Crepe Myrtles with Aphids? It’s a “Sticky Situation”.

Lisa's Landscape & Design ♦ 08/05/2012 ♦ 2 Comments

I was inspired to write this blog after a number of emails and queries about what many of us in the garden biz politely refer to as “Honey Dew”. Honey Dew is basically a kinder term for the sugar laden Aphid “leavings”,  or the many other terms one could use for the sappy mess that falls from Crepe Myrtles when they are under attack from Aphids. The problem then becomes how do we prevent them, and when we cannot, how do we treat them?

This is one of those chicken or the egg scenarios where there are a couple of reasons why our glorious Crepe Myrtles succumb to these little devils. One is that the species you purchased was not a fungal resistant variety and may be more vulnerable, the other is that the plant is stressed from environmental issues such as systemic fungus, diseases, drought or transplant. Chemical use such as weed and feed is also a negative factor in my years of consultation. The plant becomes vulnerable to pests because much like nature in general, the predator preys on the weak. When your plants are stressed, they are more vulnerable to attack so paying close attention to stressed plants and counter-attacking in a timely manner is important for you and the plant.

The second reason is from a heavy pest infestation year which can be brought on by weather factors, in a particularly a mild winter followed by a wet and humid spring. Both lead to additional problems for the plant and for the gardener. Too much rain weakens native and adapted plants and bugs are like bully’s on the playground, they seek the weak. So if your Crepe is sad, let’s talk about how we can get it in good shape for the summer and see how we can rid you of your sticky shoe soles and “dewy” showers.

This is a shot of Aphids being munched on by Lady Bug Larvae ( thanks to David Cullen) This is why it is soooo important to avoid chemicals and know who your allies are!

As you can see in the photo above, the tell-tale signs of Aphid damage are yellow spots, curling leaves and tiny little whitish, tan, beige, or dark-colored insects on the backs of the leaves.  However, what you may notice first is a sticky residue on your patio, car, or person as you enjoy the shade of said tree. Once you find out that the sticky “dew” your bathing in is Aphid “doody”, it becomes more than a little annoying, now it’s just disgusting. If your tree is weakened by fungus to begin with (as some varieties of Crepe Myrtles are more susceptible to fungus than others after a wet Spring or rain spell), they can suffer and become vulnerable to pest damage. You can also have a situation where the tree now has fungus because it is covered in sticky residue making it a perfect host. Either way, what you now have is an ugly, sticky mess that can make enjoying this space in and around the tree unpleasant.

If you have done any research at all on this problem you will find a whole host of blogs telling you to throw chemicals at your problems and as usual I am here to implore you to run as far from those blogs as you possibly can as they are doing you, your children, water, pets, plants and our planet a terrible disservice. While I am sure the Chemical companies who sell the poison appreciate the boost in sales, the trends seem to imply that people are wise to them now and going organic which has got to be hurting their bottom line ;-).  There are times when chemicals may be necessary (removing Poison Ivy for example), but for the most part, they are a last resort and certainly not where to begin with most pests. As the picture above demonstrates beautifully, you are killing the good guys as well as the bad guys with a chemical protocol.  “Bombing” any plant will result in mass murder of the many bugs, bees or flying insect who happen to find themselves on or in the vicinity.

If the tree is in an area where you are not affected by it, you can just leave it alone. It might temporarily be unattractive, leafless and sticky, but it will survive and recover fully, returning in the Spring, good as new. If the tree is in a space you use and benefit from the shade it provides, you can handle this effectively with “Safer Soap” which can be purchased online at planetnatural.com (and many other online sources), or at your local nursery which is also a great place to get “local” information. For example, it is widely suggested to use “Neem Oil” on Aphids across the blogosphere, but here in Austin Texas, Neem is a cool weather treatment, as you will fry your tree by spraying it with oil in the Pizza Oven we call a Summer day. Another great way to control pests in your yard is to let loose the Lady Bugs, Praying Mantis and  Lizards to take care of business for you. Insects can be ordered online at any number of  sources or at the webpage above,  at http://www.thebeneficialinsectco.com/,  or http://www.naturescontrol.com/controls.html  and many local nurseries carry then as well. An Adult Lady Bug can eat as many as 100 Aphids a day! ( We go back to the chemical abuse again, as if you are using chemicals in your yard you are killing the hired guns you already have.) Finally, if you can catch the problem early enough, or your tree is too tall to treat with an organic pest control spray, you can control insects like Aphids, Mealy Bugs and Stink Bugs with a hard blast of water from your hose. To control Aphids, be sure to blast the leaves from the underside as that is where the little buggers reside. Blast the leaves with a hard spray every couple of days in the early morning hours (so the sun dries them during the day) while the problem persists and eventually they will take the hint and move on as the environment becomes less hospitable to “keep shop”.

When you are cleaning up the falling leaves, be sure to bag them in plastic, tie it off and trash it. This is one of the few times (unless you are dealing with Fungus) that I will tell you not to compost. Reason? Because we do not want to have this mess all over the yard. The last thing you want to do is re-locate this problem. If you have other plants or trees near your compost pile who are vulnerable to Aphids, all you did is make their travel lighter and we prefer them dead, not re-located. As for the sticky mess that’s left behind, that is easily cleaned up with soap and water or this mixture with some baking soda mixed in for a little extra scrubbing power.

Lisa LaPaso

Lisa’s Landscape & Design    (Like me on Facebook!)                                                                                                                                                                                       

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