PREDATORY POTENTIAL OF Blaptostethus pallescens Popp AGAINST Tetranychus urticae Koch AND ITS INTRAGUILD PREDATION ON Neoseiulus longispinosus (Evans)
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Date
2021-10
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UHF,NAUNI
Abstract
ABSTRACT
The present study entitled “Predatory potential of Blaptostethus pallescens Popp against
Tetranychus urticae Koch and its intraguild predation on Neoseiulus longispinosus (Evans)” was carried
out in the Biocontrol Laboratory of Department of Entomology, Dr. YS Parmar University of Horticulture and
Forestry, Nauni, Solan (HP), during 2020-2021. The predatory bug failed to complete its life cycle on all the
tested fife stages of T. urticae and could not develop beyond the fourth nymphal instar. However, when Corcyra
cephalonica (Stainton) eggs were included in the predator’s diet along with T. urticae for 6 or 12h, the bug
developed successfully. The biological and population parameters of the bug were highest on C. cephalonica
eggs followed by T. urticae+C. cephalonica (12+12h), T. urticae+C. cephalonica (18+6h). The fecundity was
highest (190.4 eggs/female) in females reared exclusively on C. cephalonica eggs followed by those reared on
T. urticae+C. cephalonica (12+12h) (117.8 eggs/female) and T. urticae+C. cephalonica (18+6h) (98
eggs/female). The feeding and pest-kill potential of the predator was also higher on C. cephalonica eggs than on
T. urticae+C. cephalonica (12+12h) or T. urticae+C. cephalonica (18+6h). The consumption rate of adult male
and female predators was 251.8 and 410.8 on C. cephalonica eggs, which was higher than recorded for the
predator feeding on T. urticae+C. cephalonica (12+12h) (170.3 and 246.4, respectively) and T. urticae+C.
cephalonica (18+6h) (126.3 and 186.8, respectively). The predatory bug exhibited a type II functional response
to the target prey and the parameters were higher on proto- and deutonymph than on eggs and adults. The
intraguild predation of N. longispinosus by B. pallescens was not strong and the bug predated almost negligible
or a few intraguild preys. Based on these results, B. pallescens can be used against T. urticae, but repeated
applications may be required, as it will not be able to increase its population exclusively on the mite. Further
field studies are, however, required to standardize the release rates. The predatory bug can also be used
compatibly with the predatory mite, N. longispinosus as it showed only negligible intraguild predation on the
predatory mite.