A Review of the Evolution of Termite Control: A Continuum of Alternatives to Termiticides in the United States with Emphasis on Efficacy Testing Requirements for Product Registration

The global economic impact of termites is estimated to be approximately USD 40 billion annually, and subterranean termites are responsible for about 80% of the total impact. Twenty-eight species of termites have been described as invasive, and these termites are spreading, partially due to global trade, making effective control methods essential. Termite control is complex, as is the biology and behavior of this social insect group. In the U.S., termite prevention and control (with claims of structural protection) is regulated by more than one industry (pest control and building construction), and at the federal and state levels. Termite prevention has historically relied on building construction practices that do not create conducive conditions for termite infestations, but as soil termiticides developed, heavy reliance on pesticides became the standard for termite control. The concern for human and environmental health has driven the development of termite control alternatives and regulation for products claiming structural protection. Product development has also provided unprecedented opportunities to study the biology and behavior of cryptobiotic termites. Technological advances have allowed for the re-examination of questions about termite behavior. Advances in communications via social media provide unrestricted access to information, creating a conundrum for consumers and science educators alike.

Barrier Longevity of NaCl-Laden Soil against Subterranean Termites in an Earth Embankment

Subterranean termite-induced damage to earth embankments in agricultural systems occurs globally. NaCl-laden soil barriers (NLSBs) are an environmentally sustainable termite control method, and have exhibited good potential in preventing termite-related tunneling damage in Zhejiang Province, China. The persistence of the NaCl concentration in NLSBs is a key characteristic for the long-term prevention of subterranean termite infestations. This study is a scientific attempt to estimate the field efficacy and barrier longevity of NLSBs in reservoir embankments based on the Richards equation and the convection–dispersion equation using HYDRUS (2D/3D). The observed and simulated NaCl concentrations at the end of a 1915-day simulation were compared. The results indicated that the proposed model performed well and can effectively characterize the water flow and salt transport in NLSBs. The salt desalination rate of the NLSB in the upstream slope was higher than that in the downstream slope, both of which were significantly higher than that at the embankment axis. Regardless of the type of embankment (homogeneous or core-wall), the barrier longevity of NaCl-laden soil against subterranean termites can reach 50 years with an optimized NaCl/soil ratio in different parts of the embankment.

Differential time allocation of foraging workers in the subterranean termite

Background Foraging in group living animals such as social insects, is collectively performed by individuals. However, our understanding on foraging behavior of subterranean termites is extremely limited, as the process of foraging in the field is mostly concealed. Because of this limitation, foraging behaviors of subterranean termites were indirectly investigated in the laboratory through tunnel geometry analysis and observations on tunneling behaviors. In this study, we tracked subsets of foraging workers from juvenile colonies of Coptotermes formosanus (2-yr-old) to describe general foraging behavioral sequences and to find how foraging workers allocate time between the foraging site (food acquisition or processing) and non-foraging site (food transportation). Results Once workers entered into the foraging site, they spent, on average, a significantly longer time at the foraging site than the non-foraging site. Our clustering analysis revealed two different types of foraging workers in the subterranean termite based on the duration of time they spent at the foraging site and their foraging frequency. After entering the foraging site, some workers (cluster 1) immediately initiated masticating wood fragments, which they transferred as food boluses to recipient workers at the foraging site. Conversely, the recipient workers (cluster 2) moved around after entering the foraging site and received food from donating workers. Conclusions This study provides evidence of task specialization within foraging cohorts in subterranean termites.

Color Changes and Resistance Against Subterranean Termites Attack of Furfuryl Alcohol Impregnated Pine and Sengon Woods Through Graveyard Test

Pine (Pinus merkusii Jungh. & de Vriese) and sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes) are common species of woods used for many purposes. Both species are known susceptible against subterranean termite attack. This study aims to analyze the effect of furfuryl alcohol impregnation on color changes and the resistance against subterranean termites of pinewood and sengon after in-ground test for one year. Furfurylated pine and sengon woods reached weight percent gain 31.2% and 79.1%, densities 0.93 g/cm3 and 0.43 g/cm3, moisture content 3.27% and 2.88%, respectively. Furfurylated pine and sengon woods have lost weight 4.07% dan 2.09%, respectively, with the average resistance level of 9.8 on both woods while untreated pine and sengon woods lost weight were 59.02% and 35.58%, with resistance level 4 and 3.8, respectively. Resistance level scoring was conducted by refering to ASTM D1758-06. Higher resistance level and lower weight loss on both furfurylated woods compared to untreated woods showed that furfurylation could increase the wood resistance against termite attack.

The Efficacy of Pine Wood Pellets reinforced with Active Hexaflumuron Against the Subterranian Termite Coptotermes curvignathus Holmgren

Bait formulation using hexaflumuron is the most used baiting techniques because it is relatively friendly to the environment. One of the potential wood species for bait formulation for termites is pine wood. The resin in pine wood can reduce termites preference. Therefore, the resin contained in pine wood needs to be reduced so that the level of termites preference for pine wood can be increased. This study aims to determine the efficacy of the bait formulation in the form of pellets from pine wood (Pinus merkusii Jungh er de Vries) which was pre-treated with presto (0.4 bar, 100 °C) for one, two, three, four, and five hours with active hexaflumuron (0.25%) against subterranean termites Coptotermes curvignathus. Pine wood chips were treated with presto for one hour, two hours, three hours, four hours, and five hours. The treated pine wood chips then made into sawdust by 40-60 mesh. Pine sawdust then added with hexaflumuron (0.25%) and formed into pellets without adding any adhesive material and then fed to the subterranean termites C. curvignathus (JIS K 1571: 2010). Solid pine wood used as a control sample. The result showed that palatability of formulation pellet bait with active hexaflumuron (14.33%) was higher than solid pine wood (6.58%). The formulation of pellet bait with 0.25% active hexaflumuron with presto pre-treatment was able to eliminate C. curvignathus termites.

The Resistance of Modified Manii Wood with Boric acid and Chitosan/Glycerol and Heating Against Fungi and Termites

Manii wood (Maesopsiss eminii Engl.) is a fast grown species that has low durability (class IV) and requires preservation. Boric acid is generally used in wood preservation. However, its application needs to be combined with other treatments to prevent from leaching. This study aimed to evaluate the resistance of manii wood after double impregnation of boric acid and chitosan or glycerol and heat treatment. Heating temperatures were 70ºC and 140ºC. The durability test was carried out against white rot fungus (Schizophyllum commune), dry wood termites (Cryptotermes cynocephalus), subterranean termites (Coptotermes curvignathus) according to SNI 7207-2014 standard, and field test based on ASTM D 1758-08 standard. The retention of boric acid in manii wood was 15,2 ± 1,0 kg ma−3. The interaction of boric acid and chitosan/glycerol impregnations and heat treatment significantly affected the wood resistance against decay fungi and termites. Impregnation of boric acid and glycerol by heating at 140ºC increased the resistance of wood against dry wood and subterranean termites. Double impregnation of boric acid and chitosan followed by heating at 140ºC was the best treatment in this research that improved significantly the resistance of manii wood against white rot fungi, dry wood termites and subterranean termites.

BIOACTIVITY ANALYSIS OF Annona glabra L. SEED EXTRACTS FOR WOOD PROTECTION AGAINST TERMITES (Cryptotermes cynocephalus Light. AND Coptotermes curvignathus Holmgren.)

Pond apple (Annona glabra L.) belongs to the family of Annonaceae. The seed of A. glabra contains bioactive substance that is toxic to some organisms, however the effectiveness to control wood degrading termites has not yet been scientifically reported. This research analyzes the efficacy of A. glabra seed extract to wood degrading termites. Seed extraction was conducted using n-hexane and ethyl acetate. The paper disc test showed that the extract of A. glabra is toxic to Cryptotermes cynocephalus (dry-wood termites) and Coptotermes curvignathus (subterranean termites). The higher extract concentration (up to 63%) resulted in a higher termite mortality (up to 100%) and lower weight loss of paper sample (less than 1%). Ethyl acetate extract of A. glabra seeds has a better toxicity effect than n-hexane extract against dry wood termites and subterranean termites.

Soil organic matter is essential for colony growth in subterranean termites

Intrinsic dinitrogen (N2) fixation by diazotrophic bacteria in termite hindguts has been considered an important pathway for nitrogen acquisition in termites. However, studies that supported this claim focused on measuring instant N2 fixation rates and failed to address their relationship with termite colony growth and reproduction over time. We here argue that not all wood-feeding termites rely on symbiotic diazotrophic bacteria for colony growth. The present study looks at dietary nitrogen acquisition in a subterranean termite (Rhinotermitidae, Coptotermes). Young termite colonies reared with wood and nitrogen-rich organic soil developed faster, compared to those reared on wood and inorganic sand. More critically, further colony development was arrested if access to organic soil was removed. In addition, no difference of relative nitrogenase expression rates was found when comparing the hindguts of termites reared between the two conditions. We therefore propose that subterranean termite (Rhinotermitidae) colony growth is no longer restricted to metabolically expensive intrinsic N2 fixation, as the relationship between diazotrophic bacteria and subterranean termites may primarily be trophic rather than symbiotic. Such reliance of Rhinotermitidae on soil microbial decomposition activity for optimal colony growth may also have had a critical mechanistic role in the initial emergence of Termitidae.