Adenium Aticles

Mites

courtesy : Phil Davis

Mites are some of the nastiest little beasties I know of in horticulture. This discussion will be centered on Adeniums though my comments could pertain to any crop.

Adeniums are usually grown as a succulent in warmer climates and in greenhouses where outdoor culture will not be optimal; this fact makes them particularly vulnerable to the mite for their optimal growth conditions are very similar. Hot and dry with a low humidity and aided often by poor air circulation generally insures you will have an encounter with mites.

The only solution I can offer is to develop a program of diligence. Check your plants often and if things do not look, as they should, isolate the suspect plants to prevent a potential worsening of the situation.

We must be practical though. This is easy if you only have a few plants. If you have say, a few dozen or so, curative and preventative measures should be taken. We will visit that a bit later.

When spider mites are talked about, the target pest is the two spotted spider mite. Red spider mite is commonly discussed but it is the same mite, whose adult stage has an orange-red color under cooler conditions. Adult females are less than a millimeter in size with eight legs. MITES ARE NOT INSECTS, they are arthropods rendering insecticides ineffectual. Only chemicals labeled for mites will be of any use.

Mites feed by stabbing cells with their mouthparts and removing the cells contents resulting in the characteristic stippling as a common first symptom This is often accompanied by a fine webbing found on the undersides of the leaves, in the leaf axils and the tips.

The females lay up to a dozen eggs per day on the undersides of the leaves, up to 100 in her lifetime. The eggs may hatch in three days with the resulting larvae beginning to feed immediately. The adult stage is reached within 7 days at about 80 degrees and she will begin laying eggs within 3 days. Mating is not required. The hotter it is, the faster this happens and as a special bonus for us they develop faster on water stressed plants.

Cooler temperatures slow the whole process down quite a bit but to all beware. Even going through winter won’t save us. Females have the ability to hibernate in soil and benches to revive in warmer weather and re-infest again.

So, you can see that if you have more than a few plants chemical acaricides is likely the only answer to the problem.

I am going to give you an overview, through my eyes, of the current chemical control of mites. None of my comments will be specific to Adeniums. No comments should be considered specific recommendations. I caution you all to always read and follow all the labels instructions.

It would be extremely poor judgment for me not to mention the existence of many quality bio-control programs for mite control; these involve using mite predators for control. They can indeed be successful, especially in an enclosed environment. They, in my opinion, tend to be expensive, labor intensive and necessarily endless but an excellent alternative to chemical use.

Check your plants often! Did I mention, check your plants often!!

Chemicals – everyone hates them. You really need to know what you are putting on your plants and how they work. You need to familiarize yourself with the “mode of action” or how it is accomplishing its goal. Some kill on contact. Some more gradually. Some kill adults and not eggs, others eggs and not adults. Many attack all the in-between stages like nymphs and larvae. A few do all but it encourages the user to be familiar with the life cycle and its timing for success. Even with casual use it is important to know what you are doing

It is extremely important that you get good coverage with your spray. Mites are usually found on the leaf underside. Some chemicals have Translaminar activity which allows the chemical to travel from the leaf top to the bottom and thru the leaf surface. It is sometimes mentioned but in fact there are no systemic miticides. Newer chemicals have a longer residual control period but are not actually systemic in nature.

About the actual chemicals, The key element is the active ingredient, Many brands will have formulations of the same active ing.

\redient but will have different brand names. Even different areas of the country will have the same chemical with a different brand name so be aware of what you are buying. Below are a few. Some are new and some old.

 

Brand name                Active ingredient             Mode of action – stages effected

Akari                           fenpyroximate                  contact toxin       eggs , adults

Avid                            abamectin                         injestion toxin     adults  translaminar

Floramite                    bifenizate                          contact toxin       all stages

Hexygon                     hexythiazox                      contact toxin        all stages

Judo                            spiromesifen                     contact toxin        all stages

Ovation                       clofentazine                      growth regulator  eggs , nymphs

Pylon                          chlorfenapyr                      contact toxin        adults  translaminar                    

San Mite                     pyridaben                          contact toxin        adults juveniles                      

Shuttle                        acequinocyl                       contact toxin        all stages

TetraSan                     etoxazole                           contact toxin        eggs,juveniles

 

Trust me, the list above is short in comparison to all that are available and to come

It would be remiss for me not to mention a number of more “friendly”treatments. Many are very popular due to chemical fears and the need to be more “Green” oriented. I have to warn you though, If you have a serious infestation, they are not going to help you very much.

Oils and soaps – Effective if used properly otherwise may be very phytotoxic. Avoid applications on sunny days and physical removal is often necessary. They smother the pests but also clog the stomates of the plant.

Sulphur – Marginally effective. Somewhat nasty to apply (spray or dust) so protective gear is recommended.

Pepper/garlic and like concoctions – Marginally effective if commercially prepared.

Predatory insects -  An excellent choice for a grower with an enclosed area (greenhouse etc.) Does not work well for outside areas. Quite costly and not practical unless numerous plants are involved. Even when the predators do their job well, they tend to disappear for they have depleted their food source.

Please keep in mind this is s summary, not all information is here and new information becomes available rapidly. Be informed and practical with your choices. Keep your safety and the safety of others and your surroundings always at the top of your list.

The only concrete answer- Nothing is ever easy. Happy growing!

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