MSc

The availability of Medicinal plants is mainly from the natural resources
like forests and .waste lands. Today farmers of Kerala are taking up cultivation of
medicinal plants in an organised manner. A thorough survey conducted in three
different localities such as herbal gardens of College of Horticulture, Vellanikkara,
Thycaud Moos Arya Vydyasala, Chuvannamannu and Kottakkal Arya Vydyasala
Kottakkal being listed had resulted in alarming informations. Survey was done just on
ten economically important' medicinal plants, viz., Neelamari, Adapathiyan,
Chethikoduveli, Thippali, Vallippala, Thulsi, Kacholam, Karalakom, Kasthurivenda
and Madhunashini.
Complete survey of selected ten medicinal plants indicated the presence of
57 different species of insect pests of which, 44 species are new reports,
In Neelamari rate of infestation by psyllids was to a major level. Typical
symptoms of 'die back' had been observed. The five minor species include webbers,
flower beetles, treehoppers, pentatomids and alydids. The predatory coccinellids, ants
and spiders associated with the psyllids were the other new reports. Spiders were
observed to prey upon the coccinellids which inturn were psyllid predators.
Occurrence of milkweed butterfly on adapathiyan was to a major level. Tachinid flies
were found to parasitise the butterfly larvae. Chethikoduveli heavily infested by
citraka looper was a major one. A microlepidopteran belonging to the family
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Grassillaridae was found infesting on Thippali spikes. Spike thrips, thippali mealy
bugs were the other minor pests. Vallippala semilooper, a key pest was ranked as a
completely defoliating one. Its biology studied reveals that egg period to be three days,
larval instars as first, second, third, fourth and fifth, prepupal and pupal duration of 2,
2, 3, 3, 2, 1, 6.4 ± 0.1956 days respectively. Total life cycle was found to, be 22.4 ±
0.1956 days. Tylophoran bug and Asclepidian beetle which were first reports. Glossy
tiger in Vallippala was found on a major level. Lacewing bug were found to be major
one in Tulasi. But there were numerous minor pests as Tulasi leaf webber,
grasshopper, ash weevil, Pentatomid bugs and Coried bugs. Kacholam were infested

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by Lema beetle, black hairy caterpillar and swarming caterpillar which were the minor
ones. Karalakom butterfly were ranked as key pest. Its biology and management using
botanical pesticides were studied. The egg, larval duration of first, second, third and
fourth instars prepupal and pupal stages had a duration of8.2 ± 0.1405, 7.7 ± 0.1768,
7.8 ± 0.1749, 9, 7.9 ± 0.2422,1,14.8 ± 0.1749 days respectively. Total life cycle was
found to be that 56.1 ± 0.5248 days. Flea beetles were found to make the leaf papery
thin. In Kasthuri venda there were two major and 11 minor pests. The major ones were
found to be the pests of okra too. Major ones are shoot and fruit borer and leaf roller.
Defoliator in Madhunasini were parasitised by a Hymenopteran belonging to the
family Braconidae. Moth bugs and three types of passive visitors observed were also
new reports.
As the influence of weather parameters on the distribution of key pests
were studied, it was observed that with a rise in temperature there was a flare up on
Vallippala semilooper and Karalakom butterfly population. With decrease in
temperature the reduction in pest population was common for both the pests. When the
relative humidity was taken into account, it was evident that decrease in Vallippala
semilooper population was indirectly proportional to the relative humidity but it was
directly proportional to the spread of Karalakom butterfly. When the influence of wind
speed was taken into consideration it was found that wind speed had no direct
influence on Vallippala semilooper distribution but with regard to Karalakom butterfly
the spread was more with an increased wind speed. While studying the effects of total
sunshine hours in a day on the pest spread, it was clear that there was an increase in
Vallippala semilooper distribution and a reduction in Karalakom butterfly population
with increased sunshine hours.
The evaluation of botanical pesticides revealed a maximum antifeedancy
with Neem Kernel Suspension (NKS) followed by neem leaf extracts. In the case of
Vallippala semilooper hyptis ranked as the next best. While it was yellow oleander for
Karalakom butterfly. These eco-friendly approaches are new records.