Schistocerca gregaria (Forskal)

Schistocerca gregaria (Forskal)

   
Common name: Desert Locust
Ethiopian name: Yeberha Anbeta
   
Order: Orthoptera
Family: Acrididae
   
HOSTS:  
Main hosts: Polyphagous with some preference for Gramineae
   
IMPORTANCE IN ETHIOPIA:  
Minor pest of: Barley, Maize, Sorghum, Wheat
   
DAMAGE:  
  Nymphs and adults feed on the leaves and soft shoots. They eat from the margin inwards which results in irregularly shaped feeding marks. Swarms will usual completely defoliate crops.
   
INSECT BIOLOGY & RECOGNITION:  
Egg: The ovipositor is used to make a hole in the sand, about 10 cm deep. The eggs are laid in this hole and covered with a froth that hardens. The egg pod contains 70-100 eggs. Eggs are rice shaped. Each egg is 7-8 mm long and 1.0-1.3 mm broad. A female may lay 4 or 5 of these egg pods. Depending on the temperature, the development of the eggs will take two weeks or longer.
Nymph: The first worm like larva finds its way through the egg pod to the soil surface. There it molts and becomes a "hopper". Hoppers have 5 instars before becoming an adult. There are solitary and gregarious hoppers. Those two phases differ in colour and behaviour.

Schistocerca gregaria. Adult and 5 instars, length adult (to wing tip) 67 mm.
Schistocerca gregaria. Adult and 5 instars, length adult (to wing tip) 67 mm.

Adult: In swarms, adults are first pink but may become rose, brown or orange brown when conditions are cool, e.g. in mountains. When they mature the colour changes to bright yellow in males and dull yellow in females. In solitarious forms the colour is greyish or brownish, but males may become yellow when they mature. Males are 40-50 mm, females are 50-60 mm long. The translucent forewings are greenish yellow with many brown spots. Between the forelegs they have a peg like structure (compare with Locusta migratoria migratorioides). There are several generations per year.

Schistocerca gregaria. Adult locust, length (to wing tip) 63 mm.
Schistocerca gregaria. Adult locust, length (to wing tip) 63 mm.

Schistocerca gregaria. Adult with peg-like structure between the fore legs.
Schistocerca gregaria. Adult with peg-like structure between the fore legs.

   
 

Adult of Schistocerca gregaria
Adult of Schistocerca gregaria

Text adapted from:

INSECT PESTS OF CEREALS IN ETHIOPIA identification and control methods by Hein Bijlmakers, FAO/UNDP Project ETH/86/029 Crop Protection Phase II, Addis Ababa, October 1989