boll worm (PBW) is a worldwide pest of cotton. It is one of the three major
species of cotton boll worms. It is one of the biggest threats to cotton
production across the world. PBW is known to severely damage cotton up-to the
extent of 60%. It has been causing severe crop losses to Bt-cotton in India and Pakistan in recent years. Studies confirmed
that PBW developed high levels of resistance to Bt-cotton in India. Concerns of PBW resistance to Bt-cotton have also been raised in China
recently. USA has been able to manage PBW through excellent eco-friendly
approaches that are worth emulating.
inside fruiting parts and is therefore not amenable to pesticide exposure. The
worms feed mainly on cotton but can also survive on Jute, Hibiscus and Okra.
Moths are about 1 cm long and lay 200-400 eggs on flowers and bolls. Soon after
hatching, the young larvae feed on ovaries of the buds and flower, or bore into
tender green bolls. The larvae feed on developing seeds. Tender green bolls
(10-20 days old) are most preferred.
control methods hinge on five main strategies
2. Use of
short-season cultivars coupled with enforcement of a closed season
based monitoring and control methods
inundation with male-sterile moths
of transgenic, biological, ecological, cultural and chemical control methods
In Asia PBW occurs
as a late season pest that mainly infests cotton during late winters. Short
season cultivars that are harvested before the onset of winter, escape damage.
The recent PBW problem in India has been traced to ‘extending the crop duration
by an additional 60-90 days beyond the recommended 150-160 days’. The extended
crop not only allowed extra generations of PBW survival, but also
intensified selection pressure that lead to resistance development. Reverting
back to short-season cultivars and
of appropriate management strategies in India and Pakistan will play a vital
role in minimizing the uncertainties and mitigating the impending risks in