Scientific name: Mentaxya ignicollis (Walker)
Common name: Red Tef Worm
Main hosts: Tef
Alternative hosts: A few species of grasses
IMPORTANCE IN ETHIOPIA:
Major pest of: Tef
DISTRIBUTION IN ETHIOPIA:
This pest is most serious when tef is grown on black or heavy deeply cracking clay soils. It has been recorded from Shewa, Kefa and Welega regions.
The caterpillars feed on the leaves and on the milky grains.
INSECT BIOLOGY & RECOGNITION:
Egg: The spherical eggs have a diameter of 0.4-0.6 mm. The colour is light pinkish, turning brown just before hatching. The eggs are laid singly or in groups of up to 300 eggs. One female lays about 1000 eggs. Hatching takes place in 4-10 days.
Larva: The caterpillars have a reddish to light green colour. They have a faint white line on the middle of the back, some broken brown lines on each side of the body, and below this on each side a distinct white line over the full length of the body. The head and the true legs are green. A mature caterpillar is about 35 mm long. The larval period takes about 33 days. The caterpillars are active during the evening, night and early morning. During daytime they hide in cracks of the soil.
Pupa: Pupation takes place in an earthen cell in the soil. The pupa has a shiny brown colour. It is about 14 mm long. The pupal period takes on average 31 days. Most pupae will diapause during the dry season.
Adult: A grey brown moth with a wingspan of 30-40 mm the grey or light brown forewings have three dark brown and black markings on the front edge. The hind wings are white. The moth is active during the night. There are 4 generations per year.
Cultural control: Ploughing after harvest may expose pupae to birds and predators and to the sun.
Spray with Bacillus thuringiensis 16000 IU/mg WP at 700 g ai/ha. This spray is recommended only for the control of young (2nd instar) caterpillars because it has a slow action.