Pythiaceous fungi and plant-parasitic nematodes in California pear orchards: II. Incidence and distribution of parasitic nematodes in orchard soils

Abstract

Plant-parasitic nematodes of various types are prevalent in the upper root zone of pear trees in California. Monthly samplings over a 12-month period, from the same 126 orchards mentioned above, showed that the dagger nematode Xiphinema americanum and the pin nematode Paratylenchus hamatus occurred in more than 90 per cent of the orchards and in all pear-growing areas of the state. Other nematodes frequently found were species of Tylenchorhynchus, Pratylenchus, Helicotylenchus, Meloidogyne, and Criconemoides. No direct relationship was indicated between pear decline and nematodes in orchard soils.