Control of root-knot nematodes, Meloidogyne javanica, in rooted stocks of grapevine, Vitis vinifera, by immersion in nematicide solutions at different temperatures and in hot water

Abstract

The rootknot nematode Meloidogyne javanica (Treub) Chitwood is a major pest of grapevine, especially in sandy and sandy loam soils in the Murray Valley districts of Victoria, Australia. Rooted stocks of susceptible varieties are often planted in establishing new vineyards. They are produced in the Murray Valley area in nurseries where M. javanica has always been a problem. Despite soil fumigation in this area, either with DD or EDB, planting stocks produced have been found seriously infested. Since it was shown by Meagher (1960) that immersion in hot water (51.7°C for five minutes) as practiced in California (Lear and Lider, 1959) was effective in controlling root knot nematodes, growers have refused rooted stocks that have not been treated. However, in recent years 10-20% of vines treated with hot water have been found to contain viable M. javanica, suggesting that the method may not be completely effective. Since the introduction of systemic nematicides, there has been interest in the use of these chemicals as dip treatments to control nematodes in propagative stock. Literature since 1956, comprising about 50 reports and involving at least 20 crop species and 10 nematode species, gives accounts of concentration and exposure time as (' ~terminant factors for the effectiveness of chemical dips. Promising results with rootknot nematode infested propagative material of various crop species have been reported by many workers (Ahuja, 1978; Bolander and Santo, 1977; Dale, 1973; Jain and Bhatti, 1979; Overman, 1973). However, Walker and Wilson (1962) found that the efficacy of chemicals in controlling rootknot nematodes was improved by using dip treatments at temperatures above those commonly encountered in propagating sheds, but that phytotoxicity was increased with increasing temperatures. In view of the above, the current standard hot water treatment was re-evaluated and compared with immersion treatments in systemic nematicidal solutions at a range of exposure times and at temperatures that are likely to occur in nurseries.