractant of rangeland grasshoppers and a suitable oil-based carrier for insecticides. Laboratory-based olfactory tests revealed a significant, positive chemotaxis of Melanoplus sanguinipes in response to canola oil and olive oil mixtures. Small-scale field tests made by airbrush applications of 5 ml of canola oil (equivalent to 500 l/ha) to centres of aluminium rings (0.1 m²