PATHOGENICITY AND CONTROL OF THE CITRUS NEMATODE TYLENCHULUS SEMIPENETRANS ON CITRUS, GRAPE, OLIVE, LOQUAT, AND PERSIMMON SPECIES AND CULTIVARS

The pathogenicity of the citrus nematode, Tylenchulus semipenetrans, on citrus, grape, olive, loquat, and persimmon species and cultivars was determined in several greenhouse tests. The results showed that T. semipenetrans infected and reproduced successfully on all the tested fruit species and cultivars. The citrus (lime, mandarin, and sour orange), red seedless grape (‘Crimson’), olive (‘Pikwal’ and ‘Spanish’), loquat (‘Premier’), and persimmon (‘Balady) trees were highly susceptible to T. semipenetrans, while green seedless grape (‘Thompson’) vines and olive (‘Ogeizi’) trees were susceptible to T. semipenetrans. Soil amendments with dried plant materials of horseradish tree, blue gum tree, lime, crude culture suspensions of Bacillus subtilis and B. thuringiensis, Vertimec® (abamectin), and Nemacur® (fenamiphos) were effective in suppressing T. semipenetrans infection and reproduction on sour orange. The highest reductions (90-94%) in nematode reproduction (numbers of second-stage juveniles [J2]) were recorded with treatments of horseradish tree dried leaves, Vertemic, and Nemacur. Treatments with lime peel, S. subtilis, and B. thuringiensis showed 77-86% reduction in T. semipenetrans J2 densities. Amendment with blue gum tree leaves resulted in 62-62% reduction in T. semipenetrans J2 densities. This represents the first study in Egypt on the pathogenicity of T. semipenetrans on loquat.