MSc

The present study entitled “Development of botanical soap formulations
fortified with essential oils for the management of pests of brinjal” was conducted at the
Department of Entomology, College of Agriculture, Vellayani, with the objective of
assessing the bioactivity of a botanical soap formulation against the pests of brinjal.
The present study was carried out as four different experiments including
preparation of botanical soap formulations, laboratory bioassay of soap formulations
against fourth instar grubs of epilachna beetle, field assessment of soap formulations
against major pests of brinjal and evaluation of its shelf life. Leaf dip bioassay were
conducted to evaluate the efficacy of botanical soap formulations against epilachna
beetle grubs, Henosepilachna vigintioctopunctata.
After 24 hours of treatment, the highest percentage mortality (54.42) was
observed in neem oil+ citronella oil soap @ 2%. The treatments, neem oil +basil oil
soap @ 2% (38.61%), pongamia oil + citronella oil soap @ 2% (37.56%) and pongamia
oil +basil oil soap @ 2% (40.80%) were found to be on par with neem oil+ citronella oil
soap @ 2%. After 48 hours of treatment, the highest percentage mortality was recorded
for neem oil + citronella oil soap @ 2% (80.44) and were found to be on par with neem
oil +basil oil soap @ 2% (70.16), pongamia oil + citronella oil soap @ 2% (62.02),
pongamia oil +basil oil soap @ 2% (61.42).
Based on the results obtained from the bioassay, six treatments were selected for
further experiments. The treatment involving neem oil + citronella oil soap @ 2%
recorded the highest repellent effect (80 %). This was found to be statistically on par
with pongamia oil+citronella oil soap @ 2% (73.33) and neem oil + citronella oil soap
@ 1% (65.00%) 30 minutes after treatment. Sixty minutes after treatment (MAT), neem
oil + citronella oil soap @ 2% accorded 85% repellence and was found to be on par with
pongamia oil + citronella oil soap @ 2% (76.67%).
Field trials were conducted to ascertain the efficacy of botanical soap
formulations against major pests of brinjal. Among the different treatments, the
treatment involving neem oil + citronella oil soap @ 2% exhibited the highest percent
reduction in the population (59.66) of aphids after fourteen days of first spray. The same
trend was observed in the second spray schedule (57.05). Against whiteflies, pongamia
oil + citronella oil soap @ 2% recorded highest percent reduction in the population
(71.38) after fourteen days of first spray. The same trend was observed in the second
spray schedule (76.45). Neem oil soap @ 2% exhibited highest percent reduction in the
population (75.92) of leafhopper after fourteen days of first spray. The same trend was
observed in the second spray schedule (70.06). The highest percent reduction of
damaged leaves by epilachna beetle was exhibited by neem oil+ citronella oil soap @
2% (39.98) after fourteen days of first spray. The same trend was observed in the second
spray schedule (40.84). The highest percent reduction of damaged fruits by fruit and
shoot borer was exhibited by neem oil+ citronella oil soap @ 2% (69.53) after fourteen
days of first spray. The same trend was observed in the second spray schedule (43.98).
The highest fruit yield wasrecorded for the treatment, neem oil + citronella oil soap @
2% (1556.66 g/plant).
The shelf life studies revealed that after the first month, neem oil + citronella oil
soap @ 2% recorded 46.71 and 65.09 percentage mortality of grubs after 24 and 48
hours of treatment, respectively when stored under refrigerated conditions. Neem oil +
citronella oil @ 2% exhibited 43.03 and 61.25 percent mortality of grubs after 24 and 48
hours of treatment, respectively under room conditions. The treatments, neem oil +basil
oil soap @ 2% and pongamia oil + citronella oil soap @ 2% were found to be on par
with neem oil + citronella oil soap @ 2%.
This study investigated the efficacy of botanical soap formulations under
laboratory and field conditions. The results obtained from the laboratory and field
evaluation proved the potential of neem oil + citronella oil soap @ 2%, and it can be
recommended for controlling the pest population. Evaluation of shelf life of these
formulations revealed that their effectiveness remained for three months.