 |
ProCrop |
Disease Problems
Disease have been a problem in years of above normal rainfall with extended periods of high humidity. The most serious disease under these conditions in Alternaria leaf spot (Alternaria carthami) and Pseudomonus bacterial blight (Pseudomonus syringae). Alternaria is characterized by the development of large brown, somewhat irregular spots on leaves and flower bracts. The resultant loss of photosynthetic tissue reduces yield. Planting of disease free and appropriately treated seed is recommended. Safflower should never be sown on the same field town consecutive years. Growers should select varieties carefully since some are more susceptible to Alternaria leaf spot than others.
Bacterial blight has symptoms very similar to Alternaria leaf spot and usually appears after heavy rains. Symptoms include reddish brown lesions that turn white with age. These lesions usually have yellow green margins. Both disease organisms can be found on the same plant, Control practices for bacterial blight are the same as for Alternaria leaf spot, variety selection and disease free seed.
Safflower rust (Puccinia carthami) is rarely a problem. The seed borne spores of safflower rust are readily controlled by seed treatment. The planting of clean, disease-free seed and the use of seed treatments are recommended practices. Infection may occur from disease spores overwintering on safflower residue. Proper crop rotation and field selection are important.
Other diseases that could cause reduction in yield but have not been a problem in recent years in North Dakota are: 1) Sclerotinia root rot or head rot - infection from ascospores, 2) Botrytis head rot - needs wet conditions at flowering and may be a serious disease in higher rainfall areas or under irrigation, 3) Phytophthora root rot - usually occurs under water logged soil, 4) Verticillum wilt - cold, wet weather after planting is needed, 5) Fusarium wilt - needs cool, wet weather in early season and 6) Pythium root rot.
Control of these diseases is best obtained by planting disease-free seed, treating the seed with proper fungicides and crop rotation. Safflower should never follow safflower, sunflower, dry bean, soybean, mustard, canola/rapeseed or lentils in a rotation. A four-year rotation should separate these susceptible crops. When possible, select varieties with disease tolerance. Most of the newer varieties have some tolerance to the major diseases.
Back to Disease -
Safflower Menu
Back to Safflower Menu
Back to Main ProCrop Index
