Sunflower Beetle
Zygogramma exclamationis
A small cream-and-brown striped leaf beetle, one of the most damaging defoliators of cultivated sunflower. Adults shot-hole the leaves and the humpbacked larvae chew larger windows, mostly hitting young plants.
🔎 How to spot it
Adults are about a quarter inch long with a reddish-brown head and cream-colored wing covers marked by lengthwise brown stripes, the lowest of which ends in a dot like an exclamation point that gives the beetle its name. It is smaller than the Colorado potato beetle and does not feed on potato. Larvae are pale green to yellowish with a swollen, humpbacked abdomen.
🥀 Damage it causes
Adults chew small shot holes in the leaves, while the more damaging larvae chew larger window-like patches. Heavy feeding on seedlings and young plants can stunt growth, though established plants usually outgrow moderate damage. Wild sunflower sustains local populations when cultivated plants are absent.
🛡️ Prevent it
Later plantings are usually less affected, so adjusting planting date is one cultural tactic. Scout young plants as overwintered adults emerge in late spring and early summer. Tillage has little effect on overwintering adults, so it is not a reliable control.
🧯 If it is already here
Treat when adults run roughly one to two per seedling, or when larger plants show about ten to fifteen larvae per plant or a quarter of the leaf area lost, using a labeled insecticide. Natural enemies including predatory bugs, ground beetles, birds, and tachinid flies help suppress numbers. Hot, dry weather and heavy rain also kill many eggs and young larvae.
💡 Good to know
There is one generation a year, and adults overwinter in the soil and emerge in late spring. A degree-day model can predict adult emergence to time scouting. Each female can lay anywhere from a couple hundred to two thousand eggs over several weeks.
🌱 Plants it attacks
3 plants in the library can be attacked by this pest
For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.