A novel approach to control stored sorghum beetle Tribolium castaneum (Coleoptera: Tenebrionidae) in small-scale farmers’ storerooms in Kebbi- Nigeria

The aim was to develop a novel method to reduce infestations of the most common stored-product pest, Tribolium castaneum beetles, in bags of sorghum stored by small-scale farmers of Kebbi state. A survey of 240 farmers found greater quantities of sorghum than other grains (4,000 kilos/household, p<0.001) were stored and a majority in south Kebbi stored sorghum threshed (p<0.001), even though this form is more vulnerable to infestation. Inconsistencies in farmers’ perceptions of the efficacy of repellent plants were apparent. A more efficient and effective bioassay (Thigmotactic assay) was developed to identify a plant product highly repellent to T. castaneum, ‘Lem-ocimum,’ which is composed of Cymbopogon nardus (Lemongrass) plus Ocimum basilicum (Sweet basil), 0.5%w/w each (p<0.001). A paste of Lem-ocimum was applied between layers of 5kg double-bags to prevent contamination of grain within inner bag. Treated double-bags provided better protection from T. castaneum infestation than untreated single or double-bags (p<0.001) and were most effective when a high number (9-18) were placed on top of untreated bags (~1% weight loss after 5 months, p<0.01, n=150 store-rooms of 42 farmers). A survey indicated participants were satisfied with outcome of Lemocimum treatment for trials using high numbers of treated bags. Male and female farmers differed in plant species they collected and their plant-drying methods. Chemical analysis showed plant species and drying methods affected repellency; cultivated O. basilicum had higher repellent compound content and repelled more beetles (0.88±0.015) than O. africanum (0.62±0.020, p<0.001), and shade-drying repelled more beetles (0.76±0.039) than sun-drying (0.61±0.034, p<0.001). Therefore, it is recommended that double-bags treated with cultivated shade-dried Ocimum (as normally prepared by women) should be tested further in the field. Application of the Lem-ocimum treated double bags method should ensure farmers have a proportion of high quality grain to sell to the market, thereby increasing their financial status.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Greenwich

Year dc:date.issued

2013

Author dc:creator

• Utono, Iliyasu Mohammed

Advisors dc:contributor.advisor

• Gibson, Gabriella
• Coote, Hilary

• SB Plant culture

Language dc:language

en