Dwarf conifers are very prone to various problems. Today I’m going to talk about one of those troubles.
To treat spider mites on Dwarf Alberta Spruce, wash them off with a hose of water and spray the needles with horticultural oil. Keep a constant eye on the spruce and if the mites don’t go away, spray it with acaricide.
Check Dwarf Alberta Spruce regularly
The first thing to do is to keep looking around for Dwarf Alberta Spruce. Preventing the spread of spider mites is the best way to control them.
Beginning in March and continuing through fall, carefully inspect the needles. Mites are especially active during dry, warm weather.
If you see anything suspicious, take a piece of paper and shake off anything on the branch. Then put the sheet on a hard surface and crush it all with your hand. If you get a wet sheet of paper and a greenish or grayish liquid appears, it is mites.
What are the signs of spider mites?
The first noticeable symptom of the presence of spider mites is the discoloration of the needles. The mites are sucking pests and as soon as they get on the spruce they start to feed on the sap from the needles.
As a result, the needles begin to slowly dry out. First, the color changes to pale green, then to brownish green. If you do nothing, the needles will shrivel up and fall off.
If you find something wrong with your conica spruce look closer to the needles. Between the needles, there should be a very small cobweb on which the creatures about the size of a grain of sand must be present.
Use a hand lens to see better. The color of the mites can be white to grayish or even greenish. Here in the pictures, you can see the mites that are parasitic on various conifers in my garden.
Rinse spider mites off with water
Spider mites do not like wet environments. They spread most strongly in times of drought. Knowing this, you can make life very difficult for them.
If you are sure that your Dwarf Alberta Spruce is infested with mites, then wash them off with a stream of water. Use a hose with medium water pressure with a nozzle on the end of the hose.
Thoroughly wash all branches and needles. Pay particular attention to the middle of the branch; it is usually the driest place and this is where mites hide. The inner and lower branches are a favorite place for spider mites.
Wash your spruce only in the morning or evening since the wet needles can be damaged by the afternoon sun.
Wash several times at intervals of a few days. Of course, you will not get rid of the pest completely, but together with other measures, flushing can give a good result.
Use horticultural oil
The second step in getting rid of spider mites is to spray Dwarf Alberta Spruce with horticultural oil. This product is a natural insecticide that does minimal harm to beneficial insects and the environment.
Spraying needles with horticultural oil can be done any time of the year except in winter. As soon as you see mites, use a water-based solution of horticultural oil without waiting for them to spread. This product even destroys mite eggs.
You can find many quality horticultural oil manufacturers on the market. Choose the best of them. Dissolve 4 teaspoons of dishwashing soap in 1 gallon of water. Then add 4 tablespoons of horticultural oil to it and mix well. That’s it, the mixture is ready.
Sprinkle the entire spruce tree including the middle and bottom of the crown. Repeat the spraying after a week. Use a sprinkler and a fine spray to get the spray on each needle.
Horticultural oil along with washing the mites off with water usually gives good results and you won’t have to do anything else.
Spray with acaricide
In some cases, you will have to use more effective means than horticultural oil. This applies to severe mite spreading and very large damage on spruce trees. In this situation, you have to act quickly and the above methods may not be very effective.
To get rid of the spider mite fast, you need to spray the spruce with acaricide. This is a special product designed specifically for this type of pest, as mites are not insects and insecticides have almost no effect on them.
The disadvantage of acaricide is some degree of toxicity, so not all types of this product are available for purchase. But you can still find effective products that are not prohibited for use.
Spraying 1-2 sprays with an aqueous solution of acaricide is usually enough to rid the spruce of these pests.
Can Dwarf Alberta Spruce recover from spider mite damage?
In most cases, Dwarf Alberta Spruce will recover from spider mite damage. The time it will take to do this will depend on the extent of the damage and how early the pest was noticed.
If the needles have not dried out but only changed color, it will almost certainly return to a bright green color after some time. The main thing is to eliminate all mites and their eggs from the tree.
If some of the needles have fallen off, the living part of the tree will gradually increase. This will take several years as Dwarf Alberta Spruce grows very slowly.
If all of the needles have fallen, then you need to crush a few buds in different parts of the tree. If the buds are dry, then unfortunately the spruce cannot be saved. But if the buds are alive and moist, there is a high probability that the spruce will stay alive.