Sweetpotato weevil (SPW) pest management is challenging because the pest target is sub-terranean, so the application of pesticides is impractical and usually ineffective. Host plant resistance and the genetic transformation of sweetpotatoes to produce entomotoxic Bt proteins offer potential for environmentally benign pest control. Resistance can be conferred by naturally occurring hydroxycinnamic acids which protect against oviposition by adults, but these compounds are restricted to the root surface so do not protect against the cortex bound larvae where the greatest damage occurs. Resistance could be enhanced if combined with expression of Bt proteins in transformed plants, but interactions between hydroxycinnamic acids and Bt proteins remain unknown. Here the bioactivity of Cry7Aa1 protein and hydroxycinnamic acid esters was evaluated individually and in combination against SPW larvae and mortality determined. Low and high concentrations of hydroxycinnamic acid esters alone caused significantly higher mortality of both weevil species in all experiments compared to the control. SPW larval mortality was greater when tested as a combination of hydroxycinnamic acid esters and Bt protein, but this effect was additive not synergistic. Although we report no evidence of antagonistic interactions, the antifeedant effects of the plant compounds conferring host plant resistance could have reduced consumption of the Bt protein in our assays leading to a lower efficacy when combined. Further work is required to determine whether the toxic effects of Bt proteins function alongside host plant resistance in sweetpotato under field conditions.

甘薯象鼻虫（SPW）害虫管理具有挑战性，因为害虫目标是地下的，因此农药的施用是不切实际的且通常无效。寄主植物的抗药性和甘薯的遗传转化以产生具有毒性的Bt蛋白，为控制环境有害生物提供了潜力。天然存在的羟基肉桂酸可赋予抵抗力，羟基肉桂酸可防止成虫产卵，但是这些化合物仅限于根部表面，因此不能抵抗发生最大损害的皮质结合幼虫。如果将其与Bt蛋白在转化植物中的表达结合起来，可以增强抗药性，但是羟基肉桂酸与Bt蛋白之间的相互作用仍然未知。这是Cry7Aa1的生物活性分别评估蛋白质和羟基肉桂酸酯对SPW幼虫的抵抗力并确定死亡率。与对照相比，在所有实验中，单独的低浓度和高浓度的羟基肉桂酸酯都会导致两种象鼻虫的死亡率明显升高。当结合羟基肉桂酸酯和Bt蛋白进行测试时，SPW幼虫死亡率更高，但是这种效果是加和的而不是协同的。尽管我们没有报道拮抗相互作用的证据，但是赋予宿主植物抗性的植物化合物的拒食作用在我们的测定中可能减少了Bt蛋白的消耗，导致联合使用时功效降低。