PAPER TITLE :INSECTICIDAL ACTIVITY OF POWDER AND EXTRACTS OF DELONIX REGIA SEED AGAINST MAIZE WEEVIL, SITOPHILUS ZEAMAIS (COLEOPTERA: CURCULIONIDAE)

FUTA JOURNAL OF RESEARCH IN SCIENCE | VOLUME 9 NUMBER 1 2013

Paper Details

  • Author(s) : O.E. Ajayi
  • Abstract:

Toxicity of powder, ethanol and essential oil extracts of Delonix regia (Bojer ex Hook.) Raf. seed against Sitophilus zeamais (Motschulsky) was assessed in the laboratory. Four treatment levels (0.5%, 1.0%, 1.5% and 2.0% (w/w powder, w/v ethanol extract and v/v oil) were evaluated. Untreated experiment was set-up as controls for all treatments; solvent treated experiment was included for ethanol extract treatment. All treatments were replicated four times in completely randomized design. Adult mortality was monitored for 120 h at 24 h interval. Toxicity of the extracts was concentration and exposure period dependent. All the treatments applied had significant p< 0.05 effect on mortality of S. zeamais. Seed oil was the most effective while powder was the least. Mortality in oil treated experiment ranged between 7.50% and 82.50% at 24 h; 27.50% and 82.50% at 48h, and 62.50% and 100% at 72 h. At 96 h post treatment 0.5% v/v treatment caused 77.50% mortality while 100% was recorded at 1.0 – 2% v/v treatment levels. All oil treatment concentrations caused 100% mortality at 120 h post-treatment. Ethanol extract caused 2.50% mortality at 24 h, 48 h, and 72 h in 0.5%, 1.0% and 2.0% treatment concentrations while 7.50% was recorded in 1.5% treatment concentration. The highest mortality in ethanol treatment was 12.5% at 120 h post treatment in 1.5 and 2.0% w/v treatment levels. In seed powder treated experiment, mortality ranged between 0.00% and 10.00%. At 96 h post treatment, mortality was between 2.50% and 17.50% for all treatments. Seed oil had greater potential for the control of S. zeamais. Therefore it could be incorporated in integrated pest management in grain storage system. Keywords: Delonix regia, Extract, Mortality, Seed powder, Sitophilus zeamais, Toxicity