Host status and damage potential of Paratrichodorus renifer and Pratylenchus penetrans (Nematoda) to blueberry (Vaccinium spp.)

Abstract

Stubby root nematodes (Paratrichodorus species) and root lesion nematodes (Pratylenchus species) have been found in root zone soil of blueberry plants in most blueberry-growing regions of North America. Relatively little is known, however, of the reproductive potential and damage caused by these nematodes to blueberry. We performed controlled inoculation studies in a greenhouse in order to assess population growth and damage caused by Paratrichodorus renifer and Pratylenchus penetrans on a range of blueberry cultivars, including representatives of Vaccinium corymbosum (four cultivars), V. angustifolium (one cultivar) and V. ashei (one cultivar). All tested blueberry cultivars were considered good hosts to P. renifer (reproduction factor (RF) values > 1.0) except V. ashei ‘Powderblue’ which was considered a poor host (RF = 0.2 and 0.1 for trials 1 and 2, respectively). Paratrichodorus renifer reduced root biomass of susceptible blueberry cultivars; however, this effect was not consistent across trials. Pratylenchus penetrans did not reproduce on any blueberry cultivars under greenhouse conditions. Population growth and damage caused by P. renifer on V. corymbosum × angustifolium ‘Chippewa’ was assessed using field microplots. Paratrichodorus renifer reduced berry yield, canopy volume and top dry weights two years after inoculation by 40, 25 and 25%, respectively. Our results clearly indicate that P. renifer population densities increase on V. corymbosum and V. angustifolium and the nematode is potentially damaging to blueberry.