THE PEACH REPLANT PROBLEM IN ONTARIO: VI. THE RELATION OF PRATYLENCHUS PENETRANS TO THE GROWTH OF YOUNG PEACH TREES

Abstract

Further evidence was accumulated indicating that the peach replant disease decreases in severity as the interval increases in time between removal of the old orchard and the planting of new trees. The ameliorating effect of the interval may be related to the decline of Pratylenchus penetrans (Cobb, 1917) Sher & Allen, 1953. In experiments, increased growth of peach was associated with the control of P. penetrans by nematocides and P. penelrans was found to be the first nematode to attack newly developing peach roots. The populations of P. penetrans within such roots increased rapidly, then gradually declined. Generally, ectoparasites appeared later, increased relatively slowly, and occurred infrequently until late in the second growing season. The soils of all commercial peach nurseries in Ontario contain P. penetrans and the nematode may be transported in the roots of nursery stock.