Can Macrolophus pygmaeus (Hemiptera: Miridae) Mitigate the Damage Caused to Plants by Bemisia tabaci (Hemiptera: Aleyrodidae)?

Abstract

Nowadays, in protected vegetable crops, pest management based mainly on biological control represents the most sustainable alternative to pesticide use. The cotton whitefly, Bemisia tabaci, is one of the key pests that negatively impact the yield and quality of such crops in many agricultural systems. The predatory bug Macrolophus pygmaeus is one of the main natural enemies of the whitefly and is widely used for its control. However, the mirid can sometimes behave as a pest itself, causing damage to crops. In this study, we investigated the impact of M. pygmaeus as a plant feeder, by analyzing the combined impact of the whitefly pest and the predator bug on the morphology and physiology of potted eggplants under laboratory conditions. Our results showed no statistical differences between the heights of plants infested by the whitefly or by both insects compared with noninfested control plants. However, indirect chlorophyll content, photosynthetic performance, leaf area, and shoot dry weight were all greatly reduced in plants infested only by B. tabaci, compared with those infested by both pest and predator or with noninfested control plants. Contrarily, root area and dry weight values were more reduced in plants exposed to both of the insect species, compared with those infested only by the whitefly or compared with noninfested control plants, where the latter showed the highest values. These results show how the predator can significantly reduce the negative effects of B. tabaci infestation, limiting the damage it causes to host plants, though the effect of the mirid bug on the underground parts of the eggplant remains unclear. This information might be useful for a better understanding of the role that M. pygmaeus plays in plant growth, as well as for the development of management strategies to successfully control infestations by B. tabaci in cropping environments.

Mechanoecology and Chemoecology: Physical and Chemical Interactions between Insects and Plants

“…An important aspect of insect-plant interactions is the multitrophic relationships between plants, pests, and natural enemies. In this regard, Farina et al [7] analyze the damage to plants caused by the cotton whitefly, Bemisia tabaci, in presence of a predator which feeds on both insect prey and plant tissue, while Liu et al [8] study the effects of herbivore-induced rice volatiles and reveal their positive effects on spider attraction and predation ability, with beneficial effects in improving the control of rice pests.…”