Intercropping and diverse field margin vegetation suppress bean aphid (Homoptera: Aphididae) infestation in dolichos ( Lablab purpureus L.)

Autor: Steven R. Belmain, Joshua O. Ogendo, Philip K. Bett, Jane Nyaanga, Erick K. Cheruiyot, Richard Mulwa, Philip C. Stevenson, Sarah E. J. Arnold, Christine N. Mwani
Rok vydání: 2023
Předmět:
Zdroj: Journal of Plant Protection Research, Vol 61, Iss 3, Pp 290-301 (2021)
ISSN: 1899-007X
1427-4345
DOI: 10.24425/jppr.2021.137953
Popis: Dolichos (Lablab purpureus L.) is a drought tolerant legume used as food/feed and im- provement of soil fertility. The production of dolichos in Kenya, Nakuru County is however limited by insect pests like bean aphids, pod borers and whiteflies. Field stud- ies were conducted to determine the effect of cropping systems (dolichos monocrop and maize-dolichos intercrop) and field margin vegetation on bean aphids and their natural enemies. The experiment was conducted in Njoro (high field margin vegetation) and Ron- gai (low field margin vegetation) during May–December 2019 and March−November 2020 cropping seasons. Bean aphid percent incidence, severity of damage and abundance was assessed at seedling, early vegetative, late vegetative and flowering dolichos growth stages. The populations of natural enemies in the plots and field margin vegetation were monitored using pan traps and sweep nets. Species diversity and composition of the field margin ve-getation was determined using a quadrat. Results showed that location and cropping system had significant effects on bean aphid infestations. A high bean aphid incidence (38.13%) was observed in Njoro compared to Rongai (31.10%). Dolichos monocrop had significantly higher bean aphid infestation (51.63%) than the maize-dolichos intercrop system (24.62%). A highly diverse Shannon-weaver index was observed in Rongai (1.90) compared to Njoro (1.67). Dolichos monocrop had a more diverse Shannon-weaver index (1.8) than the maize- dolichos intercrop system (1.7). Rongai had the most abundant annual and perennial field margin vegetation species. The field margin species richness and diversity were higher in Rongai (81%) than in Njoro (54%). The findings of this study have demonstrated that a maize-dolichos intercrop in Rongai can reduce bean aphid damage in dolichos.
Databáze: OpenAIRE