Sequeira R V, Shields A, Moore A, De Barro P
Plant Science, Department of Primary Industries and Fisheries, Locked Bag 6, Emerald, Queensland, 4720 Australia.
Bull Entomol Res. 2009 Aug;99(4):325-35. doi: 10.1017/S000748530800638X. Epub 2008 Dec 9.
Bemisia tabaci, biotype B, commonly known as the silverleaf whitefly (SLW) is an alien species that invaded Australia in the mid-90s. This paper reports on the invasion ecology of SLW and the factors that are likely to have contributed to the first outbreak of this major pest in an Australian cotton cropping system. Population dynamics of SLW within whitefly-susceptible crop (cotton and cucurbit) and non-crop vegetation (sowthistle, Sonchus spp.) components of the cropping system were investigated over four consecutive growing seasons (September-June) 2001/02-2004/05 in the Emerald Irrigation Area (EIA) of Queensland, Australia. Based on fixed geo-referenced sampling sites, variation in spatial and temporal abundance of SLW within each system component was quantified to provide baseline data for the development of ecologically sustainable pest management strategies. Parasitism of large (3rd and 4th instars) SLW nymphs by native aphelinid wasps was quantified to determine the potential for natural control of SLW populations. Following the initial outbreak in 2001/02, SLW abundance declined and stabilised over the next three seasons. The population dynamics of SLW is characterised by inter-seasonal population cycling between the non-crop (weed) and cotton components of the EIA cropping system. Cotton was the largest sink for and source of SLW during the study period. Over-wintering populations dispersed from weed host plant sources to cotton in spring followed by a reverse dispersal in late summer and autumn to broad-leaved crops and weeds. A basic spatial source-sink analysis showed that SLW adult and nymph densities were higher in cotton fields that were closer to over-wintering weed sources throughout spring than in fields that were further away. Cucurbit fields were not significant sources of SLW and did not appear to contribute significantly to the regional population dynamics of the pest. Substantial parasitism of nymphal stages throughout the study period indicates that native parasitoid species and other natural enemies are important sources of SLW mortality in Australian cotton production systems. Weather conditions and use of broad-spectrum insecticides for pest control are implicated in the initial outbreak and on-going pest status of SLW in the region.
烟粉虱B型生物型，通常被称为银叶粉虱（SLW），是一种外来物种，于90年代中期入侵澳大利亚。本文报告了银叶粉虱的入侵生态学以及可能导致这种主要害虫在澳大利亚棉花种植系统中首次爆发的因素。在澳大利亚昆士兰州翡翠灌区（EIA）连续四个生长季节（2001/02 - 2004/05年9月至6月），对粉虱易感作物（棉花和葫芦科作物）以及种植系统中的非作物植被（苦苣菜，苦苣菜属）中的银叶粉虱种群动态进行了调查。基于固定的地理参考采样点，对每个系统组成部分内银叶粉虱的时空丰度变化进行了量化，以提供生态可持续害虫管理策略制定的基线数据。对本地蚜小蜂对大型（3龄和4龄）银叶粉虱若虫的寄生情况进行了量化，以确定银叶粉虱种群自然控制的潜力。在2001/02年首次爆发后，银叶粉虱的丰度在接下来的三个季节中下降并稳定下来。银叶粉虱的种群动态特征是EIA种植系统中非作物（杂草）和棉花组成部分之间的季节性种群循环。在研究期间，棉花是银叶粉虱最大的容纳库和来源。越冬种群在春季从杂草寄主植物源扩散到棉花，随后在夏末和秋季反向扩散到阔叶作物和杂草。一项基本的空间源 - 汇分析表明，在整个春季，靠近越冬杂草源的棉田中的银叶粉虱成虫和若虫密度高于较远棉田。葫芦科作物田不是银叶粉虱的重要来源，似乎对该害虫的区域种群动态贡献不大。在整个研究期间，若虫阶段的大量寄生表明本地寄生蜂物种和其他天敌是澳大利亚棉花生产系统中银叶粉虱死亡的重要来源。天气条件和用于害虫防治的广谱杀虫剂与该地区银叶粉虱的首次爆发和持续的害虫状况有关。
