Gardening

Scale insects can be a common problem on many types of plants ranging from indoor plants such as schefflera to plants in the landscape such as Indian hawthorn (shown above). When scale insect populations become heavy, the insects can produce large amounts of honeydew (a clear, sticky, sap-like substance). Photo by William M. Johnson

Gardening in July: Questions and Answers

by Dr. William M. Johnson, Galveston County Extension Agent - Horticulture
July 17, 2004

Question: I have a Schefflera in a well-lighted indoor location. The leaves contain numerous bumps and are sticky to the touch. The sticky material is clear and is dripping off the leaves onto the carpet which has also become sticky as result. Can you tell me the cause and how to treat it?

Answer: Based on the information provided, the most likely problem is an infestation by scale insects which produce honeydew (the clear, sticky, sap-like substance described). While aphids and certain other sucking insects can also produce honeydew, Scheffleras are more likely to be infested with scale insects.

These wallpaper as brown bumps on the twigs and leaves which can be scraped off with a fingernail. Scale insects are difficult to control, especially if they have spread to other plants in the area.

However, there are insecticides which can be used to treat scale insects. You should be sure to select one which is labeled for use on interior houseplants. Insecticidal oils (such as neem oil) and soaps (such as Safer’s Insecticidal Soap) may be your best option if the plants must be kept indoors during treatment.

Applications of insecticidal soap or horticultural oil will kill scales, but at least three treatments are usually needed to control severe infestations. Repeat every six to seven days until scales have been eradicated.  Dead scales do not fall from plants, so you’ll have to examine plants to determine whether the scales are dead or alive. Crush the scale - if it’s dry, the scale is dead; if the body is juicy or leaves a streak when smeared on a piece of paper it was alive.

If you are able to move the plant outdoors into a shady place for a few days, you may spray the plant with Orthene which is not labeled for indoor use but can be very effective at treating the scale insect problem.

However, do not expose the plant to direct sunlight as leaves may suffer sunburn. The plant can be moved indoors 4-to-5 days after treatment. Be sure to periodically inspect the plant for the presence for scale insects.

Question: Our pampas grass has really gotten out of hand. It stands almost 10 feet tall and is blocking our view of the road. It has never been pruned in all the years it has been there. What can we do with this plant?

Answer: I really like the texture and form that pampas grass can provide to a landscape especially when it produces its seed heads later in the summer. However, I always provide a cautionary note to homeowners about planting this grass.

Pampas grass can easily become a problem due to its size. Older plants are almost impossible to dig up by hand. It often takes a tractor or backhoe to get them up. However, you can manage the growth by cutting the tops back during late winter before new growth is initiated.

Cut the top growth as close to the ground as possible. Try to prune back to at least 1 foot from the ground. This will require heavy duty electric clippers or even use of a chainsaw - pampus grass is one tough plant. Wear gloves to avoid cutting yourself from the sharp edged leaves. Since pampas grass is already putting on its feathery heads, do not prune it back now. The ideal time for pruning back pampas grass is during late winter (late January to mid-February). Make this an annual project and your pampas grass will stay manageable.

Go to July 17, 2004 article on scale insects and pampas grass.

Gardening: Scale insects and pampas grass - July 17, 2004 article

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