Repellent and Antifeedant Activities of Citral-Derived Lactones against the Peach Potato Aphid.

Katarzyna Dancewicz,Antoni Szumny,Czesław Wawrzeńczyk,Beata Gabryś

doi:10.3390/ijms21218029

Abstract

Citral is well known for its antimicrobial, antifungal, and insecticidal activities. Natural sesquiterpene α-methylenelactones also exhibit a broad spectrum of biological activities. The aim of the study was to explore the effect of structural changes to citral molecules on citral behavior-modifying activity towards Myzus persicae. Specifically, the effects of the introduction of a γ-lactone moiety and methylene groups in α and γ positions of the lactone ring were investigated. The lactones were obtained in five-step (saturated lactone and γ-methylenelactone) or six-step (α-methylenelactone and α,γ-dimethylenelactone) syntheses from citral. The synthetic procedures and physical and spectral data of the lactones are presented. The settling behavior of freely moving aphids in choice and no-choice situations was monitored. The probing behavior of tethered M. persicae using the Electrical Penetration Graph (EPG) technique was also analyzed. Citral appeared a strong repellent and pre-ingestive and ingestive probing deterrent to M. persicae. The incorporation of a lactone moiety caused the loss of the repellent activity. α-Methylenelactone inhibited aphid settling and probing activities at pre-ingestive and ingestive phases. The saturated γ-lactone and α,γ-dimethylenelactone were the settling post-ingestive deterrents to M. persicae, which did not affect aphid probing activity. γ-Methylenelactone did not affect aphid behavior.

Highlights

Plants infested by aphids may be affected directly, mainly because of fluid and nutrient removal, and indirectly by virus transmission
The average yearly world crop loss due to aphids is estimated at least 2% of all losses on account of insect feeding [2]
Repellents, insect-growth regulators, oviposition inhibitors, and antifeedants have attracted a lot of attention as crop protection agents that, at least in part, might replace conventional insecticides in aphid control [5,6]

Summary

Introduction

Plants infested by aphids may be affected directly, mainly because of fluid and nutrient removal, and indirectly by virus transmission. The peach-potato aphid Myzus persicae (Sulz.) (Hemiptera: Aphididae) is one of the most noxious species. It can infest plants of over 40 different families including many economically important ones worldwide, and it is able to transmit over 100 plant viruses [4]. Considering various negative effects of conventional pesticide application, there is an increasing demand for more specific, indirectly-acting crop protection agents, such as insect behavior-modifying chemicals. Repellents, insect-growth regulators, oviposition inhibitors, and antifeedants have attracted a lot of attention as crop protection agents that, at least in part, might replace conventional insecticides in aphid control [5,6]. Synthetic analogues of natural compounds are more accessible for application

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Results