Avocado Lace Bug
This pest is widespread
The avocado lace bug (Pseudacysta perseae) was discovered on Hawai‛i Island in February 2020. There is also a population on O‛ahu and Maui. This insect goes after all species of avocado and some of the laurel family such as red bay and camphor. These insects cause very noticeably yellowing and brown spots on the leaves where the adults are feeding. These spots start in the center of the leaves.
When flipping over an affected leaf you can find all stages of the avocado lace bug. Adults, immatures, old body casings, and black shiny speckles. These black speckles are poop, where the lace bugs also hide their eggs. Healthy trees can survive an avocado lace bug infestation. Heavy infestations can cause the tree to almost completely defoliate but over time the tree can regenerate its leaves.
Avocado Lace Bug (Pseudacysta perseae)
Photos (L-R): BIISC, BIISC, Oscar Jaitt
- Adults are about 2mm long
- Yellow/white wings with a black stripe going across the body
- Wings are made up of an intricate network of sections that resembles lace
- Immature lace bugs are smaller than the adults and their lace-like wings are not visable
Symptoms of infestation:
- Yellow/brown spots that start at the center of leaves
- All life stages of the insect and black speckles are found on the underside of leaves
- Early fruit drop
Controlling Avocado Lace Bug
Small populations of the avocado lace bug are tolerable and won’t harm the tree in the long term. However, heavy infestations can cause fruit to drop early, and reduce overall tree yields. There are predatory insects that can help control the lace bug population, so avoid spraying broad range insecticides. If the population is very bad there are a few options to pick from.
If your tree is trimmed small enough for you to reach all of the leaves you can use contact sprays such as insecticidal soaps, oils, or Beauveria bassiana (pathogenic fungus). These types of insecticides only affect the insects they come into contact with so make sure that you get good coverage.
For treating very tall trees you can use a systemic pesticide such as Bio Advanced Fruit, Citrus, Vegetable Insect Control(imidacloprid). Do not treat until after the tree has finished blooming to reduce the risk to pollinators. Whenever using pesticides always make sure to read and follow the label.
If you do not want to use a systemic pesticide you can also hire an arborist to help treat avocado lacebug.