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Molecular Entomology 2013, Vol.4, No.4, 22-25
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1.4 Effect of the treatments
Overall impacts of treatment show that all treatments
were found significantly superior over control. The
most effective treatments for the management of
mango leaf webber were Diflubenzuron 0.01% (1.41
larvae per webbed mass), Trizophos (0.06%) (0.25
larvae per webbed mass), Chlorpyriphos 0.04% (0.66
larvae per webbed mass), Indoxacarb 0.01% (0.83
larvae per webbed mass), Mechanical removal
Treatment (0.91 larvae per webbed mass), Spot
Treatment (0.33 larvae per webbed mass) with
Imidacloprid which were at par with each other.
2 Methods and Materials
Various factor like mango cultivators, seasonal
activity and weather factor and tree canopy that
influence the infestation of the pests were studied.
Screening of thirty mango cultivars were carried out
against the infestation of the mango leaf webber.
Observations were recorded at fortnightly interval, the
sample size was 5 trees per cultivar. Absolute numbers
of infested webbed masses were counted in each
observation and removed after recording the
observation. Seasonal activity of the pests was
recorded on Langrah variety of the mango from May
to April at fort nightly intervals and incidence of the
pests was correlated with weather parameters.
Influence of tree canopy on the pest infestation was
studied. Mango cultivars were grouped in seven
categories characterized as the tree canopy type (TC1
to TC7) (Figure 1). Canopy type 1, large tree type
dence, branches spreading redially towards the
ground .The area around the tree trunk is not receiving
proper sun light. Canopy type 2, tree type is small and
canopy is scattered type, sunlight penetrates in each and
every part of the plant. Canopy type 3, medium size tree,
branches moves strait up with slight inclination forwards
the periphery making oval shaped in appearance.
Figure 1 No.1~No.7 various type of mango tree canopy
Canopy type 4, larged size trees, branches dense
towards the top, making shaded dense asymmetrical
periphery. Canopy type 5, tree typed is erect, well
exposed tree, trunk branches are spreading upwards
farming scattered tree canopy.
Canopy type 6, medium trees with dense canopy
branches are spreading type. Canopy type 7, very
large and spreading type of tree belongs to there
category branches emerged just about the ground level.
Efficacy of insecticides including bio-insecticide was
compared with the mechanical control method.
Observations at fortnightly interval were recorded on
Dashehari cultivaron. Pre-treatment population was
recorded by counting the actual number of webbed
mass per tree. Number of larvae per webbed mass was
not counted in pre-treatment observation just to avoid
the movement of the larvae from webbed masses. To
find out the mean number of larvae per bunch on same
date fifty infested webbed mass were examined. The
post treatment observation was recorded after 1, 3, 7,
15 days after treatments. In post treatment
observations only number of live larvae was counted
from two bunches per tree to assess the impact of
treatments. Spraying was done with the help of foot
sprayer. Before spraying to find out the actual quantity
of spray solution required for uniform coverage on
tree, spraying of water was done on control untreated
trees. After calibrating the required quantity of water
per tree, spray solution was prepared. To check the
drifting of insecticide alternate tree in a row of
Dashehari block of mango orchard was selected for
the treatment. In mechanical removal treatment, after
recording pre-treatment observation all the infested
webbed mass were removed mechanically.
References
Kavitha K., Vijaya Lakshmi K., and Anitha V., 2005, Mango
leaf webber, Orthaga euadrusalis walker (Pyrallidaea:
Lepidoptera) in Andhara Pradesh, Insect Enviroment,
11(1): 39-40
Shukla R.P., Hasseb M., and Padari R.N., 2001, Integrated pest
management in mango, Technical Bulletin CISH,
Lucknow, pp.9-11
Singh R., Lakhanpal S.C., and B.K. Karkara, 2006, Incidance
of mango leaf webber, Orthega euadrusalis (Hampson) in
high dencity plantation of mango at Deharadun, Himachal
Pradesh, 11(4): 178-179