Irrigation and soil organic matter management practices affect population development of the ring nematode, Mesocriconema xenoplax, on sweet cherry

The ring nematode, Mesocriconema xenoplax, has recently become recognized as a pest of sweet cherry in the Okanagan Valley of British Columbia, but little is known of factors governing variation in population densities among orchards. In order to assess the interactive effects of irrigation systems (drip vs micro-sprinkler) and soil treatments (non-treated control, compost, bark mulch, compost+mulch, Basamidfumigation)
on nematode populations and early tree growth, a field experiment was planted in spring of 2014 at the
Summerland Research andDevelopment Centre. The experiment was set up in a randomized complete block design with six blocks of the ten treatment combinations (60 plots total). M. xenoplax was not detected at the site prior to planting. By fall of 2014, the nematode was detected at low population densities in three of the 60 plots and by fall of 2018 and 2019, M. xenoplax was present in 38 and 48% of the plots, with overall population densities of 32 and 42 M. xenoplax/ 100 cm3 soil, respectively. In 2019, population densities were 2.4-fold greater under drip than micro-sprinkler irrigation, and population densities in the compost and fumigation
treatments were greater than in the other soil treatments. Root-zone soil was consistently wetter under drip irrigation than micro-sprinkler and we speculate that M. xenoplax activity is enhanced in wetter soil. Our data suggest that it may be possible to optimize irrigation and soil management practices to minimize the impacts of M. xenoplax on cherry trees.