Nachmias, A.
Krikun, J., The Agricultural Research Organization, Gilat Experiment Station, Mobile Post, Negev, 85-280, Israel

Potato early dying, incited by Verticillium dahliae, was found to be the major factor in reducing the yield potential of potato grown under our conditions. Immediate attempts at control involved the screening of commercial cultivars and lines bred in both the USA and Europe, and various soil fumigation treatments. This work led to the selection of cultivars with reasonably high tolerance and the elucidation of the role that the nematode Pratylenchus thornei plays in the disease syndrome. Elimination of the nematode by sprinkler applied metham-sodium in conjunction with some of the above cultivars now produces yields of 40-60 metric T/ha, depending on the cultivar and season. More recently, our research has been directed towards the use of serological methods to detect the pathogen in locally produced seed tubers and the utilization of an extracellular toxin produced by the pathogen in determining resistance to the fungus. With regard to the former, we have been able to produce an antibody that reacts solely to V. dahliae and can be used in several serological tests to determine the presence of the pathogen. Our work has also shown that utilization of the toxin offers a highly reliable technique in determining at least certain forms of resistance. © 1985 Springer.