Insects often come in droves. Some years we have fall armyworms, some years it’s a plague of grasshoppers, some years we have mysterious webs appearing all over hackberry trees. We just never know what insect might decide to show-off that season. And inexplicably, that insect is not a problem again next year.
Occasionally, what seems like “an outbreak” or “something I’ve never seen before” is actually just that the insect got in your way or you were particularly observant this season. Entomologists and our phone lines can attest to actual surges in populations. We don’t always know why this occurs; it seems the environment is nice, and the opportunistic little buggers take advantage of it.
A couple of insects that we can always count on to show up in North Texas are mosquitoes and fire ants. Isn’t it nice to have a few constants in an ever-changing world? If you have fire ants, we recommend using a bait product. A bait is a tiny bit of toxic material disguised as a tasty treat for the ant. They take the bait back to their mound, and eventually it kills them all. You can bet that ant is not invited to the next party.
Baits are highly effective and have low toxicity to non-target organisms like you, your pets and even your children. Baits are broadcast over a large area, but they do take a while (weeks, maybe a month) to do their job. If you have problematic mounds in high-use areas, you would want to do a spot treatment with an insecticide, rather than wait for the bait.
Mosquitoes are not all the same. Some are early risers, some are night owls, which is why we recommend to always wear an insect repellent when outside. An effective natural repellent is oil of lemon eucalyptus. It has shown to be as effective as DEET repellents, but it does need to be reapplied more frequently. And don’t forget to dump out standing water; even a tiny bit of water can turn into an incubator for mosquito larvae.
Plant disease can also show up when conditions are just so and cause a lot of damage some years. This year, we are seeing oak leaf blister. This is a fungus that causes the leaves to look blistered (surprise!), maybe even twisted or folded, discolored, withered and overall unhealthy.
This can cause distress to the tree owner and to the tree, but most of the time it is simply aesthetics. The disease doesn’t typically cause a lot of damage. However, you do want functioning leaves because, as you know, the leaves are the food factory for the tree. Therefore, we might consider the tree stressed, and we would want to be especially kind to it that season. Which means ensure proper watering and watch for secondary pests or problems that a healthy tree could shake off. Sound familiar? Plants aren’t always that different from people.
Just like with insects, this fungus is probably always around. However, when we have cool and moist weather at the same time, the leaves are budding out, and that’s when we start to see oak leaf blister. If you see that your tree has the fungus, we don’t recommend any kind of chemical control. Perhaps you want to do a preventative treatment next spring just to be sure. And if you have a lot of other oaks, you might want to do a preventative treatment on them.
However, the fungus likes the new growth of the tree, so by the time you see it on any of your trees, the rest of them are probably safe. As with most plant diseases and especially fungus, sanitation can make a big difference. This means cleaning up the diseased leaves once they fall to the ground and removing them. Fungi make spores, and those spores can linger around on the infected leaves. It’s a good practice that reduces the disease pressure of the area.
If you haven’t yet, check out the AgriLife Extension horticulture team on Facebook Live every Wednesday and Friday at 1 p.m. Even without a Facebook account, you can watch live. To see what’s coming up and check out the recordings of the previous live videos visit https://aggie-horticulture.tamu.edu/fblive/.