Abstract:
A survey was conducted in the important brinjal growing tracts of
Thiruvananthapuram district to study the population dynamics of the pests
and their natural enemies in the brinjal ecosystem. Laboratory experiment
and field experiments were conducted in the College of Agriculture, Vellayani
to assess the deterrency and toxicity of the different treatments on aphids,
epilachna and Leucinodes which were identified as important pests of brinjal
from the survey and the effective treatments as identified from the laboratory
experiment were carried out in the field.
=<;
Malathion alone or with garlic was found to be toxic to aphids.
Epilachna and Leucinodes.
The treatments with neem oil and Hyptis
suaveolens either alone and in combination were found to have deterrent and
toxic effects on aphids, Epilachna and Leucinodes in the laboratory
experiment. However, the effect was much pronounced when neem oil
activated with garlic was used in combination with Hyptis suaveolens.
In the field, though malathion was found to contain the pests, the effect
was not persistent for a long time and hence was not effective in the long run.
The combination of neem oil + garlic plus Hyptis suaveolens was found to
offer protection for the pest for a long period of time. On par with it were
combination of nee m oil plus Hyptis suaveolens + garlic and combination of
neem oil + H. suaveolens. The botanicals were also found to be safe for the
natural enemies like coccinellids, staphylinids and spiders. This treatment
was also found superior to other treatments in terms of net income and benefit
cost ratio and the lower unit cost of the treatment with high yield was
precisely the reason for its superiority.
