Q: What do you recommend for controlling that ugly, leaf-footed bug that attacks my pomegranates? I want to be prepared.
A: They aren’t difficult to kill with a variety of traditional pesticides. The problem is the adults are strong flyers, and we’ve had warm winters. In an orchard where everything is under your control, it is much easier to handle challenges than when you are managing a home garden surrounded by neighbors who are clueless: The bugs fly in from your neighbors’ yards.
During the winter, the adults are not hanging out around your pomegranate tree. Instead, they prefer winter evergreen plants like bottle brush, citrus and palm trees. They will stay with these trees until there are new growth and young fruit, particularly pomegranate and tomato.
This year, they might not be a problem until April because of cool weather. During warm springs, it could be as early as March.
There are three times during the season when these ugly, winged adults lay eggs. Their populations explode in numbers after each egg laying. That means it’s extremely important to start reducing their populations as early in the season as possible. Start looking for the small, brown eggs, gathered either in clusters or aligned in a row, on the bottom sides of pomegranate or tomato leaves.
If you are diligent and inspect your tree weekly and find small brown eggs, pull these leaves off and drop them in a small bottle of alcohol or vinegar. If you see adults or their offspring, called nymphs, then spray them with soap and water or vacuum them with a cordless vacuum. If you waited too long to start looking and their massive numbers shock you, then your only recourse is to spray.
The problem with spraying pomegranates with insecticides is their constant production of flowers that attract honeybees. Pull these flowers off the tree before you spray it. There will be more flowers. Use common fruit tree insecticides that control a wide range of insect pests.
Q: Do you have any suggestions for landscape soils that puff up dust and repel water when I spray it with the hose? Is this a hydrophobic soil? Is there something I can add or do to it? It doesn’t seem healthy to me.
A: Good landscape soils absorb water easily and don’t repel it if they don’t become overly dry. This puffiness is very typical of desert soils, landscape fill and other poor soils. They are hydrophobic and very dusty when disturbed, like sprayed with a hose.
Even good soils can be hydrophobic when excessively dry. Compost, peat moss, coconut coir are notorious for repelling water when added to soil and when this mix is dry. But once they have been added and the soil is kept moist, they are no longer puffy and repel water.
For this reason, I encourage you to improve the soil with amendments, like I mentioned above, where plants are planted and then cover the soil with 3 to 4 inches of mulch. The type of mulch chosen depends on the plants.
If the plants are not desert plants, then cover the soil with woodchips. If these plants are desert plants, then it’s OK to use rock. Unfortunately, if you make a plant identification mistake, you probably won’t discover it for five to seven years. Do your homework and find out where your plants originally called home, whether it was a desert or not.
If you are looking for a product (chemical) that decreases dustiness, then any liquid detergent or commercial wetting agent will work. I would recommend using a pure wetting agent such as a Castile soap or a commercial wetting agent rather than Palmolive or Dove liquid detergent that you buy at the store.
Q: Can I substitute a different product for Bayer Advanced Tree and Shrub Insect Control for controlling borers, as it is quite expensive?
A: Yes, but it’s the active ingredient on the label that’s important and how you plan to use it. It’s possible to find the same active ingredient in other products with a different product name, and they might be cheaper. But it’s important to get the same active ingredient, understand how it is to be applied and understand your cost to make an application.
Legally, I can only recommend products that have a label that supports its use for what you are trying to do. So if the label says you are to use it only for vegetables, you are legally not supposed to use it for anything but vegetable production.
If the label says it’s used for treating only ornamental trees, you cannot legally apply it to fruit trees or vegetables. Sometimes there are ingredients included that cannot be applied to other plants or crops or have not been approved to do so.
All I can tell you is if the label says that you can apply it for what you want, you can. Read and understand your label thoroughly and follow it for best results. Don’t be creative when using and applying pesticides.
Q: Is now a good time to spray roses with horticultural oil? My plants usually have a ton of aphids this time of year. Are there products that you recommend?
A: Aphids are sometimes called “plant lice,” and you can see why if you ever have problems with them. Aphids overwinter at the base of roses just under the soil surface or on weeds that are close by. Horticultural oils and insecticidal soaps are usually the safest and best products to use for controlling aphids. Neem oil will have some effects too.
I found the best control of aphids on roses is an application of horticultural oil to the upper and lower surfaces of the leaves after the leaves have just come out. Aphids wait patiently for the new growth to emerge and invade this soft, succulent tissue.
A little bit later, ants commiserate with the aphids and carry them around to new leaves and new plants for the ants benefit. If you’re going to control aphids, you might also want to consider controlling ants in the area as well.
Q: We planted a lot of new fruit trees in our community garden. I pruned most of them back to about 2 feet off the ground per your YouTube videos. I’m a little confused about the peaches because they are so large and I am afraid to prune them that hard.
A: I would be very careful pruning anything larger than about ¾ inch in diameter with peaches and nectarines. Large branches and the trunk don’t sucker very well if they are cut when they are large. When you buy larger peach and nectarine trees, you are stuck with whatever the tree has. You can manipulate growth coming from smaller limbs but not the larger ones.
Sometimes you don’t have much choice when you buy a large tree and the lowest limbs are 3 feet off the ground. If you must have lower limbs coming from the trunk and nothing is there, you might make a dramatic pruning cut to the trunk about 2 feet off the ground and hope for the best. It has sometimes worked for me. Make sure you whitewash the trunk to help protect it from sunburn.
Instead, consider leaving peach and nectarine unpruned the first year after planting and accept the limb arrangement that came with the tree. You are fine pruning plums, apricots, apples and pears low to the ground because they sucker nicely after they’ve been pruned. But large peach and nectarine trees might be a bit riskier to prune unless they are smaller in diameter.
Two reasons for pruning fruit trees low to the ground is to establish lower limbs coming from the trunk and major limbs that can shade it from sunburn and to create the scaffold limbs for bearing heavy fruit later.
Intense, direct sunlight can damage many fruit trees so shade is terribly important to the trunk and larger limbs in the Mojave Desert. When pruning to establish its architecture, a few major cuts is all that is needed.
Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.