The effects of leadwood (Combretum imberbe. L) on maize weevils (Sitophilus zeamais. L) in stored sorghum (Sorghum bicolor. L) grain
- Author
- Gandiwa, Evelin Tendai
- Title
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The effects of leadwood (Combretum imberbe. L) on maize weevils (Sitophilus zeamais. L) in stored sorghum (Sorghum bicolor. L) grain
- Abstract
-
Sitophilus zeamais. M is the major insect pest seen damaging stored sorghum in Zimbabwe. The environmental hazards of synthetic insecticides, the unreliabile supply and high costs of these chemicals resulted in the search for cheaper and safe use of the naturally available plant material to control the pest. This study evaluates effective form and rates of Combretum imberbe. L ash and leaf powder. Bioactivity of Combretum imberbe ash was evaluated under average room temperature at three different dosage levels (5g, 10g and 20g). Bioactivity of C. imberbe leaf extracts was also evaluated under the same room temperature again at three different dosage levels (5g, 10g and 20g). A negative control of untreated sorghum grain and a positive control Actellic Gold dust were also used at label rates. The effect on grain damage, weight loss and weevil mortality was assessed. C. imberbe ash and leaf powder showed significant difference between 5g and 10g on one hand and 20g and the positive control showed no statistical difference. The 20g C. imberbe ash and leaf powder that recorded the highest mortality inflicted 81.25 % and 87.5 % respectively. The sorghum grain treated with 20% C. imberbe leaf powder also showed much promise by significantly reducing the number of damaged grain by the weevil as well as weight loss of grain compared to the negative control. Grain weight loss in all botanical treatments was dose dependent ranging from 90 % in the highest dose to 46% in the lowest dose with untreated grain showing significant differences after 8 weeks.
KEY WORDS: Sitophilus zeamais, Combretum imberbe, Bioactivity
- Date
- 2022
- Publisher
- BUSE
- Keywords
- Storage insect pests
- Pest control
- Supervisor
- Dr Chikuvire, T. J
- Item sets
- Department of Crop Sciences
