Evaluation of leaves of lagundi (Vitex negundo) as corn seed protectant against the weevil, Sitophilus zeamais Motsch
1988
Md Ismael Miah Bruijah | Quiniones, A.C. (Central Luzon State Univ., Munoz, Nueva Ecija (Philippines))
The study was conducted to determine the effectiveness of dried leaves of lagundi [Vitex negundo], whole or powdered form, in protecting stored corn grains from corn weevil, Sitophilus zeamais. One and five percent rates by weight of lagundi leaf powder and whole dried leaf were compared to actellic insecticide at 6 ppm. and neem seed oil at 5 ml per kg of corn seed. The total developmental period of S. zeamais lasted 31-42 days in corn grains with 14% moisture content at 23-34 deg C and R.H. 79-87%. Results showed that dried lagundi leaves in powdered form or whole dried leaves had short residual effect on seed corn in storage since percent infestation progressively increased in all dosage after 90 days. Treatment with actellic and neem seed oil prevented weevil infestation on corn grain until the culmination of the study. Treating corn seed with fine and coarse lagundi leaf powder at diferent dosages did not inhibit oviposition of the gravid adult weevil. However, 5% fine lagundi leaf powder reduced fecundity of the adult weevil. The corn seed treated with whole dried leaves at 1 and 5 percent moisture content (11.64-11.94%) till the end of the study. Those treated with neem seed oil and actellic insecticide showed variations in their moisture content during storage.
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