Tobacco budworms

Quick facts about tobacco budworms

Tobacco budworms (Heliothis virescens), also known as the geranium budworm, are commonly found on petunias, geraniums and nicotiana. They can sometimes damage roses and other plants.

These caterpillars are seen in late summer.
They cause irregular or round holes in flower buds.

How to identify tobacco budworms

Two green and one brown caterpillar-like tobacco budworm — Tobacco budworms

A reddish caterpillar-like budworm crawling on a petunia plant — Tobacco budworm on a petunia plant

The caterpillar has white stripes running lengthwise along the abdomen.
It has numerous erect hairs on its body.
These caterpillars are commonly brown but can also be red, purple or green depending on what they are eating.
It can grow to be as large as 1 3/4 inches in length.

Life cycle

Tobacco budworms do not survive the harsh winters in Minnesota. They arrive in Minnesota during late summer by riding on air currents from the south. They may be seen one year but whether they will be seen the next year cannot be predicted.

Damage caused by tobacco budworms

A brown caterpillar-like budworm feeding on a young flower bud — Tobacco budworm feeding on a bud. Note the visible black droppings.

Hole in a red flower bud — Tobacco budworm damage

Holes in red petals and a red bud of a geranium plant — Tobacco budworm damage in geranium flowers

A green caterpillar feeding inside a ripped purple flower and a red caterpillar crawling on the stem — Tobacco budworms feeding on petunia. Note that the two budworms are of different colors.

The larvae damage flowers by chewing deep holes into the buds.
Flowers can still emerge from these damaged buds but flowers have large holes in the petals.
Tobacco budworms may also eat the flower blossoms, giving them a ragged appearance.
Small black specks of excrement may be visible on damaged flower buds.

How to protect your plants from tobacco budworms

You cannot prevent the appearance of this caterpillar, but you could take some steps to control it.

Check your flowers regularly. Handpick and destroy any caterpillars you find.
If you have a large number of susceptible flowers (of interest to the caterpillars) in your garden, you could spray a residual garden insecticide, such as bifenthrin, esfenvalerate or permethrin.

Bacillus thuringiensis, is effective on caterpillars, but does NOT work well against tobacco budworms. The tobacco budworm does not consume enough of this pesticide when it is chewing into the buds.

Jeffrey Hahn, Extension entomologist

Reviewed in 2018