Bacterial leaf blight is caused by the bacterium Pseudomonas syringae pv. syringae. The pathogen is extremely common and found on numerous weeds and other crops, but bacterial leaf blight is uncommon in the High Plains region and is generally associated with sprinkler irrigation in cool (60 to 77ºF), humid, and wet weather. The pathogen survives between crops in debris, pathogenically on alternate hosts, and epiphytically on alternate hosts and weeds. The pathogen is readily moved in irrigation water.
Bacterial leaf blight symptoms develop on the uppermost leaves after plants reach the boot stage. Small (less than 0.04 inches) water-soaked lesions expand and eventually coalesce. Initial lesions become necrotic and turn from gray-green to tan-white. Entire leaves may become necrotic, but heads and glumes are typically symptomless. Yield losses associated with bacterial leaf blight are unknown, but 50% of the plant foliage can be destroyed under disease favorable conditions.
No biological control strategies have been developed for bacterial leaf blight.
Plant high quality seed of varieties less susceptible or resistant to bacterial leaf blight. Avoid overhead irrigation, especially during cool, wet weather. Avoid reuse of irrigation tail water.
Seed treatment with copper bactericides may provide some disease control.
Product List for Bacterial Leaf Blight:
Pesticide
|
Product per 100
pounds
|
Remarks
|
|
Copper and Copper/EBDC: not all formulations are listed below |
||
|
Champ Flowable |
2 fl oz |
Seed treatment |
|
Kocide 4.5LF |
2 fl oz |
Seed treatment |
|
ManKocide |
4 oz |
Seed treatment; may provide superior suppression of copper tolerant bacteria |
|
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality. |
||
Categories: Small Grains, Disease, Bacterial Leaf Blight, Wheat, Durum, Oat, Rye, Triticale
Date: 3/8/2005