Dr. Julian Yates

“Non-chemical control strategies for preventing subterranean termite infestations.”

For many decades the principle method for preventing infestations by subterranean termites in residential and commercial structures has been with soil treatment termiticides. These pesticides ranged from the highly residual chlorinated hydrocarbons to the present third generation non-repellant compounds, and bait systems containing chitin synthesis inhibitors. However, as an alternative to chemical applications a number of physical barriers have been developed and tested for efficacy with several species of subterranean termites in the United States and Australia. This paper is a review of physical barriers that are currently commercially available in these countries.

A Non-chemical Approach for the Management of Subterranean Termites

Julian R. Yates IIIUniversity of Hawaii

Honolulu, Hawaii, USAMichael Lenz

CSIRO EntomologyCanberra, Australia

For decades organochlorine pesticides were used to prevent subterranean termites from gaining access into structures, however, they were banned in the US in 1988 and in Australia in 1995.

• These have been replaced with less residual repellent and non-repellent termiticides

• There also appears to be a move towards less reliance on pesticides for termites with a concomitant use of non-chemical management systems, particularly in Australia

Particle Barriers

Silica Sand (Ebeling & Pence 1957, Ebeling & Forbes 1988)Crushed Basalt (Tamashiro et al. 1987, 1990, 1991)Quartz & Coral Sand (Su et al. 1991)Glass Shards (Pallaske & Igarashi 1991)Diatomaceous earth (Grace & Yamamoto 1993)Granite (Smith & Rust 1990, French & Ahmed 1993, French 1991, 1994, Ahmed & French 1996)Brick, Limestone & Natural Sand (Miles 1997a, 1997b)

BASALTIC TERMITE BARRIER

•MATERIAL: Crushed Basaltic Rock•PARTICAL SIZE: 1.7 – 2.4 mm•PROPERTIES:

–Too large to move–Small gaps between particles–Too hard to chew

•APPLICATION: New construction

Monolithic Slab With Perimeter Block Wall

BTB

Cold joint

Mud tunnel

Patio Slab Addition

Backfill Against Retaining Wall

Block wall

Water proofing

BTB

Main cells

Joint cell

Hollow Tile Block

Granitgard (Granitgard Pty Ltd)

Graded stone source material of igneous or sound metamorphic rock with specific gravity of at least 2.52

Granitgard •Modeled on the Hawaiian basalt barrier system, but also has been used with other systems (e.g. PVC or bitumen coated aluminum strip shielding)

•Available since 1990

TERMIMESH•MATERIAL: Marine grade stainless

steel screen•APERTURE: 0.66 X 0.45 mm

–Ewart et al. (1991): Min. for C. fomosanus = 1.22 mm•APPLICATION: New and post-construction

•Notable diversity of physical barrier systems (PBS) available in Australia

•PBS have captured about 40% of the Australian market (2003) and growing

In Australia…•Concrete slab recognized as part of the termite barrier

•Slab has to be designed and produced to certain specifications (“engineered slab”)

•Use of “engineered slabs” has meant that PBS no longer have to cover the entire area underneath the concrete slab

•PBS are possible as partial installations just at the perimeter of brick and block constructions, and joints and service penetrations

Alterm barrier system

•5005 Marine Grade aluminum •Available since 1997• > 35 000 installations

Termite Tite Barrier System•316 Grade stainless steel, originally an aluminum alloy

•Available since 1997

•> 20,000 installations

Number of other PBS at various stages of development and approval

•One recent example: TERM-seal (TERM-seal (AUST.) Pty Ltd)

Combines a matting and a sealantApplication to wall cavities slab joints

and slab or wall penetrations

'Building-out' termites

• Take account of termite biology/foraging behavior when designing buildings

• Reducing the attractiveness of the building to termites

• Ease of inspection of structural elements, concrete slab edge exposure

• Increasing use of termite resistant materials

• Use of novel raised flooring systems out of metal and concrete products

• Ongoing site maintenance and inspections

Physical barrier systems are cost effective when computed

over the average life of a residential structure.