Host Suitability of Forage Grasses and Legumes for Root‐Lesion Nematode Pratylenchus penetrans

Abstract

Pratylenchus penetrans reduces the productivity of many forage crops in northern USA and eastern Canada. Our objective was to determine the host suitability of forage grasses and legumes for P. penetrans in greenhouse, growth chamber, and field environments. In the greenhouse and growth chamber environments, P. penetrans reproduced on all forage grasses (17) and legumes (12). Both the legumes and grasses varied (P < 0.05) for numbers of nematodes and eggs in the roots. The most suitable hosts included kura clover (Trifolium ambiguum M. Bieb.), alsike clover (Trifolium hybridum L.), white clover (Trifolium repens L.), oat (Avena sativa L.), and rye (Secale cereale L.). The least suitable hosts included pearl millet [Pennisetum glaucum (L.) R. Br.], tall fescue (Festuca arundinacea Schreber), perennial ryegrass (Lolium perenne L.), forage sorghum [Sorghum bicolor (L.) Moench], sudangrass (Sorghum sudanense Pers.), sudex (Sorghum sudanense ✕ S. bicolor), sweetclover (Melilotus alba Desr.), crownvetch (Coronilla varia L.), and MNGRN‐16alfalfa (Medicago sativa L.). Twelve legumes and 9 grasses were transplanted into a field infested with P. penetrans and one‐half the plants were treated with carbofuran (2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranol methylcarbamate). Pratylenchus penetrans reproduced on all entries. Numbers of nematodes per gram fresh root of entries in the greenhouse‐growth chamber and field tests were correlated for both the control (r = 0.60, P< 0.05) and carbofuran treatment (r = 0.48, P < 0.05). We concluded that many forage species are hosts for P. penetrans, but a few legumes and grasses are poor hosts and may be useful in forage rotations to reduce nematode populations.

Reproduction of Pratylenchus penetrans on various rotation crops in Quebec

“…(2000) reported P. penetrans suppression by pearl millet in infested tobacco fields. Thies et al (1995) observed low P. penetrans numbers in pearl millet roots. Bromegrass was also a poor host of the root-lesion nematode but to a lesser extent than the forage millet.…”

“…The root-lesion nématode, Pratylenchus penetrans (Cobb) Filipjev and Schuurmans-Stekoven, is an endoparasitic nématode that reduces yield and quality in many crops including forages (Kimpinski et al 1984;Thies et a/.1995), vegetables (Olthof and Potter 1973), potato {Solarium tuberosum L.) (Olthof 1989), and tobacco {Nicotiana tabacum L.) (Jagdale et al 2000). In Québec, rye {Secale céréale L.) and oats {Avena sativa L.) are often grown in rotation with vegetables and tobacco.…”

“…In Québec, rye {Secale céréale L.) and oats {Avena sativa L.) are often grown in rotation with vegetables and tobacco. Unfortunately, they are good hosts of P. penetrans, which multiplies to high densities in their roots (Dunn and Mai 1973;Thies et al 1995), thereby increasing initial nématode populations in the subséquent crop yr. Reduced yields in Québec due to P. penetrans damage has increased relîance on broad-spectrum fumigants priorto both potato and tobacco planting.…”

“…MacDonald and Mai (1963) hâve reported that root-lesion nematode multiplied well on soybean and râpe. Rye and oats, which are usually used as rotation crops, are known to be good hosts of the root-lesion nematode (Thies et al 1995;Florini and Loria 1990). Therefore, an interesting management approach would be to use forage pearl millet as a rotation crop instead of the usual cereals that can increase nematode pressure on subséquent crops due to their good host status.…”

Effect of crop rotation with grain pearl millet on Pratylenchus penetrans and subsequent potato yields in Quebec

“…Unfortunately, rye is a good host of P. penetrans (Bélair et al 2002;Dunn and Mai 1973;Olthof 1980;Thies et al 1995); therefore, when used as a rotation crop, rye may increase nematode damage and yield losses on subsequent crops. Soil fumigation with chemicals such as metam sodium is commonly used in Quebec potato production to control P. penetrans populations and increase potato yields.…”