Blockboard with boron-treated veneers: laboratory decay and termite resistance tests

This study is evaluated by measuring the weight loss, and the ability of white- and brown-rot fungi and termites to attack untreated and boron-treated blockboard manufactured using untreated fir (Abies bornmulleriana M.) strips sandwiched between Ekaba (Tetraberlinia bifoliolata Harms.) veneers at final assembly. The veneers were treated with either boric acid or disodium octoborate tetrahydrate, or mixtures of these chemicals, and blockboard specimens were subjected to fungal decay resistance tests performed according to the Japanese Industrial Standard (JIS) A-9201 method using the brown-rot fungus Fomitopsis palustris (Berkeley et Curtis) Murrill and the white-rot fungus, Trametes versicolor (L. ex Fr.) Quel. Blockboard specimens were also tested against the subterranean termite Coptotermes formosanus Shiraki to determine termite resistance. Blockboard specimens with boron-treated veneers demonstrated increased durability against decay fungi and termite attack. However, sealing of untreated fir strips before decay resistance tests helped reduce significantly the weight losses in blockboard with either untreated or boron-treated veneers. Although blockboard is usually used in indoor applications, incorporation of boron-based biocides may be required for increasing resistance to fungal decay and termite attack and giving fire retardancy.     

Fungicidal effects of chemical disinfectants, UV light, desiccation and heat on the amphibian chytrid Batrachochytrium dendrobatidis

The efficacy of a number of disinfection treatments was tested on in vitro cultures of the fungus Batrachochytrium dendrobatidis, the causative agent of chytridiomycosis in amphibians. The aim was to evaluate the fungicidal effects of chemical disinfectants, sterilising ultraviolet (UV) light, heat and desiccation, using methods that were feasible for either disinfection in the field, in amphibian husbandry or in the laboratory. The chemical disinfectants tested were: sodium chloride, household bleach (active ingredient: sodium hypochlorite), potassium permanganate, formaldehyde solution, Path-X agricultural disinfectant (active ingredient: didecyl dimethyl ammonium chloride, DDAC), quaternary ammonium compound 128 (DDAC), Dithane, Virkon, ethanol and benzalkonium chloride. In 2 series of experiments using separate isolates of B. dendrobatidis, the fungicidal effect was evaluated for various time periods and at a range of chemical concentrations. The end point measured was death of 100% of zoospores and zoosporangia. Nearly all chemical disinfectants resulted in 100%, mortality for at least one of the concentrations tested. However, concentration and time of exposure was critical for most chemicals. Exposure to 70% ethanol, 1 mg Virkon ml(-1) or 1 mg benzalkonium chloride ml(-1) resulted in death of all zoosporangia after 20 s. The most effective products for field use were Path-X and the quaternary ammonium compound 128, which can be used at dilutions containing low levels (e.g. 0.012 or 0.008%, respectively) of the active compound didecyl dimethyl ammonium chloride. Bleach, containing the active ingredient sodium hypochlorite, was effective at concentrations of 1% sodium hypochlorite and above. Cultures did not survive complete drying, which occurred after <3 h at room temperature. B. dendrobatidis was sensitive to heating, and within 4 h at 37 degrees C, 30 min at 47 degrees C and 5 min at 60 degrees C, 100% mortality occurred. UV light (at 1000 mW m(-2) with a wavelength of 254 nm) was ineffective at killing B. dendrobatidis in culture.     

Variation in rates of nitrogen fixation in termites: response to dietary nitrogen in the field and laboratory

Abstract. Termites contribute nitrogen to their habitat through the nitrogenase activity of their bacterial symbionts. Previous studies indicate that high levels of dietary nitrogen suppress nitrogen fixation in termites. We examined the effects of dietary nitrogen on fixation rates in termites in both field and laboratory experiments. Ten field cplonies of Reticulitermes were collected and assayed for nitrogenase activity in July 1993, October 1993, January 1994, and April 1994. The nitrogen content of the wood collected with each colony was determined. There was no correlation between termite nitrogen fixation rates and the amount of nitrogen in their food for any of the four collection periods. In laboratory experiments, nitrogen fixation rates decreased when termites were fed filter paper treated with 2% and 5% ammonium nitrate or a 5% mixture of the amino acids proline, tryptophan and leucine, compared to water-treated controls. By contrast, the nitrogenase activity of termites fed filter paper treated with 2% and 5% ammonium phosphate, a mixture of the amino acids histidine, serine and aspartic acid, or 2% and 5% urea did not differ from the controls. However, nitrogenase activity increased when termites were fed with 2% uric acid. No clear association exists between termite nitrogen fixation and the nitrogen content of their food.     

Musty odor of entomopathogens enhances disease-prevention behaviors in the termite Coptotermes formosanus

Termites often eliminate pathogens directly through mutual grooming, and are thereby prevent infections from entomopathogenic fungi. Our previous study confirmed that the antennae of Coptotermesformosanus sensitively responded to the musty odor of entomopathogenic fungi. However, it is unclear if this odor has any effect on termite behavior. The purpose of this study was to clarify the effects of fungal odor on termite behavior, especially on conidia removal. The musty odor was prepared as an aqueous solution by immersing conidia in distilled water. When untreated termites were mixed with fungal-odor-treated termites at a ratio of 4:1, mutual grooming and attack of treated termites were frequently observed. This indicated that the fungal odor triggered these behavioral responses. While some components of the fungal odor were found in all of the entomopathogenic fungi tested, the odor profiles differed among the isolates.     

Decay and termite resistance of medium density fiberboard (MDF) made from different wood species

Medium density fiberboard (MDF) production worldwide is increasing due to the development of new manufacturing technologies. As a result, MDF products are increasingly utilized in traditional wood applications that require fungal and insect resistance. This study evaluated the ability of white and brown rot fungi and termites to decompose MDF consisting of different wood species by measuring weight loss. Furnish in the boards was prepared from heart and sapwood portions of pine (Pinus nigra Arnold var. pallasiana), beech (Fagus orientalis Lipsky), and European oak (Quercus robur L.) species. Fungal decay resistance tests were performed according to ASTM D 2017-81 standard method using two brown-rot fungi, Gloeophyllum trabeum (Pers. ex Fr.) Murr. (Mad 617), Postia placenta (Fries) M. Larsen et Lombard (Mad 698), and one white-rot fungus, Trametes versicolor (L. ex Ft.) Pilat (Mad 697). MDF and wood specimens were also bioassayed against the eastern subterranean termite, Reticulitermes flavipes (Kollar) in order to determine termite resistance of the specimens. MDF specimens containing oak and mixed furnish demonstrated increased durability against decay fungi. Only pine, oak, and mixed MDF specimens met the 25% or less weight loss limit to be classified resistant according to ASTM D 2017-81 standard method. Overall, MDF specimens made from oak showed better performance than oak solid wood specimens. Accelerated aging according to ASTM D 1037-96a standard method before fungal bioassay decreased fungal resistance of the specimens. In contrast to the fungal bioassay, MDF specimens made from beech and mixed furnish showed decreased weight losses from termite attack after 4 weeks. However, none of the MDF specimens were resistant to termite attack. In severe conditions, the MDFs may require the incorporation of chemical biocides prior to board production for increasing the resistance of MDF to termite attack.     

Termites and Chinese agricultural system: applications and advances in integrated termite management and chemical control

Termites are eusocial arthropod decomposers,and improve soil fertility,crop yield,and also are used by humans for their ben efits across the world.However,some species of termites are becoming a threat to the farming community as they are directly and indirectly causing major losses to the agricultural system.It is estimated that termites cost the global economy more than 40 billion USD annually,and considerable research has been done on their management.In this review,we present the available information related to sustainable and integrated termite management practices(ITM).Furthermore,we insist that the better management of this menace can be possible through:(i)improving traditional methods to keep termites away from crops;(ii)improving agricultural practices to maintain plants with more vigor and less susceptible to termite attack;and(iii)integration of available techniques to reduce termite infestation in crops and surroundings.The application of an effective combination of traditional practices with recently developed approaches is the best option for agricultural growers.Moreover,keeping in mind the beneficial nature of this pest,more innovative efforts for its management,particularly using rapidly emerging technology(e.g.,RNA interference),are needed.     

Evaluation of mold,decay and termite resistance of pine wood treated with zinc- and copper-based nanocompounds

In this work, the resistance of black pine wood (Pinus nigra L.) vacuum-treated with zinc oxide, zinc borate and copper oxide nanoparticles against mold and decay fungi and the subterranean termites was evaluated. Some of the nanocompounds tested were forced with acrylic emulsions to avoid leaching. Results showed that mold fungi were slightly inhibited by nanozinc borate, while the other nanometal preparations did not inhibit mold fungi. Mass loss from fungal attack by Trametes versicolor was significantly inhibited by the zinc-based preparations, while the brown-rot fungus, Tyromyces palustris was not inhibited by the nanometal treatments. Notably, nanozinc borate plus acrylic emulsion imparted very high resistance in pine wood to the white-rot fungus, T. versicolor with a mass loss of 1.8%. Following leaching, all pine specimens treated with nanozinc borate, with or without acrylic emulsion, strongly inhibited termite feeding, i.e. mass losses varying at 5.2–5.4%. In contrast, the copper-based treatments were much less effective against the subterranean termites, Coptotermes formosanus. In general, nanozinc borate possessed favorable properties, that is, inhibition of termite feeding and decay by T. versicolor.     

Efficacy of tar oil recovered during slow pyrolysis of macadamia nut shells

Decay and termite resistance of wood treated with tar oil obtained from a commercial pyrolysis process of macadamia nut shells was evaluated. Vacuum-treated pinewood specimens were subjected to two brown- and two white-rot fungi based on the soil-block test method specified by the American Wood Protection Association after a 10-day-leaching process. Treated specimens were also subjected to the subterranean termite attack according to Japanese Industrial Standards (JIS) for 3 weeks under laboratory conditions. In the study, growth inhibition of selected fungi with the tar oil was also tested in vitro. Treated wood specimens at a retention level of 460 kg m⁻³ showed good protection against all the fungi tested. Mass losses in leached specimens were less than those observed in unleached specimens. Similar results were seen when the specimens were subjected to termite attack. Inhibition tests showed that higher concentrations of the tar oil are critical for inhibition of the brown-rot fungi compared to the concentrations required to impede the white-rot and sap-staining fungi tested.     

Charring does not affect wood infestation by subterranean termites

Fire is an important part of forest ecosystems, as is the insect fauna. Changes in wood brought about by fire may alter the ability of termites to use the wood, interrupting the decay cycle of woody debris. The ability of termites to find, infest, and feed upon wood after it had been charred was evaluated in the laboratory and field. Eastern subterranean termites, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), fed on char from burned wood had significantly reduced numbers of protozoa compared to termites fed on pine shavings, but significantly more than starved termites. The ability of termites to find and infest wood was not affected by surface charring. In a laboratory choice test, there were no significant differences in the onset of feeding by termites between charred and non‐charred wood boards. Likewise in the field, no differences were observed in the time to initial attack by termites on charred and non‐charred wood boards or bolts. Because termites will likely survive fires of low to moderate intensity, in most cases, there should be no disruption of the termite contribution to forest nutrient and carbon cycles.     

Responses of Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae) to three types of wood rot fungi cultured on different substrates

This study examined the responses of two termite species, the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the eastern subterranean termite, Reticulitermes flavipes (Kollar), to three types of wood decay fungi: a brown rot fungus, Gloeophyllum trabeum (Persoon: Fries) Murrill; a white rot fungus, Phanerochaete chrysosporium Burdsall; and a litter rot fungus, Marasmiellus troyanus (Murrill) Singer. We also examined the responses of termites to these three types of fungi grown on different substrates. For all three fungal species, both termite species showed a strong preference for fungus-infected sawdust over uninfected sawdust. In choice tests, both termite species preferred sawdust infected with either M. troyanus or P. chrysosporium over G. trabeum. However, termites did not show any preference for fungus-infected potato dextrose agar over uninfected potato dextrose agar. Tunneling activity of C. formosanus was greater in sand treated with methanol extracts of fungus-infected sawdust than in sand treated with extracts of uninfected sawdust. Because chemicals in the fungal extracts caused termites to tunnel further into treated sand than untreated sand, these chemicals could potentially be used to direct termite foraging toward bait stations in the field.     

Intrinsic and acquired resistance to quaternary ammonium compounds in food-related Pseudomonas spp

AIMS: To determine the sensitivity of a strain used for disinfectants testing (Pseudomonas aeruginosa ATCC 15442) and food-associated isolates to benzalkonium chloride and didecyl dimethylammonium chloride (DDAC). To determine whether the increase in bacterial resistance after adaptation to DDAC can be associated with phenotypic changes. To test the activity of alternative disinfectants to eliminate resistant Pseudomonas spp. METHODS AND RESULTS: Pseudomonas aeruginosa ATCC 15442 was among the most resistant strains tested using a bactericidal suspension test. Growth of a sensitive Ps. fluorescens in gradually higher concentrations of DDAC resulted in stable higher resistance and to some cross-resistance to several antibacterial agents, with the exception of disinfectants containing chloramine T, glutaraldehyde or peracetic acid. It was shown by microscopy that adaptation was followed by loss of flagella, and slime formation. Removal of the slime by sodium dodecyl sulphate resulted in partial loss of the acquired resistance. CONCLUSIONS: Pseudomonas spp. may adapt to survive against higher concentrations of quaternary ammonium compounds (QACs), but resistant strains can be eliminated with chemically unrelated disinfectants. SIGNIFICANCE AND IMPACT OF THE STUDY: The work supports the rotation of disinfectants in food processing environments for avoiding the development of bacterial resistance to QACs. The alternating disinfectants should be chosen carefully, because of possible cross-resistance.     

Evaluation of different woods against fungus-growing termite Odontotermes obesus (Rambur) (Blattodea: Termitidae: Macrotermitinae) for use in bait stations

Fungus-growing termites are important pests in buildings and agriculture in Pakistan and are difficult to control with existing bait systems. Development of bait systems requires the knowledge of foraging behavior of termite species. Behavior of foraging workers depends upon the quality and quantity of the food placed in the bait stations. In the current study, we tested 16 different woods (of varying density) for their susceptibility to an important fungus-growing termite, Odontotermes obesus (Rambur). The aim was to find a highly susceptible wood for use in bait stations. The woods were evaluated in no-choice and choice feeding experiments in the field by mass loss and visual ratings to the termites. Statistically significant differences were recorded (P?<?.001). Woods having low density were preferred to high density woods. Highest mass losses (%) were recorded from Ficus religiosa (86.49–87.8%), Bombax malabaricum (86.53–88.43%) and Populus euramericana (75.62–76.31%) in both no-choice and choice tests under “very heavy attack (almost collapsed) to completely consumed” visual rating category. The woods having least mass losses were Albizia lebbeck heartwood (7.03–9.91%), Syzygium cumini (14.25–19.89%) and Dalbergia sissoo heartwood (14.35–24.88%) and had “slightly to superficial attack” with minimum rating values. Ficus religiosa, B. malabaricum and P. euramericana appear suitable woods for use in bait stations for fungus-growing termites.     

Temporal changes in chlorantraniliprole and indoxacarb in four midwestern soils and bioefficacy against the eastern subterranean termite (Isoptera: Rhinotermitidae)

Temporal changes in indoxacarb and chlorantraniliprole were determined in four midwestern soils by simulating commercial field applications of termiticides. Indoxacarb (0.0625 and 0.125%) and chlorantraniliprole (0.05 and 0.10%) were applied to each soil type in a rotating cement mixer to ensure uniform distribution of active ingredient (AI). Temporal and spatial changes in termiticide concentrations were determined by sampling soil cores subdivided at different depths (0-20, 20-40, and 40-61 cm) at various intervals up to 705 d after application. Percentage loss of indoxacarb was initially greater (0-180 d) than losses after 180 d. The lowest indoxacarb extractable concentrations were detected in soils closest to the surface. Chlorantraniliprole losses with time from all soils were slower than indoxacarb, with no differences observed with soil type or depth. Bioefficacy was evaluated in laboratory glass tube bioassays that monitored the distance of termite penetration into treated soils and resulting eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), worker mortality. Bioassay data revealed that R. flavipes termites were unable to completely penetrate 50 mm of indoxacarb- and chlorantraniliprole treated soils at 0 d after treatment; however, termites were not deterred from foraging in these soils indicating no repellency to these termiticides. Termites completely penetrated (50 mm) soils treated with indoxacarb (0.0625%) by 360 d and complete penetration occurred in all soils treated with indoxacarb (0.0625 and 0.125%) by 705 d. Termites were unable to completely penetrate chlorantraniliprole-treated soils at 705 d. Mortality of termite workers was high in all chlorantraniliprole-treated soils at all sampling intervals. These data confirm that vertical differences in termiticide persistence occur in various soils.     

Decomposition of tissue baits and termite density along a gradient of human land‐use intensification in Western Kenya

Termites are important decomposers and ‘ecosystem engineers’ in tropical ecosystems. Furthermore, termite assemblages are sensitive to human land‐use intensification and often termite density and the importance of soil‐feeding termites decrease with land‐use intensification. These changes in termite assemblages may also lead to a decrease in termite‐mediated ecosystem processes (e.g. soil formation, cellulose decomposition). We compared density and functional composition of termites with cellulose removal from undisturbed primary forests to farmlands (Kakamega Forest, Western Kenya). In contrast to the expectation, we found no response of termite abundance along the gradient of land‐use intensification. However, as expected, the relative abundance of soil‐feeders decreased from primary forests to farmlands. In contrast, frequency of attack on tissue paper baits and removal of tissue showed a clear hump‐shaped relationship to land‐use intensification with high values in secondary forests. These nonconcordant patterns of density and functional composition of termite assemblages with cellulose removal by termites suggest that it may be misleading to infer changes in a process by the characteristics of the assemblage of organisms that mediate that process.     

Studies on thermal degradation and termite resistant properties of chemically modified wood

A series of experiments were carried out to examine the resistant capacity of a chemically treated hard wood, Anthocephalus cadamba (Roxb) Miq. to thermal and termite degradation. The treatment with thermosetting resins viz. urea formaldehyde (UF), melamine formaldehyde (MF) and phenol formaldehyde (PF) at 31-33 levels of weight percent gain (WPG) increased the strength property i.e. modulus of rupture (MOR) by 7.50-21.02% and stiffness i.e. modulus of elasticity (MOE) by 9.50-12.18% over the untreated one with no remarkable effect on specific gravity. The treated samples were found resistant to termite attack, while the untreated one was badly damaged by termites on 12 months' exposure to a termite colony. The thermal degradations of untreated and treated wood samples were studied using thermogravimetric (TGA) and differential thermogravimetric (DTG) techniques at heating rates 20 and 30 degrees C min(-1) in temperature range 30-650 degrees C. The treated wood was found to be thermally more stable than the untreated one.     

Valuation of efficacy and nonrepellency of indoxacarb and fipronil-treated soil at various concentrations and thicknesses against two subterranean termites (Isoptera: Rhinotermitidae)

The efficacy and nonrepellency of indoxacarb (150 SC, 150 g [AI]/liter) and fipronil (Termidor SC, 9.1% [Al]) against field-collected eastern subterranean termite, Reticulitermes flavipes (Kollar), and the Formosan subterranean termite, Coptotermes formosanus Shiraki, were evaluated for mortality and penetration into treated soil in laboratory glass tube bioassays. Both insecticides were tested at five concentrations (0, 1, 10, 50, and 100 ppm) and two thicknesses (20 and 50 mm) of treated soil. Indoxacarb caused significantly greater mortality than controls at all treatment thicknesses of > or = 10 ppm, but not at 1 ppm. Concentration and treatment thickness of indoxacarb significantly affected termite mortality. Eastern subterranean termites were significantly more susceptible to indoxacarb than Formosan subterranean termites, but there were no intercolony differences in either species. Termites completely penetrated through all treatment thickness of indoxacarb-treated soil at all concentrations, except one of the six Formosan subterranean termite replicates of 50 mm at 50 ppm, when all termites were killed before tunneling through the treated soil. Fipronil resulted in significantly faster and greater termite mortality than indoxacarb at corresponding concentrations. Concentration and treatment thickness of fipronil also significantly affected termite mortality. There was no intercolony difference in susceptibility to either insecticide in either termite. Both termite species completely penetrated 20-mm treatments of all tested fipronil concentrations, as well as 50-mm soil treated with fipronil at < or = 10 ppm. At 50 and 100 ppm fipronil, termites tunneled only a mean of 87 +/- 0.21 and 47 +/- 0.18% deep into 50-mm treated soil, respectively, before death. Both insecticides demonstrated a delayed mode of activity and nonrepellency against the two termite species.     

Resistance of phenolic-treated oil palm stem plywood against subterranean termites and white rot decay

The objectives of the study were to evaluate the effectiveness of phenolic resin in protecting oil palm stem (OPS) plywood against both subterranean termites (Coptotermes curvignathus) and white rot fungi (Pycnoporous sanguineus). Specially cooked, Low molecular weight phenol formaldehyde (LMW PF) resin was used to treat the OPS veneer whilst commercial urea formaldehyde (UF) resin was used to bond the phenolic-treated veneer. OPS plywood were produced using two types of lay-up (100% outer veneer type and 100% inner veneer type) with adhesive spread rate of 200 g/m². The results show that treatment of OPS veneer with LMW PF has significantly enhanced the resistance of OPS plywood against both termites and white rot fungi. In the termites resistance test, the percentage of weight loss for untreated samples were 19.2% (outer veneer) and 23.9% (inner veneer), while for phenolic treated samples were only 10.7% and 15.8%, respectively. The phenolic treatment was able to enhance the resistance towards termites by 38% and towards white rot fungi by 62%. The study has shown LMW PF resin can be used to protect OPS plywood from termites and white rot fungi.     

Biological alternatives for termite control: A review

Termites are a serious menace to both plants and structures. They are the most problematic pest threatening agriculture and the urban environment. They cause significant losses to annual and perennial crops and damage to wooden components in buildings, especially in the semi-arid and sub-humid tropics. Chemical control has been a successful method of preventing termite attack, but the effects of these chemicals are of concern as they create problems for our health and the environment. Biological methods could be suitable alternatives in this regard. The present paper reviews the various methods (physical, chemical, and biological) for termite control. Recent advances and past research done on termite control emphasizing biological methods are reviewed. Biological methods described include botanicals (essential oil, seed, bark, leaf, fruit, root, wood, resin), as well as fungal, bacterial, and nematode approaches. The relationship between chemical structure of active components responsible for termite control and termiticidal activity is discussed. The plants reviewed show good insecticidal properties against termites. These botanicals can be used for termite control singly and in combination. The active component from biomass can be extracted to prepare efficacious and potent biocidal formulations.     

Termite Diversity along an Amazon–Andes Elevation Gradient,Peru

Through their role as ‘ecosystem engineers’, termites provide a range of ecosystem services including decomposition, and carbon and nitrogen cycling. Although termite diversity levels differ between regions as a result of variation in regional species pool size, in general, termite diversity is thought to decline with elevation. This study (1) investigated how termite species density, abundance, functional group diversity and termite attack on dead wood vary with altitude along an Amazon–Andes altitudinal gradient in Peru; (2) identified likely environmental causes of this pattern; and (3) explored the implications of termite presence for ecosystem functioning (notably for decomposition). Termites were sampled with a standardized 100 × 2 m straight‐belt transect at five undisturbed forest sites along a gradient 190 to 3025 m, as were environmental variables and termite and fungus attack on dead wood. Termite diversity was similar to that found at comparable sites in South America, and there was little turnover of assemblage composition with elevation suggesting that montane specialists are not present. Termite diversity declined with increased elevation, though the upper distribution limit for termites was at a lower elevation than anticipated. We suggest that key drivers of this elevation pattern are reduced temperature with altitude and mid‐elevation peaks in soil water content. Also, attack on dead wood diminished with decreasing termite indirect absolute abundance, while the depth of the soil humic layer increased. We hypothesize that termite abundance is a major accelerant of decomposition rates (and associated mineralization) in Amazonian forests.     

Kinetics of uptake, clearance, transfer, and metabolism of hexaflumuron by eastern subterranean termites (Isoptera: Rhinotermitidae)

The rates of uptake, clearance, insect-to-insect transfer, and metabolism of [14C] hexaflumuron [N-(((3,5-dichloro-4-(1,1,2,2-tetrafluroethoxy)phenyl)- amino)carbonyl)-2,6-diflurobenzamide] were measured in eastern subterranean termite workers, Reticulitermes flavipes (Kollar), fed cellulose diets containing either 0.1 or 0.5% (wt:wt) hexaflumuron. The rate of uptake, level of maximum uptake, and amount of insect-to-insect transfer were concentration dependent. The clearance rate constant for hexaflumuron was independent of concentration, with a mean value of 3.2 x 10(-3)/h. This corresponds to a mean half-life for hexaflumuron inside termites of 9 d. No evidence of metabolism of hexaflumuron to additional products was detected when extracting and examining the radioactivity contained in the fecal and regurgitated material within the termite holding apparatus 40 d after exposure to the chemical. Hexaflumuron was efficiently transferred from treated to untreated termites, through trophallaxis, resulting in spread of the toxicant throughout the insect population. The combination of uptake and efficient transfer of hexaflumuron between treated and untreated termites ensures broad distribution of the material even to insects not directly exposed to the toxicant. The distribution of hexaflumuron by termite workers, along with their minimal ability to metabolize the compound to other metabolites, and their slow ability to clear the material from the termite population results in death of the entire group of termites contained within the holding apparatus.