Nan-Yao Su

A Review of subterranean termite control practices and prospects for integrated pest management programmes.

Soil insecticide barriers have been the single most important tool for subterranean termite control in the last half century, but limitations with current soil termiticides have provided the impetus to look for alternatives in recent years. One such alternative is the monitoring--baiting programme. Monitoring stations to detect termites are placed in the soil surrounding a structure. Once termites are found in the stations, monitoring devices are replaced with slow-acting baits such as the chitin synthesis inhibitor, hexaflumuron. Field studies have indicated that termite colonies were eliminated using less than 1 g of hexaflumuron. After the elimination, monitoring resumes and bait is applied if new termite activity is detected. The monitoring and baiting procedure form the basis for an ongoing programme to protect structures from subterranean termite infestation. Although the cost--benefit model developed for agricultural integrated pest management cannot be applied directly to termite control, the underlying concept for using a cost-effective approach remains the same. The benefits of the monitoring--baiting programme over conventional soil treatment are a reduction in pesticide applied per unit and the elimination of termite populations near structures, resulting in the reduction of liability and damage potential. It is expected that the data management system when used in conjunction with the monitoring--baiting programme will provide a database to improve its cost-effectiveness continuously.

Managing Social Insects of Urban Importance

Social insects have a tremendous economic and social impact on urban communities. The rapid urbanization of the world has dramatically increased the incidence of urban pests. Human commerce has resulted in the spread of urban invasive species worldwide such that various species are now common to many major urban centers. We aim to highlight those social behaviors that can be exploited to control these pests with the minimal use of pesticides. Their cryptic behavior often prohibits the direct treatment of colonies. However, foraging and recruitment are essential aspects of their social behavior and expose workers to traps, baits, and pesticide applications. The advent of new chemistries has revolutionized the pest management strategies used to control them. In recent years, there has been an increased environmental awareness, especially in the urban community. Advances in molecular and microbial agents promise additional tools in developing integrated pest management programs against social insects.

Keys to Soldier and Winged Adult Termites (Isoptera) of Florida

Illustrated identification keys are presented for soldiers and winged adults of the following 17 termite species known from Florida: Calcaritermes nearcticus Snyder, Neotermes castaneus (Burmeister), N. jouteli (Banks), N. luykxi Nickle and Collins, Kalotermes approximatus Snyder, Incisitermes milleri (Emerson), I. minor (Hagen), I. schwarzi (Banks), I. snyderi (Light), Cryptotermes brevis (Walker), and C. cavifrons Banks, Family Kalotermitidae; Coptotermes formosanus Shiraki, Reticulitermes flavipes (Kollar), R. hageni Banks, R. virginicus (Banks), and Prorhinotermes simplex (Hagen), Family Rhinotermitidae; and Amitermes floridensis Scheffrahn, Mangold, & Su, Family Termitidae.

Response of the Formosan subterranean termites (Isoptera: Rhinotermitidae) to baits or nonrepellent termiticides in extended foraging arenas.

Distance effects of three treatments, noviflumuron, fipronil, and thiamethoxam, against laboratory populations of the Formosan subterranean termite, Coptotermesformosanus Shiraki, were tested in extended foraging arenas with foraging distances of 50 m. The results showed that during the 10-wk test period, all termites were killed by noviflumuron baits, whereas the nonrepellent termiticides fipronil and thiamethoxam divided the laboratory populations into two groups after causing 25-35% worker mortality. The horizontal transfer of lethal effects of fipronil was < or = 5 m. For thiamethoxam, the distance of transfer was substantially shorter. Because of their dose-dependent lethal time, the nonrepellent termiticides did not fulfill the requirements of a liquid bait model.

Termites as Pests of Buildings

Of the more than 2,300 termite species in the world, 183 species are known to damage buildings and 83 species cause significant damage. Subterranean termites, including mound building and arboreal species, account for 147 (80%) of the economically important species. The genus Coptotermes contains the largest number of pest species (28), whereas the genus Cryptotermes, especially Cr. brevis, is the most widely introduced. The world-wide economic impact figure of termites is uncertain, but the control cost for termite pests in the United States was estimated at

Interaction between the subterranean termite Reticulitermes flavipes (Isoptera: Rhinotermitidae) and the entomopathogenic fungus Metarhizium anisopliae in foraging arenas.

1.5 billion annually in 1994. Because of differences in their life histories, control measures differ between subterranean and drywood species. Insecticide barriers are used for exclusion of soil-borne subterranean termites, whereas slow-acting baits are used for population control of subterranean termite colonies in and near structures. Whole-structure treatments (fumigation and heat), compartmental treatments (heat or cold), and local treatments (wood surface treatments or insecticide injection) are the primary tools for drywood termite control.

Agonistic Behavior Among Colonies of the Formosan Subterranean Termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), from Florida and Hawaii: Lack of Correlation with Cuticular Hydrocarbon Composition

Abstract The entomopathogenic fungus Metarhizium anisopliae (Metsch.) Sorokin was tested in the laboratory against field-collected groups of eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), in foraging arenas to determine the potential effect of a “trap and treat” protocol (trapping a part of the population, treating it with a biological control agent and releasing it back into the original population). Individual termites were treated with a suspension of M. anisopliae conidia and released back into the arenas containing untreated termites. After 5 d, 90% of the treated termites died in the arena, but untreated termites did not exhibit a significant increase in mortality within 90 d after release, indicating no transfer of viable M. anisopliae and no epizootic. Although M. anisopliae was isolated from the arenas after 90 d, the average number of fungal colony-forming units recovered was <0.1% of the conidia introduced.

Elimination and Reinvasion Studies with Coptotermes formosanus (Isoptera: Rhinotermitidae) in Louisiana

Cuticular hydrocarbon patterns of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were similar among colonies from the same geographical location. Hydrocarbon patterns of Florida colonies were easily distinguished from those of Hawaii colonies by using canonical discriminant analysis. Groups of termites from the same colony did not fight one another when placed in an arena. Intercolonial aggression was not recorded among C. formosanuspopulations from Florida but three colonies from Hawaii fought with the other Hawaiian and three Florida colonies. Of the 12 colonies (six each from Florida and Hawaii) tested, 3 Florida colonies did not direct or receive aggression from any other colony. Cuticular hydrocarbon patterns were not correlated with agonistic behavior.

Extended disease resistance emerging from the faecal nest of a subterranean termite

Abstract Three Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), colonies located inside the 12.75-ha Louis Armstrong Park, New Orleans, were selected for elimination by using the chitin synthesis inhibitor hexaflumuron. Once eliminated, each vacated foraging territory was monitored for reinvasion by neighboring C. formosanus colonies, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) colonies, or both. Each selected colony was eliminated in ≈3 mo by using baits containing hexaflumuron. Overall activity of each untreated colony in the park remained unchanged during the same period. New C. formosanus and R. flavipes activity was detected in two of the three vacated territories, and in both areas, within days of selected colony elimination. The third vacated territory was completely reoccupied by a new C. formosanus colony ≈7 mo later. Mark–recapture studies and DNA fingerprinting confirmed the distinctness of the reinvaders from eliminated and neighboring colonies.

Colony Characteristics and Seasonal Activity of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) in Louis Armstrong Park, New Orleans, Louisiana

Social insects nesting in soil environments are in constant contact with entomopathogens but have evolved a range of defence mechanisms, resulting in both individual and social immunity that reduce the chance for epizootics in the colony, as in the case of subterranean termites. Coptotermes formosanus uses its faeces as building material for its nest structure that result into a ‘carton material’, and here, we report that the faecal nest supports the growth of Actinobacteria which provide another level of protection to the social group against entomopathogens. A Streptomyces species with in vivo antimicrobial activity against fungal entomopathogens was isolated from the nest material of multiple termite colonies. Termite groups were exposed to Metarhizium anisopliae, a fungal entomopathogen, during their foraging activity and the presence of Streptomyces within the nest structure provided a significant survival benefit to the termites. Therefore, this report describes a non-nutritional exosymbiosis in a termite, in the form of a defensive mutualism which has emerged from the use of faecal material in the nesting structure of Coptotermes. The association with an Actinobacteria community in the termite faecal material provides an extended disease resistance to the termite group as another level of defence, in addition to their individual and social immunity.