RESUMEN
Application of the bio-agent fungi Trichoderma harzianum and Paecilomyces lilacinus to the naturally infested soil with citrus root nematode Tylenchulus semipenetrans and pathogenic fungi during autumn season 1999, revealed a significant decrease in their population densities compared with untreated [control] trees after two years of application. Application of Cadusafus [Rugby] and Agrifos together confirmed their high efficacy in controlling the nematode-fungi disease complex and significantly decreased their population densities. Besides the growth parameters and the yield/tree, significantly improved and increased up to 78.3, 75.6 and 71.4% of the treated trees with P. lilacinus, T. harzianum and Rugby + Agrifos, respectively two years after soil application. When foliar fertilizers sprayed to the trees regularly for 6 months [May -October] at two weeks intervals in each year, the yield/tree improved and increased more up to 80.3, 78.2 and 78.2%, respectively