Sunflowers are generally pests-free, but few creatures have an appetite for them. Deer common munch on the leaves and flower heads of sunflowers, especially when other food sources are scarce. Crows may eat newly planted seeds, while rabbits and squirrels may go after young seedlings in sunny plots. The larvae of some moths, beetles, and butterflies also find sunflower foliage edible.
Fungal diseases can also affect a sunflower’s health. Various species of rust spread reddish patches on foliage and, sometimes, stunted flowers or fruit. Powdery mildew produces powdery white spots over the plant and shriveled buds or flowers. Bacterial wilt, meanwhile, is characterized by wilting foliage and ultimately leads to stunted growth and death.
Gardeners should regularly inspect their sunflowers for signs of damage from any of these sources to maintain optimal health in the plants throughout their growing season.