Dear Neil: Attached are photos of our zinnias. This problem shows up annually. Nurseries haven’t been able to help me. Any advice you can offer will be appreciated.
A: I’ll give it a try. I assume the white powder is some type of insecticide, perhaps Sevin dust for chewing insects. So, I’ll bypass that as not being powdery mildew. The holes look like they might have been caused by snails or slugs, and the Sevin would have controlled them, so they may be past history. I really can’t tell. It looks like the plants are weak enough at this point that even their flowers are done. Honestly, they may not have enough vigor to put out another round of blooms. If you like zinnias, consider planting them in mid-August to enjoy for a fall crop. They are so much easier then, and so much more rewarding, plus their colors are so much more intense. As a side note, I’m wondering why I’m seeing so many green holly leaves on the ground in your photo, also so many spots on what appear to be pinks’ leaves. I’m hoping you’ve not used a weedkiller or weed-and-feed product anywhere near these plants.
Dear Neil: We have fought beggar’s lice in our backyard for years. We’ve pulled it up and used a line trimmer to cut it, all to no avail. How do we get rid of this noxious weed?
A: Isn’t it awful? It’s in full bloom across Texas right now, and the seeds won’t be far behind. I would suggest that you apply a broadleafed weedkiller containing 2,4-D to it as soon as you see it growing in early spring. That will keep the plants from maturing, flowering and setting their annoying seeds. Otherwise, just keep mowing and trimming it so that it can’t make seeds. You’ll eventually diminish its population down toward zero, at which point you could just dig out the remaining plants.
Dear Neil: We built a new home a year ago and planted Palisades zoysia. It looked great all of last year. In September, our (then) lawn caretaker scalped the grass, and it has never been the same since. This spring it was diagnosed by the extension service as having take-all root rot. We immediately applied sphagnum peat moss, but last week read your suggestion of the new fungicide Azoxystrobin. Is the commercial product any stronger/better than what we consumers can buy? Do you think our lawn can be saved?
A: This does look really bad. I would go ahead and apply the Azoxystrobin right away. Even if the product available to commercial applicators is stronger, it would be applied at a lower dosage, so the final result would be the same. I have to admit that I wonder if the scalping didn’t come at the wrong time or if it wasn’t done to too much of an extreme. I’m not sure why anyone would want to scalp zoysia in September. Palisades is a lovely grass if you can get it past this issue.
Dear Neil: Every year we have these insect eggs on the backs of our squash and cucumber leaves, and soon thereafter the plants start to die. What are these and what can we do about them?
A: Your photo is in low resolution, but these are squash bug eggs, and the best thing you can do is mash them with your thumb to prevent them from hatching. It’s much easier to stop squash bugs at this stage than later.
Dear Neil: I have a young magnolia tree that’s now in its second year. I notice that some of its leaves are a little yellow. Is there something it needs?
A: Look at where they are in relation to other leaves on the tree. This is the time of year that all older magnolia leaves are preparing to fall to the ground as new leaves are being produced at the ends of the branches. So it may be nothing more than old leaves that will soon fall. On the other hand, it could also be that your tree needs a feeding with nitrogen, just the same as what we give to our turfgrass. Don’t overdo it, however, and never apply any type of weed-and-feed product anywhere near any shade tree, especially a magnolia.
Dear Neil: I have large beds of Ophiopogon established beneath 50-year-old pecan trees. Several of the Ophiopogon plants have browned tips at the ends of each blade. What causes that, and what is the treatment for it?
A: Ophiopogon is the same thing as mondograss or monkeygrass. It’s just I’ve never had anyone ask about it by the name “Ophiopogon.” Well done! I have used it for very large beds beneath our pecans and oaks in the rural forest we call home, and I’ve never seen any type of disease or insect damage to it. And if I did, I wouldn’t expect it to show up at the tips of the blades. That’s usually where moisture stress appears. That’s the point farthest from the roots, so it’s the first place to dry out and the last place to get water. Be sure that area is watered properly. Dig a few test holes 5 or 6 inches deep, and look for white grub worms or their pupal cases since they’re now changing over into June beetles. A photo might have helped. I just don’t know how to advise you at this point.
If you’d like Neil Sperry’s help with a plant question, drop him a note in care of The Eagle, P.O. Box 3000, Bryan, Texas 77805. Or email him at email@example.com.