Plant–parasitic nematodes were first reported in Rubus species in North America in the 1930s, when Pratylenchus species were associated with declining red raspberries (Rubus idaeus L.) (McElroy, 1992). Of the plant–parasitic nematodes associated with raspberry, Pratylenchus penetrans, the root lesion nematode, is the most economically important (McElroy, 1991). Feeding on roots by Pratylenchus penetrans (Cobb) Filipjev and Schuurmans Stekhoven can reduce the capacity of the plant to uptake nutrients and water. Pratylenchus penetrans was shown to cause 24% mortality of ‘Willamette’ red raspberry plants after 2 years (McElroy, 1977). In other studies, soil fumigation to control P. penetrans before planting red raspberry dramatically increased yields (Seipp, 1986; Trudgill, 1986), and in one study, there was a 98% increase in yield of fumigated plots compared with non-fumigated plots containing P. penetrans in the first year of production (Bélair, 1991). Rate of decline will depend on the cultivar, but significant yield loss can occur when this nematode is left unchecked and population densities increase on raspberry plants.
Since the 1940s, growers have been able to manage plant–parasitic nematodes in raspberry by pre-plant soil fumigants and/or post-plant treatment with fenamiphos. In recent years, increased understanding of the negative environmental and health impacts of these compounds has led to restrictions or termination of their legal use. The registration for fenamiphos was cancelled in the United States [U.S. Environmental Protection Agency (EPA), 2008] and methyl bromide use in all U.S. commodities is in the process of being phased out. In addition, broadcast fumigation will become more burdensome with new EPA reregistration eligibility decisions (U.S. EPA, 2013); raspberry growers currently rely on a combination of 1,3-dichloropropene and chloropicrin for pre-plant fumigation. As a result, the raspberry industry is at a point in time when new, long-term, and economically viable P. penetrans management strategies must be developed.
A key component of any integrated nematode management program is resistance. Having resistance as a tool to manage P. penetrans in raspberries would reduce the impact of this nematode on raspberry productivity as well as reduce the need for pre- and/or post-plant chemical treatments to keep this nematode in control. Although there are red raspberry breeding programs actively developing cultivars resistant to Phytophthora rubi and Raspberry Bushy Dwarf Virus, none are currently attempting to identify sources of resistance to P. penetrans, a significant production constraint to raspberry (Bélair, 1991; McElroy, 1977). Efforts have been made to evaluate raspberry cultivars for their reactions to P. penetrans (Bristow et al., 1980; Vrain and Daubeny, 1986). Rubus idaeus ‘Newburgh’, ‘Chilcotin’, ‘Skeena’, and ‘Canby’ were susceptible to P. penetrans, whereas the other tested cultivars, including ‘Latham’ and ‘Matsqui’, had varying levels of resistance to P. penetrans (Bristow et al., 1980). Vrain and Daubeny (1986) also screened several commercially available raspberry cultivars for their reaction to P. penetrans; ‘Nootka’ was the most resistant and ‘Glen Clova’ and ‘Chilcotin’ were the most susceptible; ‘Meeker’, ‘Skeena’, ‘Willamette’, and ‘Haida’ were intermediate in reaction. The most resistant material screened in this study was not from a R. idaeus cultivar, but rather from a Japanese accession of R. crataegifolius. These results indicate that resistance might be more readily identified in Rubus species other than raspberry.
The long-term goal of this research program is to identify a source of resistance in Rubus species to P. penetrans that can be incorporated into a red raspberry cultivar of commercial quality. The objective of the experiment described here was to determine the host status of Rubus species and hybrids to P. penetrans.
Bélair, G. 1991 Effect of preplant soil fumigation on nematode population densities and on growth and yield of raspberry Phytoprotection 72 21 25
Fernández-Fernández, F., Antanaviciute, L., Govan, C.L. & Sargent, D.J. 2011 Development of a multiplexed microsatellite set for fingerprinting red raspberry (Rubus idaeus) germplasm and its transferability to other Rubus species J. Berry Res. 1 177 187
Ferris, H., Carlson, H.L., Viglierchio, D.R., Westerdahl, B.B., Wu, F.W., Anderson, C.E., Juurma, A. & Kirby, D.W. 1993 Host status of selected crops to Meloidogyne chitwoodi J. Nematol. 25 849 857
Hong, S.B., Lee, D.K., Kim, Y.H., Kong, J., Oh, S.D. & Kim, J.H. 1971 Characteristics of 7 Korean raspberry lines (Rubus crataegifolius) selected as recommendable in Korea The Research Reports of the Office of Rural Development, Suwon, Korea (South) 14 51 55
Ingham. 1994 Nematodes, p. 459–490. In: Weaver, R.W., S. Angle, P. Bottomley, B. Bezdicek, S. Smith, A. Tabatabai, and A. Wollum (eds.). Methods of soil analysis. Part 2. Microbiological and biochemical properties no. 5. Soil Science Society of America Press, Madison, WI
McElroy, F.D. 1991 Nematode parasites, p. 59–62. In: Ellis, M.A., R.H. Converse, R.N. Williams, and B. Williamson (eds.). Compendium of raspberry and blackberry diseases and pests. APS Press, St. Paul, MN
Peerbolt Crop Management 2013 Small fruit update. 15 Jan. 2014. <http://www.berriesnw.com/SFU/2013/44-SFU10-29-13.pdf>
Trudgill, D.L. 1986 Effect of soil treatments for the control of Pratylenchus penetrans (Nematoda) on the growth and yield of raspberry (Rubus idaeus) in eastern Scotland Crop Res. 26 89 109
U.S. Environmental Protection Agency 2008 Fenamiphos; product registration cancellation order. 18 Dec. 2013. <http://www.epa.gov/fedrgstr/EPA-PEST/2008/June/Day-18/p13623.pdf>
U.S. Environmental Protection Agency 2013 Implementation of risk mitigation measures for soil fumigant pesticides. 18 Dec. 2013. <http://www.epa.gov/pesticides/reregistration/soil_fumigants/>
Vrain, T.C. & Daubeny, H.A. 1986 Relative resistance of red raspberry and related genotypes to the root lesion nematode HortScience 21 1435 1437