Does Foraging Experience Affect the Responses of the Predator Dicyphus hesperus Knight to Prey-Induced Volatiles?

The predatory mirid bug Dicyphus hesperus Knight (Hemiptera: Miridae) is a native North America species with high potential as biological control agent of the potato psyllid, Bactericera cockerelli Sulcer (Hemiptera: Triozidae), which is a major solanaceous pest. Olfactory responses of D. hesperus to volatiles from plants infested with the potato psyllid and the effect of foraging experience on search efficacy were studied. Using a Y-tube olfactometer, we found that naïve females had no preference in choice tests between either uninfested tomato plants, or Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs-infested plants, and clean air. Naïve females showed an innate positive response to B. cockerelli-infested plants, but no preference when given a choice between uninfested tomato plants and E. kuehniella eggs-infested plants. However, females with experience of foraging on B. cockerelli-infested plants showed a strong preference for B. cockerelli-infested plants (78% response) in choice tests with uninfested tomato plants and E. kuehniella eggs-infested plants. Implications of learning for augmentative biological control are discussed.

Improved Sweetpotato Whitefly and Potato Psyllid Control in Tomato by Combining the Mirid Dicyphus hesperus (Heteroptera: Miridae) With Specialist Parasitic Wasps.

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) and Bactericera cockerelli Sulcer (Hemiptera: Psyllidae) are important pests in tomato, and the mirid Dicyphus hesperus Knight (Heteroptera: Miridae) has been shown as an effective predator of both pests. Although the predator was able to suppress populations of both pests, the remaining levels could still exceed tolerable levels. Thus, we here hypothesized whether the combination of D. hesperus with the specialist parasitoids Eretmocerus eremicus Rose y Zolnerowich (Hymenoptera: Aphelinidae) (whitefly) and Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) (psyllid) would result in better pest control on a greenhouse scale. For that, we conducted a trial in which we compared the results against B. tabaci and B. cockerelli in greenhouses treated with D. hesperus alone or the predator in combination with the specialist parasitoids. The results showed that the predator was able to establish and suppress B. tabaci and B. cockerelli in tomato, but the addition of the specialist parasitoids resulted in better and more cost-effective pest control. Implementation of this method would therefore increase the robustness and reliability of biocontrol-based integrated pest management programmes for tomato crops, over methods based exclusively on D. hesperus release.