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Scout Sugarbeet Fields to Check for Presence of Fusarium Yellows and Fusarium decline (6/29/17)

Fusarium yellows/Fusarium decline were first observed in May at the NDSU research site in Moorhead, MN.

Scout Sugarbeet Fields to Check for Presence of Fusarium Yellows and Fusarium decline

Fusarium yellows/Fusarium decline were first observed in May at the NDSU research site in Moorhead, MN. The fungi Fusarium oxysporum and Fusarium secorum are the causal agents for Fusarium yellows and Fusarium decline, respectively. Fusarium yellows/Fusarium decline may cause significant reduction in plant stand, root yield and extractable sucrose.

Infection may impact seedlings or older plants in fields starting early in the growing season. In seedlings and young plants, oldest leaves become yellow (Figure 1) following by wilting and death. Cross sections of roots typically will show darkening of the vascular system. On older plants (4 leaves and older), symptoms include interveinal yellowing and death of older leaves (Figure 2), sometimes distinct necrosis of half the leaf on one side of the midrib (Figure 3) which then spreads over to the other side of the mid-rib; necrosis and death of older leaves followed by death of the younger leaves. Under severe disease conditions, infected plants may die. In many instances where disease is not severe, plants may display typical foliar symptoms but survive. Roots of seedlings and older plants with distinct foliar symptoms have roots which appear healthy on the outside, but when these roots are cut in a cross section, there is a distinct darkening and damage of the vascular system (Figure 4). Roots of infected plants will not store well in piles and have very high respiration rates and low sugar concentration. The best and only way to manage Fusarium yellows is to plant tolerant varieties, several of which are available. Consult your agriculturists or seed sales representatives for Fusarium tolerant varieties appropriate for your growing area. Send plants with symptoms to Dr. Ashok Chand at University of Minnesota Crookston for confirmation of the pathogen.

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Mohamed Khan

Professor & Extension Sugarbeet Specialist

NDSU & U of MN

701-231-8596

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