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1.Mites:
a. Red spider mite (Tetranychusspp)
b. Green cassava mite (Monychellusspp)
-Mites are important pests of cassava. They are tiny and cannot be seen by naked eyes. Mite was accidentally introduced in Kenya in 1971 through Uganda from S. America through cuttings and has now become a very serious pest of cassava in tropical Africa.
Roots of Transmission:
-Wind dispersion and are generally immobile once in the field. They are found in a section of the field or a plant.
-Due to its size, the larvae and adults are easily washed off the plant by rain drops during rainy season. Thus are dangerous during dry periods.
Symptoms:
i. Yellow mottling of leaves distinguished from that of virus by the leaves reddening, wither and finally fall off.
ii. Young shoots dry
iii. The plant gets small (stunted)
iv. Reduced yield.
Control
i. Using resistant clones. Generally clones with hairy leaves.
ii. Biological control using natural enemies like predaceous mites introduced from C America
Use of chemicals. That is spraying acaricides, broad spectrum insecticides like endosalphan.
2.Cassava mealy bug (Phenococusmanihoti)
-Common in tropical Africa.
-It was introduced accidentally from C and S America to Zaire in 1973 from where it got its way to Kenya.
-Damage is caused mainly to the young shoot which gets killed. They then move to petiole and finally to leaves.
-Attacks are more severe and serious during the beginning of dry period and in clones with small leaf area.
Symptoms:
i. Dead apical shoot
ii. Decreased leaf area
iii. Small tubers and of poor quality
iv. Increased time taken between planting and maturity
Titany answered the question on August 16, 2021 at 12:03
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