Efficacy of plant extracts in the control of rodent infestations and their effects on the nutritional contents of sweet potato tuber

The use of plant extracts has been described as credible alternative to synthetic insecticides in the protection of field crops. This research work was conducted at Teaching and Research Farm, Ladoke Akintola University of Technology during the planting seasons of 2015 and 2016 to determine the efficacy of plant extracts – Tephrosia vogelii, Moringa oleiferia, Petiveria alliacea and Annona squamosa in the control of rodent infestation. The experiment was arranged in a randomized complete block design and each treatment was replicated three times. Synthetic insecticide (Lambdachyalothrin) and control were included in the experiment for comparison. Data were collected on plant stands attacked, vine length, yield and nutritional components of sweet potato tuber. The result showed that plant extracts treated sweet potato plants had significant lower rodent infestations when compared with unsprayed plant stands. Also, applied treatments had no negative effect on the vine length meanwhile yield obtained from botanical insecticides treated plants was two times higher than that of untreated plants which had the least tuber yield (0.90 t/ha). The tested plant extracts significantly improved the proximate contents of the harvested sweet potato tubers. Therefore, these plant extracts can be used in the field management of rodent infestation without any adverse effects on the nutritional components of the sweet potato tuber

Suppression of damaging effects of Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) by plant powders

Powders prepared from plant species available in Nigeria are reported to possess ovicidal, larvicidal, pesticidal, antifeedant and repellent properties against various insect pests and are regarded as environmentally compatible pesticides. This study evaluated the action of Azadirachta indica A. Juss, Hyptis suaveolens Poit. Piper guineense Thonn. & Schum and Cymbopogon citratus Gaern against the damaging effects of Callosobruchus maculatus (F.) in stored cowpea. The experiment was carried out at temperature of 30 ± 1oC and relative humidity of 72 ± 3%. The plant powders were compared at the rate of 2.5 g per 50 g cowpea seeds including the untreated control. The experiment was laid out in a completely randomized design with three replications. The results showed that all the botanicals gave protection to the stored cowpea seeds and significantly (p<0.05) reduced mean adult emergence and seed weight loss (3.75-4.06%) caused by C. maculatus when compared with the untreated control (6.07%). The number of emerged adults from untreated seeds progressively increased with time of exposure compared to the treated seeds. The increasing order of effectiveness of the botanicals in terms of their insecticidal activities against C. maculatus was P. guineense, C. citratus, H. suaveolens, and A. indica. The study, therefore, shows that the botanicals could serve as protectants against C. maculatus in stored cowpea seeds.Keywords: Botanicals, Callosobruchus maculatus, Cowpea, Damage, Mortality, Protectant