Most of our South Florida native insects do not cause enough damage to trees and plants to be a cause for worry. However, as global travel among countries has increased over the past century, insects have been brought away from their native environments. These insects often have no natural predators in the new country where they arrive, so they are free to live, eat and reproduce without danger of being eaten. They out-compete native insects for food resources and can wreak havoc on native trees.
Here in the Tampa Bay and Sarasota areas, we unfortunately have many insect pests that you should be on the lookout for when you notice a tree becoming unhealthy.
- Asian citrus psyllid: This small brown-and-black insect strikes fear in the hearts of many citrus farmers in Florida. It carries a bacteria that enters the tree while the larvae eat the foliage and causes citrus greening. As of yet, there is no cure for this disease, which prevents nutrient flow through the tree and causes fruit to drop early and not ripen.
- Bark beetles: Though extremely small, these insects are mighty in large numbers. Within a few days, their numbers can go from just a couple dozen to thousands. They feed on the bark of trees and can destroy the xylem–the layer of vascular tissue in the tree that carries water and nutrients to the branches and leaves.
- Dogwood borer: These clear-winged moths lay their eggs on the bark of dogwood trees. The larvae burrow into the living wood and consume the tree from the inside-out. Their activity can permanently disfigure a tree, stunting its growth where they attack. If left unchecked, they can kill a tree within 1-2 years.
- Sri Lanka weevils: White-grey and ¼ inch long, these insects are attracted to a range of host trees, including most fruit trees. They seem to particularly target mango and lychee trees. The larvae consume the roots of the tree, while adults feed on the leaves and buds.
- Tent caterpillars: A common sight in late spring is the gauzy white “tents” that appear on the tips of tree branches. These silky masses are made by adult moths while molting. They lay eggs on trees, and the larvae can completely defoliate the tree as they eat and grow. However, infestation of tent caterpillars is not necessarily a death sentence; most trees are able to regrow their leaves after the caterpillars have matured and left.
Ways to Protect Your Trees
The best method of prevention is to keep your trees healthy. Pests often target unhealthy trees because they are easier to infest. Trees have natural responses to stressors like infestation, and will be able to combat it more effectively when they are healthy.
- Trim and prune the branches in winter when trees are more dormant–the wound heals faster at this time, and most adult pests are less active during this period as well.
- Mulch to protect tree roots and prevent damage to the trunk from mowing equipment.
- Fertilize regularly so they are getting all the nutrients they need to remain healthy.