formosan subterranean termites (coptotermes formosanus shiraki): an emerging threat to pecan...

Formosan Subterranean Termites (Coptotermes formosanus Shiraki): An

Emerging Threat to Pecan Agroecosystems?

Robert Puckett & Chris Swain

Center for Urban and Structural EntomologyDepartment of Entomology

Texas A&M University

Outline

• Formosan Termite Invasion History (U.S.)

• Formosan Termite Status (U.S.)

• Formosan Termite Behavior

• Research Objectives

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.

• 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).

History of Formosan Termites in the U.S.

U.S. Distribution - 1967

Found in Hawaii and 3 states in the continental U.S.

U.S. Distribution - 2009

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

  Texas Distribution - 1967

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

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.

Distribution of Formosan Termites in Texas in 2009

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.

Damage to Trees in Baytown, TexasAugust 2008

Damage to Trees in Baytown, TexasAugust 2008

Signs of Tree Infestation

Tree in Unidad Park (Baytown, TX)

Tree in Unidad Park (Baytown, TX)

Tree in Unidad Park (Baytown, TX)

Tree in Unidad Park (Baytown, TX)

Tree in Unidad Park (Baytown, TX)

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.

U.S. Distribution of Pecans

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.

Tree Species Preference of Formosan Termites

*Ring & Henderson. 2007. Louisiana Agriculture.

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.

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

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.

Leaf Volatiles: Experimental Design

air flow

air flow

air flow

air flow

air f

low

air flow

air flow

air f

low

Control

C1

C2

C3

Leaf Volatiles: Experimental Design

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.

Cultivar Preference: Experimental Design

Acknowledgements

USDA-ARS Pecan Breeding Program

Dr. Tommy Thompson

Dr. L.J. Grauke

Grant Heller (Student-Worker)

Plea for Cooperation• If you suspect Formosan termites in your pecans, please contact:

Center for Urban & Structural Entomology

Department of Entomology

Texas A&M University

College Station, TX

979.845.5855

http://urbanentomology.tamu.edu/