Efficacy of linalool and nerolidol for protecting stored maize seeds from Prostephanus truncatus and Sitophilus zeamais, and aflatoxin-producing fungi

The botanically derived terpenoids linalool and nerolidol were evaluated as post-harvest protectants of maize (Zea mays L.) seed against two major storage insects, Prostephanus truncatus (Horn) and Sitophilus zeamais Motsch., and the aflatoxin-producing fungus Aspergillus flavus Link. Analytical standards (≥ 97 % purity for linalool and ≥ 67 % purity for nerolidol) were applied to seeds (50 g) at 11.18 µmol·g⁻¹ and 7.87 µmol·g⁻¹ respectively, and compared with a commercial fungicide (Betallic EC) and an untreated control. At the test dose, linalool achieved 93.3 % repellency against P. truncatus and 100 % repellency against S. zeamais; corresponding values for nerolidol were 86.7 % for both species. Both terpenoids caused significant adult mortality and sharply reduced F₁ progeny emergence relative to controls (p < 0.05). Surface-inoculated kernels showed marked suppression of A. flavus mycelial growth. Complete fungal growth inhibition (100 %) was obtained with linalool and Betallic EC; nerolidol also reduced colony expansion and visibly restricted sporulation. Quantification of aflatoxins revealed parallel reductions in AFB₁ and AFB₂ titres. These findings demonstrate that linalool and nerolidol possess dual insecticidal and antifungal activities. When applied preventively to clean maize, the compounds can lower insect infestation, curb fungal colonization, and thereby lessen aflatoxin contamination under laboratory conditions during storage. Their efficacy supports further development as environmentally compatible alternatives or supplements to synthetic protectants in small-scale and commercial grain-storage systems.