Rent Shop Volunteer Join

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
2 ratings

Thursday - January 27, 2011

From: Melbourne, Australia
Region: Other
Topic: Cacti and Succulents
Title: Scale on Agave attenuata from Melbourne, Australia
Answered by: Barbara Medford

QUESTION:

I have an agave attenuata in a pot. It has been attacked by scales. I have been spraying it every 3-4 days at night with a chemical sold to me by the local gardening store. It's not helping and I am worried that the scales will take over the entire plant and kill it. At the moment, the only unaffected parts are in the middle and not yet opened out into leaves. I am wondering if the next step is to cut off the affected leaves? I have read your page on pruning agaves so I am prepared if that is the next step.

ANSWER:

We were just going to mention that Agave attenuata is native to Mexico, not to North America, which is our ordinary range of expertise, when we noticed you were writing us from Melbourne, Australia. It's not native there, either. We don't know what your climactic conditions are, or your normal temperatures, but we will try to find some literature that will perhaps help.

Begin by reading this article from the University of Arizona Cooperative Extension on Problems and Pests of Agave, Aloe, Cactus and Yucca. You will have to scroll down to Page 6 "Fungal diseases of leaves and pads," and then to Pages 9 and 10, "Coccineal scale, coccide scale, soft scale."

Next, take a look at this University of California Integrated Pest Management website on managing pests of the agave family (agaves and yuccas). Clicking on "Armored scales" on the right-hand side of that page will take you to a page to help you identify and then manage the scale you are experiencing. This article emphasizes that you need to know which scale you are dealing with in order to choose the proper control. Possible controls are discussed, and you should then be able to obtain a specific spray or oil for the appropriate treatment.

The article on diseases and pests of agaves is quite extensive, but you should read it all as it advises against the spraying of certain controls. It does not, however, recommend pruning. You would probably want to hold off on pruning and try to get the scales to go away, or at least become more manageable, then prune only heavily damaged leaves.

 

More Cacti and Succulents Questions

Is Sedum recommended for a greenroof project in Houston
July 23, 2008 - Would you recommend using Sedum for a green roof project in Houston, Texas? Will the humidity effect the sedum? If sedum would be a poor choice, what would you recommend for Houston?
view the full question and answer

Night-Blooming Cereus not Blooming
September 04, 2014 - I have a plant called a night-blooming cereus, which during the warm season, is supposed to have blooms that come out at night and close up but don't fall off when morning approaches. But my cereus h...
view the full question and answer

Thorny shrub for deterring break-ins in southeast Texas
February 05, 2013 - Looking for a very, very, thorny three or four foot tall shrub for in front of windows to deter break-ins. Considering Rosa Rugosa rose but it is not native.
view the full question and answer

Non-native jade plant from Pauline SC
August 24, 2012 - Do jade plants grow in South Carolina; if, so where?
view the full question and answer

Loss of bloom stalk on Yucca filamentosa from Scotch Plains NJ
April 27, 2013 - We have 3 Yucca filamentosa L. planted together, in NJ. A friend of ours was helping to remove the weeds, little did she know and removed the blooming stalk from the plants. By the time I saw, it was ...
view the full question and answer

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