Integrated Area Wide Management

When only chemical or physical barrier treatments were available, there was little opportunity for area-wide termite management without the application of huge volumes of long-lived toxins over large areas. With vast areas untreated, the termite populations simply found new sources of food including untreated homes or trees. Only with the advent of the newer chemicals that could achieve termite population reduction was an area-wide management approach possible. Reducing termite populations within an area rather than merely repelling colonies makes it possible to accom plish area-wide population management of termites rather than protecting individual structures. In the integrated management scheme, emphasis is given to the use of advanced termite detection technologies and the application of population reducing treatments to remove the termite pressure in the area. Certainly other termite management strategies are incorporated into the scheme including improved construction practices, the use of pressure-treated wood, moisture management and physical devices to exclude termites. However, the centrepiece of the area-wide management concept is large-scale termite population reduction.

3.1. Formosan Subterranean Termite Populations in New Orleans

Climatic factors in the New Orleans area are quite favourable to the Formosan subterranean termite. Once introduced into the ports in and around New Orleans, infestations increased steadily and spread undiscovered until 1967. Researchers with the Louisiana State University Agricultural Center (LSUAC) have been monitoring the relative population of the termite in New Orleans' French Quarter since 1989. During the ensuing decade populations of the termite increased rapidly with a 35-fold increase in light trap captures being noted from 19891999 (Henderson 2000). During this time increased swarms and termite damage were noted even in properties having repellent ter-miticide barriers, although it is estimated that only around 20% of the properties within the French Quarter had been treated.

Because of the increased presence of the termite and the damage that it was causing, and because of the historic nature of the French Quarter, the US Congress established a research programme in 1997 to develop new technologies to control the termite and to demonstrate the effectiveness of products already available on the market. The approach chosen for the latter was an integrated area-wide pest management strategy. The United States Department of Agriculture-Agricultural

Figure 1. New Orleans French Quarter test area. The original 15 block treatment area (Area 1) is outlined near the centre of the figure. The test area was expanded in 2002 to include the second bold line and includes all blocks surrounding the original treatment area and extends to the Mississippi River constituting Area 2. The third treatment area was initiated in 2004 and is indicated by hatching (Area 3). Small squares indicate the placement of in-ground monitors while alate traps were located at each intersection within the French Quarter. Area 4 comprises the Mississippi River Levee and Area 5 is comprised of the remaining blocks.

Figure 1. New Orleans French Quarter test area. The original 15 block treatment area (Area 1) is outlined near the centre of the figure. The test area was expanded in 2002 to include the second bold line and includes all blocks surrounding the original treatment area and extends to the Mississippi River constituting Area 2. The third treatment area was initiated in 2004 and is indicated by hatching (Area 3). Small squares indicate the placement of in-ground monitors while alate traps were located at each intersection within the French Quarter. Area 4 comprises the Mississippi River Levee and Area 5 is comprised of the remaining blocks.

Research Service (USDA-ARS) in New Orleans led the development of the area-wide strategy within the French Quarter to reduce the termites' density and thereby lessen the threat of further damage to structures through a comprehensive programme of inspection and area-wide treatment.

Cooperation was established among LSUAC, the New Orleans Mosquito and Termite Control Board, and local pest management professionals to provide a non-repellent liquid or monitoring/baiting treatment to every property within the treatment area. To establish area-wide management, only those treatments that were believed to have population-reducing effects were allowed to be applied to properties enrolled into the programme. Independent monitors of two types were established in both treated and untreated areas to determine population densities: in-ground traps and alate sticky traps (Fig. 1).

Commencing in 1997, property owners within a 15 square block area in the heart of the French Quarter were notified through town hall style meetings, the news media and through direct contact letters to begin enrolment in the programme. Cooperators launched the programme through educational efforts to explain the treatment options and to obtain citizen cooperation. Standard commercial pest control contracts were established between the property owners and pest control operators, while payments were made with funds provided by the programme. Enrolment reached 100% of the properties within two years. The greatest impediment to enrolment was making contact with property owners or managers since many of them were located out of town or country.

Since the inception of the programme the treated area has been twice expanded, increasing from 15 centrally located square blocks to

Figure 2. Typical city block within New Orleans' French Quarter. Note that many of the buildings share walls and there are numerous trees in courtyards.

encompass 47 square blocks largely spanning the entire French Quarter. All of the properties within these areas have been treated using population reducing treatment technology. In addition to the complete treatment of structures within the French Quarter, bait treatments have been established in the Mississippi River levee and along heavily infested railroad tracks between the French quarter and the levee (Fig. 1).

Regular meetings are held with citizens to report progress and to continue to solicit their assistance in rapid identification of areas of termite outbreaks so that immediate remedial control treatments can be initiated. In addition, programme participants meet regularly with participating pest management professionals to ensure compliance with the programme guidelines and to reinforce the notion of termite control through area-wide population management, a major shift in management paradigm for many of the operators.

3.2. Physical Impediments to Establishing Area-Wide Management

New Orleans' French Quarter is one of the most heavily termite-infested areas in the continental USA, and its architectural styles and construction contribute both to the rapid buildup of termite populations and to making treatment to mitigate the termites more difficult. Throughout the roughly 78 square blocks that comprise the French Quarter, most buildings on each block are connected to one another through shared common walls (Fig. 2).

A large majority of the buildings date to early to mid 19th century constructions of sandstone brick and lime mortar which wick the plentiful moisture available in New Orleans' subtropical climate up from the ground and into the upper storeys of the properties. Frequently, wooden structural beams were directly inserted within the multiple course brick walls, thus providing moisture directly into the beam. Many properties have flat roofs and parapet walls that retain moisture and allow the attic beams to remain moist. Frequently the structures lack crawl spaces or attic access to allow for thorough traditional termite inspections.

The common wall construction prevents liquid termiticides from being applied in a continuous band into the soil surrounding the structure; it also prevents the typical placement of in-ground baiting stations at the prescribed (approximately 300 centimetres) spacing interval. The multiple course brick construction also makes difficult the application of liquid termiticides to all possible voids within the walls and thereby prevents a complete chemical treatment of the structures. Moreover, the physical connection of many of the structures within a block allows termites infesting one property direct access to other properties within that block without having to travel through the subtending soil. Thus, even complete and proper soil treatments as typically applied would never have the opportunity to contact and thereby control such aerial colonies.

Many properties within the French Quarter also have central courtyards containing planters with large living trees that are themselves susceptible to termite attack and termite population build-up. These planters often have irrigation systems that provide a constant source of moisture for the termites even in times of periodic drought (Fig. 2). Treatment of trees for termites has never been traditional

Table 1. Percentage ground monitoring stations visited by termites in each French Quarter area. Declines in termite populations over the four years are highly significant for only Areas 1 and 2.

Year

Area 1

Area 2

Area 3

Area 4

Area 5

2001

6.45

8.33

6.25

n.a.

10.35

2002

5.17

5.43

5.66

22.9

6.88

2003

2.26

7.04

7.59

36.8

9.04

2004

3.20

4.94

9.01

33.2

8.99

among pest management professionals and until recently no protocols even existed for such treatment. This situation certainly contributed to the rapid build-up of termite populations and until area-wide management was implemented, these termite populations had neither been considered nor targeted for treatment.

3.3. Effect of Area-Wide Management on Termite Populations within the French Quarter

To assess the effectiveness of the area-wide population management programme in the French Quarter, two methods were used to estimate populations. Sticky traps established at every intersection within the French Quarter were used to monitor alates throughout the lifetime of the programme. Statistically significant reductions in alate population densities were noted in the first two treatment areas when compared with populations of the untreated areas within the French Quarter (Guillot et al. 2005). As shown in Table 1, differences were also detected in the frequencies of in-ground monitoring stations that were infested when comparing treated versus untreated areas. The frequency of visits by termites to in-ground monitoring stations within the areas treated for greater than two years (Areas 1 and 2) was also reduced by approximately 50%, while no reduction was noted in the untreated or newly treated areas (Areas 3, 4 and 5) (Table 1).

A 50% reduction in the alate populations was noted in Areas 1 and 2 after a period of two years (Fig. 3). It should be noted that it takes approximately a full year for all properties to be enrolled within the programme and for treatment to be completed. Furthermore, it must also be noted that control may take longer to achieve particularly with the bait treatments.

Prior to bait placement, termites must be detected within the monitoring stations and only then is the toxin applied. While some bait stations are discovered by termites almost immediately after installation, it may take

Figure 3. Alate captures in each of the zones in the French Quarter by year (1998-2004). Downward arrows indicate the initiation of treatments. Note the decline in alate captures in each of the treatment zones after two years. Treatments in Areas 3 and 4 were initiated in 2004 while Area 5 remains untreated.

Figure 3. Alate captures in each of the zones in the French Quarter by year (1998-2004). Downward arrows indicate the initiation of treatments. Note the decline in alate captures in each of the treatment zones after two years. Treatments in Areas 3 and 4 were initiated in 2004 while Area 5 remains untreated.

many months for termites in the area to manifest themselves in the ground monitors. Moreover, the bait toxins are also designed to be slow acting to enable the toxin to spread throughout the colony; thus the time to achieve control is expected to be longer than with direct application of liquid termiticides. The results to date also indicate that while the termite population has been significantly reduced within the first two years of treatment, it has remained fairly stable at that level even after additional years of continued monitoring.

To understand the residual levels of termites within the treated zones, an extensive inspection programme has begun using infrared cameras, microwave motion detectors and acoustic devices in addition to thorough traditional visual inspections for the presence of termites. Rigorous inspection of the trees within courtyards in the French Quarter has also been included. Furthermore, during the course of these inspections it became readily apparent that the pest manage-

ment professionals were using less than the ideal number of bait station placements because of the common wall issues and inability to install the stations.

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