Leaf Roller in Cotton Crop

Cotton Insect Pests Leaf roller

Common Name : Leaf roller

Local Name : Pane Gundalnari ali

Scientific Name : Sylepta derogata Fab.

Family : Pyraustidae

Order : Lepidoptera

Pest Category: Foliage feeder

Leaf Roller Live Video : https://www.agritechguru.com/2019/12/Cotton-Leaf-Roller.html

Distribution and status: 
                               
                               Africa, Australia, Burma, Sri Lanka, Japan, Java & China. Minor pest.

Host range:

                      Cotton, Bhendi, Abutilon Indicum, and other malvaceous plants.

Description of Insect Stages:

Cotton Leaf Roller Life Cycle

Egg: 

          an egg is a round, smooth and pale white in color.

Larva:

Cotton Leaf Roller Egg Stage in Cotton

         The larva is glistening green in color and semi-translucent with a dark brown head. They become pinkish before pupation. Fully-grown larva measures up to 22-30 mm.  Bright green (glistening) with a dark head and prothoracic shield

Pupa:

         The pupa is reddish-brown in color and typical in having eight spines with Hooked tip at their extremity.

Adult: 

Cotton Leaf Roller in Larva Stage in Cotton

          The moth is medium-sized with yellow wings having a series of brown wavy markings. They are delicate, 12.5 mm long and with a wing expanse of 25 mm. Head and thorax are dotted black.  Bright green (glistening) with a dark head and prothoracic shield.

Bionomics:

                 Egg period: 2-4days, green round. 250-300 eggs/female laid on the ventral surface of the leaves. Larva:2- 3 weeks, glistening green with a dark head. Pupa: 6-12 days. Pupates within the roll or ground or fallen leaf. The adult is a medium-sized cream-colored moth with wavy markings. 

Nature of Damage:

Cotton Leaf Roller in Larva Stage

           The larvae feed on the lower surface of leaves when they are young and as they grow, they feed on the edges of leaves and roll inwards up to the midrib into a trumpet shape fastened by means of silken thread and feed on leaf tissues. The larvae remain inside the roll and feed outside the marginal portion of the leaves.

Cotton Leaf Roller in Larva Stage

Severe infestation results in complete defoliation of the plant.

Symptoms:

Leaves are folded downwards individually or in groups, and larvae are seen in groups amidst fecal materials inside the fold. Leaves at the bottom of the crop canopy show symptoms at low infestation levels. Defoliation of the whole plant is seen under severe infestations. The infestation spreads to neighboring plants and hence the symptoms of the pest are patchy. The plants under shades along the field borders are more vulnerable to the attack by the pest.

• Leaves rolled in the form of trumpets fastened by silken threads
• A marginal portion of leaves eaten away



Cotton Leaf Roller Symptome

• Plants defoliated in a severe attack

Life History:

         Eggs are laid singly on the undersurface of the leaves along the midrib and bigger veins. The moth lays as many as 200 eggs. The egg, larval and pupal periods occupy 2-3, 15-18 and 7-8 days, respectively. The larva molts six times before pupation. Pupation takes place mostly on the plants, inside the rolled leaves and sometimes on the shed leaves on the ground. The life cycle is completed in 23-53 days.

Cotton Leaf Roller Pupa Stage

   

Seasonal Dynamics:

        It is an important sporadic cotton pest. Damp and cloudy weather is conducive to the growth and rapid multiplication. In years of low temperature, high humidity and number of cloudy and rainy days, the incidence of the pest is generally high. Infestations occur in shady and weedy conditions.

Managment : 

• Collection and destruction of shredded plant parts
• Hand-picking and destruction of grown-up caterpillars
• Spray any one of the following insecticides
  • chlorpyriphos 20 EC 2.0 l/ha
  • dichlorvos 76 WSC 1.0 l/ha

• Spray carbaryl 50 WP 2 Kg or phasolone 2.5 L in 1000 L of water/ha.

Cotton Leaf Rollerin Adult Stage

Leaf Roller Live Video : https://www.agritechguru.com/2019/12/Cotton-Leaf-Roller.html