Resistance of cassava cultivars to green spider mite, Mononychellus tanajoa (Bondar) infestation in Nigeria

EZULIKE, T.O. and EGWUATU, R.I

ABSTRACT: One thousand cassava cultivars in the germplasm were screened for resistance to the cassava green spider mite. Mononychellus tanajoa (Bondar) under natural field infestation. Twenty-one cultivars were identified as possessing levels of tolerance or resistance to the mite. These were subjected to artificial
populations of M tanajoa in the greenhouse in order to confirm either their tolerance or resistance. Of the twenty-one cultivars, TMS 4(2) 1425 was found to be the most tolerant to M tanajoa infestation, followed by 74/538, Anti – Ota, 73/93, 30195 and 1531 in that order. These six cultivars supported fewer numbers of mites and four of them, TMS 4(2) 1425, 73/93,74/538, 74/538 and Anti – Ota, had pubescent leaves associated with resistance. Mite density and damage were not correlated with variations in leaf hydrogen cyanide content. This factor did not appear therefore to have influenced the mite resistance observed in the cassava cultivars.

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