Preliminary surveys of peach orchards showed the presence of Meloidogyne hapla, M. incognita, M. incognita var. acrita and M. javanica on Prunus amygdalus[Prunus dulcis] var. amara and P. pérsica stocks, the commonest being Ai. javanica on both stocks, and the least common M. hapla (found only on P. pérsica). In a survey of a single orchard where only M. javanica was found, 7 of 8 Yunnan stocks were infested, 3 of 6 Shalil and one of 3 S-37. No infestation was found on 3 apricot rootstocks (var. Klabi) or on Marianna or Myrobalan plum rootstocks. Very light infestations were found on sour and sweet sports of P. cerasus. In a 3-year-old peach orchard infested with M. javanica the rootstocks Shalil, Elberta and Beladi were all infested, S-37 showed some resistance and Klabi apricot was completely resistant. The resistance of S-37 was vary variable, some trees being free from infestation and others badly galled. The authors consider that the conflicting results are due to the high degree of variability amongst the peach seedlings and that the problem of resistance can be solved by the production of clones by vegetative propagation. M.T.F.
Preliminary surveys of peach orchards showed the presence of Meloidogyne hapla, M. incognita, M. incognita var. acrita and M. javanica on Prunus amygdalus[Prunus dulcis] var. amara and P. pérsica stocks, the commonest being Ai. javanica on both stocks, and the least common M. hapla (found only on P. pérsica). In a survey of a single orchard where only M. javanica was found, 7 of 8 Yunnan stocks were infested, 3 of 6 Shalil and one of 3 S-37. No infestation was found on 3 apricot rootstocks (var. Klabi) or on Marianna or Myrobalan plum rootstocks. Very light infestations were found on sour and sweet sports of P. cerasus. In a 3-year-old peach orchard infested with M. javanica the rootstocks Shalil, Elberta and Beladi were all infested, S-37 showed some resistance and Klabi apricot was completely resistant. The resistance of S-37 was vary variable, some trees being free from infestation and others badly galled. The authors consider that the conflicting results are due to the high degree of variability amongst the peach seedlings and that the problem of resistance can be solved by the production of clones by vegetative propagation. M.T.F.