Antixenotic and antibiotic impact of synthetic and plant extracted chemicals against Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) at different storage periods in stored wheat

Abstract

Lesser grain borer, Rhyzopertha dominica
(Fabricius) (Coleoptera: Bostrichidae) is a major pest of
stored products. A research work was conducted to
evaluate the efficacy of the two pyrethroids i.e.
deltamethrin, and cypermethrin @ 2.5 ml/liter and three
botanicals, i.e. leaf extracts of Azadirachta indica,
Moringa oleifera and seed extract of Datura stramonium
@ 5% concentration by dipping the jute sacks into their
solutions (50 ml solution per bag) to check the repellant
action of these chemicals against the R. dominica in wheat
stored for four storage intervals (15, 30, 45, and 60 days).
Different treatments of the chemicals tested, and storage
periods showed a significant effect on the penetration of
insects into the bags and mortality of insects. Degree of
antixenosis and antibiosis showed a negative correlation with the storage periods. Among the two pyrethroids and three
botanicals, deltamethrin and cypermethrin conferred an
effective control of the target insects for one month which
lessened gradually in the second month. Maximum antixenosis
of 62.13% and 61.63% were shown due to application of
deltamethrin and cypermethrin, respectively at 15 days of the
storage interval, while a minimum of 49.60% and 49.71%,
respectively were shown due to same treatments at 90 days of
the storage period. Similarly, the decreasing order of
antixenosis percentage (non-preference) against botanicals at
15 days interval was 40.04%>35.17%>28.31% against D.
stramonium, A. indica and M. oleifera, respectively. The
application of deltamethrin and cypermethrin induced
maximum antibiosis of 94.83% and 94.86%, respectively
against R. dominica after 15 days of storage period as
compared to botanicals and control treatment. © 2020
Department of Agricultural Sciences, AIOU