Now that we’ve had six weeks’ exposure to hot, dry conditions, that’s when the challenging questions start rolling out. (Like an avalanche.) I’ve assembled some of the most common ones in the hopes that you’ll find my answers useful.

Take a quick scan.

Shiny, sticky crape myrtles

What are the little white specks on the trunks of my crape myrtles? And why are the leaves and trunks shiny and sticky?

I’m seeing outbreaks of crape myrtle bark scale across Metroplex landscapes. Nothing like we faced following the wet spring of 2007, but nonetheless, enough to let us know that this foreign invader is still with us.

In all the United States, it was first observed in Richardson, Texas, in 2004. We really didn’t know what we had, but we have since discovered that it came from China. For several years it was confined to northern Dallas and Collin counties, but in subsequent years the pest has spread across Texas and the Gulf South. Large-scale research projects are underway involving 15 to 20 nursery organizations and Land Grant (agriculture) universities.

We have learned that it is not a major health threat to our crape myrtles. It’s more annoying than it is damaging. As with many other pests with piercing/sucking mouthparts, it exudes a sticky “honeydew” residue onto leaves, stems, and hard surfaces below. Given several weeks, a black sooty mold fungus will develop in the honeydew substrate.

To get rid of the sooty mold we must remove or prevent the honeydew. To avoid the honeydew, the best thing is to prevent the insects in the first place. That involves applying a soil drench of Imidacloprid systemic insecticide in mid-May. But we are where we are now, and it’s currently best to wash the trunks down with soapy water and heavy-duty sponges, then to spray the plant with the same insecticide as we try to remove the scales that are already there.

You may also be seeing nymphs or adults of an unusual ladybird beetle that is predatory to the scale insects. With black wings and two conspicuous orange-red spots on the wings, it is called the “twice-stabbed” ladybug. They are extremely efficient at reducing numbers of the scale insects. Note that when the scales have been devoured, you’ll still see their white shells. You can tell if a scale insect is alive by pressing on it. If it oozes red fluid when pressed, it was alive. If it is only dry and flaky, the scales are dead.

Peeling tree bark

“Why is bark peeling off the trunk of my maple tree?”

In almost all cases that’s due to sunscald, and it’s almost always on the south or west sides of the trunks of trees that are relative newcomers to our landscapes. The same thing will happen to Shumard red oaks and Chinese pistachios, two other thin-barked trees. It shows up two or three years after planting. That’s because those trees have been taken out of protected nursery surroundings and suddenly thrust into intense summer sunlight.

The damage, however, is done the first year or two that the new tree is in the ground even though the bark doesn’t start cracking and falling for another year or two. By that time, there’s not much you can do but wait to see if the tree can heal itself. In the future, however, new trees should always have their trunks protected with paper tree wrap for the first couple of years.

Dead Leyland cypress branches

“Why are large branches of my Leyland cypress dying?”

That is a fungal disease called Seiridium canker, and it’s almost impossible to prevent or control. It started attacking Leyland cypresses 25 or 30 years ago, and it has systemically taken down 80 or 90 percent of them across Texas in the ensuing years. Then it moved on to Italian cypresses, and I’ve seen it attacking Arizona cypresses most recently. Large branches turn brown, and when you inspect the trees carefully, you’ll often see cascades of black sap running down their trunks. Fungicides don’t help at all.

Junipers are facing a similar fate, with fungal twig blights from Phomopsis and Kabatina. Entire sections of the plants die very quickly. Cultivars Blue Point, Table Top Blue, and Spartan are all notoriously susceptible. It’s best just to start looking for replacements.

Damage to St. Augustine grass

“How can I tell the difference in damage from grub worms, chinch bugs, and gray leaf spot in my St. Augustine grass?”

You can rule out white grub worm damage for this time of year. They’re the larval form of June bugs. They have just had their annual flight, then mated, and laid their eggs in the turf. Those eggs will hatch by early August and damage won’t begin to show until late August, September and October. Note however, that we rarely have serious outbreaks of white grub worms like we did several decades ago.

Chinch bugs will always be in the hottest, sunniest parts of your yard. The turf there will look dry. You’ll water it, but it won’t bounce back overnight. When you use your fingers to part the grass at the interface of healthy grass and dying turf you can see the chinch bugs scattering around on the soil surface. They’ll be BB-sized, black with irregular white diamonds on their wings. You’ll also see tiny red nymphs mixed in with the adults. They will all be near the outer perimeter of the infected space. Treat with a labeled insecticide. Water moderately after the application.

Gray leaf spot is a fungal disease that shows up in hot weather. We are certainly in its prime time currently. Infected turf will take on a sickly yellowed color in irregular patches. When you look at the yellowed leaf blades carefully, you’ll see grayish-brown, diamond-shaped lesions along some of their midribs. Nitrogen fertilizers stimulate this fungus, so withhold feedings from mid-June into early September. Treat current outbreaks with Azoxystrobin turf fungicide.