Forum

The Pink 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.

PBW feeds 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.

The main control methods hinge on five main strategies

1. Deployment of Bt-cotton

2. Use of short-season cultivars coupled with enforcement of a closed season

3. Pheromone based monitoring and control methods

4. Mass inundation with male-sterile moths

5. Integration 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

implementation of appropriate management strategies in India and Pakistan will play a vital role in minimizing the uncertainties and mitigating the impending risks in cotton production.