Subterranean Termite Activity Research Articles

Demonstration Project Reporting Detection of Subterranean Termite (Blattodea: Rhinotermitidae) Infestation and Spray Polyurethane Foam

Demonstration Project Reporting Detection of Subterranean Termite (Blattodea: Rhinotermitidae) Infestation and Spray Polyurethane Foam

A Simulation of Salt Transport in NaCl-Laden Soil Barrier to Control Subterranean Termites in an Earth Embankment

Subterranean termite activity can increase the hydraulic conductivity and water infiltration of filling soil, and therefore affects the stability of an earth embankment and subsequent safety. As a physical barrier for sustainable termite management, NaCl-laden soil barrier (NLSB) is a promising alternative for subterranean termite control in earth embankments. This novel technology can prevent tunneling and penetration of subterranean termites into the interior of an embankment and has been widely employed for more than 20 years in Zhejiang Province, China. The efficacy and longevity of NLSB depend on the long-term presence of NaCl concentration in soil barriers. The aim of this study is to develop an understanding of water flow and salt transport in NLSB based on the two-dimensional Richards’ equation and convection dispersion equation using the HYDRUS software package. Conceptual and numerical models of NLSB are modeled using scenario analysis according to water level fluctuations, saturated hydraulic conductivity, and rainfall infiltration conditions. Furthermore, the center and spread variance of a solute mass over a 100-year period are quantified using moment analysis. As flood frequency, saturated hydraulic conductivity, and rainfall infiltration flux increase, salt desalination in NLSB significantly increases. When the rainfall infiltration flux is 1% of the annual average rainfall, the total amount of salt transport and leaching can increase by 55%. Moreover, these results facilitate better long-term sustainable management of existing sites and optimal design of future NLSBs.

Wood Decomposition After an Aerial Application of Hydromulch Following Wildfire in a Southern California Chaparral Shrubland

Severe wildfire can affect many soil properties, and organic mulches are often applied to the soil surface to mitigate these changes and reduce erosion, particularly on steep slopes. After the southern California Cedar Fire burned 110,000 ha in 2003, hydromulch was applied to reduce sediment losses. In 2004 we established a study to assess the effect of hydromulch on organic matter decomposition at the soil surface and in the mineral soil using aspen (Populus tremuloides Michx.) and pine (Pinus taeda L.) wood stakes as standard substrates. Mass loss of both aspen and pine stakes in this dry Mediterranean ecosystem was lowest on the soil surface and increased with mineral soil depth. Wood stake decomposition appeared to be lower in the hydromulched soil than in the untreated control, but variability of subterranean termite activity in study replicates and the possible loss of hydromulch soon after application make this result questionable. Termites were clearly shown to have a major role in belowground wood decomposition, and could affect slope stability after wildfire. They also should be considered in planning OM decomposition studies in soils where they are present.

Field Trials With 0.5% Novaluron Insecticide Applied as a Bait to Control Subterranean Termites (Reticulitermes sp. and Coptotermes formosanus [Isoptera: Rhinotermitidae]) on Structures.

A field study was initiated in 2009 with 0.5% novaluron the BASF Advance Termite Bait System, which was 100% effective in controlling Reticulitermes sp. Holmgren and Coptotermes formosanus Shiraki infestations on 11 structures in the Texas City, TX area. Stations with inspection cartridges (cellulose tablets) and monitoring bases (southern yellow pine) and independent monitoring devices were installed in an alternating pattern around each structure and were inspected every 30 d postinstallation. When subterranean termite activity was confirmed on the inspection cartridge or the monitoring base, the inspection cartridge was removed and replaced with a bait cartridge containing 0.5% novaluron insecticide on a proprietary matrix (124 g/cartridge) in a station. Once the novaluron-treated bait was inserted, inspections of that station were made on a 4-mo cycle until no termite activity was observed. The mean time to achieve control of the subterranean termites on the structures was 10.5 mo post initial installation of bait. Mean time to achieve control of the termites on the structures after the baits were installed was 5.4 mo. Control of the termites on the structures required consumption of a mean of 1.3 bait cartridges (166.2 g) of 0.5% novaluron bait matrix per structure. These results indicate that the baits with 0.5% novaluron were effective in controlling termites on the structures used in this study.

Genetic Analysis of Termite Colonies in Wisconsin.

The objective of this study was to document current areas of subterranean termite activity in Wisconsin and to evaluate genetic characteristics of these northern, peripheral colonies. Here, amplified fragment-length polymorphism was used to characterize levels of inbreeding, expected heterozygosity, and percent polymorphism within colonies as well as genetic structure among populations sampled. Genetic analysis revealed two species of termites occur in Wisconsin, Reticulitermes flavipes (Kollar) and Reticulitermes tibialis Banks, both found in the southern half of the state. Colonies of both species in Wisconsin are thought to represent the northern boundary of their current distributions. Measurements of within colony genetic variation showed the proportion of polymorphic loci to be between 52.9-63.9% and expected heterozygosity to range from 0.122-0.189. Consistent with geographical isolation, strong intercolony genetic differences were observed, with over 50% of FST values above 0.25 and the remaining showing moderate levels of genetic differentiation. Combined with low levels of inbreeding in most collection locations (FIS 0.042-0.123), we hypothesize termites were introduced numerous times in the state, likely by anthropogenic means. We discuss the potential effects of these genetic characteristics on successful colony establishment of termites along the northern boundary compared with termites in the core region of their distribution.

Biological performance of wood–plastic composites containing zinc borate: Laboratory and 3-year field test results

Six different formulations of wood–plastic composites (WPC) fabricated from wood and polypropylene (PP) were tested in the laboratory against decay and termites and in a protected above-ground field test in southern Japan. Variables examined included comparisons of untreated and zinc borate (ZnB) incorporated formulations, wood content ratio, wood particle size and increased surface area via surface grooves (channels) to promote moisture infusion. A standard method originally designed to test durability of solid wood was modified for testing WPC. Wood decay fungi and Formosan subterranean termite activity in laboratory and field tests resulted in different mass losses, post-decay moisture contents and field test ratings depending on their wood and ZnB content. The results show that as wood content increased, mass losses also increased. Addition of ZnB at 1% (w/w) retention level significantly decreased mass losses of wood–plastic composite when exposed to laboratory decay and termite tests. The effects of surface grooves and wood particle size were less important, compared to wood particle content. All WPC tested were highly resistant to fungal decay under protected above-ground field conditions during 36months. Termite attack, on the other hand, started at earlier stage reducing mean ratings 1year after the installation.

Biological Decay and Termite Resistance of Post-Treated Wood-Based Composites under Protected Above-Ground Conditions: A Preliminary Study after 36 Months of Exposure

Five kinds of commercially available wood-based composites (softwood plywood, hardwood plywood, medium density fiberboard, oriented strand board, and particle board, hereinafter abbreviated as SWP, HWP, MDF, OSB, and PB, respectively) post-treated with alkaline copper quat (ACQ) and copper azole (CA) were exposed to decay and subterranean termite activity under protected above-ground conditions in a southern Japan field test site for three years. Variables examined included comparisons of untreated and treated wood-based composites, preservative type, and retention levels. Both biological attacks developed with time. Termite damage started earlier, and the severity of attack was higher than decay fungi. Untreated MDF and PB were highly resistant to field conditions during the 36 months. Untreated OSB, HWP, and SWP were the least resistant composite types. ACQ and CA treatments significantly improved the durability of the wood-based composites resulting in 64.4%, 47.9%, and 22.5% higher termite ratings when compared to their untreated controls for OSB, HWP, and SWP, respectively. Preservative types and increased retentions did not significantly affect the decay and termite ratings. These results suggest that ACQ and CA post-treatments at exterior protected and unprotected (K3) and double K3 retention levels significantly improved durability of wood-based composites tested but failed to provide full protection.

The impact of subterranean termite activity on water infiltration and topsoil properties in Burkina Faso

ABSTRACTFew quantitative experimental studies have been carried out on the influence of subterranean termite activity on the water infiltration capacity of crusted soils in the semi‐arid Sahelian region. These studies found increased infiltration rates on soils that were affected by foraging galleries of subterranean termites. In this paper, remarkable results are presented from crusted agricultural fields in the Sanmatenga region in Burkina Faso with clear termite activity compared to reference fields without termite activity. Fine‐scale rainfall experiments were carried out and general topsoil (upper 5 cm) characteristics were measured. Infiltration rates were found to be significantly slower on plots affected by subterranean termite activity. These results are contradictory to the findings reported in general literature. On the basis of topsoil property measurements, the reduced infiltration rates cannot be indisputably explained, and we suggest that the main responsible factor for a reduction of infiltration was related to differences in topsoil surface (upper 3 mm) properties. Two hypotheses are formulated in an attempt to explain the reduced water infiltration rates on termite plots. Copyright © 2012 John Wiley & Sons, Ltd.

Taphonomic evidence of a human skeleton gnawed by termites in a Moche‐civilisation grave at Huaca de la Luna, Peru

AbstractA human skeleton from a Moche grave at Huaca de la Luna, Trujillo, Peru, shows evidence of taphonomic bone modification due to subterranean termite activity. Information related to the occasional osteophagous diet of termites on mammal and human remains is reviewed and detailed. Copyright © 2009 John Wiley & Sons, Ltd.

Effects of Temperature, Directional Aspects, Light Conditions, and Termite Species on Subterranean Termite Activity (Isoptera: Rhinotermitidae)

Subterranean termite activity was investigated using field monitoring stations placed around 16 public schools in the triparish New Orleans metropolitan area of Louisiana. With the exception of one school, monitoring stations revealed the presence of Formosan subterranean termites. Native subterranean termites were found in six of the schools. The number of attacked monitoring stations varied significantly with light conditions at different directional aspects and termite species. For example, >50% of first-time attacked monitors by subterranean termites were at east with shade, north with shade, and south with shade placements. Formosan subterranean termites attacked a higher percentage of monitoring stations that were located in east with direct sun, east with shade, and north with direct sun. Native subterranean termites attacked a higher percentage of monitoring stations placed on south with direct sun, south with shade, and north with shade locations. Directional aspects at attacked monitoring stations by termites and corresponding average temperature at a depth of 10.2 cm from the foundation were not significantly correlated. Soil temperature readings 10.2 cm from the foundation did significantly affect seasonal foraging activity of subterranean termites.

Decomposition Patterns of Surface Leaf Litter of Six Plant Species Along a Chihuahuan Desert Watershed

-Mass losses from litter bags of surface creosote bush litter placed along a Chihuahuan Desert watershed were measured to answer the following questions: (1) Do edaphic factors affect organic matter losses? (2) Are there differences in mass losses between the litter of the site-dominant plant species and creosote bush leaf litter? We hypothesized that (1) mass losses of all litter types would be higher at the base of the watershed and lower on the upper portions of the watershed and (2) mass losses of the litter of the sitedominant plants would be higher than those of creosote bush leaf litter in the same site. Mass losses from creosote bush leaf litter did not follow the moisture-organic matter gradient present in the watershed. Mass losses were higher at mid-slope run-on areas than in upper-slope erosional sites and the dry lake basin. Mass losses were highest where subterranean termite activity was the highest. There were differences between losses from the litter of the site-dominant and creosote bush leaf litter in some instances, but these differences were not attributable to differences in lignin content nor C:N ratio. Mass losses of litter of site-dominant species were not always higher than that of creosote bush leaf litter in the same site. Mass losses were best described by the double exponential model.

TERMITE (ISOPTERA) SUPPRESSION WITH TOXIC BAITS

AbstractA field trial with toxic-bait blocks for suppression of subterranean termite activity was initiated in Toronto. Decayed, mirex-impregnated red pine wood blocks 2.5 × 3.8 × 0.5 cm were placed individually in soil at 1.5-m intervals. Attack on bait blocks effectively suppressed termite activity for 3 years in the eight plots. The method offers a cheaper, environmentally sound, effective alternative to conventional soil-poisoning methods.