Pine Wilt Disease and Resources for Homeowners on New Jersey’s Barrier Islands

A Japanese pine showing early signs of Pine Wilt Disease.

New Jersey’s barrier islands hold immeasurable value. From the oceanfront beach, which provides habitat to critically endangered shorebirds to nest to the wave protection of the mainland and human infrastructure from strong storms, these dynamic areas have been shaped by the ocean over thousands of years. As we have built along the coast, our resilience has been tested, storm after storm. We have adapted, by raising our homes and hardening shorelines, and altered the landscape, by manufacturing dunes and building jetties, to help rein in the power of the Atlantic Ocean.

One such method of helping to control erosion was to plant trees, specifically the Japanese black pine (Pinus thunbergii). They were a perfect fit for an island landscape as they have an excellent tolerance to salt and could grow in the sandy soil. After the Great Storm of 1962 they were distributed to help stabilize the sand and create larger dunes on the island. Groups like the Garden Club of Long Beach Island gave them away, planted them in sparse areas, and sold them to the public within the last decade. Since then, times have changed and so has the local climate. With storms becoming stronger, summers growing hotter, and the number of cold days shrinking, many plant communities have been stressed by these environmental factors. A barrier island is a hard place for any tree to grow.

Here on Long Beach Island, since black pines were first introduced we have seen a steady decline in their overall health. This has been more evident on the north end of the island, where there are more forested areas and black pines. While there is no concrete answer on why the black pines are dying, generally it is believed that stress from environmental factors plays a huge role in their decline. Stressed trees are more likely to succumb to disease and drought. According to the USDA, “Pine wilt is a disease of pine (Pinus spp.) caused by the pinewood nematode (Bursaphelenchus xylophilus),” which is native to North America.

Our goal for this special project is to work in partnership with Garden Club of LBI and partners to educate homeowners about pine wilt disease and provide resources to increase the use of native woody vegetation on barrier islands.

Objectives:

  1. Create an educational brochure about pine wilt disease and/or pine beetle infestations, tree care and native tree suggestions. Brochure can be distributed to local businesses, Garden Club events, Chamber of Commerce, LBI landscapers.
    1. Identification ~ symptoms
      • Caused by a native nematode, Pine wood nematode (Bursaphelenchus xylophilus), which may be transmitted by pine bark beetle, which may be more numerous due to warmer temperatures on average, with less extreme cold events during winter, due to global climate change.
      • Affected trees may not show symptoms, such as dull or faded needles until it’s too late… Trees that are stressed (droughty conditions, saltwater intrusion, heat stress, improper care) are more vulnerable to attack. Stressed trees should be examined for signs of beetle activity. Sawdust Sawdust being expelled from various points on the tree’s trunk is a sure indication that the beetles are active.
      • Nematode – rapid change of needle color from green to gray-green to brown or light tan, beginning in late summer. Wood brittle and dry. Lack of sap from cut branches. Lack of drill holes, sawdust or pitch tubes. Wood discolored with blue stain fungus.
      • Pine beetles – sawdust, small “drill” holes, or “pitch tubes” – mix of sap and sawdust – present in bark of affected trees.
      • These beetles are normally not a problem in healthy trees, however, if trees are weakened by drought, construction damage, lightning or soil disturbances, the beetle can attack
      •  

Affected species

  1. Non-native pine spp.
  2. Highly susceptible species include Japanese black pine (Pinus thunbergii).
    1. Prevention and Treatment
      1. Prevention is key!
      1. Keep trees at maximum vigor by watering during droughty periods, fertilize in early spring and late fall for best results (insert more text from Rutgers Extension, and include link: http://njaes.rutgers.edu/pubs/publication.asp?pid=fs031 
      1. Mulch trees with natural wood chips. Do not pile mulch around trunk in a volcano shape. Mulch in a donut shape.
      1. Remove stressed or infested trees to reduce abundance of bark beetles.
      1. DO NOT CHIP AND SPREAD IN AFFECTED AREAS!
      1. If beetles are still a threat use pesticide as a last resort – consult with pesticide applicator for treatment of affected trees using nematicidal avermectin compounds (abamectin and emamectin benzoate) are labeled for the prevention of pine wilt. Cannot rule out death of tree!
      1. Need to determine need for removal of tree and threat of wood chips if left on properties…
    1. Tree Care
      1. Proper mulching
      1. Proper watering
      1. Feeding/Fertilizing – http://www.mortonarb.org/trees-plants/tree-and-plant-advice/horticulture-care/fertilizing
      1. Pruning           
    1. Suitable alternatives
      1. Native trees –
        1. Pitch pine – best in sheltered areas
        1. Eastern red cedar – most tolerant to barrier island conditions
        2. Links to native nurseries –
          1. Clemenson
          2. Pinelands
          3. Any locals who sell natives?

 Partners

Resources:

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