Background atmospheric burden of nematodes in California's Sacramento Valley

Abstract

Arid and semi-arid regions of the world, southwestern United States, North Africa and the Mediterranean basin, Asia, Australia, and elsewhere periodically suffer dry wind storms of high intensity that lift and carry soil particles long distances. It has long been suspected that aerial transport of nematodes might be a factor in their distribution (Filipjev and Sehuurmans Stekhoven 1941). Although nonviable cysts of the golden nematode of potatoes were collected from a trap suspended 150 cm above a heavily infested field, viable cysts were found in wind-blown soil collected from the surface of snowdrifts some 300 meters from an infested field (Chitwood, 1951). Subsequently White, 1953, suggested that strong winds over infested potato fields were capable of transporting potato root eel worm to other fields. In a report from West Texas, a region with frequent dust storms, sediment from dust traps were found to contain 23 genera of nematodes, half of which were plant-parasitic forms (Wari: and Cox, 1951). In a review concerned with world dissemination of the cereal cyst nematode it was suggested that wind transport was the primary mode of dispersion of the nematode in the wheat fields of Australia (Orr and Newton, 1971; Meagher, 1977). In heavy dust storms several centimetres of topsoil (and its associated burden of nematodes) may be transported considerable distances. However, the carrying potential of wind under mildCl" conditions is poorly understood. This study was intended to assess the dissemination of soil and nematodes under the wind conditions of a normal summer in the Sacramento Valley of California.