Watch for micronutrient deficiencies in sugarbeets

Manganese and boron deficiency are common micronutrient problems found in sugarbeets.

When scouting sugarbeet fields, growers should keep a watchful eye for manganese (Mn) and boron (B) deficiency. These two micronutrients are the most common deficiencies seen in Michigan’s lake bed soils. Sugarbeets are considered a highly responsive crop to manganese if nutrient concentration is low and deficiency symptoms are seen. The response to boron is considered moderate. Micronutrient deficiencies can generally be minimized with one or two timely foliar applications.

Symptoms of manganese normally occur as chlorosis in the younger leaves and can be seen as netted veining viewed against the light. As severity of the symptoms increase, leaf blades on deficient plants can fade from green to a uniform yellow with a metallic grey to purplish luster. This is often accompanied by gray to black freckling along the veins. Soils with higher pH or organic soils are most prone to deficiency. Foliar applied manganese sulfate type materials are most effective and will get the most manganese into the plant. These materials can be mixed with fungicides. However, antagonism (reduced efficacy) may occur if mixed with Round-Up. Chelated manganese fertilizers can safely be mixed with both fungicides and Round-Up. However, chelated manganese can be less effective because less nutrient is supplied to the plant. Follow directions and reapplication intervals if needed according to each specific fertilizer product.

Boron deficiency symptoms in sugarbeets first occur as white, netted, chapping of upper blade surfaces or wilting of tops. Later, if deficiency becomes severe, transverse (crosswise) cracking of petioles develop; the new leaves in the growing point may turn black. Internal and external crown darkening symptoms often can be seen. Symptoms are mostly observed in low organic, sandy soils and under droughty conditions. The boron carrier most frequently used is sodium borate and can range from 10 to 20 percent nutrient. Boron products are marketed under different trade names. Always follow labeled directions for rate and reapplication intervals when applying materials. These products can be antagonistic when applied with Round-Up, but are generally safe to apply as a tank-mix with fungicides.

If sugarbeet producers have concerns about adequate nutrient sufficiency or confirming symptoms that are seen, a foliar analysis should be considered. Foliar testing services are available through local fertilizer suppliers and Michigan State University soil testing laboratory.

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