Christmas Tree Shipments Infested with Pests

NR12-14 – November 23, 2012

HONOLULU – Shipments of Christmas trees from the Pacific Northwest have been found to be widely infested with slugs and other pests that are not found in Hawaii, causing about half of the shipments to be held for treatment by the Plant Quarantine Branch (PQ) of the Hawaii Department of Agriculture (HDOA).

As of today, agricultural inspectors have inspected 150 shipping containers of Christmas trees and wreaths from six maritime voyages.  Of the 150 containers, 74 were or are being held for pest identification or improper paperwork.

Of the 74 containers held:

  • Six containers have been treated and released
  • 15 containers were released due to low risk pests of pests that are already found in Hawai`i.
  • Four containers were sent back to the shipper at the shipper’s request.
  • 49 containers are pending treatment.

PQ inspectors are ordering treatment of the infested containers either by 100 percent shaking of each tree in the container or by hot-water treatment, depending on the type of infestation.  The shaking method is being used for wasp infestations, while the hot-water treatment is being used for slug infestation.  These methods have been used in years past, but the infestations found this year are very extensive. The hot-water treatment is the same type that the department has been using to treat plants infested with coqui frogs.

The Christmas tree shippers are being required to provide labor power to unload, shake and reload Christmas trees under the supervision of PQ inspectors.

HDOA expects that an additional 100 containers will arrive between now and Christmas.

The department realizes that Christmas trees are a treasured holiday tradition, said Carol Okada, Manager of the Plant Quarantine Branch.  We are doing our best to treat and clear the trees as soon as humanly possible.

The concern about the heavy infestation of slugs is that they may carry the parasite, Angiostrongylus cantonensis, or rat lungworm, which causes a disease that affects the human brain and spinal cord.

Once an invasive pest or disease becomes established in Hawaii, it may have a devastating impact on Hawaii agriculture by causing damage to crops and is often costly for the state and growers to control.  Invasive species may also harm Hawaii’s unique ecosystem.


More information on rat lungworm is available from the Hawaii Department of Health: