Tobacco Caterpillar Or Tobacco Cutworm Or Leafworm in Cotton

Cotton Insect Pests Leafworm or Tobacco Caterpillar

Common Name: Leafworm or Tobacco caterpillar

Local Name: Tambakhu khanari ali

Scientific Name: Spodoptera littoralis Boisd.

Family: Noctuidae

Order: Lepidoptera

 Pest Category: Foliage feeder

                    The cotton Leafworm or Tobacco Caterpillar or Tobacco Cutworm          ( Spodoptera littoralis) is a highly polyphagous species feeding on plants of 40 families, containing 87 species of economic importance. It originates in Egypt and is currently found in Africa, the Canary Islands, the Middle East and parts of Mediterranean Europe including the Balearic Islands, Madeira, and the Azores.
                                                                                                                                  

Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Superfamily:	Noctuoidea
Family:	Noctuidae
Genus:	Spodoptera
Species:	S. littoralis

Distribution and status:
                       India, Sri Lanka, Indonesia, Bangladesh, Pacific Islands, China, Pakistan, Korea, and Japan. It is a regular pest and has the potential to be a serious pest.

Host range: 
                     Groundnut, Citrus, Soybean, Cotton, Tobacco, Castor, Pulses, Millets, Safflower, Banana, Cabbage, Tomato, Sweet Potato, Bhendi, Chillies, etc. 

 Description of Insect Stage

Egg:

Tobacco Catapillar Life Cycle in Cotton

         Each egg mass contains 300-350 eggs which are arranged in rows up to three layers and are covered by scales from the body of the females.

Larva:

        Caterpillars are pale green with dark markings initially which later turn dark brown with numerous transverse and longitudinal bands. The Larva of Spodoptera are gregarious at first but later spread over the plant and become brown to grey-brown or black with irregular spots and lines.

Tobacco Catapiller Larva Stage in Cotton

Pupa: 

           Pupae are dark brown in color Pupation occurs in soil.

Adult: 

           The adult is stout with brownish forewings with paler lines along the veins, and pearly whitish hind wings.

Bionomics:

Tobacco Catapiller Larva Stage in Cotton

                 Larva pale greenish with dark markings; gregarious in the early stages. Adult: Moth with wavy white markings on a brown forewing. Hind wings white with a brown patch along the margin. Refer to the groundnut for further information on the duration of life stages.

Nature of Damages :

       The larvae feed gregariously on the undersurface of the leaves and skeletonize them
leaving only the midrib and veins in severe cases. They also attack flowers, buds, and squares causing considerable loss.

Tobacco Catapiller Larva Stage in Cotton

Symptoms:

         Skeletonization resulting in the papery appearance of leaves with only veins left out is the typical damage. Leaves defoliate and shedding of squares with feeding holes occurs when larvae are in large numbers.

Life History:

       Egg, larva and pupal periods are 3-4, 13-20 and 8-10 days respectively. The life cycle completed in 50-60 days.

Tobacco Catapillar Adult Stage in Cotton

Seasonal Dynamics:

         The incidence occurs during the months of August, September and October coinciding with the grand growth period of the crop. The occasional nature of the occurrence of this insect on cotton rendered its seasonal incidence unrecorded

Management of Defoliators:

          In the case of semi-looper, a significant loss in leaf area occurs only when young plants are attacked. The population is highly regulated by the parasitoids and the pathogens that affect naturally. In endemic areas of leaf roller, all the rolled leaves with larvae in them should be collected and destroyed during the early stage of attack by the pest. Spread to neighboring plants should be minimized to nil that the plant stand is maintained. To monitor Spodoptera, pheromone lures are available. however, planting of few castor plants along the borders of the cotton fields serves as

indicator plants for Spodoptera. No action thresholds exist for foliage feeders but chemical treatments are needed if a significant proportion of cotton plant stand is destroyed. Anyone chemical option recommended for bollworm control should be used in case of threat to crops stand

Management

•            Use of light trap to monitor and kill the attracted adult moths or set up the sex pheromone trap Pherodin S.L. at 12/ha to monitor the activity of the pest and to synchronize the pesticide application, if needed, at the maximum activity stage.
• Growing castor along border and irrigation bunds. 
• Removal and destruction of egg masses in castor and cotton crops. 
• Removal and destruction of early-stage larvae found in clusters that can be located easily.
• Collection and destruction of shed bolls and flowers. 
• Hand-picking and destruction of grown-up caterpillars. 
• Spray any one of the following insecticides using, a high volume sprayer covering the foliage and soil surface. Chlorpyriphos 20 EC 2.0 L/ha; dichlorvos 76 WSC 1.0 L; Spraying Nuclear Polyhedrosis Virus at 1.5 x 1012 POB per ha or 200 larval equivalent (LE)/ ha.
• Spraying of insecticide should be done either in the early morning or in the evening and NPV in the evening.
• Use of poison bait pellets prepared with rice bran 12.5 kg, jaggery 1.25 kg, Carbaryl 50%WP 1.25 kg and water 7.5 L. This bait can be spread in the fields in the evening hours so that the caterpillars coming out of the soil, feed and get killed.