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For large production of

For large production of sunflowers, soil preparation (to avoid compact soil), row width, and proper seed distribution are major facts to prevent issues.
In terms of insects, it is best to watch the fields. Many insects are attracted to the field during flowering, including beneficials; therefore, insects should be properly identified before indiscriminately spraying. When insect problems develop, we advise you to contact your county extension agent or specialists for the recommended insecticides in your state.
In terms of most diseases, fungicidal protection is not normally economical; growing resistant varieties, if available, and using pest management practices is the best way to minimize losses.
In terms of weeds, early season control is what it is all about. Sunflowers can compete with weeds but not until they're more mature. Hopefully, you destroyed early emerged weeds prior to planting. Consider applying a herbicide (example: Treflan, Amiben). Sunflower seedlings are strongly rooted, so they can be harrowed (with a revolving hoe) during the 4 to 6 leaf stage. After they emerge, harrow should be done across the rows on a warm, sunny day to get best weed kill and little crop injury.