Cause Xiphinema rivesi has been found in Washington cherry orchards with Cherry rasp leaf virus. Xiphinema was overall the third-most prominent genus of plant-parasitic nematode found in the Okanagan of BC, being found in 51% of cherry blocks. Dagger nematodes are migratory ectoparasites found only in soil. Their main importance is as a vector for virus diseases such as Tomato Ringspot, Tobacco ringspot virus (found in the Grand Ronde area of Oregon) and Cherry rasp leaf virus.
The threshold for dagger nematode is 10 nematodes/100 g soil but is based only on years of observations. The actual threshold could be much higher if a virus is not present and lower if every nematode has and can transmit the virus.
Symptoms In the absence of virus, large roots can become necrotic while the tips of fine root hairs may be swollen. In heavy infestations, yields are poor and growth stunted.
Sampling Collect soil samples in spring.
- Avoid sites with high soil populations of dagger nematodes.
- Long rotations may help, but control weeds since dandelion can be a virus host.
- Preplant soil fumigation. Consult or hire a professional applicator to be sure it is done safely and effectively.
- Basamid G. Avoid application when soil is over 90°F. Do not apply within 3 to 4 feet of growing plants or closer than the drip line of larger plants. Do not harvest within one year of application. 5-day reentry. Restricted-use pesticide.
- Telone II at 27 to 35 gal/A broadcast, or 24 fl oz per single tree planting site delivered 5 ft deep. 5-day reentry. Restricted-use pesticide.
- Ecozin Plus at 25 to 56 oz/A is registered for use after planting through a drip irrigation system. Label suggests using additives to aid penetration into the soil and to make applications in the morning. Efficacy in the Pacific Northwest is unknown. 4-hr reentry. O
- Velum Prime at 6.5 to 6.84 fl oz/A can be used after planting using drip, trickle of micro-sprinklers. May be applied day of harvest. Group 7 fungicide. 12-hr reentry.
Reference Akinbade, S.A., Mojtahedi, H., Guerra, L., Eastwell, K., Villamor, D.E.V., Handoo, Z.A. and Skantar, A.M. 2014. First Report of Xiphinema rivesi (Nematoda, Longidoridae) in Washington state. Plant Disease 98:1018. (Abst)
Forge, T., Munro, P., Midwood, A. J., Philips, L., Hannam, K., Neilsen, D., Powers, T. and Zasada, I. 2021. Shifting Prevalence of Plant-Parasitic Nematodes in Orchards and Vineyards of the Okanagan Valley, British Columbia. Plant Health Progress. https://doi.org/10.1094/PHP-10-20-0079-RS