Reaction of Some Cassava Accessions to Red Spider Mite Tetranychus kanzawai Kishida) Infestation

Author(s): Emilia N Bernardo and Nelson M. Esguerra


A satisfactory technique for evaluating cassava accessions/varieties for resisitance to the red spider mites in the field or screenhouse was developed. Of the 295 entries tested, 50 showed varying levels of tolerance to the pest when tested in the field. At a much higher mite population in the screenhouse, however, practically all the accessions showed lower levels of tolerance although leaves of the more tolerant accessions 17, 29, 33, 48 and 49 were still green when the susceptible checks began to get defoliated. Differences in tolerance levels were most evident 3 weeks after artificially infesting each plant with 20 reproducing adult mites. Significant antibiotic effects of the resistant hosts on the pest were not detected.

Keywords : Red spider mite. Tetranychus kanzawai. Evaluation technique. Cassava accessions. Tolerance.

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