By Nikki Phipps
(Author of The Bulb-o-licious Garden)
Sunflowers are popular mainstays in many home gardens and growing them can be especially rewarding. While sunflower problems are few, you may encounter them on occasion. Keeping your garden clean and free of weeds and debris, however, is your best line of defense in preventing these sunflower problems from occurring.
Pest Management in Sunflower Plants
Not many pests bother the sunflower and those that do only wreak havoc in large numbers. The most common sunflower pests include the following:
- Sunflower Beetles – Sunflower beetles typically feed on the leaf foliage and in small numbers or older plants may seldom hurt the plants. However, on younger sunflower plants, the first true leaves can be severely damaged or completely consumed.
- Cutworms – Cutworms can also damage the leaves of young sunflowers, leaving notches or holes. Wilting may also occur. Again, these are usually not a major issue unless there is a heavy infestation.
- Sunflower Borers – Sunflower borers and stem maggots burrow into the stems of sunflower plants to feed. This can quickly kill the vegetation and other parts of sunflower plants, especially in large numbers.
- Sunflower Moths – Sunflower moths are one of the most destructive pests to sunflowers, laying their eggs within the flowers. Once the eggs hatch, the larvae move into the flower heads to feed, ultimately destroying the plants.
- Grasshoppers - Grasshoppers and various caterpillars also enjoy nibbling on sunflower foliage. While rarely a major problem, large numbers can quickly defoliate plants.
Pest management in sunflower plants involves prevention. Keeping the area free of weeds and debris can help. Damage can also be reduced by treating the area before sunflower pests become well established. Later planting, such as in June or July, may also help alleviate any problems. While there are many broad spectrum insecticides available for sunflower use, organic insecticides, which are deemed safer, can be used as well – including Bt products.
Sunflower Problems with Disease
Although sunflowers can be affected by some disease problems, rarely is this an issue, as these plants are typically quite hardy. Various leaf spot diseases may cause surface spots or yellow patches. Rust, verticillium wilt, and powdery mildew can also affect sunflower plants on occasion.
However, the most common threat to these plants is Sclerotinia stem rot, also known as white mold. This fungus can cause sudden wilting of leaves, stem cankers and root or head rot. Crop rotation can reduce the likelihood of this disease as well as proper watering practices.