Bug FAQRagweed Leaf Beetle (Zygogramma suturalis)
Zygogramma suturalis · Order: Coleoptera · Family: Chrysomelidae
It feeds on common ragweed and related Ambrosia species and can have two to three generations per year depending on the region. Adults emerge in late April or early May, larvae appear from mid-May to early July, and a second larval generation occurs in early August.
Source: Wikipedia
How to recognize it
The beetle has a brown head and pronotum with yellow wing covers that show two broad brown bands, one across the middle and one along the suture.
Source: Wikipedia
Size
It is a small leaf beetle.
Source: Wikipedia
Where it lives
Adults and larvae feed on common ragweed and related Ambrosia species.
Source: Wikipedia
What it eats
Both adults and larvae eat Ambrosia artemisiifolia, A. psilostachya, and A. trifida.
Source: Wikipedia
Life cycle
In the United States it produces two generations per year, while Chinese populations can have up to three generations. At about 26 °C, females live roughly 82 days and males about 68 days.
Source: Wikipedia
When you see it
Overwintering adults start feeding in late April or early May when ragweed seedlings are only 2 to 5 cm tall. First-generation larvae appear in mid-May to early June and reach maturity by early July. A second generation of larvae is seen during the first two weeks of August.
Source: Wikipedia
Where it comes from
It is native to Canada and the United States.
Source: Wikipedia
Where it is found in the US
Recorded in 22 of 51 states and DC. Most records: Michigan, Georgia, North Dakota, Virginia, Kansas, Kentucky, Alabama, Iowa.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What plants does it feed on?
Both adults and larvae eat common ragweed (Ambrosia artemisiifolia) and related species A. psilostachya and A. trifida.
Source: Wikipedia
When are they active during the year?
Overwintering adults begin feeding in late April or early May, first-generation larvae appear in mid-May to early June and mature by early July, and a second larval generation shows up in early August.
Source: Wikipedia
Same family (Chrysomelidae)
Spotted Cucumber BeetleDiabrotica undecimpunctataDamages trees, gardens or crops
Bean WeevilAcanthoscelides obtectusDamages trees, gardens or crops
Cowpea WeevilCallosobruchus maculatusDamages trees, gardens or crops
Swamp Milkweed Leaf BeetleLabidomera clivicollisDamages trees, gardens or crops
Alder Leaf BeetleAgelastica alniDamages trees, gardens or crops
Dogbane Leaf BeetleChrysochus auratusSources
- Wikipedia: https://en.wikipedia.org/wiki/Calligrapha_suturalis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-28 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-28.