One is that the plant has actual mites. Then you’ll need to treat it with some spray. Mites can also be killed in winter cold climate if you are willing to let the tree receive some cold treatment, or just cut off the most of the top growth. A lot of the in-ground trees get killed to ground over winter. I guess mites probably won’t survive in that kind of environment.
Then the plant may not have live mites, but infected with FMV virus. Many plants are like that with various degree of infection. Then you just need to give them good treatment and let them grow stronger. Then they can fight the way out of the FMV virus.
Some tress may not respond well. Then it is probably better to acquire a more healthy tree, than wasting another year or two to wait for the weak tree to get started again.
Is there a clear temperature threshold where the mites get killed over the winter? I see some symptoms consistent with FMV in a few of my plants that were rooted as cuttings this spring. Most of these were sourced from trees growing outdoors here in the PNW, where figs don’t generally suffer any winter dieback with overnight temperatures usually near freezing or just below for a couple months straight, and occasional brief hard freezes. Here’s an example of what I’m referring to as suspected FMV, this one is a “Niagara Black” fig:
FMV and mites have been discussed many times here before.
I recall that mites will die if the entire top is killed at the ground level. Most of my trees are those heritage fig trees that get killed to ground every year. They do not show any FMV symptoms.
Also, I recall mites can survive in dormant buds. So if you wrap trees or take container trees in storage, mites can still survive.
I think in general, there are more mites in the South than in the North. So always quarantine new plants if you can. Container trees are affected more than in-ground trees.
To be sure this is FMV or mites, invest in some microscope to examine them. Not sure the cost.
I think this part answers my question… sounds like if the dormant buds can survive the winter, so can the mites. Since fig trees in the ground here don’t die back, any mites on their buds probably will also survive.
I’ll wait until next year to see if they outgrow the symptoms. I’m mostly wanting to avoid FMV spreading to any of my other trees that don’t show symptoms, even though maybe they have dormant infections anyhow.
The only way to eliminate FMV is not to trade with anyone and bring in new fig materials. Then over years, plants grow more healthy and entirely dominate the FMV virus. But FMV is not 100% eliminated. It just becomes very weak and won’t cause any harm.
I believe there are 3 mites of concern hosted by F. carica: two are active on leaf tissue and the other in leaf bud and stem joints. One of the leaf mites is a symbiotic vector of fig rust while the other two are vectors of FMV. All three need live joint tissue to survive plant dormancy.
