(News article for August 14, 2020)
In some cases, once we can see a problem with a plant, it’s too late to do much about it. In these situations, it’s important to take action to prevent problems before they’re observed.
When people harvest satsumas, they sometimes notice dark areas on the inside of the fruit, where a yeast has caused a dry rot. The yeast is transmitted by leaffooted bugs. These insects, as well as a number of other factors, can also cause fruit drop.
People often refer to leaffooted bugs as stink bugs, but their body shape differs from that of shield-shaped stink bugs like the brown and southern green stink bugs. The bodies of leaffooted bugs are more elongate. The adults of the species most often seen here are dark brown and have a white stripe across their bodies. The name leaffooted bug comes from the flattened appearance of the rear legs.
The bodies of leaffooted bug juveniles, or nymphs, are orange or reddish brown. They look similar to the juveniles of some beneficial assassin bugs.
Start watching for leaffooted bugs in August and keep a lookout for them as fruit ripens.
Keeping weeds down around citrus trees can help reduce leaffooted bug populations. Small numbers of leaffooted bugs can be knocked off into soapy water. (They can smell, so you may want to wear gloves.)
If numbers of leaffooted bugs are too great to be dealt with by hand, an insecticide can be applied. Malathion is one insecticide recommended for leaffooted bugs on citrus.
The pyrethroid insecticides (active ingredients ending in “thrin,” plus esfenvalerate) are often effective on true bugs – a category that includes leaffooted bugs and stink bugs – but few home garden insecticides with pyrethroid active ingredients are labeled for use on fruiting citrus trees. I did find one, Ferti-lome Broad Spectrum Insecticide, that contains bifenthrin. You have to look through the label to see that it’s allowed to be used on citrus.
There are also products that contain horticultural oils or pyrethrins (the natural chemical from which the synthetic pyrethroids are derived) that could be used for leaffooted bugs nymphs. Insecticides are generally more effective on juveniles than adults.
Make sure that any product you’re planning to use is labeled for use on citrus. Follow label instructions, and only use insecticides when necessary.
Let me know if you have questions.
Contact Mary Helen Ferguson.
Trade names are included for the convenience of the reader. No endorsement is intended for brands mentioned, nor is criticism meant for ones not mentioned.
Adult leaffooted bug. (Photo by Raj Singh)
Leaffooted bug nymphs. (Photo by M.H. Ferguson)
The LSU AgCenter and the LSU College of Agriculture