褐稻虱生物型田间监测技术的研究

褐稻虱田间群体各个体在同一水稻品种上的蜜露分泌量有很大差别。结合蜜露分泌量和群体建立2种方法进行的田间监测结果表明:广东省广州市石牌地区和增城县农田的褐稻虱属生物型1。采用单一的蜜露分泌量测定法不能准确反映褐稻虱群体中各个体的生物型属性。因此,在进行田间生物型监测时应结合使用其它抗性指标,其中群体建立试验是一种省时、省工、准确的监测方法。     

五种林木果树上的小穴壳菌的病原相关性研究

将从苹果、枣、板栗、杨树、泡桐上分离得到的5株聚生小穴壳菌(Dothiorella gregaria Sacc.)经人工交互接种,形态特征观察及生物学特性、菌丝融合、酯酶同工酶测定,证明该5株小穴壳菌之间有差异,但具有相同的种的遗传物质,在5种寄主上可以相互侵染,认为在种内应存在有专化型。     

Hap4型棉蚜取食西葫芦后的寄主适应性变化

棉蚜寄主间转移是常见的现象,在寄主转移过程中的寄主适应能力转变是其重要的生物学特性。为了解棉蚜取食西葫芦不同世代后,对其他寄主适应能力的转变,探究取食经历对棉蚜寄主适应性变化的影响,本试验利用寄主转接试验,将采自棉花上的Hap4型棉蚜转接到西葫芦上,分别测定取食西葫芦不同世代后,对棉花、黄瓜和西葫芦的适应能力。结果显示,随着取食西葫芦代数的增加,Hap4型棉蚜对原寄主棉花的适应性逐渐降低。Hap4型棉蚜取食西葫芦一代后就对黄瓜有良好的寄主适应性,并呈现较为稳定的趋势。Hap4型棉蚜对西葫芦的寄主适应性随着在西葫芦上取食代数的增加而降低,但强于在原寄主上的寄主适应性。除此之外,本试验也发现取食西葫芦后的Hap4型棉蚜的寄主适应性表现为黄瓜>西葫芦>棉花。植食性昆虫的取食经历影响其寄主适应能力,Hap4型是棉蚜主要的生物型之一,其取食经历直接影响其寄主适应性,研究结果为生产中作物布局及棉蚜的生态调控技术应用提供理论基础。     

Lack of fitness costs associated with pyriproxyfen resistance in the B biotype of Bemisia tabaci

BACKGROUND: The insect growth regulator pyriproxyfen has provided effective control of the whitefly Bemisia tabaci Gennadius in many countries. Here, whether or not fitness costs were associated with pyriproxyfen resistance in a laboratory‐selected resistant strain (QC02‐R) of the B biotype was determined. RESULTS: Mortality caused by pyriproxyfen and fitness traits over time were measured in unselected and selected hybrid strains, which were created by crossing individuals of the resistant strain with individuals of a susceptible strain. Fitness costs were not associated with resistance in QC02‐R, as mortality caused by pyriproxyfen did not increase over time in unselected hybrid strains and fitness traits were similar in unselected and selected hybrid strains. Using a new method to examine the inheritance of resistance, based on data from fitness cost experiments, it was estimated that pyriproxyfen resistance is controlled by two loci in the QC02‐R strain. CONCLUSION: The lack of fitness costs associated with pyriproxyfen resistance could promote the evolution of resistance in field populations with similar traits to QC02‐R. Copyright © 2008 Society of Chemical Industry     

Coactivity of sulfide ingredients: a new perspective of the larvicidal activity of garlic essential oil against mosquitoes

BACKGROUND: The activity of several garlic oil ingredients against Culex pipiens L. larvae was studied. In addition to diallyl sulfide (DS) and diallyl disulfide (DDS), the garlic oils used included one essential oil (EO) and two semi‐synthetic garlic essential oils (SSGEO1 and SSGEO2), which resulted from the enrichment of EO with DS and DDS standards respectively. The oils were compared with respect to their toxicity. RESULTS: The chemical composition of the tested oils was evaluated by means of gas chromatography–mass spectrometry. Experimental data from the tested samples revealed high toxicity. In detail, DDS (6.09 mg L^?1) was the most active, followed by SSGEO2 (7.05 mg L^?1) and EO (8.01 mg L^?1), while SSGEO1 and DS were relatively inactive. CONCLUSION: The addition of DDS to EO did not change the toxic effect of the essential oil, whereas the presence of DS in excess produced an enriched essential oil with low toxicity. Furthermore, the antagonistic effect of DS and DDS against the other components of EO was shown by the application of two equations obtained from the literature. Their larvicidal performances were correlated, for the first time, with their detailed chemical composition. Data analysis strongly indicated the toxicity of the other EO sulfur ingredients. Copyright © 2008 Society of Chemical Industry     

桃蚜体色生物型种群动态研究

1993-1995年连续3a对桃蚜在7种主要寄生植物-桃树,烟草,油菜,杏树,甘蓝,白菜和萝卜上不同时期4种体色生物型（红色型,绿色型,黄绿色型和褐色型）种群消长动态进行了系统调查。并对优势生物型的优势度与优势集中性时间变化格局作了剖析。     

耐水星、农得时雨久花生物型杂草的发生及防治

研究了不同生物型雨久花对水星和农得时的耐性差异．耐性生物型的GR50比感性生物型高2．42和2．80倍．禾大壮和西草净的配合使用对耐性雨久花的鲜重防效达95％以上，丁草胺和扑草净、西草净、扑草净的鲜重防效达80％以上．     

四川省姜瘟病菌生物型鉴定初报

根据Hayward鉴定青枯菌生物型的方法 ,对四川雅安、乐山、眉山、简阳、温江、宜宾等六地分离得到的 5 5个姜青枯菌菌株进行鉴定 ,结果表明 :四川省姜青枯菌共有Ⅰ型、Ⅲ型、Ⅳ型和Ⅴ型等 4个生物型。其中以Ⅲ型和Ⅰ型为主要的生物型 ,分别占总样的 5 8 1 %和 2 7 3%。     

棉田间作蔬菜防治B型烟粉虱

在室内用"Y"形嗅觉仪以棉花为对照测定了B型烟粉虱对6种蔬菜的选择性,不同蔬菜对B型烟粉虱诱集率的大小为:菜豆花生茴香芫荽芹菜韭菜。除了烟粉虱对菜豆的选择系数为正值外,烟粉虱对其他几种蔬菜的选择系数均为负值。6种蔬菜与棉花间作,结果表明:间作棉花上的烟粉虱成虫数量与对照存在显著差异。除了间作菜豆棉花上的烟粉虱成虫数量比对照增加外,间作花生、茴香、芫荽、芹菜、韭菜的棉花上烟粉虱成虫数量比对照均减少。     

新疆B型烟粉虱对不同类型杀虫剂的抗性与分析

应用浸叶法研究了新疆B型烟粉虱对4类不同作用机制杀虫剂的抗药性。结果表明,被测种群对氯氰菊酯和联苯菊酯的抗性指数分别为2100～6200和1000～2200,属于高抗性;对氯化烟酰类杀虫剂产生了低至中等抗性,对吡虫啉的抗性指数为4～86,且抗性指数呈上升趋势,对噻虫嗪的抗性指数为10～22,对啶虫脒的敏感性最佳;对昆虫生长调节剂吡丙醚的抗性指数为22～54;对阿维菌素仍然表现敏感。由此认为,拟除虫菊酯类杀虫剂在新疆已不再适用于烟粉虱的防治,而对受抗药性影响较小的氯化烟酰类杀虫剂(如吡虫啉、噻虫嗪和啶虫脒)、昆虫生长调节剂吡丙醚以及阿维菌素等新型杀虫剂,仍然可以限制性地在不同化合物间交替使用。