Meloidogyne arenaria Development in Three Clover Populations

Abstract

Root‐knot nematodes (RKN; Meloidogyne spp.) limit productivity of red clover (Trifolium pratense L.) in southeastern USA. Root‐knot nematodes damage root systems affecting water and nutrient uptake and predispose plants to other soil‐borne pathogens. Penetration and development of M. arenaria (Neal) Chitwood Race 1 on three clover populations differing in resistance levels were evaluated in two greenhouse experiments conducted in two years (1993 to 1995). The RKN susceptible cultivar Kenstar red clover, a red clover breeding selection designated FLMR6 with moderate RKN resistance, and a highly RKN resistant species T. stoioniferum Muhlenberg, running buffalo clover (RBC), were grown in Cone‐tainers (Stuewe and Sons, Inc., Corvallis, OR) and inoculated with 450 M. arenaria Race 1 second‐stage juveniles (J2) 21 after se ed germination. Numbers of J2, J3‐J 4 (thi rd‐stage or fourth‐stage juvenile nematodes), and adults at 1, 2, 4, 8, 16, 24, 36, 48, 60, 80 (Exp. 2), and 120 (Exp. days aft er inoculation (DAI) were measured. Fecundity was characterized by counting number of egg masses and total number of eggs per plant at 80 and 120 DAI. Kenstar had more J2 in roots at 4, 36, 48, 60, 80, and 120 DAI than FLMR6 or RBC. At 48 DAI, more J3‐J4 were found in Kenstar than in FLMR6 or RBC. Fewer adults were found in FLMR6 and RBC than in Kenstar at 36, 48, 60, 80, and 120 DAI. At 120 DAI, adult numbers in FLMR6 and RBC were 2.4 and 0.2%, respectively, of the number in Kenstar. Number of egg masses and total number of eggs per plant on Kenstar were greater than on FLMR6 and RBC. The reduced fecundity of M. arenaria on the FLMR6 red clover breeding selection suggests this population should be evaluated for use in rotations with RKN susceptible crops.