Sadof Clifford S, Linkimer Mildred, Hidalgo Eduardo, Casanoves Fernando, Gibson Kevin, Benjamin Tamara J
Entomology Department, Purdue University, West Lafayette, IN 47907-2089, USA.
Environ Entomol. 2014 Apr;43(2):320-7. doi: 10.1603/EN13236. Epub 2014 Feb 10.
Weeds and their influence on pest and natural enemy populations were studied on a commercial ornamental farm during 2009 in the Atlantic Zone of Costa Rica. A baseline survey of the entire production plot was conducted in February, along a 5 by 5 m grid to characterize and map initial weed communities of plants, cicadellids, katydids, and armored scales. In total, 50 plant species from 21 families were found. Seven weed treatments were established to determine how weed manipulations would affect communities of our targeted pests and natural enemies. These treatments were selected based on reported effects of specific weed cover on herbivorous insects and natural enemies, or by their use by growers as a cover crop. Treatments ranged from weed-free to being completely covered with endemic species of weeds. Although some weed treatments changed pest abundances, responses differed among arthropod pests, with the strongest effects observed for Caldwelliola and Empoasca leafhoppers. Removal of all weeds increased the abundance of Empoasca, whereas leaving mostly cyperacaeous weeds increased the abundance of Caldwelliola. Weed manipulations had no effect on the abundance of katydid and scale populations. No weed treatment reduced the abundance of all three of the target pests. Differential responses of the two leafhopper species to the same weed treatments support hypotheses, suggesting that noncrop plants can alter the abundance of pests through their effects on arthropod host finding and acceptance, as well as their impacts on natural enemies.
2009年，在哥斯达黎加大西洋地区的一个商业观赏植物农场，对杂草及其对害虫和天敌种群的影响进行了研究。2月，沿着一个5×5米的网格对整个生产地块进行了基线调查，以描述和绘制植物、叶蝉、螽斯和盾蚧的初始杂草群落。总共发现了来自21个科的50种植物。设立了七种杂草处理方式，以确定杂草控制措施如何影响我们目标害虫和天敌的群落。这些处理方式是根据特定杂草覆盖对食草昆虫和天敌的报道影响，或种植者将其用作覆盖作物的情况来选择的。处理方式从无杂草到完全被当地杂草物种覆盖不等。尽管一些杂草处理方式改变了害虫的数量，但节肢动物害虫的反应各不相同，对考德氏叶蝉和小绿叶蝉的影响最为明显。清除所有杂草增加了小绿叶蝉的数量，而保留大部分莎草科杂草则增加了考德氏叶蝉的数量。杂草控制措施对螽斯和盾蚧种群的数量没有影响。没有一种杂草处理方式能降低所有三种目标害虫的数量。两种叶蝉对相同杂草处理方式的不同反应支持了这样的假设，即非作物植物可以通过对节肢动物寄主寻找和接受的影响以及对天敌的影响来改变害虫的数量。
