Spider mites are one of the few pests that bother Adeniums.
Spider mites can cause injury to Adeniums ranging from leaf loss to death of young plants, if left unchecked long enough. In other words “Don’t put your head in the sand and hope they’ll go away” if you see evidence of spider mites on your Adeniums.
Don’t panic! Spider mites can be bothersome, but with good culture and diligence you will have little trouble eliminating them from your Adeniums and preventing their return.
The most critical aspect of controlling spider mites on your Adenium plants, after proper culture, is understanding the mites life cycle and the need to break it. In plain English this means that most chemical controls will require at least 3 applications at 5-7 day intervals to assure complete control.
Now for some boring facts that you need to be aware of: spider mites are part of the Tetranchidae family. They are classified as a type of arachnid (spider). Spider mites are very small and difficult to see with the naked eye. Invest in a magnifying glass or some really high power reading glasses to help you spot them. They range in color from brown to yellow to green. Their color varies throughout their life cycle.
There are a number of symptoms that indicate mite infestation on Adeniums. These symptoms include discoloration or bronzing of the Adenium leaves. The leaves may also appear scorched. If you have a nasty spider mite infestation (large colony) you may see webbing on the leaves. If things have gotten so far out of hand that you see webs, I’d strongly suggest trimming off the foliage from your Adeniums. Use your head if you do trim off the leaves. Don’t drop them into the dust bin in your greenhouse. Seal the leaves in a bag and get them away from ALL of your plants.
Spider mites develop from eggs. Their eggs are usually laid near the base and veins of Adenium leaves during warm months. These eggs are round and large – often larger than the female spider mite herself. After the mites hatch, the eggs often remain on the leaves. This is useful in diagnosing spider mite issues as the spent eggs are fairly easy to see. Most spider mite activity occurs during the warmer months. Spider mite populations can build rapidly during these times because spider mites can become full-grown, and reproduce, within just one week of hatching. Fast development coupled with high rates of egg production can lead to a rapid increase in the mite population. See why I said ignoring them isn’t a good idea?
Spider mites thrive under dry conditions. Dry and windy conditions are even better for them. This is largely due to the way they dispose of waste. Simply put, they rid themselves of waste by evaporating it through their skin. This process becomes increasingly difficult as ambient humidity levels rise. The mites can’t take in much liquid from your plants leaves if they can’t eliminate waste. Adenium sap is not terribly nutritious so spider mites need to process a lot of it to function and reproduce effectively. We’re not too scientific around here and refer to the effects of ample humidity as control by bloat.
Nearby weeds, trees, and shrubs may be hosting spider mites.
We had a client, who collected Adeniums, that perpetually complained to us that none of the methods we recommended were effective in controlling her spider mite woes. She insisted that she had followed our instructions to the letter, and was beside herself, so I agreed to make a house call.
What I found was her fighting a losing battle. She had a large tree growing directly over a section of the benches her Adeniums were growing on. The tree was infested with spider mites.
We pruned off a couple of the lower branches that were over her Adeniums, treated the tree with a systemic miticide, mulched the ground heavily under the tree, and had her increase the humidity by running a sprinkler onto the mulch a couple of times a day. Now she sends us pictures of her beautiful Adeniums blooming as often as she used to send cries for help.