African Sumac With Curled Leaves

Q. New growth on my African sumac has curled leaves and it looks like aphids or something is attacking them. I thought sumacs were desert trees and didn't a have a lot of issues so I'm surprised by this development.

A. African sumac does get aphid problems. Aphids are more of a problem during cool weather and the problem usually disappears with the heat.  But aphids will hang around during the heat and cause problems as well. A good indicator of aphids is the presence of ants.

            If the aphid problem is bad enough you may see leaf yellowing and leaf drop, sticky or glossy leaf surfaces. The stickiness is aphid excrement which is sugary and attracts the ants.

            Soap and water sprays will get them under control if applied every few days. Soapy sprays do not hang around very long.

            Or you can use a systemic insecticide applied to the soil around the base of the tree and watered in. The poison moves up the tree to the leaves and poisons the aphids. This may be safer to use and more environmentally friendly than spraying the entire tree with a pesticide.

            Remember that African sumac is a very messy tree with lots of leaf drop. If you don't want a mess, you might not want African sumac.

Watch for Aphids This Time of Year

This time of year is a busy time for home horticulturists. Now that we have finished fertilizing landscape and fruit trees and increased irrigations as temperatures warm, we turn to pest problems.

What to do When Your Indoor Palm Has Sticky Leaves

Q. My indoor palm plant has developed a sticky-looking, shiny appearance on the leaves.  Also, small, 1/16" brown spots/bumps on the leaves and stems.  What is this?

Scale on palm leaf but unfortunately the plant also has spider mites
judging from the yellow speckled appearance of the leaf

A. This is probably one of the scale insects. It is living under this brown bump and sucking plant juices while totally protected by this bump or shell they build on top of themselves.

            This brown bump is what keeps them alive when pesticides are sprayed on the plant. BUT they are susceptible to poisons or insecticides that are taken up into the juices INSIDE the plant.

            So, systemic insecticides, those that are applied to the soil or sometimes sprayed on the leaves and taken up through the leaves, can be quite effective on these protected insects. Since it is a palm and you are not eating anything from it you can use these types of poisons on these plants.

            You will have to try to find one at a nursery or garden center that carries a systemic insecticide that has a label specifically for houseplants and controlling scale insects. The shiny stuff on the leaves is sticky since this is the sugary excrement of these scale insects falling on the leaves. Frequently it attracts ants.