Biological Efficacy of Two Plant Powders as Mothcidal Agents Against Sitotroga cerealella (Olivier, 1789) (Lepidoptera: Gelechiidae) Infesting Paddy Rice
NJE Vol. 34: 9-17, 2018
Oyeniyi, E. A.
Department of Biology, Federal University of Technology
P. M. B. 704, Akure, Ondo State, Nigeria
Abstract: This study investigated the mothcidal efficacy of powders of Alstonia boonei (De wild) stem bark and Acalypha godseffienna (Muell Arg.) leaf at ambient temperature (28±3ºC) and relative humidity (75±6%) against adult Sitotroga cerealella infesting paddy rice. Adult Sitotroga cerealella were exposed to both botanical powders using contact toxicity test at 1-5g/20g of paddy rice and mortality was assessed after 24, 48, 72 and 96 hours post-treatment respectively. The control experiment was also set-up for each botanical. Generally, both botanical powders significantly (p<0.05) evoked higher moth mortality when compared to control. But, none of both plant powders elicit complete moth mortality (100%) at all the experimental dosage and exposure time. Lower dosage of A. boonei was however required to achieve 50% (24 hours: 0.672; 72 hours: 0.006) mortality in S. cerealella when compared to that of A. godseffienna (24 hours: 1.546; 72 hours: 0.238). Also, A. boonei at all experimental dosage significantly reduced (p<0.05) emergence of S. cerealella when compared to control while A. godseffiana applied only at 2-5g/20g of paddy rice significantly reduced (P<0.05) adult emergence when compared to control. The effect of A. boonei on the percentage inhibition rate of S. cerealella was significant (F4,15 = 6.69; P = 0.003) while that of A. godseffiana was not significant (F4,15 = 1.65; P = 0.213). It could therefore be concluded that powders of both botanicals could help in the management of S. cerealella infesting rice grains in Nigeria.
Keywords: Alstonia boonei, Acalypha godseffienna, Inhibition rate, Mothcidal, Sitotroga cerealella.