Field Demonstration of Heat Technology to Mitigate Heat Sinks for Drywood Termite (Blattodea: Kalotermitidae) Management

With heat treatments to control drywood termites (Blattodea: Kalotermitidae), the presence of heat sinks causes heat to be distributed unevenly throughout the treatment areas. Drywood termites may move to galleries in heat sink areas to avoid exposure to lethal temperatures. Our studies were conducted in Crytotermes brevis-infested condominiums in Honolulu, Hawaii to reflect real-world condominium scenarios; either a standard heat treatment performed by a heat remediation company, or an improved heat treatment was used. For improved treatments, heated air was directed into the toe-kick voids of C. brevis infested cabinets to reduce heat sink effects and increase heat penetration into these difficult-to-heat areas. Eight thermistor sensors placed inside the toe-kick voids, treatment zone, embedded inside cabinets’ sidewalls, and in a wooden cube recorded target temperatures of above 46 °C or 50 °C for 120 min. Pre-treatment and follow-up inspections were performed at 6 months posttreatment to monitor termite inactivity using visual observations and by recording the numbers of spiked peaks on a microwave technology termite detection device (Termatrac). In improved treatment condominiums, significantly higher numbers of spiked peaks were recorded at pre-treatment as compared to 6 months posttreatment. Efficacious heat treatment protocols using the improved methods are proposed.

Field Demonstration of Heat Technology to Mitigate Heat Sinks for Drywood Termite (Blattodea: Kalotermitidae) Management

With heat treatments to control drywood termites (Blattodea: Kalotermitidae), the presence of heat sinks causes heat to be distributed unevenly throughout the treatment areas. Drywood termites may move to galleries in heat sink areas to avoid exposure to lethal temperatures. Our studies were conducted in Crytotermes brevis-infested condominiums in Honolulu, Hawaii to reflect real-world condominium scenarios; either a standard heat treatment performed by a heat remediation company or an improved heat treatment was used. For improved treatments, heated air was directed into the toe-kick voids of C. brevis infested cabinets to reduce heat sink effects and increase the heat penetration into these difficult-to-heat areas. Eight thermistor sensors placed inside toe-kick voids, treatment zone, embedded inside cabinets’ sidewalls, and in a wooden cube recorded target temperatures of above 46 °C or 50 °C for 120 minutes. A pretreatment and follow-up inspections were performed at 6 months posttreatment to monitor termite inactivity using visual observations and by recording the numbers of spiked peaks on a microwave technology termite detection device (Termatrac). In improved treatment condominiums, significantly higher numbers of spiked peaks were recorded at pretreatment as compared to 6 months posttreatment. Efficacious heat treatment protocols using the improved methods are proposed.

Anti-termite activities of Indonesia’s essential oils against invasive drywood termite for wood product protection

The Indo-Malayan drywood termite, Cryptotermes cynocephalus (Light) (Kalotermitidae), is considered one of the most invasive drywood termites in the Southeast Asian region. Once infesting a timber, the colony of a drywood termite is very difficult to be controlled. Thus, the best way to mitigate a new infestation of a drywood termite is by applying chemical protection on wood. In recent years, particular attention has been given by researchers to develop and use organic termiticides, such as essential oils extracted from plants as active ingredients. The objective of the present study is to evaluate the repellency performance of several economically important essential oils from Indonesia, such as Clove (Eugenia caryophyllata), Cubeb Pepper (Piper cubeba L), and Lemon Grass (Cymbopogon winterianus Jowitt) against a drywood termite, C. cynocephalus. The test was performed by subjecting various concentrations of essential oil toward C. cynocephalus in the force-feeding test method. Sample weight-loss was evaluated after two weeks test. The results suggested that Clove oil has the highest repellence performance against C. cynocephalus, followed by Lemon Grass and Cubeb Pepper oils. The Termite mortality rate was also recorded to understand the toxicity performance of those essential oils.

Distribution record of the invasive drywood termite Cryptotermes domesticus (Haviland) in Riau Province, Sumatra Island, Indonesia

The domestic drywood termite, Cryptotermes domesticus (Haviland), has been referred to in past literature as a native species originating in the Southeast Asia region. The species come to prominence due to its destructive damage to a dried wood log by creating passages and nests inside the wood. Its economic importance makes the species one of the monitored species in inter-island transport as part of a biosecurity initiative by the Indonesian Government. In the present study, we collected drywood termites’ specimens from four locations in Riau Province, Sumatra Island, and conducted morphological identification. In the end, we verify the presence of C. domesticus in all four sites studied. This finding establishes the continued presence of the species in Sumatra, one of the areas reported as the native distribution of the species other than Java and Kalimantan following the Holmgren reports in 1913. We believe this report can be an addition to the current status of C. domesticus in Sumatra and also be an addition to the biosecurity initiative list of monitored species regarding the C. domesticus native range in Indonesia.

Heat Technology Aiming to Mitigate Structural Heat Sinks for Drywood Termite (Blattodea: Kalotermitidae) Management

With heat treatments to control drywood termites (Blattodea: Kalotermitidae), the presence of heat sinks, which have insulating properties, causes heat to be distributed unevenly throughout the treatment areas. Drywood termites may move to galleries in heat sink areas to avoid exposure to lethal temperatures. To mitigate heat sink effect, studies were conducted in Crytotermes brevis-infested homes in Honolulu, Hawaii to reflect real-world scenarios; either a standard heat treatment performed by a heat remediation company or improved heat treatment methods were used. For improved treatments, heated air was directed into the toe-kick voids of cabinets to reduce heat sink effects. Eight thermistor sensors were placed inside toe-kick voids, in the treatment zone, embedded inside cabinets or the sidewall, or in a wooden cube to monitor internal and ambient temperatures to ensure sufficiently high heat reached all areas. Target temperatures above 46 °C or 50 °C were recorded in all areas for 120 minutes. A pretreatment inspection was conducted, and follow-up inspections were performed at 6 months posttreatment to confirm termite inactivity using visual observations and a Termatrac device. In improved treatment homes, no termite activity was found after treatment. Efficacious heat treatment protocols for structures using the improved method are proposed.

Transoceanic voyages of drywood termites (Isoptera: Kalotermitidae) inferred from extant and extinct species

Termites are major decomposers of organic matter in terrestrial ecosystems and the second most diverse lineage of social insects. The Kalotermitidae, the second-largest termite family, are widely distributed across tropical and subtropical ecosystems, where they typically live in small colonies confined to single wood items inhabited by individuals with no foraging abilities. How the Kalotermitidae have acquired their global distribution patterns remains unresolved. Similarly, it is unclear whether foraging is ancestral to Kalotermitidae or was secondarily acquired in a few species. These questions can be addressed in a phylogenetic framework. We inferred time-calibrated phylogenetic trees of Kalotermitidae using mitochondrial genomes and nuclear ribosomal RNA genes of ~120 species, about 27% of kalotermitid diversity, including representatives of 22 of the 23 kalotermitid genera. We found that extant kalotermitids shared a common ancestor 81 Mya (72-91 Mya 95% HPD), indicating that a few disjunctions among early-diverging kalotermitid lineages may predate Gondwana breakup. However, most of the ~40 disjunctions among biogeographic realms were dated at less than 50 Mya, indicating that transoceanic dispersals, and more recently human-mediated dispersals, have been the major drivers of the global distribution of Kalotermitidae. Our phylogeny also revealed that the capacity to forage is often found in early-diverging kalotermitid lineages, implying that the ancestors of Kalotermitidae were able to forage among multiple wood pieces. Our phylogenetic estimates provide a platform for a critical taxonomic revision of the family and for future comparative analyses of Kalotermitidae.

Tomato tolerance and purple nutsedge control with sulfuryl fluoride mixes

Sulfuryl fluoride (SF) is currently utilized as a fumigant for control of drywood termites and insects in building structures, vehicles, wood products, post-harvest commodities, and food processing facilities. This research investigated the feasibility of using SF as a preplant soil fumigant for Purple nutsedge control in plastic-mulched tomato production. SF treatments included SF injected through drip tapes or SF injected through drip tapes a few hours following shank injection of chloropicrin (Pic). Results revealed that SF alone at 224, 336, or 448 kg ha−1 was generally less effective compared to when it was applied in conjunction with Pic at 168 kg ha−1. SF alone provided inconsistent control of purple nutsedge. In contrast, SF plus chloropicrin (Pic) (SF + Pic) was as efficacious or more efficacious on purple nutsedge than the industry standards including 1,3-dichloropropene (1,3-D) plus Pic (1,3-D + Pic) and metam potassium. None of the fumigant treatments visually injured tomato plants, stunted growth, or adversely affected tomato yield. In one of the four tomato seasons, tomato plants growing in plots fumigated with SF + Pic resulted in taller tomato plants and higher markable yields. Results indicate that soil fumigation with SF + Pic is safe on plastic-mulched tomato and effectively controls purple nutsedge.

Volatile Essential Oils Can Be Used to Improve the Efficacy of Heat Treatments Targeting the Western Drywood Termite: Evidence from Simulated Whole House Heat Treatment Trials

Colonies of western drywood termites, Incisitermes minor (Hagen) (Blattodea: Kalotermitidae), are difficult to detect and treat due to their cryptic nature. The use of heated air to create lethal temperatures within infested wood serves as a nonchemical treatment option targeting whole structure or large portions of the structure. However, the presence of hard-to-heat areas and potential risk of damage for heat-sensitive items are recognized as important challenges. Here, we tested if a localized injection of volatile essential oil could be utilized to address the heat sink issue, potentially increasing the overall efficiency of heat treatments against drywood termites. Artificially infested wooden blocks were placed in several locations of the test building, and heat treatments were conducted. For the treatment group, a small amount of essential oil (methyl salicylate) was added in the blocks prior to the heat treatment. All blocks placed in uninsulated wall voids had 92–100% termite mortality by day 7. However, the presence of a large concrete wall in the subarea hindered heating of blocks therein, resulting 36–44% mortality by day 7 when there was no essential oil treatment. Incorporation of the essential oil substantially increased the control efficacy for the subarea, resulting in more than 90% mortality. This approach might also be helpful in reducing the risk of potential heat damage during heat treatment without compromising its control efficacy.