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  • Author or Editor: John C. Snyder x
  • Journal of the American Society for Horticultural Science x
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Abstract

Spider mite behavior was characterized on leaflets, varying in extent of expansion, from mite-resistant Lycopersicon hirsutum and mite-susceptible L. esculentum plants. Survival, mortality, avoidance, and fecundity of the mites were related to Type VI trichome density and/or other covariants of leaflet development. At equivalent Type VI densities L. hirsutum leaflets were more resistant than those of L. esculentum. Thus, differential density of the Type VI trichome did not account fully for the resistance of the L. hirsutum plants. Mite mortality was associated with the presence of the L. hirsutum Type VI trichome tips and mite avoidance was associated with other factors that covaried with L. hirsutum leaflet development and leaflet surface.

Open Access

Abstract

A full-sib family of F2 individuals from a cross between mite-susceptible Lycopersicon esculentum Mill and mite-resistant Lycopersicon hirsutum Humb and Bonpl. was assayed for trichome characters and resistance to spider mites (Tetranychus urticae Koch). Mite responses primarily were associated with density of the Type IV trichome and, to a much less degree, with the leaflet surface bioassayed and phenol content of the Type VI trichome tip. Mite survival on F2 hybrids with at least 5.6 Type IV trichomes per mm2 was comparable to that on L. hirsutum.

Open Access

Abstract

Trichome secretion composition, glandular trichome densities, and spider mite resistance were measured for 10 accessions of Lycopersicon hirsutum Humb. & Bonpl., a wild, South American relative of tomato exhibiting high arthropod resistance. The sesquiterpene hydrocarbons zingiberene and γ-elemene were identified as major volatile components of Type VI trichome secretions from L. hirsutum f. typicum (hir) plant introduction (PI) 251303. These compounds predominated trichome secretions from five other hir accessions, whereas the methyl ketones 2-undecanone and 2-tridecanone predominated trichome secretions from five accessions of L. hirsutum f. glabratum (gla). Type IV trichome densities were greater on gla than on hir accessions, whereas Type VI trichome densities were greater on hir than on gla. Type VI trichome densities were greater on plants cultured under a 14- to 15-hr photoperiod (LD) than on plants cultured under an 8-hr photoperiod (SD) for gla, but not hir, accessions. Type IV trichome densities were greater under SD than under LD conditions for all accessions. In general, hir accessions were more resistant to mites (Tetranychus urticae Koch) than gla accessions. Spider mite resistance was correlated with Type IV trichome density on hir, but not on gla, accessions. Differences in Type IV trichome densities alone between hir and gla do not explain the greater mite resistance of hir accessions.

Open Access