Variegated Grasshopper

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Variegated Grasshopper

Zonocerus variegatus

Insect


In a Nutshell

  • Adults are dark green with yellow, orange or black markings on their bodies.
  • Feeding damage on leaves, petioles and sometimes stems.
  • Severe defoliation may ensue, mostly during the dry season.

Hosts

Capsicum & Chili

Eggplant

Lettuce

Manioc

Melon

Okra

Onion

Potato

Soybean

Sweet potato

Tomato

Symptoms

The variegated grasshopper feeds on a variety of crops in west and equatorial Africa. It chews on leaves, petioles, and sometimes also on green stems, leading to severe defoliation.The damage is more common on older than on younger plants, and is more severe in the dry than in the wet season. In manioc varieties, a single defoliation caused by Z. variegatus does not cause permanent damage, as the plant may recover quickly. Successive defoliations however can cause reduced tuber quality or death of the entire plant.

Trigger

Adults are dark green with yellow, orange or black markings on their bodies. They live in dense groups and can migrate from farm to farm using their olfaction to detect food. The female lays egg pods in pinkish to yellow capsules just below the soil surface in cool, soft, damp areas. The eggs will only hatch with the beginning of the dry season. The insect chews on leaves, petiole and partly on stems of a variety of crops and some weed plants. Their peak feeding activity is during the cool temperatures of the mornings. It can also act as vector for cassava bacterial blight. The insect defends itself against antagonists with a chemical excretion that contains the alkaloid pyrrolizidine.

Biological Control

Use neem oil, it is natural insecticide. The fungus Entomophthora grylli and the parasitoid fly Blaesoxipha filipjevi was found to affect adult populations. It is also possible to catch and destroy the animals attracted by the flowers of Chromolaena odorata. Captured grasshoppers can be crushed in water and sprayed as repellant over the fields. Spores of the fungus Metarhizium flavoviride sprayed in kerosene and peanut oil kill high amounts of grasshopper field populations.

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatments if available. Insecticides can be sprayed at all larval stages, but it is more advantageous to spray in early development stages. Cypermethrin is a broad–spectrum insecticide used against the grasshopper, but it has toxic effects on non-target organisms, including humans. Chlorpyrifos and pyrethroids also can be used.

Preventive Measures

Plant early to avoid peak populations.,Dig out the egg pods from the oviposition sites in the soil.,Pick adult grasshoppers manually.,Remove weeds in and around fields.,Plant companion species such as Calapogonium species.,Plow suspected fields to expose eggs to predators.