MSc

The research work entitled “Arthropod diversity in drumstick Moringa oleifera
Lam.” was carried out at the Department of Agricultural Entomology, College of
Agriculture, Vellayani from 2020 to 2022 with the objective to document pests, natural
enemies and pollinators associated with drumstick and to assess their seasonal
incidence.
The documentation was done from Instructional Farm Vellayani, Farmer’s field
in Thiruvananthapuram district and College of Agriculture, Vellanikkara. Forty one
insect pests and one non-insect pest were documented. Among them, 12 each were from
the order Hemipetra and Lepidoptera, 11 from Coleoptera, 4 from Thysanoptera, 2 from
Diptera and one non insect pest from the order Acarina. The stink bug (Stenozygum
speciosum Dallas), tea mosquito bug (Helopeltis bradyi Waterhouse), ash weevil
(Myllocerus curvicornis Fab., Myllocerus anamalainus Marshall), flower thrips (Thrips
parvispinus Karny) stem weevil (Alcidodes fabrici Marshall), semilooper (Zurobata
vacillans Walker), fruit fly (Diarrhegma modestum Fabricius) and red spider mite
(Tetranychus udaipurensis Gupta and Gupta) were reported for the first time as pest of
drumstick from Kerala.
Studies on biology of Protrigonia zizanialis, S. speciosum and Streblote siva
Lefebvre were carried out under laboratory condition. P. zizanialis had an average of
2.9 + 0.23, 9.2 + 0.24 and 7.7+ 0.15 days of egg, larval and pupal period respectively.
S. speciosum recorded egg and nymphal period of 6 + 0.25, 39.1 + 0.34 days
respectively. S. siva had an average egg period of 6.5 days, larval period of 26 days and
pupal period of 13 days.
Natural enemies associated with pests of drumstick were also documented.
Spiders were prominent predators followed by coccinellid beetles. A total of 27 spiders
belonging to 13 genera were recorded from drumstick. Apart from spiders, 19 insect
predators were documented, which include Coleoptera (8), Diptera (4), Mantodea (4),
Neuroptera (1) and Hemiptera (1). A hymenopteran parasitiods Gryon sp. from the
family Scelionidae were found parasitizing on eggs of coreid bug Cletus bipunctatus
Herrich-Schaffer and Ooencyrtus sp. from the family Encyrtidae were found
parasitizing on pupae of syrphid predator Dideopsis aegrota Fabricius. Two tachinid
parasitoids were also found parasitizing on larvae of Eupterote mollifera Walker.
For the documentation of pollinators, a study was conducted during the
flowering season of drumstick at College of Agriculture, Vellanikkara. In the orchard,
five trees were selected randomly and from each tree, five inflorescences (total 25
inflorescences in 5 trees) were selected. Population of insect visitors were recorded by
visual observation for a period of 10 days from 0600 to 1900 h. A total of 14 insect
pollinators were recorded which include 7 species from Hymenoptera, 4 species from
Lepidoptera and 3 species from Diptera. In Hymenoptera, Apidae was the dominant
family followed by Vespidae and Halictidae. Among Apidae, Xylocopa sp. was the
most abundant pollinator with mean population of 1.36 /inflorescence/day.
The seasonal incidence of insect pests and associated predators on the
drumstick was conducted at College of Agriculture, Vellayani. Helopeltis antonii
Signoret was the most prevalent insect pest of drumstick and was found throughout the
year and the highest populations was recorded during April (10.00 plant-1
), followed by
March (9.60 plant-1
), January (9.40 plant-1
) and February (9.20 plant-1
). P. zizanialis,
Myllocerus spp. and E. mollifera, were the important defoliators found in drumstick.
Highest population of P. zizanialis (12.8 plant-1
), Myllocerus spp. (10.8 plant-1
) and E.
mollifera (86.40 plant-1
) was recorded during the month of April, January and May
respectively. However, the population of spiders and praying mantis were observed
throughout the year. The peak population of spiders (11.4 plant-1
) and praying mantis
(2.8 plant-1
) was found during the month of March. In the correlation studies, population
of sucking pests and defoliators were negatively correlated with rainfall except for E.
mollifera and positive correlation was observed with temperature. Spiders and praying
mantis population were found significantly negatively correlated with relative humidity
and positively correlated with temperature.
From the present study 110 species of arthropods belonging to 88 genera, 50
families and 8 orders were found associated with Moringa oleifera. This includes 41
insect pests, one non insect pest, 27 spiders, 19 insect predators, 4 parasitoids, 14 insect
pollinators and 4 species of ants. H. antonii was the most prevalent insect pest of
drumstick and was found throughout the year. P. zizanialis, Myllocerus spp. and E.
mollifera were the important defoliators found in drumstick. Spiders were prominent
predators followed by coccinellid beetles. Hymenopterans were the most common and
abundant pollinators in drumstick. In the correlation studies, population of sucking
pests and defoliators were negatively correlated with rainfall except for E. mollifera
and significant positive correlation was observed with temperature. Spiders and praying
mantis population were found significant negative correlation with relative humidity
and rainfall but positively correlated with temperature.