Complex Problem Currently Facing Louisiana's Number One Sugarcane Variety

By Dr. Jeff Hoy, LSU AgCenter Plant Pathologist

Non-rust problem very evident now. For lack of a better name will call it brown stripe complex. Mainly in L 01-299 but can also affect HoCP 04-838 and HoCP 09-804. Very complicated problem that is showing throughout industry. The big rains and brief dry periods in between have synchronized cultivation activity and suddenly resulted in reports coming in from all over about hard hit fields with some reports of stool death. It is affecting plant cane and stubble with hard to explain variability between and sometimes within fields.

Brown stripe is a strongly stress related disease - just about any kind of stress - and we have had a combination that all are contributing. It is set up first of all by a mild winter resulting in early growth of the crop and weeds. The crop is trying to grow under low fertility conditions affected by the low temperatures in March continuing into April then with injury from herbicides. Prowl has been widely applied to help control itchgrass, and this appears to be an important factor. But, there are a number of different new combinations that are being tried. The rains following applications of herbicides that can move in the soil appears to have resulted in variable amounts of yellowing within and between fields. This effect is more evident in sandy soils and stubble fields harvested early, particularly for seed. Other factors that could affect variability could include soil pH and organic matter/residue.

Unfortunately, 299 is a very susceptible variety that is sensitive to herbicides. Is there a significant impact on yield when severe symptoms occur? Not sure but think maybe (hope) not. Early damage is not as detrimental to sugarcane as the grain crops because of its indeterminate growth habit. The crop is not growing much at this time and usually makes more tillers than can survive to millable stalks. It should recover once the temperatures warm and the fertilizer kicks in.

There is concern that brown stripe may be getting worse due to the widespread planting of 299 - that it is more severe now and will begin to persist longer into the season. Early efforts to control brown stripe with fungicides have not been encouraging. The rust fungicides do not seem to help, but it is hard to tell if a fungicide is effective if the plants are not growing during the protection period. We hope to get more information on fungicide efficacy.

So, some fields are struggling affected by a "multiple whammy". There is not much to be done other than get out fertilizer when you can and wait for the crop to take off. The Australians have a saying: She'll be right, mate! I am hopeful that is applicable for this situation. 

I appreciate receiving your observations about this complex, perplexing problem by text or phone. Please feel free to contact me by either means.

Regards, 

Jeff Hoy

Department of Plant Pathology and Crop Physiology

Room 302 Life Sciences Building

Louisiana State University

Baton Rouge, LA 70803

Telephone: 225-578-1392

Mobile: 225-485-4227