Russavage Emily M, Helms Anjel M, Thompson Morgan N, Szczepaniec Adrianna, Rooney William L, Kerns David L, Eubanks Micky D
Department of Entomology, Texas A&M University, College Station, TX, USA.
USDA-ARS, Sugarbeet Research Unit, Fargo, ND, USA.
Pest Manag Sci. 2025 Apr 9. doi: 10.1002/ps.8813.
A promising strategy to optimize biological control of insect pests is selecting crop varieties with indirect defense traits. Indirect plant defenses recruit natural enemies to kill pests and include chemical attractants like herbivore-induced plant volatiles. In prior laboratory assays, we found sorghum (Sorghum bicolor L.) cultivar ATx3409/RTx436 infested with sorghum aphid (Melanaphis sorghi Theobald) was attractive to natural enemies and emitted more chemical attractants than two other cultivars. In this field study, we manually infested 9-week-old sorghum plants with aphids and quantified differences in natural enemy and aphid densities among cultivars throughout the growing season. We also used field cages to control access of natural enemies to plants and estimate their effects on aphid suppression.
We found strong evidence that indirect plant defenses confer economically relevant control of aphid pest populations and that laboratory assays can accurately predict natural enemy recruitment in the field. In 2022, there were three times more lady beetles (Coleoptera: Coccinellidae), lacewings (Neuroptera: Chrysopidae and Hemerobiidae), hover flies (Diptera: Syrphidae), and parasitoids (Hymenoptera: Braconidae and Aphelinidae) per aphid on ATx3409/RTx436 than on the other two cultivars. In the field cage experiment, natural enemies reduced aphid densities by up to 83% one week after aphid infestation. ATx3409/RTx436 was the only cultivar to remain below the economic threshold throughout the growing season, indicating that this cultivar would not require any pesticide applications to control aphids. In 2023, there were similar abundances of natural enemies and aphid densities across cultivars, the latter of which remained near zero throughout the growing season, likely due to extremely hot temperatures and drought that may have contributed to aphid mortality.
Our findings demonstrate that indirect plant defenses enhance biological control and deliver economically important pest suppression. Cultivar screening and selection for indirect defense traits provides a promising avenue to improve crop protection and breeding for resistance. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
优化害虫生物防治的一种有前景的策略是选择具有间接防御特性的作物品种。植物间接防御会吸引天敌来杀死害虫，包括化学引诱剂，如草食动物诱导的植物挥发物。在之前的实验室试验中，我们发现感染高粱蚜（Melanaphis sorghi Theobald）的高粱（Sorghum bicolor L.）品种ATx3409/RTx436对天敌有吸引力，并且比其他两个品种释放出更多的化学引诱剂。在这项田间研究中，我们人工用蚜虫感染9周龄的高粱植株，并在整个生长季节量化了不同品种间天敌和蚜虫密度的差异。我们还使用田间笼子来控制天敌接近植株的情况，并评估它们对蚜虫抑制的影响。
我们发现有力证据表明植物间接防御对蚜虫种群具有与经济相关的控制作用，并且实验室试验能够准确预测田间天敌的吸引情况。2022年，与其他两个品种相比，ATx3409/RTx436上每只蚜虫对应的瓢虫（鞘翅目：瓢虫科）、草蛉（脉翅目：草蛉科和褐蛉科）、食蚜蝇（双翅目：食蚜蝇科）和寄生蜂（膜翅目：茧蜂科和蚜小蜂科）数量多出三倍。在田间笼子试验中，蚜虫侵染一周后，天敌使蚜虫密度降低了多达83%。ATx3409/RTx436是整个生长季节中唯一保持在经济阈值以下的品种，这表明该品种无需使用任何农药来防治蚜虫。2023年，不同品种间天敌数量和蚜虫密度相似，后者在整个生长季节中一直接近零，这可能是由于极端高温和干旱导致蚜虫死亡。
我们的研究结果表明，植物间接防御增强了生物防治效果，并实现了具有经济重要性的害虫抑制。对间接防御特性进行品种筛选和选择为改善作物保护和抗性育种提供了一条有前景途径。© 2025作者。由John Wiley & Sons Ltd代表化学工业协会出版的《害虫管理科学》。本文由美国政府雇员撰写，在美国其作品属于公共领域。
