Here's how to find and treat Lychee Erinose Mites on your lychee trees | Sally Scalera
A new pest in the state is a serious threat to lychee trees, so everyone growing a lychee tree will want to learn how to protect it. This new insect is the Lychee Erinose Mite and goes by the scientific name Aceria litchii.
LEM is a native of Asia where it is also considered a major pest of lychee (Litchi chinensis) trees. It is a world traveler and has made its way to Hawaii, Australia and Brazil, and is considered a prioritized pest in the continental United States and other territories. LEM was first discovered in Florida in a lychee grove in Sarasota County in 1955 and again in 1995 in Miami-Dade County on imported plants from China. In both of those cases, they were eradicated and never became established in the state. In 2018 LEM was discovered again in Lee County, and can now be found in Charlotte, Sarasota, Manatee, Pinellas, Martin, Palm Beach, Broward, Miami-Dade, Collier, Hendry and Brevard counties. On Nov. 1, 2022, FDACS suspended eradication efforts statewide because of the widespread distribution of LEM and a lack of funding.
As their feeding damage continues, it causes the leaf epidermal cells to become a reddish-brown hairy mass that becomes very visible on the entire underside of the leaf, causing the leaf to become distorted and curled.
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Because of their extremely small size, LEM can be spread by air currents, honeybees, tools, humans (that touched symptomatic leaves), and the movement of infested plants. Cleaning your tools after pruning infested branches and changing your clothes before moving to another area of lychee trees will help stop their spread. All tools and equipment used on lychee trees, including clippers, loppers, hand saws, chain saws and hedgers should be washed with a 10% bleach solution (one to nine parts water) before being used on another tree.
You can also protect your tree from this potentially devastating pest by helping it tree grow as healthy as possible. Just in case you missed my previous article on Citrus Greening, here are the steps to take to help your Lychee tree (and other plants suffering from insect pests and/or diseases.)
Test the soil around your lychee unless a soil test has been done in the past year trees so you can fertilize correctly. The University of Florida tests the soil for $10 and measures the soil pH and the levels of phosphorus, potassium, magnesium, sulfur, copper, manganese and zinc. Our UF/IFAS Landscape and Vegetable Garden Test form can be found at edis.ifas.ufl.edu. Search for Landscape and Vegetable Garden Test Form. Be sure to use crop code 602 for woody ornamentals.
Re-mineralize the soil with rock powder (i.e., Azomite, etc.) to provide important trace elements from a volcanic source for healthier trees and more nutritious fruit. Rock powder will also benefit trees, plants and the lawn.
I always recommend establishing the biology around the root systems throughout your yard so your trees, plants and lawn can grow as plants do in natural areas where humans are not broadcasting synthetic fertilizers and applying pesticides. I also believe in growing healthy plants so insect pests won’t visit your yard. Inoculate the soil around your lychee tree by applying a product that contains a variety of beneficial bacteria and mycorrhizae (i.e., Bushdoctor Kangaroots or Microbe Brew, Plant Success Great White, etc.) For easy instructions on how to do this, contact the UF/IFAS Extension Brevard County Master Gardeners at brevard-mg1@ifas.ufl.edu.
Next, spray the foliage of your trees with liquid seaweed (i.e., Maxicrop, Liquid kelp, etc.) to supply more than 60 trace elements and growth hormones. Aim to spray the foliage weekly. Use a hand pump-up sprayer to apply the solution to both sides of the foliage. Don’t worry if you can’t spray all the leaves, because the tree will translocate the nutrients throughout the canopy.
Testing at the University of Rhode Island showed that tomato plants sprayed with an aspirin solution every two to three weeks had a boost in their defense mechanism called Systemic Acquired Resistance or SAR. Dissolve three chewable low-dose aspirin in a cup of hot water and add enough cold water until you have a gallon. Then add the liquid seaweed to that gallon to spray everything at once. Use a hand pump-up sprayer to apply the solution to both sides of the foliage. For citrus trees (avocado, mango, avocado, fig, peach, vegetable plants, etc.) aim to spray the aspirin and liquid seaweed mixture weekly, if possible.
Apply a top dress about ¼-inch thick to the soil with organic matter (i.e., earthworm castings, compost, etc.) within the dripline of your tree to increase the organic matter content of the soil, and inoculate the soil with protozoa, bacteria, etc.
To create a diverse soil food web, consider growing plants within and outside the dripline of your lychee tree to provide the soil microbes with additional root exudates. This can be accomplished by growing a variety of ground covers and cover crops. For ideas of both ground covers and cover crops to grow, email the Master Gardeners at the email mentioned earlier.
Hopefully, you won’t find any abnormal new growth on your lychee trees, but if you are going to discover evidence of LEM, it’s much better to find it at the beginning of an infestation, because your trees will fare much better. If you have any family or friends who are growing lychee trees, share this information with them also. This weekend is a great time to start implementing these suggestions to help your Lychee trees grow their healthiest to protect them from the Lychee Erinose Mites that are here in the county.
Sally Scalera is an urban horticulture agent and master gardener coordinator for the University of Florida’s Institute of Food and Agriculture Sciences. Email her at sasc@ufl.edu.
This article originally appeared on Florida Today: Lychee Erinose Mites have spread to trees across Florida
