Clean grape leaves at base to rid plant of skeletonizer cocoons

Q: Although I was able to control the grape leaf skeletonizer all summer, I came back from a three week trip with 99 percent of the leaves stripped and dried up. The grapes were picked in August and September. Should I still treat the vines with Bt or just forget it since it is October and the leaves would have soon turned brown anyway?

A: These insects have multiple generations during the growing season and protection from Bt only lasts a few days. I would just let it go at this point. The only thing I consider a little bit is regrowth (new leaves produced) when the temperatures are still warm. Regrowth will drain stored food reserves from inside the plant.

These reserves are used for next year's production, but there should be plenty of "food" left even if it regrows this fall. I would not worry about it if that happens.

Make sure you clean up the leaves at the base of the plants. This is where the pupal stage (cocoon) will overwinter, and if you do not clean up this debris the attack on the plants next year will be earlier and more intense. The adults are winged moths so they will come from your neighbor's vines as well.

Q: I have a wild bush in my backyard with blackberries. The leaves are velvety, not shiny. The flowers are tiny, white four-petal clumps. The berries were green and now turning black. I looked up blueberry plants online but their leaves are glossy and the flowers bell-shaped, so I am stumped. Can you eat the fruit or should I take it out?

A: I would have to see a picture of the fruit, flowers and leaves to be sure, but frequently I get pictures from people asking me to identify black nightshade in their garden. I am guessing this is what you have. It is fairly common in home gardens because it is a seed contaminant and a weed in potted plants.

I have posted a picture of black nightshade on my blog so take a look at that and see if I guessed it right. The leaves can be variable, but the fruit and flowers are not. Fruit is the size of a garden pea and flowers are smallish and can be white but with five petals, not four.

Black nightshade is poisonous to humans and livestock. You should not be eating the fruit or any portion of this plant. The leaves of the plant can vary tremendously, but generally the berries are the dead (no pun intended) giveaway.

There are strains, "races" or subspecies found in other countries where it is used as a food, in herbal remedies for disease, animal feed and other things. However, these races are thought to be lower in toxicity because the levels of toxins in these plants are variable as well.

In the U.S., it is called "American nightshade" and in other countries it is usually given a label for that particular country or region. In the U.S., this plant has been the source of illness and death in livestock (the leaves) and children (the berries). It can be composted without any problems but consuming the leaves or fruit is likely moderately to highly toxic.

Q: Our lawn was laid with sod last spring. It's a fescue blend and no one has been able to figure out what our problem is and we are slowly losing the lawn. The edges are beginning to die and now it's working its way in.

A: Without getting on my hands and knees and pulling on the grass to see if it is loose in the soil and looking for bugs, I would have to say it sounds like insect damage. In fescue, it is most likely grubs but if it is a blend with Kentucky bluegrass there might be some other insects involved.

As the temperature and humidity drop, the chances of damage from disease are lessened. See if the grass pulls up easily in recently damaged areas. Old, dead grass will pull up easily so that is not a good clue but recently killed grass that is still green will not pull up if killed from a disease.

If my description fits the problem you are having, treat the area with a lawn insecticide and keep pets and kids off of the lawn until it is dry. Follow label directions precisely for good control.

Q: Several months ago I purchased a dwarf Meyers lemon tree. I planted it in a purchased soil mix. I had to use a pickax to get a large enough hole to plant it. It really did not grow much over the summer. I put a sheet over it to protect it from the bright sun and it's still not looking good. I fertilized and watered it every day. I have seen huge lemon trees at a condominium development next door so I know they will grow in my area.

A: Meyer lemon is not terribly difficult to grow here if the soil is prepared well and the plant is protected from winter cold extremes.

Using a pickax to make a hole of any size in the Las Vegas Valley is not unusual when our soils are dry. They are much easier to dig, or open up, when they are wet. Most of our soils will drain adequately provided there is not a layer of caliche present.

My suspicion is the problem is with the planting hole, how it was amended and your watering schedule. If you dug the hole and prepared the soil for planting properly, you should not need to water daily. Having neighbors who successfully grow Meyer lemon trees is a good indicator you will also have similar results.

I am not a big fan of "finished" or "complete" soil mixes purchased in bags. I prefer to use the existing soil taken from the hole, amend it with compost and use it for planting.

When planting, the planting hole needs to be only deep enough to accommodate the container and roots. No deeper than this. The only reason for a deeper hole is because of poor drainage. If water drains from the hole in several hours it is good enough.

What is much more important is the width of the hole. It needs to be at least three times the diameter of the container. Wider is even better. When the soil is removed from the hole, remove any large rocks and amend this soil with about 50 percent compost by volume.

Once planted, the tree needs to be staked to keep the roots from moving. This is done for one season only. I like to use a 3-foot length of 3/8-inch rebar pounded into the hole immediately next to the tree and the tree taped to it with green flexible nursery tape. It is easy to do and inexpensive.

When using soil mixes it is always a good idea to thoroughly saturate the planting hole with water from a hose. Do this three or four times after planting. Never plant a tree in a hole with a dry soil mix. It should always be wet.

It is also an excellent idea to flush the soil of excess salts immediately after planting. This is by flooding the planting hole with water several times and allowing it to drain each time. This will also help remove air pockets. Build a bowl or moat around the tree so it can be filled with water.

I assume your tree will be on drip irrigation and not watered by hand with a hose. Watering by hand with a hose seldom works because people are people and do not have the patience to stand there and deliver enough water slowly so that the roots of the plant are thoroughly wetted at each watering. Maintain a moist soil around the roots as the fruit is developing or the fruit will drop.

The tree will benefit from a 3- to 4-inch layer of wood chips on the surface of the soil. Adding compost to the soil surface every couple of years will help keep the trees healthy.

As far as fertilizers are concerned, apply one after harvest and another as the fruit are developing. Use a fruit tree fertilizer (rose fertilizer will work as well).

The usual minor elements in short supply include iron, manganese and zinc. Magnesium is also reported as a problem with citrus, but I usually focus on additions of iron chelates once a year applied after harvest.

— Bob Morris is a horticulture expert living in Las Vegas and professor emeritus for the University of Nevada. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.