Spider Mites!

The itsy bitsy spiders…they’re everywhere!

Pictured above is a juniper with what looks like fur. Those are Spider mites. They live in dense evergreens. Spider mites are no big deal to outdoor trees and shrubs most of the time but, when the infestation gets really dense to the point of showing the fur, they will cause damage. Their natural enemy is larger spiders and bugs but the larger bugs can’t keep up.

Rain is what keeps them in check. I’m sure you’ve heard ‘down came the rain and washed the spider out’.
Since we have not had rain, these little buggersare having their way with the evergreens.

 Your first impulse might be to go to the garden store and buy chemicals that kill these bugs. Now is not the best time for treatment. If you kill spider mites with chemicals you also kill their predators. While the spider mites regenerate about every 2 weeks, their predators don’t come back for 4-6 weeks. If you think the infestation is bad now, wait until there are no other bugs protecting your evergreens. It’s like leaving teenagers alone. That might be okay for a few hours but for a few weeks? Insane!

The best thing to do now is to hose down your evergreens, spray them off with a hard stream. You can also get one of those feeders that you put at the end of your hose. Put about a teaspoon of dish soap in it and
spray the trees and shrubs with soapy water. You may have to do this once a week, but it is much better than using chemical.

Dormant oil at the beginning of the season is very helpful. This suffocates the early overwintered eggs and
gets rid of the initial generation. While that doesn’t sound like much, it is a great help. It is too hot now to use dormant oil so, for now, wash your evergreen shrubs and trees.
We love getting your questions. Keep sending them!


Certified Arborist

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