390 C. M. Naik et al.
Introduction
Cashew ( Anacardium occidentale L.) is an im-
portant cash crop. With the rapid expansion of
cashew crop acreage, the insect pest problems
also increased in Karnataka, South India. This
is quite apparent from the fact that the produc-
tion is not in pace with the increase in area. In
spite of the adoption of recommended package
of practices, decline in production is mainly due
to tea mosquito bug (TMB) H. antonii Signo-
ret. More than 50 insect pests are recorded on
cashew in India (Devasahayam and Nair 1986 ).
Amongst them, TMB alone causes 30–100 %
yield loss (Abraham and Nair 1981 ) in outbreak
situations (Sundararaju and Sundarababu 1999 ).
TMB causes serious damage to the tender leaf,
growing tip, inflorescence, apple and the nut.
Cashew grows wild in nature; and in Karnataka,
South India, the Horticulture Department and the
government encourage cashew plantation in vast
stretches of wastelands/degraded/government
lands. Private owners of the lands are also en-
couraged to cultivate cashew. Wherever cashew
grows, people tend not to use insecticides to sup-
press pests. Therefore, eco-friendly management
practices are desired for the TMB and other pests.
Material and Methods
During 2006, six field surveys on pests were con-
ducted in cashew plantations of coastal, maidan
(plane landscape) and other habitats of Karna-
taka to find activity of ants, species composi-
tions, flushing shoots damaged by H. antonii and
other pests and number of healthy nuts. Attempts
were made to establish ant colonies on cashew
trees in Brahmavara, Puttur and Chintamani ca-
shew plantations of 2 ha each at each location. O.
smaragdina species of ants were released on five
randomly selected cashew trees after the release
of ants. Observations were recorded for 1.5 years
at periodic intervals (2–3 months duration). The
natural ant colonies of O. smaragdina on exist-
ing trees with terminal branches with ants were
incised, and ants were held in perforated poly-
thene bags and released on the labelled cashew
trees and periodic observations were recorded
for 3 years. Studies on seasonal activity of egg
parasitoid of Telenomus sp. on TMB in Coastal
Karnataka was investigated using field surveys.
Data were collected from two study sites at Brah-
mavar and in Pethri village cashew plantation.
The cashew plant parts (shoot, petioles, midrib
and panicles) containing eggs of H. antonii were
collected at monthly intervals and counted under
a zoom stereomicroscope. They were treated
with carbendazim 0.1 % solution for 10 min.
After treatment, samples were dried to remove
the dampness of carbendazim solution placed in
a plastic container completely wrapped in a black
paper (Geisberger 1993 ) to record the emergence
of parasitoids and percentage of TMB egg para-
sitization.
Predatory ants associated with cashew plan-
tations and their effect on H. antonii population
was assessed at 20 locations in west coast and
maidan Karnataka. Observations were recorded
on insecticide-sprayed and non-sprayed cashew
plantations in October–February, 2006–2007 and
2007–2008, to determine the differences in TMB
infestation and occurrence of natural enemies.
The ant specimens were identified by Mr. T. M.
Mushtak Ali, Department of Agricultural Ento-
mology, UAS, GKVK, Bangalore. Abundance
and effectiveness of predatory ants were deter-
mined on their predominance and predation of
TMB on cashew in coastal Karnataka. Data on
the ant colonisation and damage on reproductive
parts of the tree and yield (kg/tree) were also re-
corded.
Indices for assessing abundance of predatory
ant O. smaragdina were made based on quick ex-
amination of an individual cashew tree (Way and
Khoo 1991 ) as follows.Keywords
Botanicals · Cashew · Management practices · Tea mosquito bug