Utilizing local plant extracts to control Diamondback moth in round cabbage

Abstract

Diamondback moth (Plutella xylostella L.) with abbreviation DBM is a detrimental pest that mostly attacks cabbage and other vegetables in Brassicaceae family. The build-up of resistance in DBM due to continuous and indiscriminate use of synthetic insecticides have refocused farmer's perspectives to plant based extracts. Plant extracts are generally compatible with natural enemies of pests therefore are considered eco-friendly. This study was done to evaluate the push effect of Garlic (Allium sativum L.), Chili (Capsicum frutescens L.) and Seaweed extract on the activity of DBM. All three treatments; chili extract, garlic extract, and seaweed extract were generally effective in controlling DBM than the reference group (control treatment). Separation of means by Student-newman-keuls (SNK) test showed that Diamondback moth (DBM) abundance under seaweed extract was significantly low (2.18±0.32, p< 0.05) followed by chili extract (3.22±0.43, p< 0.05). There was no significant difference in DBM abundance under garlic extract and control treatment. For defoliation, only control treatment recorded a significant increase in DBM population (5.40±0.64, p< 0.05). The other three plant extracts had similar low non-significant abundances (p> 0.05). Data on LAI did not show any significant differences in all the treatments meaning treatments did not affect LAI (p> 0.05). This study found that both seaweed and chili extracts were effective in controlling P. xylostella in round cabbage. Both extracts are recommended for use since they differ in their mechanism pathways to protect crops.

Field Application of Ethanolic and Aqueous Chili Extracts to Control Diamondback Moth (Plutella Xylostella L.) in Cabbage (Brassica Oleracea Var. Capitata L.)

“…When compared to garlic, chili was more effective in suppressing the abundance of P. xylostella (Baidoo & Mochiah, 2016). Diamondback moth (DBM) continues to be a destructive pest of cabbage, especially in the Vudal area and other tropical regions (Iamba & Malapa, 2020;Iamba, Malapa, et al, 2021;Iamba & Waiviro, 2021;Zhang et al, 2016).…”

“…The humidity is considered high with an average rainfall of 2780 mm per year and an intervening mild dry season (Malagat & Iamba, 2021a). The average relative humidity in a day ranges from 77-79% with a mean temperature of 27-29 °C (Iamba, Yoba, et al, 2021). These meteorological conditions are suitable and conducive for plant cultivation (Howcroft, 2002).…”

“…These response variables demonstrated the efficacy of the two chili treatments on P. xylostella. The procedure and protocol used were adopted from (Iamba, Malapa, et al, 2021). The abundance was the number of P. xylostella larvae counted during each sampling time.…”

“…The market value and quality of cabbage heads are greatly reduced since the larvae of DBM create feeding holes in the leaves, damage the growing buds, and tunnel into mature heads. Control using synthetic insecticides has been unsuccessful due to the build-up of resistance in DBM over time (Iamba, Malapa, & Yoba, 2021;Xia et al, 2013). The negative impacts of synthetic insecticides on human health, the lack of expertise and equipment for safe handling among smallholder farmers thus suggest alternative approaches to pest management (Amoabeng et al, 2013;Coulibaly, Cherry, Nouhoheflin, Aitchedji, & Al-Hassan, 2007;Ntow, Gijzen, Kelderman, & Drechsel, 2006).…”

“…Extracts derived from leaves, flowers, fruits, and seeds of insecticidal plants have shown ovipositional deterrence, feeding reduction, and larval mortality of P. xylostella on treated cabbage leaves (Abbasipour, Mahmoudvand, Rastegar, & Basij, 2010;Charleston, Kfir, Dicke, & Vet, 2005;Chen, Chang, Hou, & Cheng, 1996;Shin-Foon & Yu-Tong, 1993). Plant extract from chili, Capsicum frutescens, has been proven to reduce the activity of P. xylostella in cabbage (Iamba & Malapa, 2020;Iamba, Malapa, et al, 2021;Iamba & Waiviro, 2021;Iamba & Yoba, 2019). Homemade extracts of hot pepper and garlic produced positive results as emamectin benzoate (ATTACK®) while proving more better than the insecticide lambda-cyhalothrin (BOSSMATE®) by reducing the impact of P. xylostella larvae and B. brassicae (Fening et al, 2013).…”