Repellent activity of Cymbopogon citratus and Tagetes minuta and their specific volatiles against Megalurothrips sjostedti

Abstract

Cowpea is an important source of protein for people in Africa. However, the crop suffers major damage and yield losses due to bean flower thrips, Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae). Although companion plants are known to reduce the damage caused by insect pests, the role of their volatiles in repelling pests from target plants has been the subject of few investigations. Here, we used the Y‐tube olfactometer experiments and chemical analyses to investigate the effect of volatiles from cowpea flowers and two companion plants; lemongrass, Cymbopogon citratus and Mexican marigold, Tagetes minuta on the olfactory responses of M. sjostedti. The results revealed that M. sjostedti males and females were repelled by the volatiles from freshly cut leaves of C. citratus. The combination of freshly cut leaves of C. citratus and cowpea flower was repellent to females but not to males. The female thrips, but not males, were repelled by the volatiles from the vegetative stage of T. minuta. Fifty‐four compounds were identified in the volatiles from two herbal plants. Among the major compounds, citral and a 4‐component blend comprised of dihydrotagetone, (Z)‐3‐hexenyl acetate, limonene and (Z)‐β‐ocimene repelled females but dihydrotagetone alone attracted females. While myrcene combined with cowpea flower volatiles enhanced the attraction of females M. sjostedti, when tested alone was not attractive. These results highlight the potential of volatiles from C. citratus and T. minuta to repel M. sjostedti females. The use of these plants as companion plants in a cowpea cropping system could reduce M. sjostedti infestation.

Repellency Mechanism of Natural Guar Gum-Based Film Incorporated with Citral against Brown Planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae)

“…One of most widely recognized effects shown by plant essential oils is a repellency activity on insect pests, and this could cause a significant reduction of the target pest populations on plants. Citral, one typical kind of plant secondary metabolite and a major compound of essential oils (EOs), also exhibits repellent effects on some insect pests [ 29 ], such as Aedes aegyptis [ 12 ], Aedes albopictus [ 13 , 30 ], Rhopalosiphum padi [ 31 ], Megalurothrips sjostedti [ 32 ], and Bactrocera cucurbitae [ 33 ]. In the present study, GC film, which incorporated the bioactive essential oil citral, showed a repellency effect against BPH, as determined by the 60.00% repellency recorded.…”

Chemical Compounds Emitted from Mentha spicata Repel Aromia bungii Females

“…Some studies have shown that myrcene is an aggregation synergist [ 34 ] for Monochamus alternatus (Coleoptera: Cerambycidae) [ 35 ] and Megalurothrips sjostedti (Thysanoptera: Thripidae) [ 36 , 37 ]. However, A. bungii females showed significant repulsion to 100 µL, 200 µL, and 500 µL myrcene in the semi-field cage bioassays, and 100 µL myrcene significantly reduced the number of A. bungii females choosing the host plant.…”

Exploring non‐host plant‐based management strategy with lemongrass, garlic and guava volatiles for the African citrus triozid

“…Likewise, garlic plant is repellent against the cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae) (Pahla et al., 2014), red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) (Mobki et al., 2014), the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) (Karavina et al., 2014) and D. citri (Mann et al., 2011). Lemongrass has been successfully used as an intercrop in the management of the eggplant fruit and shoot borer, Leucinodes orbonalis Guenee (Lepidoptera: Crambidae) (Calumpang et al., 2013) and as a repellent against the larvae of the bean flower thrips, Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae) (Diabate et al., 2019) and toxic to the diamondback moth, P. xylostella L. (Ohsawa, 2008).…”