Native Plants
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.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
rate this answer
Tuesday - November 18, 2008
From: Los Angeles , CA
Region: California
Topic: Cacti and Succulents
Title: Cochineal bugs on cactus
Answered by: Nan Hampton
QUESTION:
Mr. Smarty plants. I have purple prickly pear cactus that are developing small white flake like spots, mostly where the thorns would be. Why is this happening and how can I cure it?ANSWER:
Your cactus sounds as if it is infested with cochineal bugs (Dactylopius sp.). They are small scale insects that feed on the cactus. They produce fluffy white wax that hides their bodies as they feed on the cactus and protects them from the elements (drying out, in particular) and from predation. The fluffy wax also serves as a sail or balloon to float on the wind and take the bugs to a new patch of cactus. The bugs produce carminic acid that also helps protect them from predation, especially from ants. This carminic acid in the bugs has been used by indigenous peoples of southwestern North America, Central America and sub-tropical South America to make a brilliant red dye for centuries, perhaps millennia, to produce beautifully colored textiles. Originally, the cochineal bugs were limited to the New World. When the European explorers visited and saw the beautiful red cloth of the natives, they took the cochineal bugs back with them and now they occur all over the world. When a synthetic red dye was produced the demand for cochineal bugs decreased, although they have also been used to help control cactus popuations. Recently, however, after it was determined that the synthetic red dyes can have adverse health side effects, there has been a renewed interest in growing cochineal bugs for red dye. The dye made from the bugs is currently used in cosmetics and as food coloring. Because of this, controlling cochineal bugs hasn't really been a priority and, therefore, there isn't a lot of information that I have been able to find for controlling them. However, click here to read what one grower recommends. If your infestation is small, I suggest scraping them off (carefully, to avoid the sharp cactus spines) and disposing of them. You might also be able to wash them off with a water under pressure. Test a small area first to be sure that you don't injure your cactus and gather up and dispose of any of the insects that you wash off the cactus.Here are a few links to more information about the cochineal bugs:
Gateway to Sedona with a bit the history of the using the bugs for dye.
Wayne's World with excellent photos of the bugs.
You can read instructions for making and using a natural dye from the cochineal in Using the Cochineal Bug and Dying Things Red!!
More Cacti and Succulents Questions
Need help with century plant in Willis, TX
September 21, 2014 - Ok so I have two gorgeously monstrous century plants in my yard..I love em BUT I don't know if the have ever bloomed but since I am removing pups as fast as I can during the rainy season I'm assumin...
view the full question and answer
Damage to yucca in San Marcos TX
October 18, 2010 - Dear Mr. Smarty Plants, thank you for helping me with my buffalo grass is San Marcos TX back in the spring, my lawn is gorgeous thanks to you!
I really need your help as someone sabotaged my beauti...
view the full question and answer
Controlling Cochineal Insects on Cholla Cactus
July 07, 2011 - We have cochineal insects on a cholla cactus. Will they kill the plant? What should we do to get rid of them if water spraying them won't work?
view the full question and answer
Preserving the agave bloom for decoration from Sedona AZ
April 28, 2012 - I have an agave century plant which is starting to bloom. Is there some way I can preserve the flower as a decoration piece?
view the full question and answer
Starting yucca from seed from Austin
December 24, 2012 - I would like to start a soft leaf yucca recurvifolia from seed. Is that possible?
Also, I've looked for seed on dried flower stalks, and I'm not sure that what I'm finding is the seed, and I ...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |