Poster: Diseases of Plants: Disease Detection & Diagnosis
Vermiform plant-parasitic nematodes on soybean in North Dakota and their relationship with soybean cyst nematode
G. YAN (1), G. Yan (2), A. Plaisance (3) (1) North Dakota State University, U.S.A.; (2) North Dakota State University, Department of Plant Pathology,, U.S.A.; (3) North Dakota State University, Department of Plant Pathology,, U.S.A.
Plant-parasitic nematodes (PPN) are an important group of pests on soybean. The occurrence and population densities of PPN other than soybean cyst nematode (SCN; Heterodera glycines) are unknown in soybean fields of North Dakota. A survey was conducted in 2015 in soybean fields or fields with history of SCN to ascertain the incidence and abundance of vermiform PPN and their possible association with SCN. Vermiform and cyst nematodes were extracted separately from each sample (100 cm3 soil) and then identified and quantified. Out of the 155 soil samples collected from 14 counties in North Dakota, 144 were found to be infested with PPN. Eight genera of vermiform PPN were detected including Helicotylenchus (incidence: 49%; highest density: 1,800; average density: 174), Tylenchorhynchus (41%; 340; 30), Paratylenchus (37%; 2,480; 151), Pratylenchus (19%; 245; 9), Xiphinema (7%; 180; 4), Paratrichodorous (4%; 60; 1), Hoplolaimus (3%; 140; 2), and Mesocriconema (1%; 300; 2). Both SCN juveniles (24%; 1,200; 46) from soil and SCN eggs (56%; 21,540; 501) from cysts were counted, but weak correlation was found between them for all samples (r = 0.489; p <0.0001). Poor or no correlations between population densities of each genus of vermiform nematodes and SCN were observed with r ranging from - 0.307 to 0.248. More soil samples will be collected in 2016 to confirm the occurrence and abundance of nematodes in soybean fields and the relationship of vermiform nematodes with SCN.