Host an Event Volunteer Join Tickets

Support the plant database you love!

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Saturday - January 23, 2016

From: Winchendon, MA
Region: Northeast
Topic: Pests, Herbs/Forbs, Wildflowers
Title: Caterpillars on Milkweed in MA
Answered by: Anne Van Nest

QUESTION:

I have found every year a black/red caterpillars on my milkweed. They eat everything! I have never been able to find out what they are or how to get rid of them.

ANSWER:

The milkweed tussock caterpillar (Euchaetes egle) is a common summertime feeder on milkweeds (Asclepias spp.) and dogbane (Apocynum spp.) in a huge area from southern Canada to Texas. Wikipedia says that the older caterpillars are gregarious and sport tufts of black, white and orange hairs with a black head. This coloration mimics the monarch butterfly caterpillar in a hope to ward off predators. The adult butterfly is a gray and yellow with rows of black dots on the dorsum.

Willow House Chronicles has a blog post about your caterpillar. Barefootheart says: The Tussock moth label is a misnomer, as these moths are classified with tiger moths. Another tiger moth caterpillar that you are probably familiar with is the Woolly Bear.

Some people have an allergic reaction, developing a rash, after handling these caterpillars, so it is not a good idea to pick them up, no matter how cute and fuzzy them may look.

Female moths lay large batches of eggs, and while the caterpillars are tiny, they live together on one plant before dispersing. Monarch butterflies are well know to also use milkweed as their larval food source, but Wagner notes that Monarchs tend to prefer young shoots, while Tussocks are content to eat older foliage. The caterpillar will overwinter in a cocoon and emerge as a moth next year.

 

These caterpillars will most likely be an annual visitor to your milkweeds and a sustainable strategy should be to encourage more milkweeds fluorish so that there is plenty of host plants for you and your visiting insects.

 

From the Image Gallery


Swamp milkweed
Asclepias incarnata ssp. pulchra

Common milkweed
Asclepias syriaca

Common milkweed
Asclepias syriaca

Common milkweed
Asclepias syriaca

Butterflyweed
Asclepias tuberosa

Butterflyweed
Asclepias tuberosa

Butterflyweed
Asclepias tuberosa

Red milkweed
Asclepias rubra

Zizotes milkweed
Asclepias oenotheroides

More Pests Questions

Help for Collapsing Tradescantia
August 14, 2013 - My tradescantia has completely collapsed at the crown. The stems are yellowish. This happened once before when I had it planted in full sun and I just had to discard it. This time I have one plante...
view the full question and answer

Cause of yellowing buffalo grass (Bouteloua dactyloides)
June 07, 2008 - We are getting large yellow areas in our buffalo grass lawn and think this is probably due to grub worms. Are grub worms the likely culprit and if so, what is the best way to get rid of them? We don...
view the full question and answer

White fuzz on Christmas tree from Lewisburg PA
January 04, 2011 - Our Canaan fir Christmas tree is now coated with white fuzz after being up for 4 weeks. The fuzz looks like spider webs, but it is also in clumps around the needles. When you rub your finger on it, ...
view the full question and answer

Identity of small objects that look like tiny pecans
November 14, 2013 - Dear Mr. Smarty Plants, I am doing my science fair project on acorns. Last year I measured how many acorns and other nature-y stuff fell into a baby pool from a live oak tree in my backyard every ...
view the full question and answer

Problems with non-native yellow lantana from Elgin TX
June 17, 2012 - Why do my yellow lantana buds turn brown and do not open fully? The sprinkler system does not spray onto the lantana.
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.