Symptoms of Damage

• Regular circular boreholes on bolls.
• Presence of granular faecal pellets outside bore hole.
• Larva seen hanging in bore hole with head and part of abdomen thrust inside.

Identification and Biology :

• Destructive stage: Larva
• Eggs: Sub-globular, yellowish white in colour. Laid singly on shoots, buds, bracts tender bolls. Egg period: 4-7 days.
• Larva: Greenish brown with brownish grey lines and dark grey yellow stripes on lateral sides. Larval period: 5-18 days.
• Pupa: Brown coloured. Pupation in soil. Pupal period: 10-14 days.
• Adults: Stout- yellowish brown with ‘V’ shaped speck, greyish wavy lines and black mark on forewings Hind wings whitish with brown or black border along outer margin, Adult longevity: 10-12 days .


                                           
                                                                                                                 

Life Cycle of American Bollworm

Economic threshold level:

• ETL: 10% infested fruiting parts or one egg or one larva/plant.

Integrated Management

• Pest monitoring through light traps 1 /acre, pheromone traps 5 /acre and in situ assessments by roving and fixed plot surveys has to be intensified at farm, village, block, regional and State level.
• Synchronized sowing of cotton preferably with short duration varieties.
• Avoid continuous cropping of cotton both during winter and summer seasons in the same area as well as ratooning.
• Avoid monocropping.
• Growing of less preferred crops like greengram, blackgram, soyabean, castor, sorghum etc., along with the cotton as intercrop or border crop or alternate crop.
• Removal and destruction of crop residues to avoid carryover of the pest to the next season.
• Judicious use of nitrogenous fertilizers.
• Judicious water management for the crop.
• Application of Nuclear Polyhedrosis Virus (NPV) at 1.2 x 1012 POB / acre in evening hours at 7th and 12th week after sowing.
• Application of Bacillus thuringiensis var. kurstaki 5%WP 300-400g/acre or Beauveria bassiana 1.15%WP 160g/acre.
• Inundative release of egg parasitoid, Trichogramma chilonis at 2.5 cc / acre at 15 days interval 3 times from 45 days after sowing.
• Release of predator Chrysopa zastrowi sillemi at 40000 / acre at 6th, 13th and 14th week after sowing.
• ULV spray of NPV at 1.2 x 1012 POB / acre with 10% cotton seed kernel extract, 10% crude sugar, 0.1% each of Tinopal and Teepol.
• Avoid indiscriminate use of insecticides, particularly synthetic pyrethroids.
• Avoid combination of insecticides as tank mix.
• Adopt proper delivery system using spraying equipments like hand compression sprayer, knapsack sprayer and mist blower to ensure proper coverage with required quantity of spray fluid and avoid ULV applications or Akela spray applications.
• Proper mixing and preparation of spray fluid for each filling of spray fluid tank
• At early stages of square formation apply one of the following insecticides viz.,
• Azadirachtin 0.03% EC 1000ml/acre or Diflubenzuron 25% WP 120-140g/acre or Emamectin benzoate 5% SG 76-88g/acre or Fipronil 5% SC 800ml/acre or Flubendiamide 20% WG 100g/acre or Flubendiamide 39.35% SC 40-50 ml/acre or Indoxacarb 14.5% SC 200ml/acre or Novaluron 10%EC 400ml/acre or Pyridalyl 10% EC 300-400ml/acre or Chlorantraniliprole 18.5% SC 60ml/acre or Lufenuron 5.4% EC 240ml/acre or Spinosad 45.0% SC 66-88ml/acre.
• During boll formation and maturation stage, apply any one of the following insecticides viz.,Chlorantraniliprole 18.5% SC 60 ml/acre or Lufenuron 5.4% EC 240 ml/acre or Spinosad 45.0% SC 66-88ml/acre.

Feeding injury

Circular bore hole

Eggs  

Larva

Pupa

  Adult