Common Pest Alert: Spider Mites
July 26, 2017
Spider mites are a common pest that are not always easy to spot. The mites themselves are tiny so that by the time their damage is visible, the population is well out of control. The nearly microscopic critters suck on plant tissues, typically forming colonies clustering on the undersides of leaves.
How do you know it’s spider mites?
You can confirm spider mite infestations by looking for speckled marks on the foliage as well as a thin, silky spider web-like coating and an overall lack of vigor. Severe infestations can cause a sticky substance called honeydew to coat the leaves as the insects deplete the sap, creating a wet appearance, a dripping effect and eventually leaf drop. Hotter temperatures and drought stress will exacerbate the problem as their life cycle can be complete in as few as seven days in warm weather.
How to treat spider mites?
Evaluating the vitality of the tree is the first step. For mild infestations, a diluted solution of liquid seaweed in a strong hose-end sprayer can dislodge a significant number of the bugs and take down the population. Horticultural oils are also an effective treatment. An organic approach allows for a more diverse eco-system and lets natural predators survive to assist in controlling problems. Some advanced infestations might require a systemic insecticide that goes in through the root system of the tree and kills anything sucking or rasping on the foliage. But we always assess the overall health of the tree first before deciding on a more aggressive treatment approach.
After the proper treatment is administered, it's time to focus on getting the tree back to health. This can include fertilizer, root stimulation, alleviating soil compaction and, of course, deep weekly waterings that penetrate the entire root zone. As with most pest and disease problems, overall well-being is essential. Plants in distress are much more susceptible to these issues. When spider mites appear, there is often another underlying reason; heat and water stress are common in plants with spider mite infestations.
Keeping an eye out for pests such as spider mites can help control infestations before they get out of hand.