Lady bugs changing to mature stage. (Contributed Photo)

Dear Neil: How can I find someone qualified to tell me if a very large tree needs to be taken down? I’ve gotten conflicting comments.

You need a Certified Arborist. He or she will be a member of the International Society of Arboriculture, and they will have taken and passed all the tests that are required for that certification. That organization has both a professional side of its website as well as one for consumers. The homeowner side is labeled as www.treesaregood.org and it has, right up front, a page dedicated to helping you find a certified arborist. You enter your Zip Code and radius within which you’d like to search, and it will list all the arborists who are certified within that area as well as their contact information. I’m certain they are used to giving second opinions. And, if you do need to have the tree removed, you’ll find excellent information online about questions you should ask before hiring an arborist. I recently spent several hours researching that very topic for a story I was writing elsewhere. I was amazed at what good help there is out there.

Dear Neil: Regarding crape myrtle bark scale – Southeastern Virginia has been battling this pest for years. The scale itself will not kill the plants. However, the sooty mold is the real problem. The more insects, the more sooty mold there is. The mold covers the leaves which reduces photosynthesis. It also covers the thin bark resulting in poor respiration. After several years of uncontrolled pests, the plant will die. I’ve seen even plants with 8-in. diameter trunks require removal after 3 to 5 years. Foliar applications of dormant oil do not work. Contact sprays offer very limited control. Systemic insecticides do the job. After two years the pests are gone and the sooty bark has sloughed off. In my opinion this is not a pest to be ignored.

I appreciate your taking time to write. I suspect you may not have seen my prior writings of having been involved with this pest since the first week it was brought to a nursery in the North Dallas suburb of Richardson. I took it to the Texas A&M Center in Dallas and worked alongside their entomologists who in turn sent it to the University of Florida (where much work on scale insects is done) and to the Smithsonian (where scales are identified). We were assuming it to be a mutation of azalea bark scale, a long-known pest.

Research trials were begun in 2007 on several miles of crape myrtle medians in the Crape Myrtle Trails of McKinney (Texas), a project I helped found, and the conclusion from TAMU entomologists was that the systemic insecticide Imidacloprid applied May 15 as a soil drench offered the best control of crape myrtle bark scale (the name that by then had been assigned to the pest) and also crape myrtle aphids.

A few years later a group of Texas A&M horticulturists made a visit to China, and to their surprise, they found the pest abundant on Chinese cities’ crape myrtles. That was confirmation that the insect had been imported from China – that it was not a mutation of another species here in the United States.

I have not seen a recommendation for application as early as you suggested, nor for a second treatment at the later date you listed in your note, therefore I did not include them as I retyped your message. I also have never observed here in Texas, working with crape myrtles many days per month for the past 30 years, any plants dying specifically from either the scale or the sooty mold that develops in the honeydew left behind by the pests. The plants are certainly weakened, and flower production is severely reduced, so you’re correct in saying that we need to bring this pest under control.

However, I have learned to encourage people to watch for the twice-stabbed lady bug. That voracious predator really reduced our population of bark scale after the initial burst. We just had to teach people what the immature stages look like so they would hold off on spraying (which wasn’t going to do much good on the scale anyway).

I hope that helps fine tune a few things. We are almost in total agreement. Given a few more years for your population to reach an equilibrium, I’ll bet we will be. Thanks, again, for writing!