Dwarf Skimmia Disease
Hello, my male and female dwarf skimmia are rapidly losing color and looking sick despite proper feeding watering, and application of Organocide on the leaves per the label's instructions. Due to a small amount of webbing and similar pictures online, I went to look for spider mites. I found very red, very fast-moving mites and some other insects that might be thrips. The attached photos are the best I could get given the limitations of my camera, the magnifying lens and the speed of the insects. Do you have any thoughts on what type of mites/thrips I might have, and which predatory mites might be beneficial to buy? Thank you.
Montgomery County Maryland
The insects in your photos are not causing any plant damage. Do not spray a pesticide unless you know what you are spraying for.
Middle photo is a predatory mite which feeds on pests like spider mites. You do not need to buy predatory mites. They are already in your landscape. http://extension.umd.edu/hgic/insects/predatory-mites
Right photo is a spring tail. They do not bite and feed primarily on algae, fungi, pollen and decaying organic matter. http://extension.umd.edu/hgic/springtails
Skimmia - We cannot say for sure what is going on. If they were planted in the last year or so, it may be a lack of establishment. Planting too deeply, excessive mulch, etc. What was your planting technique? Did you cut and spread the roots out before planting? Container-grown plants sometimes become root bound with their roots tightly coiled around in the container. These plants need special treatment to loosen the roots when planted.
Container plants establish faster if you disturb the “around the pot” growth direction of the roots. Use a sharp knife or blade to cut four one-inch-deep cuts the length of the root ball. New roots will rapidly grow from the cut areas of the roots. Dig the planting hole deep enough to accommodate the plant with the top of the root ball level with, or just slightly above, ground level. Fill in soil around the root ball and firm the soil to eliminate air pockets. See planting process and after care. http://extension.umd.edu/hgic/trees-and-shrubs/planting-process
Skimmias can be tricky to grow. You did not mention where your skimmia is located. They grow best in partial or full shade. They can be prone to discoloration in the winter. You may need to transplant if they are located in a sunny area. Also, they prefer a moist, acid high organic soil. You can also test your soil for pH and any nutrient deficiencies. http://extension.umd.edu/hgic/soils/soil-testing