Sustainable Management of Tea Mosquito Bug Helopeltis antonii Signoret ... 391
- (Few) less than 20 workers/tree; no trails; very
few or no homopterans; no nests
++ (Moderate number) > 20–50 Oecophylla
smaragdina
+++ (Common) > 50–500 Oecophylla smaragdina
usually some distinct trails on tree trunk or
canopy but rarely on ground
++++ (Abundant) > 500–1000 Oecophylla sma-
ragdina; well-defined trails in canopy and
occasionally on trunk and along ground
+++++ (Very abundant) > 1000 Oecophylla smarag-
dina or with strong trails; interconnecting or
virtually all trees across their canopies and or
along ground
The effectiveness of biopesticides and insec-
ticides against TMB infestation were tested at
Zonal Agricultural Research Station, Brahma-
vara on cashew cultivar, V-4. Three sprays were
given in sequence on new flush, panicle emer-
gence and nut and fruit developmental stages of
the trees. Treatments were replicated thrice in a
randomized block design.
Treatment ml/l or %
Pongamia oil–pongamia oil–pon-
gamia oil
2–2–2PSKE–PSKE–PSKE 2–2–2
Neem oil–neem oil–neem oil 5–5–5
NSKE–NSKE–NSKE 2–2–2
Beauveria bassiana–Beauveria
bassiana–Beauveria bassiana
2–2–2Monocrotophos–λ-cyhalothrin–
carbaryl
0.05–0.005–0.10PSKE–λ cyhalothrin–carbaryl 2–0.05–0.10
Beauveria
bassiana–λ-cyhalothrin–carbaryl
2–0.005–0.10NSKE–λ cyhalothrin–carbaryl 2–0.05–0.10
Monocrotophos–endosulfan–car-
baryl
0.05–0.05–0.10Control 0.10
t-test was adopted for comparison of two treatment
means
PSKE pongamia seed kernel extract, NSKE neem seed
kernel extract
Results and Discussion
Field surveys revealed that of 1520 cashew trees
across different habitats of Karnataka, preda-
tory green ants were detected in 40 % cashew
trees. However, nesting colonies of the ant were
found only on 18 % cashew trees. Ant fauna of
cashew trees comprised six species, O. smarag-
dina being the dominant species. The number of
flushing shoots damaged by H. antonii where
ants were found was less (14.50 %) compared to
trees where green ants were absent (37 %). Un-
disturbed patches with native vegetation where
branches of the cashew trees were touching each
other or other trees/bushes held the ant colonies
of O. smaragdina.Predatory Ants on TMB
The abundance of different ant species foraging
on cashew trees was observed at 20 locations of
coastal Karnataka and Chintamani (Table 1 ). In
coastal Karnataka, the ground ant species Dia-
camma rogasum Loguill and Camponotus com-
presus Fabricius were observed to be less abun-
dant and nesting on the cashew tree was low to
negligible. The arboreal species, O. smaragdina,
was observed at all the locations surveyed.
In non-sprayed plantations, O. smaragdina
population was abundant and occupied the en-
tire cashew tree canopy. The other species of
ants were absent on the trees colonized with O.
smaragdina. It has well-defined colonies that it
defends aggressively against other ant species.
The trees colonized by O. smaragdina were in-
terconnected with well-defined trails of worker
ants invariably using aerial connections, where
the canopies overlapped. Trails of O. smaragdina
were observed on the ground where canopies
were not overlapping. The incompatibility of O.
smaragdina and the other ants was confirmed by
spatial separation at the edges of their territory.
In the maidan tract of Karnataka, eight ant
species foraging in cashew ecosystems were ob-
served. O. smaragdina was abundant and nesting
on the cashew tree branches was recorded. The
other species of ants were not competing with the
predominant species, O. smaragdina. Other ant
species were found foraging at the edges of the
tree canopy. O. smaragdina makes nests by spin-
ning silk between leaves with moderately sized,
densely spaced cashew leaves, around 5–6, medi-
um sized nests were recorded per tree. Each nest
consisted of leaflets with the ventral side wound