Response of "Troyer" citrange seedlings infested with Tylenchulus semipenetrans Cobb in three different soils

Abstract

The effect of several plant parasItIC nematodes on their host may be greatly influenced by physical and chemical characteristics of the soil. The citrus race of burrowing nematode Radopholus similis (Cobb) Thorne was favoured by a coarse-textured soil, whereas Pratylenchus coffeae (Zimmermann) Filipjev-Schuurmans Stekh. was favoured by a fine textured soil (O'Bannon et al., 1976; Tomerlin and O'Bannon, 1973). Also, damage to crops infested by Meloidogyne species is usually greater in sandy soils than in fine-textured soils (Sasser and Taylor, 1978). The citrus nematode Tylenchulus semipenetrans Cobb tolerates many soil types (Cohn, 1972), but the population densities of this nematode increased more rapidly in a fine-textured soil or in soils high in organic matter than in coarse sands (O'Bannon, 1971, 1976). The purpose of this study was to evaluate the influence that three Sicilian soil types may have on the population dynamics of T. semipenetrans and on the nematode damage induced on « Troyer >> cit range [Citrus sinensis (L.) Osb. x Poncirus trifoliata (L.) Raf J seedlings, and subsequent effect of the nematodes on the seedlings in a glasshouse test, in Sicily, in 1976-1978.