Comparative Efficacy of Wood Ash and Leaf Powder of Aquaria salicifolia Against Sitophilus zeamais and Acanthoscelides obtectus

TL;DR

This study compares the effectiveness of wood ash and leaf powder from Aquaria salicifolia in controlling beetle pests that damage stored maize and beans.

Contribution

The study demonstrates that wood ash and leaf powder from Aquaria salicifolia are effective natural alternatives to chemical insecticides for pest control.

Findings

Wood ash at 40 g/kg caused 100% mortality in bruchids after 10 days.

Both substances significantly reduced F1 progeny, population increase, and grain damage.

Wood ash was more effective than leaf powder in controlling both beetle species.

Abstract

Maize and beans are very important sources of proteins and carbohydrates, and these grains are widely cultivated and stored for further use and consumption. During their storage, maize and beans are seriously attacked by beetle pests, namely, Sitophilus zeamais and Acanthoscelides obtectus, respectively. The pest management of these beetles is mostly carried out by the use of chemical insecticides, which are not environmentally friendly. In this regard, the insecticidal efficacy of Aquaria salicifolia leaf powder and wood ash was assessed on S. zeamais and A. obtectus concerning their effects on adult mortality, progeny inhibition, repellence, population increase and grain damage in the fluctuating laboratory conditions. Each biosubstance was mixed with grain at different contents (5, 10, 20 and 40 g/kg). Mortality was determined for 1, 3, 7, 10 and 14 days post‐treatment. All treatments were displayed on the shelves in the darkness. Four repetitions were carried out for each test, and the experiment was done in a complete randomized block design. The substances significantly caused mortality in the study coleopteran compared to the negative control, with wood ash being more effective than the leaf powder. 40 g/kg of wood ash caused 100% mortality to the bruchids after 10 days of exposure, while 40 g/kg of leaf powder caused 100% mortality after 14 days of exposure. For the weevils, the leaf powder was less effective as the highest dosage causing 37.50% in 14 days whereas wood ash caused 73.75% mortality in the same period. The production of F1 progeny and rate of population increase as well as percentage of damaged grains and weight losses were reduced significantly by both substances, which were also repellent. Considering these findings, A. salicifolia products could favourably be used as an alternative to chemically synthesized insecticides employed in the conservation of maize and beans during storage.

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