Pest Management News – March 31, 2015

Grain Sorghum

Iron Chlorosis and Sorghum Downy Mildew are two common seedling problems found in the Coastal Bend. Both are reoccurring problems in fields when planting to sorghum.Iron Chlorosis Field800

Iron Chlorosis can be identified by the interveinal yellowing on leaves of plants. Extension Publication “Correcting Iron Deficiencies in Grain Sorghum” states:

“Producers have had to rely on foliar amendments to Iron Chlorosis sorghum IMG_0196place available iron into the plant. If early deficiency symptoms are observed or occur every year on certain fields, banded foliar treatments should begin as early as sufficient leaf area is present to intercept the material used. This is usually 10 to 14 days after the sorghum has emerged. A common mistake is not starting ferrous applications soon enough and then failing to follow-up with subsequent needed applications.

A spray solution can be prepared using 20 pounds of iron sulfate (copperas) in 100 gallons of water, plus a spreader sticker, and spraying the solution over the crop row at 5 gallons per acre (10 to 14 days after emergence). After the first treatment, products should be applied as required at 7 to 10 day intervals using the same solution concentration, but increasing application rates to 10 to 15 gallons per acre.”

This publication can be found at: Correcting Iron Deficiencies in Grain Sorghum

Sorghum Downy Mildew (SDM) is a soil borne disease of sorghum which is usually managed through the use of seed applied fungicide and resistant hybrids. In recent years, a pathotype of SDM has developed resistance to Sorg Dwny Mildew012fungicides.  This resistant SDM has been found locally in recent years Calhoun Refugio and Victoria Counties.

As your fields emerge, look for signs of SDM. The disease is easy to detect early in the season before the unaffected plants outgrow the diseased plants. Infected seedlings are pale yellow or have light-colored streaking or mottling on the leaves, often accompanied by a white, fuzzy growth of the fungus on the underside of leaves.

More information on Sorghum Downy Mildew can be found at: SDM-Symptoms

Sorghum Planting Rate Trials

I am still looking for locations to plant sorghum planting rate trials.

Call me to set a planting rate trial up on your farm. 361-920-1138.

We can plant and harvest seeding rate trials from the cab of the tractor and harvester without delaying either of these activities.

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