Sticky Substance on Leaves?

Question:

I brought my bay plants in for the winter. They have developed a sticky, shiny substance all over the leaves. I don't see any insects but did spray them when I noticed this substance. Today I notice that it has even dropped onto the window sill close to the plant.

What could this be and how do I cure it? I've washed the plant throughly and sprayed it.

Hardiness Zone: 5b

Roberta from China, ME

Answer:

Roberta,

What you're describing sounds like an aphid infestation. Aphids are tiny (1/32"-1/8") soft-bodied insects that make their living sucking the juices (sap) from plants. There are several types of aphids and they come in several colors: green, pink, black, gray and white. Some have wings and others are wingless. Colonies can form quickly, and in large numbers, both the adult and nymph form can drain enough plant sap to cause the distortion of the leaves, buds and flowers. They can stunt the plant's growth and in severe cases, kill them. Their feeding can also spread viral diseases.

The sticky substance on the leaves of your bay plants is honeydew. This is a sweet, sticky substance excreted by aphids as they feed. Along with attracting ants (they love to eat it), honeydew also supports the growth of sooty mold. Unless you're facing a large infestation of aphids, sooty mold often causes more problems for plants than the aphids.

The easiest and best way to get rid of aphids is to do exactly what you did-wash off your plants with a strong stream of water (you may need to repeat this a few times) and spray them with an insecticidal soap.

Ellen