pine tree pest

Asked June 17, 2013, 2:29 PM EDT

One of my pine trees has it's needles turning brown. If it is the pine beetle should I be able to see them and what is a general spray I can use to treat all my pines?

Grays Harbor County Washington forestry insect issues pine trees pine beetles horticulture

1 Response

My first question is it a pine tree for sure. Pine trees have their needs in bundles of 2, 3 or 5. If the needles are attached directly to the stem as singles than it could be a Douglas fir, spruce or hemlock if it is a native tree to Washington state. If it is a Douglas fir and the needles are turning brown it could be one of two things.

first it could be swiss needle cast. This disease attacks two year and older needles. you will find little black pepper like spots on the under side of the needles. The needle cast prevents he tree from stopping moisture loss thru the needles when it is hot and dry. They needles turn yellow and fall off. You will not see the damage on the new growth. You can spray the new needles to stop the spread of the fungus from the older needles. A good garden store will be able to help you with the proper sprays. The best time to spray is when the needles are about 1 inch long and again when the are full grown but still soft green.

We have seen lots of damage from 2012 drought that is showing up as dead tops, limbs and total tree. You will see no signs of disease just trees that turn rusty red when the needles die Trees growing on gravel soil or in conditions where there roots are restricted from taking up moisture will show the most signs of drought stress.

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