If you have eucalyptus trees, you might have noticed white, crusty growth on the leaves. Or maybe you saw a sticky, blackened mess of fallen leaves under a eucalyptus tree. These are signs of the redgum lerp psyllid, one of the most common psyllid pests that damages eucalyptus trees in California.

The adult psyllid is very small and as nymphs, they are concealed under a waxy cap, or lerp. As they feed, they excrete honeydew which can lead to the growth of black sooty mold, the source of those sticky leaves under the tree.

Although under biological control in coastal areas, this pest is still a problem under some growing conditions and on specific Eucalyptus species. Cultural practices to manage...

Weeds are usually thought of as native plants we don't want in areas such as landscapes, fields, or vegetable gardens either because they reduce economic output or they are considered aesthetically displeasing. Invasive plants are generally non-natives that infest natural ecosystems and can become problems.

There are four distinctions between a weed and an invasive plant. The first is how they are introduced to an area. Weedy plants in gardens, landscapes, or in agricultural fields are usually accidentally introduced. While that is sometimes true for invasive plants, they are more often intentionally introduced as ornamental plants, for aquarium use, or for food or fiber...

Damage and...