Fall Armyworm

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Fall Armyworm

Spodoptera frugiperda

Insect


In a Nutshell

  • Young larvae eat leaf tissue from one side, leaving the opposite side intact.
  • They might feed on seedlings until buds and growing points are destroyed.
  • Larger larvae leave a characteristic pattern of perforations and ragged margins on the leaves.
  • They might also attack the reproductive structures and young fruits.

Hosts

Bean

Cabbage

Capsicum & Chili

Cotton

Lettuce

Maize

Peanut

Potato

Rice

Sorghum

Sugarcane

Wheat

Symptoms

The larvae of the fall armyworm cause damage by feeding on all plant parts. Young larvae initially eat leaf tissue from one side, leaving the opposite epidermal layer intact (windows feeding). Seedlings can be fed upon up to the destruction of buds and growing points. Larger larvae leave a characteristic row of perforations and ragged margins on leaves, as well as lines of larval frass. They can also cut the base of the plant or attack the reproductive and young fruit structures. In case of heavy infestation, fall armyworm larvae can cause extensive defoliation.

Trigger

Eggs are laid in tight clusters of 100-300 on the undersides of the leaves, usually covered with scales. The larvae are light tan or green to nearly black, with stripes running along the flanks and a yellowish line along the back. The moth has white transparent hind wings and brown front wings mottled with lighter and darker marks. Each forewing has a noticeable whitish spot near the extreme tip. Diet and temperature determine the length of the different life cycle phases. Cool, wet springs followed by warm, humid weather favor the life cycle of the insect.

Biological Control

A number of parasitic enemies keep fall armyworm larvae down to moderate numbers. Wasp parasitoids include Cotesia marginiventris, Chelonus texanus and C. remus. The most commonly used parasitoid fly is Archytas marmoratus. Predators include ground beetles, spined soldier bugs, flower bugs, birds or rodents. Bio-insecticides containing neem extracts, Bacillus Thuringiensis or Baculovirus Spodoptera, as well as Spinosad can be sprayed.

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatments if available. Recommended insecticides include esfenvalerate, chloropyriphos, malathion and lamba-cyhalothrin. Farmers are also advised to go for poison bait based on these insecticides for grown up larvae.

Preventive Measures

Plant more resilient plants.,Monitor the moths presence and mass-catch them with light or pheromone traps (10/ha).,Plant early to avoid peak populations.,Weed control is recommended.,Harvest early to avoid consistent damage.,Plow the land to expose larvae and pupae to high temperatures.