En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

Sunday - April 14, 2013

From: Aledo, TX
Region: Southwest
Topic: Pests, Seeds and Seeding, Cacti and Succulents
Title: Black bugs on yucca from Aledo TX
Answered by: Barbara Medford

QUESTION:

We have flowering yuccas that have thousands of small black bugs that seem to be hurting the plant. They are not on any other foliage in our beds. What do I use to get rid of them??

ANSWER:

When we answer a question about a plant, we always like to have a more specific species for an example. There are 28 yuccas native to North America and 18 native to Texas. According to this USDA Plant Profile Map Yucca pallida (Pale-leaf yucca) is native to Parker County. That may not be the precise yucca you have, but the bugs on it would probably be the same for all members of the Yucca genus.

We believe you might be seeing the larvae of Tegeticula yuccasella or yucca moth. At the Lady Bird Johnson Wildflower Center, we frequently clean the seeds that have been gathered of native plants in Texas, including the yucca. Sometimes when we have young people volunteering for this, we get a certain amount of squealing when a little black worm emerges out of the center of a stack of yucca seeds in their pod. Those seeds have to be abandoned and not saved for our seed bank, because the depredations of the moth larvae have destroyed the usefulness of the seeds. Please read this article on Yucca and Yucca Moths from the Chihuahuan Desert Center. The yucca and the moth are interdependant so destroying the moth is not a good practice.

If, however, you feel that it is something else that is damaging your plant, read this article from Arizona Cooperative Extension on Problems and Pests of Agave, Cactus and Yucca.  You will have to scroll down to Page 6 to find the section on Insects. If some of these match what you are seeing, the article gives some management suggestions.

 

From the Image Gallery


Pale-leaf yucca
Yucca pallida

Pale-leaf yucca
Yucca pallida

Pale-leaf yucca
Yucca pallida

More Cacti and Succulents Questions

Getting rid of yucca plants in Blanco, TX
May 12, 2009 - How does a person get rid of Yucca plants? We have four fig trees that do not bear figs, what do we need to do? We live in SE Blanco County, Texas.
view the full question and answer

Should I remove the flowering stalk from my Dasylirion leioiphyllum?
March 23, 2009 - We transplanted a plant that is new to us but going through your photos on your website, it appears that we have a Dasylirion Leiophy. My question is this.. Are we supposed to cut the 6' stem that f...
view the full question and answer

Cactus failing to thrive in New York City
November 21, 2008 - My cactus seems to be either weak or dying. Its long stems are bending and softer than the rest. What is happening to it?
view the full question and answer

Loss of agaves to freezing weather in Austin
March 04, 2011 - Dear Mr. Smarty Plants: I live in Austin and lost all my agaves in the subfreezing weather this winter. Around town, I've noticed some agaves that seemed to tolerate the cold just fine and other tha...
view the full question and answer

Plants that are deer resistant for high desert climate in Utah
January 23, 2008 - We are building in a high desert climate in Dammeron Valley, Utah. We want plants that are both deer resistant and require little watering. Can you advise which plants (shrubs, flowers, cacti) that ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center