Tobacco Caterpillar

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Tobacco Caterpillar

Spodoptera litura

Insect


In a Nutshell

  • Feeding damage on leaves and pods.
  • Defoliation.
  • Moths with grayish-brown bodies and variegated forewings.
  • Egg clusters on upper leaf blades.

Hosts:

Capsicum & Chili

Eggplant

Cucumber

Tomato

Cabbage

Black & Green Gram

Cotton

Soybean

Garlic

Rice

Maize

Banana

Peanut

Mango

Symptoms

Freshly-hatched larvae feed gregariously on leaves, scraping the leaf tissue and completely stripping the plant. Older larvae disperse and feed voraciously on foliage at night. During the day, they usually hide in the soil around the base of the plants. In lighter soils, the larvae can reach the groundnut pods or roots and damage them. Due to extensive feeding, only petioles and branches are left behind.

Trigger

Adult moths have grayish-brown bodies and variegated forewings with white wavy markings on the edges. The hindwings are translucent white with brown lines along the margins and the veins. Females lay hundred of eggs in clusters on the upper leaf blades, covered with golden brown scales. After hatching, the hairless light-green larvae disperse quickly and start feeding gregariously on leaves. Older larvae are dark green to brown with dark spots on the flanks and somewhat clearer bellies. Two yellow longitudinal bands run along the sides, interrupted by black triangular spots. An orange band runs dorsally between these spots. Larvae feed during the night and take refuge in the soil during the day. Larvae and adults thrive at temperatures between 15 and 35°C, optimum at 25 °C. Low humidity and higher or lower temperatures reduce the fecundity and prolong their life cycle.

Biological Control

Parasitoid wasps of the species Trichogramma chilonis, Telenomus remus or Apanteles africanus feed on eggs or larvae. Bioinsecticides based on Nuclear Polyhedrosis Virus (NPV) or Bacillus thuringiensis also work well. Alternatively, the insect pathogenic fungi Nomuraea rileyi and Serratia marcescens can be sprayed on leaves. Bait solutions based on rice bran, molasses or brown sugar can be distributed on the soil in the evening hours. Plant oil extracts of neem leaves or kernels and extracts of Pongamia glabra seeds are highly effective against Spodoptera litura larvae. For example, azadirachtin 1500 ppm @ 5 ml/l or NSKE 5% can be used during the egg stage and prevents the egg from hatching.

Chemical Control

Always consider an integrated approach of preventive measures together with biological treatment if available. Extensive insecticide use can lead to resistance in the pest. To control the young larvae, several types of insecticides could be used, for example products based on chlorpyrifos (2.5 ml/l), emamectin (0.5 g/l), flubendiamide (0.5ml/l), or chlorantraniliprole (0.3 ml/l) as well as indoxacarb and bifenthrin. Bait solutions also effectively reduce populations of older larvae, for example poison bait (5 kg rice bran + 1/2 kg jaggery + 500 ml chlorpyrifos).

Preventive Measures

  • Check for tolerant varieties in your market.
  • Sow early to avoid peaks in insect populations.
  • Irrigate regularly to avoid prolonged mid season drought.
  • Plant trap crops like sunflower, taro and castor oil plant around and within fields.
  • Plant repellent plants such as Ocimum spp.
  • (basilicum).
  • Build bird perches in several places in the field.
  • Use light or pheromone traps to attract the moths.
  • Check your fields for signs of the disease such as egg masses, feeding damage or the presence of larvae.
  • Collect egg masses and larvae from trap plants and host plants and destroy them.
  • Remove weeds 15-20 days after sowing.
  • Handle your plants carefully during cultivation and avoid plant damage and injuries.
  • Take care of the hygiene of your tools and equipment.
  • Plow deep to expose Spodoptera pupae to natural enemies and weather-related factors.