INSECTICIDAL POTENCY OF SOME INDIGENOUS PLANT EXTRACTS AGAINST RICE WEEVIL, Sitophilus oryzae (L.) (CURCULIONIDAE: COLEOPTERA)
Date
2013-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR.
Abstract
Experiments were conducted to study the bioefficacy of some indigenous plant extracts
against rice weevil, Sitophilus oryzae L. in the laboratory of the Department of
Entomology, Hajee Moharnimad Danesh Science and Technology University (HSTU),
Dinajpur during the period from April to October 2012. The petroleum ether —" of
seed of ata (Annona reticulata) and castor (Ricinus communis), leaf of karabi (Nerium
olender), marigold (Calendula officinalis) and nishinda (Vitex negundo) at 0.5, 1.0 and
1.5 % concentration were evaluated for their repellent, direct toxic and residual effects
against rice weevil. The results showed that all five plants extracts were effective in
checking insect infestation and had different toxic, residual and repellent effects against
rice weevil. Among the tested plant extracts, ata seed extract showed the highest toxic
effect (64.18 % mortality) and lowest number of F1 adult (7.75 %) emergence but castor
seed extract showed the lowest toxic effect (21.66 % mortality) and highest number of F1
adult (18.08 %) emergence. Mortality percentage was also found directly proportional to
the level of concentrations of plant extracts and to the exposure period. The repellent
effect of ata, castor, karabi, nisinda and marigold extracts showed that the five plant
extracts had moderate repellent action on rice weevil. Ata seed extract also showed the
highest repellency (49.45 %) while castor seed extract provided the lowest repellency
(33.62 %). Residual effect of ata seed extract was also higher than all other plant extracts.
Considering all the concentration and efficacy, the order of toxicity of plant extracts was
ata » karabi » marigold » nishinda >» castor.
Description
The people of Bangladesh store different kinds of grains both for the seed and food
purposes because preservation of reserve food grain stocks is necessary to ensure a
continuous supply at stable price. It has gained much popularity among the farmers due
to its higher production. Losses due to insect infestation are the most serious problem in
grain storage, particularly in villages and towns of developing countries like Bangladesh.
The climate and storage conditions, especially in the tropics, are often highly favourable
for insect growth and development (Jacobson 1982).
Keywords
Tested plant materials, Collection and preparation of botanical powders, Preparation of plant extracts