Slide Information

• Pine Wilt Nematode

• Megan Kennelly

• Kansas State University

First found in Kansas in 1979

Pine wood nematode

Pine Wilt

Photo by Judy O’Mara

Image from Jon Appel, Kansas Dept of Agriculture

Pine wilt hosts

• Common on Scots

• Also starting to see it on Austrian pine, and Mugo

• Drought stress– Beetles prefer to lay eggs where resin flow is

reduced

Pine Wilt: Symptoms

Rapid wilt/death. Needles yellow then brown.

Lack resin. Branches dry, brittle. They snap rather than bend

Image from: http://www.extension.iastate.edu/Publications/SUL9.pdf

Beetle overwinters in pine trees

-start emerge ~ May 1st.

female male

Images from:http://www.extension.iastate.edu/Publications/SUL9.pdf

May 1 : adult beetles emerge

*Lay eggs, (prefer drought stressed/dying)*Nematodes enter tree and feed on bluestain fungi.Lay eggs all season

Beetles feed in healthy trees

Nematodes are inside the trachea (breathing tubes) of the beetle.Beetle carries up to ~80,000 nematodes

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Egg-laying phase

Feeding phase

*Beetle larvae develop in the tree.*Larvae feed in cambium layer, then burrow deeper into the tree*Larvae turn to pupae*Nematodes are attracted to pupae*Pupae emerge as adults, and the cycle continues

Nematodes leave beetles and enter tree through feeding wounds.

Nemas eat plant cells, and tree dies

Image from:http://www.extension.iastate.edu/Publications/SUL9.pdf

The nematode in the tree

• Once in the tree, the nematode spreads around in resin ducts. Feeds on resin cells (healthy trees) or blue-stain fungi (in dead trees)

• When food is running out, nematode seeks out the beetle. Nematodes produce 4th stage larvae which hitch a ride with the beetle. This larva is a “dispersal” stage, tolerates drying. (dauer larvae)

• Nematode can’t spread by itself: it needs the beetle

• Beetle can fly several miles

• We can also spread nematode and beetle in nursery stock, firewood

Sanitation is Critical Component in Controlling Pine Wilt

• Tree removal before April 1 – Reduces nematode and

pine sawyer numbers

• Don’t leave stumps– Root removal not necessary

• Don’t stack wood.• Chip or burn dead trees.• Sanitation must be

coordinated effort.– Pine sawyers strong fliers

Two new products for pine wilt

• Greyhound and Pinetect

– Both are 2% Abamectin

• Contact companies (Rainbow Tree Care, Arborsystems) for more information

• Need to be applied by trained treecare professionals

Injections

• Not 100% effective

• No curative activity

• Carefully evaluate tree beforehand

• Proper technique

• Repeat every 2 years

• Expensive