Tea and in addition inject toxic substances (Roy et

Tea
mosquito bug, Helopeltis theivora Waterhouse (Family: Miridae) is one of
the most dreaded polyphagous pest. This pest has emerged as a commonly
occurring major pest of cashew (Srikumar and Bhat, 2013, Vanitha et al., 2014)
and large cardamom plants by sucking the sap from the leaves developing dark
brown streak stains (Kalitha et al., 2016). In tea it causes damage to the
tune of 10 -50% followed by subsequent crop loss (Bora et al., 2007).
This pest recently is causing severe economic loss to the North Bengal tea plantations
due to environmental changes (Mukhopadhyay and Roy 2009).

Nymphs
and adults both suck the sap from pluckable buds, young leaves and tender stems
and in addition inject toxic substances (Roy et al., 2009 a) which
results in appearance of reddish brown sunken spots which eventually turns dark
curl up and deform. Severe infestation may cause shoots to produce dieback
symptoms (Roy et al., 2015). Moreover, this pest causes ovipositional
damages to the tender tissues. It attacks only the young shoots which are the
actual crop of tea (Rahman et al., 2005). Therefore, cause considerable
economic losses.

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Chemical
control would continue to be the first line of defense against this pest.
However, control failures due to pesticide resistance have increased the
difficulty in economic tea production (Gurusubramanian et al., 2008 and
Saha et al., 2013). To combat the damage there has been a rise in
pesticide use every passing year which further aggravated the problem and has
led to significant rise in cost of management (Sannigrahi and Talukdar, 2003).
Hence, as traditional and cultural practices alone cannot give satisfactory
control over the pest menace (Vanlaldiki et al., 2013), small and
marginal farmers are compelled to use chemical insecticides in order to
cultivate lucratively. In order to address the aforesaid problems new
insecticides can be thought as alternative and effective new bio-rational and
eco-friendly molecules that are safe to natural enemies and non-target
organisms and also to human health and environment (Chakraborty et al., 2010,
Reddy et al., 2014).

Tea mosquito bug, Helopeltis
theivora Water-house (Hemiptera: Miridae) is one of the most serious pests
of tea in Bangladesh. It is also widely distributed in India, Sri Lanka,
Viet-nam, Indonesia, Malaysia and Africa. It is also a phytophagous pest of
coffee, cocoa, cashew etc. A group of genomes are treated as a mosquito bug.
This bug bears no relation to mosquito and the name ‘Tea Mosquito Bug’ is
simply a misnomer. It is considered as one of the major pests of Bangladesh tea
because it attacks only to the young shoots that are the actual crop of tea.
Ahmed (2) reported that 10-15% of tea crop is lost annually by Helopeltis which
sometimes may go up to 100% crop loss. Both the nymphs and adults damage the
plant by sucking sap from young leaves, buds and tender stems. Due to intensive
feeding by nymphs and adults, leaves curl up and are badly deformed. In
addition to direct crop loss, damage by Helopeltis leads to
debilita-tion of bushes resulting in die-back with crows-feet and delayed or
meager flushing thereafter consequently almost the entire crop is lost. Mamun
(6) described that many differ-ent tactics are used in IPM strategy for tea
mosquito bug in tea plantation, including cul-tural practices, biological
control agents, pest-resistant varieties, physical barriers and chemical
pesticides etc.