Welcome to the Zambia Agriculture Research Institute
The Zambia Agriculture Research Institute provides high quality, appropriate and cost effective services to farmers, generating and adapting crop, soil and plant protection technologies.
Cassava Mealybug was first reported in Zaire in the early 1970s and was later identified as Phenacoccus manihotis, a pest species indigenous to South America. It may therefore have been introduced to Africa through vegetative planting material. Its occurrence has since been reported in many countries in Africa where CM has caused tremendous loss in cassava yield through leaf loss and weakening of planting material (stem cuttings) and consequently tuber yield reduction which has been estimated up to 70%.
What damage does CM cause to cassava?
Initially the CM attacks the terminal ends of cassava shoots which become stunted and the leaves curled and folded (Fig. 1). The inter-node length is reduced (Fig. 2), causing twisted stems, and the emerging leaves compressed together into ‘bunchy tops’. When the attack becomes very serious plants die starting with the top most growing point of the plant, where the highest pest population is found.
Fig. 1 Leaf curling and folding due to CM attack on cassava
The attack of CM on lower leaves and natural leaf fall in the dry season causes a so called “candle-stick” appearance. The affected plants may produce lateral leaves but even these become attacked by the pest.
CM damage reduces cassava yield by reducing the capacity of the plant to form tubers, and by reducing the quality of leaves as a vegetable. The twisting of stems also reduces the quantity and quality of planting material. Since the attacked plant loses leaves more weeds tend to grow under such plantations.
Fig. 2 Reduced inter-nodes due to CM attack on cassava
How can CM be recognized?
CM occurs on leaves, shoot tips, petioles and stems. The insect looks almost round in shape without wings pink in colour and with short feelers. The body is wholly covered with white waxy material. (Fig. 1, Fig. 2).
How can CM spread?
The pest is dispersed passively by wind and through use of infested planting material to establish a new cassava field.
How can CM be controlled?
1)
Use resistant or tolerant varieties which are released or recommended by the Root and Tuber Improvement Programme at Research Stations.
2)
Plant cassava early in the rainy season to allow the crop to establish well before the dry season, because a strong plant is more likely to withstand pest invasion.
3)
Avoid burning cassava plantations at harvest for the burning indiscriminately kills insects including the natural enemies that have been released to attack the pest.
Mission Statement
To contribute to the improvement of the welfare of the
Zambian people through the provision of technologies &
services that enhances household, food, security and
equitable income generating opportunities for the farming
community and agricultural enterprise.
ZARI Head Quarters
Mt. Makulu Central Research Station
Private Bag 7
Chilanga.
Tel: +260211278130/380
Fax: +260211278130/41
Email:mtmakulu@zamnet.zm
Email:zaridirector@zari.gov.zm
