There are spots on my leaves. How can I tell if they are caused by an insect or disease?

The first step is accurately identifying the plant. Many insects and diseases are host specific. It is also important to consider any abiotic factors that could cause damage to your plant or leave it susceptible to insects or disease. Is it possible the plant is drought stressed or had herbicide overspray contact the leaves? Has anything in the environment changed recently? Was the plant recently fertilized? Where are the damaged leaves—all over the plant or only on new growth? Are there any wounds on the plant? Ask probing questions and find out as much history on the plant as you can. Insect damage to plants comes from either chewing, sucking, or boring. Indications that insects with chewing mouthparts are feeding on your plants include missing chunks of leaves or stems, skeletonization of leaves or leaf mining. Insects with sucking mouthparts remove sap from plant cells, which can cause stippling (spotting), discoloration, or drooping of leaves, or lead to honey dew. Boring insect larvae tunnel into the plant beneath the bark, leaving sawdust toothpicks on tree trunks or sawdust mounds below. Their adult forms can feed on leaves or twigs. You may look for the insects themselves, insect parts, or frass (excrement). Some fungal diseases can leave spots on leaves. The diseases generally produce “target-like” spots, each with a dark center, yellowing ring, and a brown or red margin between the dead tissue and the live green tissue of the plant.

There are small bumps on the leaves of my hackberry, is it going to die?

This is most likely insect galls. Galls are abnormal growth of plant cells due to an injection of a chemical by an adult or larval form of an insect. These chemical causes the plant tissue to swell and become misshapen, forming the bumps you see. Insects often live inside the galls for a short period of time, gaining shelter from predators and feeding off the swollen plant tissue. Galls are quite common on plants like hackberry and oaks. The damage, generally cosmetic, will not kill the plant.

There are many black bugs with orange stripes on their backs flying around in my grass. It looks like somebody spit on my grass in spots.

These are most likely two-lined spittlebugs. Both adults and nymphs damage turf by sucking out the plant juices from leaves and stems. They also produce a spittle mass, which is nothing more than a nuisance. In late summer adults can also fly to hollies to feed and cause holly leaves to drop prematurely. Following good turf management practices, reducing excessive thatch, and avoiding overwatering will help manage spittlebugs. Plant a more tolerant turfgrass species such as St. Augustinegrass or zoysiagrass, and avoid centipedegrass if possible. On ornamentals and grape vines, a strong spray of water may be sufficient for management.

How do I get rid of fire ants?

Red imported fire ants expand naturally and steadily in our area because their reproductive rates are high and our winters are mild. The mounds are unsightly, and their stings are painful. Both baits and contact insecticides are effective management tools. Common active ingredients are hydramethylnon, spinosad, methoprene, and pyriproxyfen. In bait formulations the active ingredients are shared by the ants in a mound, including the queen (which is the only ant in the colony that can lay eggs), usually resulting in more effective management. Contact products containing the active ingredients acephate, carbaryl, or pyrethroids produce management in a few days if broadcast over the landscape, or in a few hours if applied to individual mounds. Both require water (rainfall or irrigation) to become active. An exception is a product with the active ingredient fipronil, which produces long lasting effects when broadcast in late May to early June. Fipronil will provide five to six months of management. Repeat treatment in November if ant mounds reappear in the fall, as sometimes happens. Be sure to read and follow product labels closely before application in order to achieve desired results. To determine if you have fire ants, look for two nodes between the thorax and abdomen. Other ants only have one. For more information regarding fire ant management in the home landscape type “fire ants + extension” into your internet search engine.

More information on insects