Question
QUESTION: Hi
Our aralia (chicken gizzard) tree seems to have a case of some spider mites.  Not horrible yet but clearly there.
We kept clipping off the branches which seemed to be affected but they seem to be on most of the branches.   We spayed the plant with soapy water and also sprayed the leaves with plain water weekly.   The plant otherwise is doing very well.
What do you find is the best solution for these little pests.  Do we need to go with a chemical pesticide?  

Also, on the soil in the pot, there seemed to be other little bugs and we've noticed tiny flying bugs (perhaps gnats) around the house.

On another matter, our Ming aralia (not the one with the spider mites) tree, which you have advised us on before seems to be on it's last legs.  Almost all the leaves dropped off though there is some new growth.  Not sure when to consider it "dead".  

Thanks in advance for your wisdom.

Jon & Savanna

ANSWER: Hi Jon,

Spider mites are so small you can get a half-dozen of them on the head of a pin. If you treat only the ones you can see, you will miss many of them. So, trimming leaves and branches will not help control the problem. Plain water spray is not effective. A solution of liquid soap and water is effective, but only if you thoroughly drench ALL leaf and stem surfaces until they are dripping wet. Thoroughness of coverage is critical because if you miss a few of these tiny critters, they will reproduce and return to haunt you in several months when they once again reach a critical mass. If you are thorough, then there is no need for using pesticides.

Fungus gnats are the adult form of fungus gnat larva that live in the top layer of the soil feeding on decaying organic matter - damp soil and rotting roots. They are almost always associated with soil that is not allowed to dry out sufficiently deep into the pot. Their original source is poor quality potting mix, either at the nursery or from potting mix you used if you unwisely opted to repot.

The winged adults will die on their own within a week or so. Treat the fungus gnat larvae by removing all loose soil from the surface that is not in direct contact with the roots. This extra soil serves no useful purpose, but it does harbor many of the gnat larvae. Then, allow the soil to dry as deep as possible into the rootball so you deprive the larvae of the moisture they need to survival. Finally, you can spread a thin layer of sand across the surface of the soil. The sharp particle edges will carve up the larvae as they move to the top of the soil.

Any plant that has lost most of its leaves has also probably lost most all of its roots and that is usually fatal because there is no way for the plant to absorb essential water and nutrients from the soil. Take any healthy remaining stem tip cuttings and try to propagate new plants from them.

The presence of plant pests is nearly always a sign of a plant under stress for other reasons - usually inadequate light or improper watering. Given the problems you are having with your plants, it seems that you need to get a better handle on your watering routine.

I have written articles on  plant pests and repotting on that I will email for free to you (or anyone else) who sends a request to me at [email protected].

Please let me know if any of this is unclear or if you have any additional questions.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

Visit my website at: A link to PlantCareExperts.com



---------- FOLLOW-UP ----------

QUESTION: THis is extremely helpful.  Thanks very much.
We are curious to know actually where the spider mites come from?  I assume they were already on the tree when we purchased it.  

Is there any need to worry about spider mites on a Fiddle Head Fig?  We don't see any on this.

Thanks,
jon & Savanna

Answer
Hi Jon,

Yes, the spider mites were probably on the plant at the time of purchase, perhaps in such small numbers that they were not easy to detect. Spider mites reproduce very rapidly when a plant is under stress and when the surrounding air is warm and dry.

Ficus lyratas rarely attract spider mites, but it is always a good idea to check your plants monthly to make sure there are no signs of any other pests. My article on plant pests will help you understand just what to look for.

~Will