ROLE OF TERMITES IN DRY LAND ECOSYSTEM AND THEIR MANAGEMENT
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Date
2019-05-24
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UNIVERSITY OF AGRICULTURAL SCIENCES, GKVK BENGALURU
Abstract
Present investigation was carried out at the University of Agricultural Sciences,
GKVK, Bengaluru during 2016-18. Maximum termite damage to bait was noticed in
maize followed by sunflower and finger millet ecosystem. Influence of abiotic factors on
termite activity was 67.60, 49.30 and 26.20 per cent in maize, sunflower and finger millet
ecosystem, respectively. Total rainfall, in situ soil moisture and minimum soil
temperature exhibited significant positive impact on the termites activity. Odontotermes
obesus constructs conical shaped mound with one or more hollow turrets. The height and
circumference of the mound varied based on the age of the colony. Inner mound wall
possessed small pin holes distributed more on the top portion. The royal chamber was flat
based hard earthen structure located with a mean depth of 27±5.03 cm. Mound height
found significant positive correlation with depth, length, breadth and inner height of the
royal chamber and length of the queen. Different shaped unilocular fungal combs were
distributed 20-40 cm above and below soil surface. Eggs, nymphs, workers, soldiers and
alate nymphs were present in the fungal combs. A small supplementary royal chamber
with king and queen was also present. Composition of sand, silt and clay content varied
in different portion of the mound, royal chamber and earthen sheetings with dominance
of clay content. Earthen sheeting soil was slightly acidic with 0.51, 0.01 and 0.01 % of
OC, N and K content, respectively. The combination of surrounding soil + mound soil +
FYM (75: 10 : 15%) medium supported maximum plant height, pod production and
higher soybean yield. Bifenthrin @ 0.05%, chlorpyriphos @ 0.1 % and clothianidin @
0.075% treated soil protected the baits up to 20 months. Bifenthrin 2.5% EC was found
more toxic with the LC50 of 4.35 and 4.93 ppm against O. obesus and O. horni,
respectively.