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

Sunday - June 20, 2010

From: Austin, TX
Region: Southwest
Topic: Pests, Cacti and Succulents
Title: Dealing with beetles feeding on cholla cactus
Answered by: Nan Hampton

QUESTION:

Hi Mr. Smarty Pants, I bought a Cylindropuntia imbricata from the Wildflower center and it was growing like crazy. I recently noticed a lot of beetles feeding on it. Some are black and some are gray. I have searched online for what to do about it and have not found any suggestions. Can you help please?

ANSWER:

Jack Kelly and Mary Olsen in the Arizona Cooperative Extension publication, Problems and Pests of Agave, Aloe, Cactus and Yucca, lists the cactus longhorn beetle (Moneilema gigas) as a pest on pricklypear (Opuntia sp.) and cholla (Cylindropuntia sp.) cactus.  I am assuming these are the beetles on your cholla but the treatment solution would probably work no matter what the insects are.  Their suggested treatment is to hand pick the beetles from the plant.  This sounds a bit daunting considering the spines you would encounter on the cholla but you might try long needle-nose pliers or tweezers to grab them with.  Carry a wide-mouthed jar of salad oil (you could use old oil you have used for frying) to put them in.  This will kill them, of course, and you won't have sprayed nasty chemicals around to do the job.  You will probably need to do this over several days to get them all and then keep monitoring the cactus for new ones.  You can keep your bug-filled jar of oil and add the new ones to it and dispose of the bugs and oil in an eco-friendly manner when your jar is full or all the bugs appear to be gone.  (Don't flush the oil down the toilet or pour it down the drain!  See the City of Austin Water Utility's Stop the Grease Glob page for proper disposal methods.) Alternatively, you could use a jar of rubbing alcohol to drop them in.

Here are more photos and information on the cactus longhorn beetles.

 

More Cacti and Succulents Questions

Leaves turning black on Agave americana
June 06, 2008 - Dear Mr. Smarty Plants- We have a ~5-year-old agave americana that began to have leaves turn yellow (to black in some areas) just this past spring (2008). A neighbor's tree had started to overhang t...
view the full question and answer

Blue agave with freeze damage in Lockhart TX
March 16, 2011 - I recently planted a blue agave plant, and 4 days after I planted it the temperature dropped to 20 degrees at night. The plants are still alive but 75% of the outer limbs turned brown. What do I do wi...
view the full question and answer

Can I trim back my 20 ft Yucca plant?
May 11, 2009 - I have a yucca tree which is about 20 ft. tall, has four main trunks. I would like to prune it to approx. 10 ft. but wonder if that will kill it or if new shoots will come out up near the cut.
view the full question and answer

Soil for Agave americana
March 20, 2007 - Can you give me some information on soil admendments for growing Agave (Century Plant)? I kept it in a pot during the winter and now I am ready to plant it in my beds
view the full question and answer

Mystery cactus in Williamson County, Texas
May 27, 2008 - We have a cactus plant on our place that I have not seen anywhere else in central Texas. The flowers are bright yellow with wine-red centers, but very sparse--only one flower blooms at a time. The p...
view the full question and answer

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