Formosan Subterranean Termites (Coptotermes formosanus Shiraki): An Emerging Threat to Pecan Agroecosystems?

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Formosan Subterranean Termites (Coptotermes
formosanus Shiraki) An Emerging Threat to
Pecan Agroecosystems?

• Robert Puckett Chris Swain
• Center for Urban and Structural Entomology
• Department of Entomology
• Texas AM University

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Outline

• Formosan Termite Invasion History (U.S.)
• Formosan Termite Status (U.S.)
• Formosan Termite Behavior
• Research Objectives

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History of Formosan Termites in the U.S.

• Native to eastern Asia.
• First described as a species in 1909 from
  specimens collected from the Asian Island of
  Taiwan (formerly Formosa).
• Reported in Hawaii in 1913 but believed to have
  been present on the island since 1869.
• Believed to have been introduced to the
  Continental U.S. after WWII in infested materials
  retuning from the Pacific theater by military
  ships.

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History of Formosan Termites in the U.S.

• Coptotermes spp. was first discovered in the
  continental U.S. in 1956 around the Houston Ship
  Channel in Pasadena Texas (Harris Co.).
• It is likely that the species was here several
  years before they were discovered.
• C. formosanus was first identified in 1962 in
  Beaumont Texas (Bill Clarke).

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U.S. Distribution - 1967
Found in Hawaii and 3 states in the
continental U.S.
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U.S. Distribution - 2009

• Found in Hawaii and 14 states in the
  continental U.S.

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Texas Distribution - 1967
 

• In 1967 there were only 2 TX counties known to be
  infested with Formosan termites.

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Distribution of Formosan Termites in Texas in
2009

• In 2004 there were 19 infested TX counties.
• In 2009, 30 TX counties were known to be infested.

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Distribution of Formosan Termites in Texas in
2009
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Formosan Termites and Trees

• Formosan termites feed on both dead and living
  wood, attacking at least 50 plant species in the
  U.S.
• Infestations in living trees often go undetected.
• Infested trees with weakened branches may fall
  over on their own or with strong winds.
• After hurricane Andrew in 1992, 60 of the 360
  felled trees sampled in New Orleans were infested
  with Formosan termites.
• An investigation of coastal trees felled by
  hurricane Rita revealed that 40 of large trees
  marked for landfills were infested with Formosan
  termites.

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Damage to Trees in Baytown, TexasAugust 2008
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Damage to Trees in Baytown, TexasAugust 2008
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Signs of Tree Infestation
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Tree in Unidad Park (Baytown, TX)
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Tree in Unidad Park (Baytown, TX)
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Tree in Unidad Park (Baytown, TX)
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Tree in Unidad Park (Baytown, TX)
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Tree in Unidad Park (Baytown, TX)
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Economic Importance

• An estimated 1.7 billion is spent on termite
  treatment, damage and repairs annually in the
  U.S.
• In Louisiana, 500 million is spent on termite
  treatment, damage and repairs annually.
• New Orleans estimates that 20-25 percent of the
  cities trees are infested with Formosan termites.
  Annual control exceeds 100 million.
• There are no products currently registered for
  the treatment of the interior of any nut or fruit
  bearing tree.
• Texas and Louisiana are two of the leading
  producers of pecans in the U.S.

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U.S. Distribution of Pecans
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Formosan Termites/Pecans in Texas

• Texas was the third highest producer of pecans in
  2008.
• However, little is known about pecan and Formosan
  termite interactions.

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Tree Species Preference of Formosan Termites

Ring Henderson. 2007. Louisiana Agriculture.
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Research Objectives

• Investigation of olfaction preference of Formosan
  termites to green leaf volatiles of pecan
  cultivars.
• Identify degree of pecan cultivar-specific
  selectivity by Formosan termites attack.
• Identify cultivar-specific feeding preference of
  Formosan termites.

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Leaf Volatiles Experimental Design

• Plant leaf volatiles can attract, repel or have
  toxic effects on insects.

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Leaf Volatiles Experimental Design

• Center Petri dish containing 250 termites.
• One Petri dish containing experimental control
  and 3 containing wounded leaf samples (hole
  punch) of different cultivars surrounding the
  center Petri dish.
• Plastic tubing connecting all 4 Petri dishes to
  the center Petri dish.
• Equal amounts of air flow applied to each Petri
  dish.
• Termites will remain in total darkness in the
  Petri dishes for 48 hours.

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Leaf Volatiles Experimental Design
C2
air flow
air flow
air flow
air flow
C1
C3
air flow
air flow
air flow
Control
air flow
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Cultivar Preference Experimental Design

• Collect wood from 50 pecan cultivars (30 relic
  20 commercially important cultivars).
• 5 samples per cultivar weighing between 3 to 5 g.
• Samples will be dried, weighed and rehydrated.
• Samples will be placed in a 12 cm Petri dish
  containing approx. 55 g of sand (1.5 ounces of
  water per 55 g of sand).
• 250 FST will be allowed to feed for 8 days.
• Samples will be removed, dried and reweighed.

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Cultivar Preference Experimental Design
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Acknowledgements
USDA-ARS Pecan Breeding Program Dr. Tommy
Thompson Dr. L.J. Grauke Grant Heller
(Student-Worker)
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Plea for Cooperation

• If you suspect Formosan termites in your pecans,
  please contact
• Center for Urban Structural Entomology
• Department of Entomology
• Texas AM University
• College Station, TX
• 979.845.5855
• http//urbanentomology.tamu.edu/