Cause Three genera, the ring nematode, (Mesocriconema spp.), the stubby root nematode (Paratrichodorus spp.), and the sheath nematode (Hemicycliophora spp.) are the most common in the Pacific Northwest. A survey in the mid-1990s of 53 Oregon and Washington cranberry beds showed the incidence and population densities of these nematodes were slightly higher in weak areas of beds but not significantly greater than in strong areas. It has been suggested that nematode parasitism may increase the severity of root-rot diseases caused by soilborne pathogen fungi, but this has not been demonstrated experimentally. No nematode-resistant cranberry cultivars are known.
Symptoms These three nematodes have been reported in greenhouse studies to reduce runner growth and to cause darkened, stunted, or galled roots. It is unclear what role they play in cranberry plant health under field conditions.
Sampling Soil samples may be collected for nematode analysis to determine whether population densities may be potentially damaging.
Cultural control Most data suggest that nematode control is not warranted in mature beds. However, the establishment of new plantings may be reduced on nematode-infested sites.
- Vine cuttings from beds with a history of nematodes should not be used to establish new plantings.
Chemical control Soil fumigation is recommended before replanting on land with a history of nematode problems.
Biological control
- MeloCon WG (Paecilomyces lilacinus strain 251) at 2 to 4 lb/A plus a soil wetting agent can be applied to established plants, although it might be better used when applied to plants just before planting. Stable for only days at room temperature, weeks in the refrigerator or for a year if frozen. Unknown efficacy in the PNW. 4-hr reentry. O
Reference Forge, T.A., Pinkerton, J.N., Koch, C., Fitzpatrick, S. and Sabaratnam, S. 2009. Plant-parasitic nematodes associated with highbush blueberry and cranberry in British Columbia, Washington, and Oregon. Canadian Journal of Plant Pathology 31:120-121.