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Oral: Nematodes


Interaction between Fusarium and soybean cyst nematode on soybean
P. OKELLO (1), A. Adhikari (1), A. Varenhorst (1), S. Osborne (2), E. Byamukama (1), F. Mathew (1) (1) South Dakota State University, U.S.A.; (2) USDA-ARS, U.S.A.

The soybean cyst nematode (SCN), Heterodera glycines, and Fusarium spp. are soilborne organisms that constrain soybean [Glycine max L.] production in the United States. While Fusarium and SCN are known to coexist in soybean fields, our knowledge of how these organisms interact and the implications for management is limited. The objective of this study was to determine if any interaction occurs between Fusarium spp. and SCN on soybean under greenhouse conditions. Pre-germinated soybean seedlings of SCN-susceptible (Williams 82) and SCN-resistant (Jack) cultivars were grown in cone-tainers filled with a sand-clay soil mixture (2:1) infested with inoculum of either of the four Fusarium spp. (F. proliferatum, F virguliforme, F. sporotrichioides, and F. subglutinans). A suspension of 2,000 egg/ml suspension of SCN HG type 0 were used for inoculations at planting. The experiment was set up as factorial design with five replications for each treatment (Fusarium alone, SCN alone, and a combination of SCN and Fusarium) and repeated twice. After 39 days, disease severity as percentage of lesion length on soybean roots and SCN egg counts from soybean roots were evaluated. For disease severity, significant effects of the treatment involving Fusarium spp. was observed on the two soybean cultivars (P = 0.01). Our results from the interaction study between Fusarium spp. and SCN illustrates the need for developing targeted approaches to manage the Fusarium-SCN complex on soybean.