Essential oils-based repellents for the management of Myzus persicae and Macrosiphum euphorbiae

Aphids are one of the major agricultural pests in the world. Their pest management in pepper greenhouses is based on integrated control with release of natural enemies and pesticide treatments used in specific conditions. Essential oils may be used as an eco-friendly alternative for the control of this pest. In this work, we study the repellent effect of essential oils and pure compounds against aphids by two-choice bioassays. (E)-anethole, geraniol, farnesol, and (Z)-jasmone were the most repellent compounds for Myzus persicae and Macrosiphum euphorbiae (RD50 = 0.011 - 0.086 mu l/cm(2)). Farnesol at dose of 10 mu L attracts natural enemies of aphids, Aphidius colemani adults and Sphaerophoria rueppellii larvae, in y-tube olfactometer bioassays. A residual toxicity bioassay, using a computer-controlled spraying apparatus, showed a slight toxicity (< 20% mortality) against larvae of S. rueppellii when exposed to treatments of (E)-anethole, farnesol, or (Z)-jasmone individually. The foliar application of farnesol+(E)-anethole (1:1) nanoemulsions on plants infested with aphids resulted in a reduction of the population growth ratio of M. persicae (ri = - 0.78) and M. euphorbiae (ri = - 3.85). Among the tested compounds, farnesol is a promising compound to be introduced in aphid management for its potential as a repellent and aphicide, as well as an attractant of some natural enemies of this pest.

Automated summary

Essential oils and pure compounds such as (E)-anethole, geraniol, farnesol, and (Z)-jasmone were found to have repellent effects against aphids. Farnesol was also shown to attract natural enemies of aphids. Among the compounds tested, farnesol showed promise as a repellent, as well as an attractant for natural enemies of aphids.