Texas Rice: Leaf Blast Reemerging in 2013
Leaf blast (click on photo to enlarge) has been detected in several varieties including Rex in an experimental rice field located in Jefferson County, Texas. The disease was as severe as last year with many lesions detected on lower and upper leaves. Affected rice was at the late tillering stage.
Lesions of leaf blast were first observed on June 20, apparently resulting from continuous rainy days of June 7 through 10.
Reemergence of leaf blast in Texas indicates the potential threat of this disease to Texas rice production. In 2012, leaf blast was also detected at this time of the year, which resulted in a severe outbreak of rice blast in Texas. This is the second year of the occurrence of rice blast after many years of absence of this disease in Texas.
Texas farmers and crop consultants should be watchful for rice blast this year again. Blast is one of the most explosive and damaging diseases in rice, which can completely destroy the crop within a short period of time under most favorable conditions.
Timely and proper management of rice blast is critical to reducing the damage caused by this disease. The presence of leaf blast in the field is usually the indicator to apply a fungicide for control of this disease.
Fungicides are available but fungicide timing is very important. Remember:
- If a single application is made, it should be applied at the heading stage (50 to 70% heads emerging from the boot.
- If two applications are needed because of severe disease pressure, the first application should be made at boot (2-4 inch panicle) followed by the second application at heading.
- Trifloxystrobin-containing fungicides (Stratego, 16-19 oz/A; and Gem, 3.1-4.7 oz/A) are most effective.
- Azoxystrobin-containing fungicides (Quadris, 12-15 oz/A; Quilt, 28‐34 oz/A; and QuiltXcel, 21‐28 oz/A) also are effective.
- Maintaining a continuous flood is one of the most effective management practices to reduce the damage caused by rice blast.