CT—43乳剂防治几种蔬菜害虫的应用效果初报

应用CT—43双毒乳剂防治小菜蛾,菜青虫和豆荚螟有较好的防治效果。以500倍稀释液防治菜青虫的平均防效为93.9％,防治小菜蛾的平均防效为84.8％,防治豆荚螟的平均防效为83.2％,对棉铃虫的防治效果为86.5％。防治效果受虫龄和气温的影响较大。CT—43双毒乳剂对斜纹夜蛾高龄幼虫防治效果欠佳。     

Cross-resistance and inheritance of resistance to Bacillus thuringiensis toxin Cry1Ac in diamondback moth (Plutella xylostella L) from lowland Malaysia

A field population of Plutella xylostella from Malaysia (SERD4) was divided into five sub-populations and four were selected (G2-G5) with the Bacillus thuringiensis insecticidal crystal (Cry) toxins Cry1Ac, Cry1Ab, Cry1Ca and Cry1Da. Bioassay at G6 gave resistance ratios of 88, 5, 2 and 3 for Cry1Ac, Cry1Ab, Cry1Ca and Cry1Da respectively compared with the unselected sub-population (UNSEL-SERD4). The Cry1Ac-selected population showed little cross-resistance to Cry1Ab, Cry1Ca and Cry1Da, (3-, 2- and 3-fold compared with UNSEL-SERD4), whereas the Cry1Ab-SEL sub-population showed marked cross-resistance to Cry1Ac (40-fold), much greater than Cry1Ab itself. In contrast, the Cry1Ca- and Cry1Da-SEL sub-population showed little if any cross-resistance to Cry1Ac and Cry1Ab. The mode of inheritance of resistance to Cry1Ac was examined in Cry1Ac-selected SERD4 by standard reciprocal crosses and back-crosses using a laboratory insecticide-susceptible population (ROTH). Logit regression analysis of F1 reciprocal crosses indicated that resistance to Cry1Ac was inherited as an incompletely dominant trait. At the highest dose of Cry1Ac tested, resistance was recessive, while at the lowest dose it was almost completely dominant. The F2 progeny from a back-cross of F1 progeny with ROTH were tested with a concentration of Cry1Ac that would kill 100% of ROTH. The mortality ranged between 50 and 95% in seven families of back-cross progeny, which indicated that more than one allele on separate loci were responsible for resistance to Cry1Ac.     

小菜蛾对阿维菌素的抗性机制及交互抗性研究

用叶片药膜法研究了阿维菌素抗性小菜蛾 Plutella xylostella （L.）品系 对常用药剂的交互抗性谱以及增效醚（PB）和磷酸三苯酯（TPP）的增效作用。小菜蛾对阿 维菌素与高效氯氰菊酯、溴氰菊酯、氰戊菊酯和联苯菊酯等菊酯类药剂间具有比较低的交互 抗性，对后者抗性为3～20倍，对阿维菌素的抗性为575.6倍；对氟虫脲和氟啶脲没有交互抗 性。PB和TPP对阿维菌素分别增效8.2和5.5倍，说明小菜蛾对阿维菌素的抗性可能与多功能 氧化酶（MFO）和羧酸酯酶有关。通过差光谱技术测定了阿维菌素抗性和敏感小菜蛾细胞色 素P450的含量，抗性品系是敏感品系的1.38倍。     

小菜蛾抗性稳定性及抗性治理对策研究

试验表明，福州地区田间小菜蛾已对有机磷、氨基甲酸酯及拟除虫菊酯产 生高抗性。脱离选择压力3代后，小菜蛾的抗性水平迅速下降。Bt预处理可提高抗性和敏感小菜蛾幼虫 对有机磷的敏感性，尤其对抗性小菜蛾增效极显著，对敏感小菜蛾AChE的 Ki值则影响不 大。据此提出在抗性治理中，应轮用或换用不同毒理机制的杀虫剂，且其间隔至少为2～3代。     

小菜蛾弯尾姬蜂室内批量繁殖的技术

报道小菜蛾弯尾姬蜂室内批量繁殖工艺技术。实验室温度：20℃－25℃，光照：L：D12：12，相对温度：65％－70％，40m^2温室面积用于栽培甘蓝。在此条件下，每周可生产2000头－3000头小菜蛾弯尾姬蜂，可田间释放寄生蜂防治小菜蛾15亩－20亩。     

对小菜蛾高毒的苏云金杆菌菌株筛选试验初报

从田间自然死亡的小菜蛾虫尸中分离到Ｂ．ｔ．９４１９茵株，经复壮选育及摇瓶考核，在自选培养基上生长良好，２４ｈ孢子开始脱落形成晶体，３６ｈ全部形成晶体。晶体大、宽棱形、角尖。４８ｈ发酵液含菌量为３５亿／ｍＬ。经发酵液对小菜蛾毒力测定，４８ｈＬＣ_５０：对照ＨＤ－１含菌量为２７４ｍＬ／Ｌ，而９４１９仅１２４ｍＬ／Ｌ。     

苍耳等药用植物提取物对小菜蛾的拒食作用和产卵忌避效果

室内采用叶碟法,研究苍耳(Xanthium sibiricumPetril)等8种药用植物乙醇提取物对小菜蛾(Plutel-la xylostella)的拒食和产卵忌避活性。结果表明,苍耳(果实)、雷公藤(根)和商陆(根)乙醇提取物对小菜蛾4龄幼虫的取食均有较强的抑制作用,选择性拒食率分别为86.16%、49.06%和43.82%;非选择性拒食效果仍以苍耳(果实)提取物最好,达45.23%。选择性产卵忌避率以雷公藤(根)提取物为最高(69.52%),其次是苍耳(果实)和山苍树(枝叶)提取物,分别为62.50%和57.72%,雷公藤(根)、商陆(根)、窃衣(茎叶)和苍耳(果实)的非选择性产卵忌避作用均在77%以上。苍耳和雷公藤提取物在对小菜蛾的拒食和产卵忌避的各测试中,均表现较强活性。     

小菜蛾γ- 氨基丁酸受体基因片段的克隆、表达及特征分析

 利用反转录多聚酶链式反应(RT-PCR) 对小菜蛾( Plutella xylostella ) 的γ - 氨基丁酸a(GABAa) 受体基因cDNA片段进行了克隆和序列分析。通过简并性上游引物和下游引物扩增出小菜蛾GABAa受体基因248 bp的cDNA片段。该cDNA基因片段的氨基酸与已报道的烟芽夜蛾(Heliothis viresce)的GABAa受体基因氨基酸序列同源性为100%。以GABAa受体基因片段为基础, 构建了优化的半定量RT-PCR法, 以18S rRNA为内标, 研究小菜蛾不同组织以及不同发育阶段GABAa受体基因表达的差异。结果表明, GABAa受体基因在头部表达量最高, 胸部次之, 腹部最低; 在不同发育阶段的表达量差异不大。     

1.5%甲氨基阿维菌素苯甲酸盐乳油防治小菜蛾、甜菜夜蛾田间药效试验

田间试验表明,1．5％甲氨基阿维菌素苯甲酸盐乳油对小菜蛾和甜菜夜蛾有良好的防治效果,2 000-3 000倍液药后10d防效仍分别达80％以上。     

香泽兰提取物微胶囊剂对小菜蛾产卵驱避作用研究

试验观察了创制的香泽兰提取物微胶囊剂对小菜蛾成虫产卵的驱避作用。室内测试结果表明香泽兰提取物微胶囊剂对小菜蛾产卵具明显的驱避活性,随着使用浓度升高而驱避活性逐渐增强,处理后2d,500～4000mg/kg时小菜蛾着卵量分别降低了67%～91%;随着处理时间延长驱避作用逐渐下降,但持效期较长,处理6d后2000mg/kg驱避效果仍可达到84%。田间使用香泽兰提取物微胶囊剂防治小菜蛾产卵的驱避作用好、持效期长,使用8d后各浓度效果均可达到80%以上,最高可达94%。