Pratylenchus species associated with blueberry (Vaccinium spp.) and weed species in the Pacific North-west of North America

Abstract

Blueberry (Vaccinium spp.) is a rapidly growing segment of the agricultural sectors in the Pacific North-west (PNW) of the USA and Canada. Plant-parasitic nematodes are commonly found in blueberry production fields, with root lesion nematodes (Pratylenchus species) reported as being widespread; however, the identity of these populations associated with blueberry roots has not been previously determined. Eleven blueberry production fields were sampled in 2009 and blueberry and weed roots and associated soil samples were collected in the spring and autumn to quantify and molecularly identify Pratylenchus species. The dominant species found in blueberry roots and associated soil was Pratylenchus crenatus. Across seasons, P. crenatus was recovered from 47 and 53% of blueberry root samples, at mean population densities of 66 and 50 nematodes/g root in spring and autumn, respectively. Several weed species were also identified for the first time as hosts for P. crenatus. These included Bellis perennis, Bromis sp., Calystegia sepium, Capsella bursa-pastoris, Cynodon dactylon, Echinochloa crus-galli, Epilobium angustifolium, Hypochaeris radicata, Polygonum lapathifolium, Sencio sp., Sonchus sp., Taraxacum officinale and Trifolium sp. In addition, Epilobium angustifolium, Senecio sp., and Trifolium sp. were excellent hosts for P. crenatus with > 6000 nematodes/g root. Our results demonstrate that P. crenatus is the primary root lesion nematode species present on blueberry in the PNW and that many of the weeds found in blueberry fields are also hosts for this nematode. The effect of P. crenatus on blueberry health and productivity remains to be determined.