5种药剂对异色瓢虫安全性测定试验

在室内进行了5种杀虫剂对异色瓢虫的毒力测定试验,结果为高效氯氰菊酯毒力最高,其次为三氟氯氰菊酯,毒死蜱居中,啶虫脒和阿维菌素最低.拟除虫菊酯类杀虫剂对异色瓢虫的毒力最大,有机磷类杀虫剂居中,氯化烟碱类和生物源类杀虫剂的毒力最小,因此,在对蚜虫进行综合防治的过程中,选用氯化炯碱类和生物源类杀虫剂比较适宜,可避免对其天敌异色瓢虫造成较大伤害.     

杏仁蜂成虫习性观察及防治药剂筛选

[目的]试验9种杀虫剂对杏仁蜂的灭杀效果,筛选出适宜的化学防治药剂.[方法]2011年室内外观察杏仁蜂的习性,进行9种杀虫剂对比试验.[结果]杏仁蜂在泰安市的成虫发生期为4月中下旬,羽化率为60.9％,成雌雄比为1.5∶1,成虫具有趋光和趋黄色习性.室内外9种杀虫剂对比试验结果表明:2.5％高效氯氟氰菊酯EC1.25 mg/L对杏仁蜂成虫触杀效果达100％,成虫发生期喷洒1次的防治效果为57.6％,高于其他试验药剂的防效;1.8％阿维菌素EC 0.45 mg/L对成虫无触杀活性,但田间防治效果仅次于高效氯氟氰菊酯.[结论]建议在杏仁蜂成虫发生期进行化学防治,适宜杀虫剂为高效氯氟氰菊酯和阿维菌素,连续喷洒2次.     

5种杀虫剂对入侵我国美洲棘蓟马成虫室内毒力测定

[目的]美洲棘蓟马Echinothrips americanus Morgan是国内新报道的外来种类,可对多种温室作物造成危害.采用玻璃残留处理法测定了5种杀虫剂对美洲棘蓟马成虫的毒力.[结果]5种杀虫剂对美洲棘蓟马成虫的毒力排序为毒死蜱＜啶虫脒＜阿维菌素＜高效氯氰菊酯＜多杀霉素.[结论]在防治中应避免使用毒死蜱等对该虫毒性较低的杀虫剂进行防治,尽量选用毒性较高的生物源类杀虫剂多杀霉素,交替使用菊酯类和烟碱类农药.     

不同类型杀虫剂对北京地区Q型烟粉虱的毒力测定

[目的]近年来Q型烟粉虱在我国许多地区危害严重,但关于Q型烟粉虱对杀虫剂的抗性研究甚少.采用浸叶生测法分别测定了7种杀虫剂对北京地区Q型烟粉虱成虫的毒力.[结果]结果表明7种药剂对烟粉虱成虫的毒力排序:阿维菌素>甲氨基阿维菌素苯甲酸盐>多杀霉素>啶虫脒>吡虫啉>毒死蜱>敌敌畏.[结论]在北京地区防治烟粉虱时应选用敏感性高的抗生素类杀虫剂,交替使用新烟碱类农药,限制使用有机磷类农药.     

烟碱类杀虫剂对异色瓢虫搜寻猎物行为影响的评价

利用Y形嗅觉仪观测了烟碱类杀虫剂影响异色瓢虫对苹果叶片与绣线菊蚜、苹瘤蚜复合体的选择行为.结果表明,在正常生长状况下,苹果叶片释放的挥发物对异色瓢虫无明显引诱作用,而苹果叶片受到蚜虫危害后所释放的挥发性次生物质则对异色瓢虫有明显的招引作用;在杀虫剂处理后,烟碱类杀虫剂并不会影响异色瓢虫的搜索行为.     

黄荆提取物对几种害虫的杀虫活性

研究了黄荆种子二氯甲烷提取物对5种害虫的杀虫活性以及对天敌异色瓢虫的安全性。结果表明：黄荆提取物对菜青虫、小菜蛾、麦长管蚜和桃蚜都有较高的杀虫活性，尤其是对菜青虫的活性最高，稀释100倍，处理4龄幼虫死亡率可达93．3％。但对大猿叶甲的杀虫活性则很低。黄荆提取物对异色瓢虫幼虫有一定的杀虫活性，但对其成虫无任何影响。本研究结果为开发利用这一新的杀虫植物资源提供了依据。     

辛硫磷与阿维菌素对桉树枝瘿姬小蜂的混配增效作用

[目的]研究不同作用机制的杀虫剂混配对桉树枝瘿姬小蜂增效作用。[方法]采用玻管药膜法测定辛硫磷与阿维菌素混用对桉树枝瘿姬小蜂成虫的生物活性,研究2种药剂的联合增效作用。[结果]辛硫磷与阿维菌素对桉树枝瘿姬小蜂具有一定的生物活性,并以有效成分7∶1混配,表现增效作用,共毒系数为220.38,对幼虫、蛹和成虫的校正死亡率分别为76.47%、66.67%和64.00%,优于单剂单独使用。[结论]辛硫磷与阿维菌素混用对桉树枝瘿姬小蜂有增效作用,其中以有效成分7∶1混配增效作用最好。     

2种玻璃药膜法测定速灭威对异色瓢虫的毒性比较

笔者比较了指形管药膜法和玻璃板药膜法测定速灭威对异色瓢虫的毒性结果差异。结果表明,采用指形管药膜法速灭威对异色瓢虫的半致死用量(LR50)为3.07 g a.i./hm~2;玻璃板药膜法LR50值为243 g a.i./hm~2,2种不同的玻璃药膜法对异色瓢虫的LR_50值差异达到了79倍,说明指形管药膜法测定瓢虫对农药的敏感性更强。     

8种药剂对黄蓟马的室内生物活性及田间防效

[目的]筛选防治黄蓟马的有效药剂及用量.[方法]选择8种杀虫剂,采用浸叶法对黄蓟马成虫进行室内生物活性测定,并结合防效试验进行效果验证.[结果]室内生物活性测定结果表明:25％噻虫嗪WG、10％吡虫啉WP、50％噻嗪酮SC和1.80％阿维菌素EC对黄蓟马有较高的活性.田间药效结果表明:10％吡虫啉WP 4.14 g a...     

阿维菌素在罗汉果和土壤中的残留及消解动态

[目的]利用田间农残试验方法,研究阿维菌素在罗汉果和土壤中的残留消解动态及最终残留量,为该农药在罗汉果上的合理使用提供参考依据.[方法]通过建立的超高效液相色谱法分别测定罗汉果和土壤中阿维菌素的残留量.[结果]在消解动态试验中,阿维菌素在罗汉果和土壤中的消解动态均符合一级动力学方程,半衰期分别为1.4～2.6、3.2～...     

Influence of Diet on Fecundity, Immune Defense and Content of 2-Isopropyl-3-Methoxypyrazine in Harmonia axyridis Pallas

Food type can affect all functional aspects of an insect's life. We investigated the effects of different diet regimes on life history parameters of the ladybird beetle Harmonia axyridis. Furthermore, we tested the importance of elytral color, sex, and diet on chemical and immune defense in this species. We also compared hemolymph from cohorts of H. axyridis and Coccinella septempunctata (Coleoptera: Coccinellidae) fed different diets to examine effects on the 2-isopropyl-3-methoxypyrazine (IPMP) content in these beetles. No effects of diet on the duration of larval development and on adult weight were found. We detected, however, significantly higher fecundity and oviposition rates when female H. axyridis were reared on pea aphids than when reared on eggs of Ephestia kuehniella. Males and females did not differ in their immune response. Elytral color affected both immune defense and chemical defense. The antimicrobial activity of the hemolymph differed only when morphotypes were tested against E. coli. Moreover, we observed an effect of elytral pigmentation on IPMP content. The succinea 2 type (orange without dots) had the lowest IPMP content in two out of three feeding regimes compared to the succinea 1 (orange with dots) type. Depending on diet, IPMP contents differed in both species leading to higher contents either in H. axyridis or C. septempunctata. Furthermore, aphid species ingested during larval development significantly affected IPMP content in adult beetles. These results implicate new aspects for risk assessment of H. axyridis in viticulture.     

A Well Protected Intruder: The Effective Antimicrobial Defense of the Invasive Ladybird Harmonia axyridis

The harlequin ladybird Harmonia axyridis (Coleoptera: Coccinellidae) is a polyphagous predatory beetle native to Central and Eastern Asia. Since 2007 it has established all over Central Europe. In order to elucidate which defense strategy is responsible for its high resistance to diseases, we tested hemolymph as well as eleven main components of the headspace of H. axyridis for antimicrobial activity against Gram-positive (Bacillus subtilis, B. thuringiensis ssp. tenebrionis, Micrococcus luteus) and Gram-negative bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae). While three of the volatile compounds weakly reduced the growth of microorganisms, hemolymph of adults and larvae of H. axyridis strongly inhibited the growth of Gram-positive and Gram-negative bacteria as well as yeast. Furthermore, we compared the antimicrobial activity in the hemolymph of H. axyridis and Coccinella septempunctata. Antimicrobial activity in H. axyridis was about a thousand times higher compared to hemolymph from C. septempunctata. In contrast to C. septempunctata, the antimicrobial activity in H. axyridis was present without prior challenge. Minimal inhibitory concentration (MIC) of the hemolymph of H. axyridis was lowest against E. coli and yeast followed by B. subtilis, and was highest against entomopathogenic B. thuringiensis ssp. tenebrionidae. Furthermore, MIC values of the hemolymph obtained from live beetles were significantly lower than from frozen insects. This suggests that the active antimicrobial compound is affected by freezing and subsequent thawing of the beetles. Potential implications of our findings for the competitive advantages of H. axyridis over C. septempunctata are discussed.     

3种杀虫剂不同剂型对葡萄蓟马的室内生物活性及田间防效

[目的]为明确避雨栽培葡萄上3种常用杀虫剂及不同剂型对葡萄蓟马的室内生物活性和葡萄不同生长期的田间防治效果。[方法]试验采用浸液饲喂法测定了葡萄蓟马的室内种群活性,并进行田间防效试验。[结果]3种杀虫剂对葡萄蓟马的室内生物活性啶虫脒和阿维菌素较高,吡虫啉相对较低,依次为啶虫脒EC>啶虫脒WG>阿维菌素EC>吡虫啉EC>吡虫啉WG;田间防效试验发现,在葡萄的花前期和浆果生长期啶虫脒施药后1 d的防效均在60%以上,施药后7 d啶虫脒和阿维菌素的防效均在80%~95%,而吡虫啉的防效在不同时期施用均低于80%;不同剂型间,乳油表现出相对较好的防治效果。[结论]阿维菌素和啶虫脒可推荐为避雨栽培葡萄上防治蓟马的首选药剂,2者属于不同类型杀虫剂,适宜交替使用,能降低蓟马对杀虫剂快速产生抗性的风险,应该在葡萄花期前对蓟马进行防除,防止其数量暴发。     

5％阿维菌素·噻唑膦复配型微胶囊悬浮剂制备及性能

[目的]为了降低阿维菌素和噻唑膦的分解以及对作物的药害,提高其药效,制备阿维菌素·噻唑膦复配型微胶囊悬浮剂。[方法]以甲苯二异氰酸酯(TDI)和乙二胺为反应单体,阿维菌素和噻唑膦为芯材,二甲苯为溶剂,采用界面聚合法制备微胶囊。[结果]该微胶囊的平均粒径为6.095μm,近似圆球形,表明光滑,阿维菌素和噻唑膦的包封率分别达到99.51%和80.86%,载药量分别为1.03%和4.02%,悬浮率分别为85.43%和97.74%。该微胶囊悬浮剂的缓释性能优于85%噻唑膦原药、20%噻唑膦水乳剂、1.8%阿维菌素乳油和3%阿维菌素水乳剂;该微胶囊悬浮剂具有优异的屏蔽紫外光降解性能。[结论]阿维菌素和噻唑膦通过界面聚合法微胶囊化后可以显著增强其缓释和屏蔽紫外光降解性能。     

Host plant iridoid-based chemical defense of an aphid,Acyrthosiphon nipponicus,against ladybird beetles

A Rubiaceae-feeding aphid,Acyrthosiphon nipponicus, is seldom attacked by the ladybird beetle,Harmonia axyridis. A potent deterrent against the beetle was isolated from the aphid and identified as paederoside, an iridoid glycoside originating in the aphid's host,Paederia scandens. The iridoid content was as high as 2% of the intact body weight, and a large portion was found in the cornicle secretion.     

温度对齐墩螨素毒力的影响

在室内采用浸渍玻片法和浸渍植株法分别测定了不同温度下齐墩螨素对棉红蜘蛛和水稻黑尾叶蝉的毒力。结果表明,在18℃、24℃、30℃、35℃时齐墩螨素对棉红蜘蛛的LC50值分别为0.0063、0.0027、0.0018、0.00053 mg/L,而对水稻黑尾叶蝉的LC50值分别为0.2068、0.1544、0.102 9、0.044 41 mg/L。说明齐墩螨素对昆虫的毒力属于正温度效应,即毒力随温度的升高而逐渐增强。     

Quantification of Canavanine, 2-Aminoethanol, and Cyanamide in Aphis craccivora and its Host Plants, Robinia pseudoacacia and Vicia angustifolia: Effects of These Compounds on Larval Survivorship of Harmonia axyridis

The cowpea aphid Aphis craccivora that infests the black locust Robinia pseudoacacia shows toxicity to its predator, the multicolored Asian ladybird beetle, Harmonia axyridis. In contrast, the same aphid species that infests the common vetch, Vicia angustifolia, is suitable prey for H. axyridis larvae. Previously, it was reported that the toxicity of A. craccivora infesting R. pseudoacacia was due to canavanine and 2-aminoethanol, but there was some doubt about the toxicity of these compounds and their concentrations in the aphids. In the present study, we determined the concentrations of cyanamide, canavanine, and 2-aminoethanol in A. craccivora infesting the two host plants. In the extracts of A. craccivora that infested either of the host plants, canavanine was undetectable, and 2-aminoethanol was detected at the concentration of 3.0–4.0 μg/g fresh weight. Cyanamide was detected in the extract of A. craccivora that infested R. pseudoacacia (7.7 μg/g fresh weight) but not in that infesting V. angustifolia. The toxicity of canavanine, 2-aminoethanol, and cyanamide was evaluated against H. axyridis larvae in a bioassay by using an artificial diet containing these compounds at various concentrations. Cyanamide exhibited 10–100 times stronger toxicity than canavanine and 2-aminoethanol. These results indicate that the toxicity is at least partly due to cyanamide, which is present in the toxic A. craccivora that infests R. pseudoacacia but absent from the non-toxic A. craccivora that infests V. angustifolia.     

Effect of conspecific and heterospecific feces on foraging and oviposition of two predatory ladybirds: role of fecal cues in predator avoidance

Growing evidence suggests a flow of chemical information from higher to lower trophic levels that affects foraging and oviposition of prey in response to potential risks from predators. This was investigated in two species of ladybird predators of aphids, Harmonia axyridis and Propylea japonica. H. axyridis is known to be the stronger intraguild predator and P. japonica to be the more frequent intraguild prey in interactions of these two species. These ladybirds share aphid prey on mugworts, hibiscus, and Italian ryegrasses in fields of northern Japan but largely avoid each other on the same plant. Fecal cues of these ladybird predators were found to contribute in their assessment of predation risk from conspecific and heterospecific competitors in common habitats. Gravid females of H. axyridis reduced rates of feeding and oviposition when exposed to feces of conspecifics, but not when exposed to feces of P. japonica. In contrast, gravid females of P. japonica reduced feeding and oviposition when exposed to feces of both H. axyridis and its own species. Females of both ladybird species exhibited similar behavior in response to water extracts of feces. For P. japonica, the influence of heterospecific feces was greater than that of conspecific feces. Our results demonstrate that feces of ladybirds contain odors that have the potential to deter the feeding and oviposition activities of conspecific as well as heterospecific ladybirds. Such deterrence allows these insects to avoid predation risk. Differences in responses of the two predators are discussed.     

Peramine and Lolitrem B from Endophyte-Grass Associations Cascade Up the Food Chain

Endophytic fungi in cool-season grass species produce herbivore-toxic alkaloids, which are assumed to harm higher trophic levels along food chains. Previous studies have shown fitness disadvantages for higher trophic levels that feed on aphids that were exclusively reared on perennial ryegrass (Lolium perenne) infected with the endophytic fungus Neotyphodium lolii. However, it is unknown whether the alkaloids produced by the fungus-grass association can be assimilated by plant sap-sucking insects like aphids. Using an ultra high performance liquid chromatography method combined with mass spectrometry, we provide the first evidence that the alkaloids peramine and lolitrem B are present in aphids (Rhopalosiphum padi) and in aphid predators when the aphids are reared on endophyte-infected grass. We conclude that alkaloids can enter the plant sap of the grass and are responsible for longer pupal stages of the ladybird Harmonia axyridis and for fitness disadvantages of aphids and their predators as shown in previous studies.