广聚萤叶甲对广东佛冈豚草的控制作用

Control effect of common ragweed Ambrosia artemisiifolia with Ophraella communa in Fogang,Guangdong Province

广聚萤叶甲Ophraella communa是恶性入侵杂草豚草Ambrosia artemisiifolia的一种重要专一性天敌。为了评价其对广东省豚草的野外控制效果,2009和2010年分别在佛冈进行释放,试验调查了释放后的种群动态及其对豚草的控制效果。结果表明:广聚萤叶甲在广东省佛冈县可成功建立自然种群。广聚萤叶甲释放后,其虫口密度不断增加,豚草植株的死亡率也不断上升,2009年豚草死亡率低于20%,2010年叶甲对豚草的控制作用较好,豚草死亡率可达到95%以上,而大量豚草死亡后,广聚萤叶甲的虫口密度又急剧下降。广聚萤叶甲种群扩张与气象因子有密切关系,温度偏低是5～6月广聚萤叶甲的种群数量难以扩增的主要因素,大雨频繁和光照偏少也一定程度上限制了其种群增长,7～8月是广聚萤叶甲种群激增的关键时期,此时其种群数量急剧增加。

Ophraella communa LeSage is an important natural enemy of the invasive weed Ambrosia arte- misiifolia Linn. In order to evaluate the field control effect of O. communa against A. artemisiifolia in Guangdong Province, the natural enemy was released in Fogang, population dynamic of O. communa and control effect of A. artemisiifolia in the field were studied through investigation in 2009 and 2010. The resuhs showed that O. communa was able to establish local population in Fogang, Guangdong Province Population density of O. communa increased rapidly and mortality of ragweed plants rose after releasing the natural enemy. The field control effect of O. communa against common ragweed in 2010 was better than in 2009, and the mortality of A. artemisiifolia was over 95% in 2010, but less than 20% in 2009. The population density of O. communa decreased sharply after mass death of ragweed. Population devel- opment of the beetle was closely correlated with meteorological factors. Low temperature was main factor which led to low population of O. communa in May and June, and heavy rainfall, short sunshine might limit its population reproduction to some extent, while the beetle was rapidly increased to a higher level in the key period of reproduction between July and August.