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Hortiscope: Sticky schefflera likely has mites, needs pruning

Apple maggots require insecticides to control. Hanging a fake apple trap with a sticky substance to attract the insects will also work.

Q: I am experiencing new tree growth below my established malus prairie fire. Will these volunteer trees be an exact copy of the mother tree or will they be another type of apple tree? I am assuming these trees come from the fallen fruit because I have dug up one of the volunteer trees and found it is not connected to the mature tree.

A: Thanks for the good question! The seedlings and suckers from your mature tree will not be the same type of prairie fire. Seedlings reflect the genetic makeup of the tree, but can vary all over the place.

The suckers from the root system will be identical to the root stock the prairie fire is grafted to. If you want to venture into experimental horticulture, collect some of these seedlings and plant them in an innocuous spot on your property to see how they turn out. If you like the trees, keep them. If not, remove them.

Q: I have a schefflera tree that is having some problems. Its leaves become very sticky. I have used insecticides for scale and spider mites. The plant is then OK for a little while, but then the problem returns. Should I repot it or prune it down to 3- or 4-inch branches? It does have some new growth on it. It sits by a kitchen window that faces south and west, so it gets plenty of light. Any suggestions on how to take care of this problem?

A: Whatever this insect or mite is, it is surviving your best attempts to get this taken care of. I would suggest that you prune it back heavily. Repot the tree using fresh potting soil and a new pot. Dip the entire plant into an insecticidal or miticidal soap solution. If this doesn't take care of the problem, dump the plant.

Q: We hope you can help us figure out what's wrong with our honey crisp apples. We have a tree that was planted about 15 years ago. It did not bear fruit for quite a few years. However, since it started, we have enjoyed these wonderful, crisp, juicy apples.

In 2008, some of the apples weren't as good. Some had brown spots inside and tasted bitter.

In 2009, we had many apples on the tree, but many did not get very big. This may have happened because of our cool growing season. Many of the apples were bumpy and sort of mottled on the outside and had brown spots on the inside.

What do you think has happened to our honey crisp? This tree is in our backyard next to a haralred apple tree that bore beautifully this year.

A: This sounds like an apple maggot problem got started on your tree. The high density of apples you had on the tree made it worse. Remove any apples that are on the tree. When the snow disappears next spring, pick up and remove any fallen fruit that is on the ground. Spray an insecticide that contains carbaryl (Sevin) at petal drop and again every 10 days or so going into July. You also want to hang a fake apple trap or two.

The trap is covered with a sticky substance that will act as a monitoring device to see what insects are coming into the tree's canopy. The apple maggot is a small fly that is identified easily. If any significant numbers start showing up on the false fruit, resume spraying. The Sevin also acts somewhat as a fruit thinner, so you should have fewer but better fruit. I would hang a couple of the false apple traps on your haralred to make sure that this pest doesn't also decide to raise a family in this tree!

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail