International Journal of Tropical Insect Science (2011) 31, 269-276

L.K. Murungi, M. Knapp, D. Salifu, J. Wesonga, A. Nyende, P. Masinde and B. Torto (2011)
Differential effects of various African nightshade species on the fecundity and movement of Tetranychus evansi (Acari: Tetranychidae)
International Journal of Tropical Insect Science 31 (4), 269-276
Abstract: The tomato red spider mite Tetranychus evansi Baker and Pritchard is a serious pest of solanaceous plants worldwide. Management of this oligophagous pest in African nightshades has been a challenge to smallholder African farmers due to its high reproductive rate and rapid development of resistance to synthetic pesticides. The aim of the present study was to determine the influence of leaf trichomes on T. evansi by comparing its fecundity and movement on the leaf surfaces of five African nightshade species, namely Solanum sarrachoides Sendter, S. villosum Miller, S. tarderemotum Bitter, S. americanum Miller and S. scabrum Miller. Data were recorded in the laboratory at 23 ± 1°C, 50-70% relative humidity and a 12 h light:12 h dark photoperiod for the effect of trichome type and density of the abaxial leaf surface on mite fecundity. Distances travelled by mites on the leaf surface from the edge of a thumbtack pin inserted on the leaf were also recorded. Different trichomes, glandular and non-glandular types, were identified. There was a significant negative correlation of fecundity and distance walked by mites with the density of glandular trichomes. Significantly fewer eggs were laid on S. sarrachoides in comparison with the other Solanum species. The distance walked by mites was also significantly shorter in this species, indicating that higher densities of glandular trichomes interfere with mite movements. These results suggest that African nightshade genotypes differ in their levels of resistance to T. evansi, which is partially associated with differences in trichome types and their densities.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Baldwyn Torto, Markus Knapp

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus evansi