Two Spotted-Spider Mite
Species:
Tetranychus urticae
General Info:
Mites are small soft-bodied arachnids. Their body consists of an oval shape with two red beady eyes located on their head. One of the characteristics that differentiates arachnids from insects is leg count. Arachnids have 4 pairs of legs, while insects have 3 pairs.
The two spotted-spider mite feeds on agricultural and horticultural plants using their specialized mouthpart called a stylet. This special tool is pierced into the plant to extract nutrients from the plant’s tissues. A few mites will not cause a great decline in plant health, however; female mites quickly populate at a generous rate.
Symptoms:
Small chlorotic/mottled spotting on leaves, leaf drop, bronzing leaves, wilt, leaf drop
Stippling on leaves are a sign of mite feeding.
Image by University of California Cooperative Extension. Click on image for more info.
Signs:
Mites are pretty small, and not always the easiest to spot with the naked eye. Use a magnifying glass! Look under leaves, look at fruits. Mites molt as they age, leaving behind a white ghostly cast. Webbing is also associated with spider-mites.
Mite castings remain on plant surface.
Image by University of Maryland Extension.
Look-a-likes:
Symptoms of mite damage are also symptoms of other biotic and abiotic diseases. Evenly distributed chlorosis is most likely a result of an abiotic issue, unlike pest damage which results in sporatic, unsymmetrical patterns.
Leaf wilt is associated with drought stress, as well as a pathogenic diseases. Evenly distributed mottling in leaves usually indicates a nutrient deficiency.
Treatment Options:
Spray infected plant surfaces with insecticidal soaps or oils. These are contact pesticides, which means the mites must be present in order to kill. These products work by suffocating the mites. There is no residual effect. These products are safe and are recommended by the University of California Extension Integrated Pest Management (IPM) protocols.
Please refrain from using synthetic pesticides such as pyrethrins and imidacloprid. Overuse of these products caused generations of resistant mites. Always follow the label!
Fun Footage:
Mark and I experienced many mite infestations. While working on his experiment, he noticed tracks of mites along his plated media. Please not this video content does NOT contain the described two-spotted spider mite. I just wanted to show you the body of a mite and all of its loveliness under the scope. We hope you enjoy watching the wriggly blob as much as we did.
