Despite potential negative interactions between biological control agents, the release of multiple agents against invasive alien weeds is often justified. The leaf-feeding beetle Mada polluta Mulsant (Coleoptera: Coccinellidae), released against Tecoma stans (L.) Juss ex Kunth var. stans in South Africa, has so far been unable to contain the weed. Consequently, the root-feeding flea beetle Heikertingerella sp. (Coleoptera: Galerucinae) was introduced to complement M. polluta. The effects of the interaction between the two beetles on their performance and on the target weed were studied on potted T. stans plants in a quarantine glasshouse to assess whether they were additive, synergistic or negative. There was no significant difference in the percentage survival of the P1 adults of either beetle when tested alone or in combination. Mada polluta produced significantly more F1 adult progeny than Heikertingerella sp. when tested alone, while both beetles produced significantly fewer offspring when tested in combination. Leaf damage by M. polluta alone was higher than that caused by Heikertingerella sp. alone, but in combination was not significantly higher than damage by M. polluta alone. Although both beetles on their own caused a significant reduction in leaf density relative to the control, leaf density was significantly lower when in combination. Despite significant reductions in plant height relative to the control, the differences between the three beetle treatments were not significant. Although competitive interactions caused a trade-off between agent proliferation and their impact on the growth of T. stans, these data need to be confirmed in the field.

尽管生物防治剂之间存在潜在的负面相互作用，但通常有理由证明多种药物可针对入侵性外来杂草进行释放。喂食Tecoma stans（L.）Juss ex Kunth var的以叶为食的甲虫Mada polluta Mulsant（鞘翅目：Coccinellidae）。到目前为止，南非的stans尚无法遏制杂草。因此，生根的跳蚤甲虫Heikertingerella sp.。引入了鞘翅目（鞘翅目：Galerucinae）来补充M. polluta。在盆栽T. stans上研究了两个甲虫之间的相互作用对其性能和目标杂草的影响。隔离温室中的植物来评估它们是加性的，协同的还是阴性的。单独或组合测试时，甲虫的P1成虫的存活百分比没有显着差异。Mada polluta比Heikertingerella sp产生的F1成虫后代明显更多。当单独测试时，两个甲虫组合测试时产生的后代明显减少。单独的M. polluta造成的叶片伤害高于Heikertingerella sp。造成的伤害。单独使用，但组合使用的污染并没有明显高于M. polluta造成的破坏独自的。尽管两个甲虫都相对于对照导致叶片密度显着降低，但组合使用时，叶片密度显着降低。尽管相对于对照，植物高度显着降低，但三种甲虫处理之间的差异并不显着。尽管竞争性相互作用导致了病原菌的扩散及其对锡霉菌生长的影响之间的平衡，但是这些数据需要在现场进行确认。