Question
Hi and thanks in advance for any help possible. I'm a commercial fern grower, and have been having issues with microsorum diversifolium, rhizoctonia treatment and thrips treatment helped for some time, but issue does not seem to be solved.   Am I crazy or am I seeing possible mite damage, with stippling on leaf before it is infected by rhizoctonia?   Are mites more common on ferns now than previously seen?

Answer
Thanks for your question.

I have not seen a proliferation of mites on Microsorum (or other ferns) in Florida, no.  Of course that does not mean that you don't have them though.  In my experience, fern pests are usually limited to worms, aphids, and slugs.  Some long term crops can get scale and mealybugs.  In general, thrips and mites are the least likely to occur.

Microsorum should be a fairly disorder-free crop, and I have never had to deal with mites, thrips, or Rhizoctonia.  To test for mites, of course you would have to place the plant under a hand lens and, in some cases, a microscope.  Treatments, also, would need to target both adult and egg stages, so a pretty comprehensive approach is unavoidable (if you do indeed have a mite infestation).

In order to provide you with a more accurate opinion, of course I would need to actually look at some plants.  You can have them delivered to my Apopka facility or we can pick a couple up next week.  Alternatively, your local extension service should be able to help you with a specific identification and course of action.

If you wish to discuss further, feel free to call my office 407-889-7868.  My company (ARC Ferns) is Florida's largest fern propagator and supplier so we should be able help you out.

Thanks again!  

Dan C.