Evaluation of Host Suitability in Prunus for Criconemella xenoplax

Authors

  • S. W. Westcott III
  • E. I. Zehr

Abstract

Methods were developed for screening Prunus selections for host suitability to Criconemella xenoplax. The relative host suitability of selections was based upon a doubling accumulation value (ß) that was defined as the number of degree-days (base 9 C) required for doubling of an increment of the initial nematode population. The ß value characteristic for C. xenoplax (139 ± 8 degree-days) on suitable hosts was similar to the average ß value determined for several peach rootstocks known to be suitable hosts. The ß values were 144 ± 21 for Halford, 141 ± 16 for Lovell, and 138 ± 10 for Nemaguard. A higher value for ß could indicate poorer host suitability or resistance of a selection to C. xenoplax. All of 369 Prunus accessions tested, including eight accessions that had survived well on a field site infested with C. xenoplax, were suitable hosts. Apparently, resistance to C. xenoplax was not a factor in survival of the accessions planted in the field. Seedlings from P. besseyi, P. pumila 'Mando', and two interspecific hybrids, Redcoat and Sapalta IR 549-1, failed to support nematode population increase in 44-81% of tests conducted, but all selections supported population increase in some tests. These accessions may have resistance mechanisms that are active only under specific conditions. Key words: carrying capacity, Criconemella xenoplax, degree-day, host suitability, Mesocriconema xenoplax, modelling, nematode, peach, population increase, Prunus, resistance.

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Published

1991-10-15

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Section

Articles