Effects of essential oils from the Brazilian pepper tree, eucalyptus and citronella on brassica aphids Brevicoryne brassicae and Myzus persicae (Hemiptera: Aphididae) and their parasitoid Diaeretiella rapae (Hymenoptera: Braconidae)

Abstract

Essential oils (EOs) are alternatives to synthetic insecticides used to control aphids that attack brassica species. However, the effects of species such as the Brazilian pepper tree (BPEO) Schinus terebinthifolius (Raddi), lemon eucalyptus tree (LEEO) Eucalyptus citriodora (Hook), and citronella grass (CGEO) Cymbopogon winterianus (Jowitt) on these organisms, as well as on beneficial insects, has been poorly studied. This work was aimed to evaluate the activity of BPEO, LEEO, and CGEO, at concentrations of 0.5% and 1%, on aphids Brevicoryne brassicae (Linnaeus) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) applied on leaf discs and/or cabbages, as well as the chemotaxic effects on its natural enemy Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae). The results showed that the essential oil of C. winterianus had a higher mortality rate for B. brassicae (100%) (0.5%, 48 h) and M. persicae (98.99%) (1%, 48 h). The average number of aphids (both species) found on cabbage leaf discs treated with 0.5% and 1% of the three essential oils (separately) was always lower than those found on leaf discs treated with water. Essential oils at 1% presented significantly higher mortality rates for B. brassicae and M. persicae than the control treatment. Females of D. rapae were attracted to plants of green cabbage with essential oil (0.5%) of S. terebinthifolius, but did not respond to E. citriodora and were significantly responsive to plants sprayed with water when contrasted with those in the presence of C. winterianus oil.

Semisynthetic compounds for controlling Colletotrichum lindemuthianum on bean seeds

“…Biofungicides can be produced from the extracts and essential oils of citronella and lemongrass. They are naturally sourced substances studied by research groups in the pharmaceutical, food, and agricultural eISSN 1899-007X sciences (da Silva et al 2023). The complex composition of the bioactive compounds exhibits antifungal, antibacterial, insecticidal, and antimicrobial activity.…”

“…It is based on these challenges that innovative technologies involving the synthesis and chemical modification of natural compounds have been proposed for the control of many pathogens. The synthesis of semisynthetic compounds allows for the improvement of biological activities exhibited by natural and unmodified molecules, reducing the volatilization of essential oils and providing higher enhancement when applied to crops (Zhang et al 2021;da Silva et al 2023).…”