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Monthly Archives: March 2016

Pine trees are not native to Kansas, however they have been planted for use in windbreaks and as ornamentals. Pines in Kansas are susceptible to environmental stressors which makes them susceptible to disease and insect infestation. The three most common treatable or preventable pine problems in Kansas are tip blight, needle blight, and pine wilt.

Tip Blight

Tip Blight is a fungal infection (Diplodia pinea) which affects most pines in Kansas. If left untreated this disease can be lethal, especially to mature pines. Infection occurs as buds start to expand and is worse in years with a wet spring.

What to look for:

Tip blight in pine
Tip Blight. The new needles (candles) failed to form.
  • New candles (shoots) fail to grow
  • New growth is stunted, yellow, or tan
  • Cankers
  • Black specks (fungal fruiting bodies) are visible on 2-year-old cones and affected needles in late summer or fall
  • Symptoms start in lower part of tree but trees may have symptoms over entire tree

Control of Tip Blight

Normal Pine Candle
Normal candle growthPine cone with tip blight Black spots on pine cone indicating tip blight.
  • Removal of dead branches will not prevent spread since infected pine cones remain on tree
  • Adequately water tree to improve vigor (do not wet needles when watering as that could contribute to the spread of the fungal spores)
  • Trees should be treated with a fungicide when new shoots are emerging, usually the 3rd week in April
  • Trees should be sprayed a second time 10 to 14 days after the first treatment
  • If a 3rd treatment is desired or required it should be sprayed 10 to 14 days after the second treatment
  • Coverage is essential so tall trees may require a professional such as Wellnitz Tree Care

Dothistroma Needle Blight

Dothistroma needle blight is a serious fungal infection of both Austrian and ponderosa pines. The disease will cause premature needle drop one year after the tree has been infected. Multiple years of infection can result in tree death.

What to look for

Needle Blight
A mild case of needle blight. Needles are yellow to brown at tip with green bases. Older needles are affected.
  • Red to brown spots grow around green needles
  • Tip of needle turning brown while base is green
  • Older needles are more affected than younger needles
  • Tiny black fungal structures may be on surface of needle
  • Needles nearest the ground are most affected
  • New infections typically occur in late summer to early fall

Control of needle blight

  • Cultural practices include
    • Proper plant spacing
    • Remove the lowest branches to improve air circulation
    • Proper mulch and water to increase vigor (do not wet needles when watering as that could contribute to the spread of the fungal spores)
  • Chemical control
    • Copper fungicide applied at the beginning of the growing season will protect the tree
    •  Multiple years of treatments may be required to get the disease under control

Pine Wilt

Pine wilt is caused by a nematode that is spread from tree to tree by the pine sawyer beetle. The nematode feeds on the tree’s vascular system causing tree death in a few weeks to months. The beetles begin emerging around the first of May. Scots pine is very susceptible but an increasing number of Austrian pines are becoming affected.

What to look for

Pine Wilt
This pine has pine wilt. The tree died in a matter of weeks over the summer.
  • Pine wilt is most apparent between August and December
  • Trees will die in a short period of time
  • Needles become discolored gray-green to yellow then brown
  • Needles stay on tree for up to a year after death
  • Wounds will have reduced to no resin production
  • Often there will be signs of the pine sawyer beetle

Control of pine wilt

  • If a tree is suspected of pine wilt, have it tested
  • Pine wilt positive trees must be destroyed immediately by chipping or burning wood (do not save for firewood)
    Frass
    Frass or “sawdust”, an indicator of pine sawyer beetle infestation.
  • Increase the vigor of trees to ward off beetles (proper watering and mulching)
  • Preventative injections can be done every 2 years but these injections will not cure a tree which is already infected

 

 

 

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