Search for Alternative Control Strategies of Drosophila suzukii (Diptera: Drosophilidae): Laboratory Assays Using Volatile Natural Plant Compounds

Abstract

Drosophila suzukii (Diptera: Drosophilidae), is native to southeastern Asia and invaded Europe during the past decade. It causes serious economic damage in cherries and soft fruits. Control strategies rely on few insecticides with varying success. Due to environmental concern, the use of synthetic chemicals is restricted. Therefore, research effort is put into the quest for alternative substances applicable in chemical pest control. In laboratory assays, we tested 17 volatile plant compounds from different chemical classes for their contact toxicity, feeding modification, and oviposition repellency. Toxicity through contact with treated surfaces was evaluated after 1 h, 4 h, and 24 h; effects on food uptake were observed with capillary feeding (CAFE)—tests and oviposition trials compared egg numbers laid in raspberry medium with or without treated filter paper. Cinnamon oil and its components had the highest contact toxicity with an LC90 = 2–3%, whereas lemongrass oil, its main components, and farnesol were less toxic (LC90 = 7–9%), and geraniol was the least toxic. In CAFE tests, feeding stimulation was observed through 0.1% and 1% solutions of citronellol, lemongrass oil and farnesol. Cinnamon oil, cinnamaldhyde, and ethyl cinnamate were not consumed at a concentration of 1%. In the presence of citral, eugenol, and lemongrass oil, oviposition was reduced, and in the presence of limonene, no eggs were deposited. The natural products found most efficient in either bioassay will be further tested under field conditions.

Essential Oils as a Source of Ecofriendly Insecticides for Drosophila suzukii (Diptera: Drosophilidae) and Their Potential Non-Target Effects

“…Our phytochemical analyses revealed that the most frequent compounds found in these EOs were linalool (5.0 and 70.8%), neral (9.1 and 28.7%), geraniol (5.5 and 91.7%), geranial (22.1 and 44.6%), menthol (45.3 and 96.8%), and 1,8-cineole (36.8 and 40.1%). Although the chemical composition differs among the 19 selected EOs, there are reports of common functional groups of monoterpenes, such as α-pinene, citral, citronellal, citronellol, linalool, menthol, menthol, and 1,8-cineol, that have multiple chemical properties against D. suzukii such as toxicity, repellency, and deterrence of feed and oviposition [ 6 , 31 , 34 , 39 ]. It is also known that the efficacy of EOs on D. suzukii depends on the composition and proportions of the main substances, as demonstrated for C. verum [ 31 ] and Gaultheria fragrantima [ 40 ].…”

“…Although the chemical composition differs among the 19 selected EOs, there are reports of common functional groups of monoterpenes, such as α-pinene, citral, citronellal, citronellol, linalool, menthol, menthol, and 1,8-cineol, that have multiple chemical properties against D. suzukii such as toxicity, repellency, and deterrence of feed and oviposition [ 6 , 31 , 34 , 39 ]. It is also known that the efficacy of EOs on D. suzukii depends on the composition and proportions of the main substances, as demonstrated for C. verum [ 31 ] and Gaultheria fragrantima [ 40 ]. Likewise, the interactions of minority constituents contained in EOs have been reported to have synergistic action, providing a significant increase in the effectiveness of formulations for arthropod pests [ 26 ].…”

“…This information supports the hypothesis that all components in the EOs show a significant positive correlation with the mortality of flies, either by their combination or an adequate proportion of these substances [ 27 , 28 , 29 ]. Accordingly, studies by [ 31 ] observed that D. suzukii is susceptible to the toxic action of EOs, particularly from C. verum and Cymbopogon spp. Moreover, other studies have shown that EOs of the genera Cinnamomum and Cymbopogon are toxic to Diptera [ 41 , 42 ].…”

“…Some EOs have been tested in the laboratory for the management of D. suzukii , including contact insecticides, larvicides, and oviposition and feeding inhibitors [ 6 , 24 , 31 ]. Some field studies have employed EOs in monitoring bait traps to attract or repel D. suzukii adults [ 32 , 33 ].…”

Suppressive Impact of 6-Benzyladenine, A Plant Growth Regulator, on the Adult Performance and Reproductive Potential of Galleria mellonella L. (Lepidoptera: Pyralidae)

“…Also, other studies showed that kinetin reduced the egg-laying capacity of the fruit flies (Kaur and Rup, 2002). Apart from PGRs, various plant-derived compounds had been reported to detrimentally inhibit the oviposition efficiency of some insect pests, such as S. littoralis by Nerolidol (Hamadah et al, 2020) or Farnesol (Hamadah et al, 2021); S. oryzae by Eugenol (Chaubey, 2016); the melon worm Diaphania hyalinata by Rotenone (Silva et al, 2016) and the vinegar fly Drosophila suzukiiby citral and eugenol (Eben et al, 2020).…”