IPM for Termites—Termite Baits

25th Year of Publication

Volume XXV, Number 1/2, January/February 2003 IPM for Termites—Termite Baits

By William Quarles Photo courtesy of the USDA

ermites are an important part of the ecosystem, as T they recycle dead and decay- ing wood and have other beneficial effects on the world around us. However, destructive termites cost property owners in the U.S. at least $1 billion each year in treat- ments and repairs (Su and Scheffrahn 1990a; Nutting and Jones 1990). Fortunately, not all termite species cause damage. Economically important termite species in the U.S. can be roughly classified into two general types— drywood or subterranean (see Box A). Drywood termites nest and spend most of their life cycle inside wood. Subterranean termites live and nest in the ground and forage in and aboveground, and cause more damage to homes and other structures than drywood termites Termite baits can provide effective, long-term protection against termite (Ebeling 1968). damage. The bait shown here is being installed underneath pavement to protect historic structures in New Orleans. There are a variety of treatments available for termite infestations. tor for termites, baiting technology and chitin synthesis inhibitors. Until recently, homeowners have may act as a bridge between con- Some of these materials have been relied primarily on chemical barri- ventional termite treatments and lab tested, others have progressed ers in soil to prevent subterranean an IPM approach. through full-scale field trials to termite damage. Because chemical Possible baits range from sim- EPA registration and commercial- barriers are not always reliable, are ple ones that a homeowner can ization. This article briefly reviews costly, may not give long-term pro- construct, to hi-tech approaches the history of termite baiting and tection and may damage the envi- such as the Sentricon® baiting describes attractants, baiting tech- ronment, research on alternatives system. As the technology has niques, and toxicants. The follow- has escalated over the past few matured, a variety of baiting tech- ing article in this issue discusses years (Lewis et al. 1996; Gold et al. niques have been combined with a field trials and commercially avail- 1996; Grace et al. 1996). broad array of active materials. able products. One alternative is the use of One approach is to adopt the baits. In theory, baits could be active ingredients of cockroach used by pest control operators baits (see Quarles 1995). Thus, In This Issue (PCOs) or even homeowners to boric acid, hydramethylnon, and IPM for Termites– reduce foraging pressure and sulfluramid have surfaced as toxi- Termite Baits 1 destroy subterranean termite cants in termite baits. Another Termite Bait Update 10 colonies around a home. As PCOs approach is to employ precisely become more comfortable with the targetted biorationals such as Classified Ads 24 idea of using bait stations to moni- insect growth regulators (IGRs) Update

the termites to a slow-acting toxi- The IPM Practitioner is published ten times The Baiting Concept per year by the Bio-Integral Resource cant. There were a number of prob- Center (BIRC), a non-profit corporation The termite baiting strategy lems with this approach, including undertaking research and education in inte- involves two distinct steps. First, a the need for dry conditions. grated pest management. method is found to attract a large Dusting of galleries is still being Managing Editor William Quarles number of termites. One sure way investigated as a means of termite Contributing Editors Sheila Daar to attract termites is to deploy a control. Since arsenic compounds Tanya Drlik food source such as wood, paper, or Laurie Swiadon are too dangerous, they have been corrugated cardboard. Alternatively, replaced by materials less toxic to Editor-at-Large Joel Grossman active galleries in structural infes- mammals, such as silafluofen Business Manager Jennifer Bates tations can be utilized. Since ter- (French 1994; Grace et al. 1992), Artist Diane Kuhn mites are already feeding there, or boric acid salts (Grace et al. these termite "dining halls" are For media kits or other advertising informa- 1990; Quarles 1998). Silafluofen is natural areas to set baits (French tion, contact Bill Quarles at 510/524-2567. a new pyrethroid that is less 1994). Advisory Board acutely toxic to rats than boric After relatively large numbers of George Bird, Michigan State Univ.; Sterling acid (see Table 1 for toxicity infor- termites have accumulated, they are Bunnell, M.D., Berkeley, CA ; Momei Chen, mation). However, a 5% silafluofen Jepson Herbarium, Univ. Calif., Berkeley; exposed to a slow-acting toxicant or Sharon Collman, Coop Extn., Wash. State IGR. The slow poison can be added dust killed 100% of the Formosan Univ.; Sheila Daar, Daar & Associates, to food, or applied to active galleries, termites tested within 2 hrs in lab Berkeley, CA; Walter Ebeling, UCLA, Emer.; tests, and thus may act too quick- Steve Frantz, NY State Dept. Health; Linda where workers are sure to be Gilkeson, Canadian Ministry of Envir., exposed by contact and ingestion. A ly to be used in a baiting strategy Victoria, BC; Joseph Hancock, Univ. Calif, slow-acting, undetected toxicant or (Grace et al. 1992). Berkeley; Helga Olkowski, Dietrick Inst., Not all the experts believe that Ventura, CA; William Olkowski, Dietrick Inst., IGR is necessary because termites Ventura, CA; George Poinar, Oregon State wall off or block tunnels or galleries subterranean colonies can be suc- University, Corvallis, OR; Ron Prokopy, Univ. when they sense a problem with cessfully killed just by dusting ter- Massachusetts; Ramesh Chandra Saxena, mites in galleries or shelter tubes. ICIPE, Nairobi, Kenya; Ruth Troetschler, PTF their food supply or environment Press, Los Altos, CA; J.C. van Lenteren, (Su et al. 1984). Grace and Abdallay (1990) think Agricultural University Wageningen, The The baiting approach relies that gallery dusting with a slow tox- Netherlands. heavily on termite biology and the icant is effective only for drywood Manuscripts termites, not subterranean species. The IPMP welcomes accounts of IPM for any social nature of termite colonies. pest situation. Write for details on format for Through mutual grooming and These researchers believe the num- manuscripts. trophallaxis, the delivery agents of ber of termites exposed by merely dusting a gallery is too few to kill a Citations the baiting system are actually the The material here is protected by copyright, termites themselves. Orally con- subterranean colony and recom- and may not be reproduced in any form, mend a trap-treat-release process. either written, electronic or otherwise without sumed toxicant or IGR in the food written permission from BIRC. Contact is transferred by trophallaxis (see William Quarles at 510/524-2567 for proper Box A) from foraging workers to the Food Baits publication credits and acknowledgement. rest of the colony. Topically applied Until recently, application of Subscriptions/Memberships toxicant such as a poisonous dust food baits for termite control was A subscription to the IPMP is one of the ben- is transferred by mutual grooming efits of membership in BIRC. We also answer not very successful. Failures were pest management questions for our members from foraging workers to the rest of probably due to application of an and help them search for information. the colony. A variant of the baiting Memberships are $60/yr (institutions/ ineffective toxicant or use of a poor libraries/businesses); $35/yr (individuals). process is the trap-treat-release baiting matrix. For instance, in the Canadian subscribers add $15 postage. All approach. To insure proper expo- 1930s Randall and Doody (1946) other foreign subscribers add $25 airmail sure to the toxicant, termites are postage. A Dual membership, which includes were unable to get termites to eat a combined subscription to both the IPMP trapped at a food source, then baits of arsenic trioxide in sucrose and the Common Sense Pest Control dusted with toxicant and released Quarterly, costs $85/yr (institutions); $55/yr solutions. Australians during this (individuals). Government purchase orders to destroy their nest (Grace and time had some success with 5.8% accepted. Donations to BIRC are tax- Abdallay 1990; Grace et al. 1990; (w/w) sodium arsenite suspended deductible. Grace 1991; Myles 1996). FEI# 94-2554036. in treacle. The mixture was poured into active termite galleries. Change of Address Baiting Galleries When writing to request a change of address, Lack of success until recently please send a copy of a recent address label. In the 1930s, Randall and was also due to lack of motivation. © 2003 BIRC, PO Box 7414, Berkeley, CA Doody (1946) treated subterranean With the development of apparent- 94707; (510) 524-2567; FAX (510) 524-1758. termites by blowing arsenic trioxide ly successful chemical barrier All rights reserved. ISSN #0738-968X into active termite galleries. In lab- treatments, baiting technology was oratory experiments they had largely forgotten until the 1960s found that whole colonies could be and 1970s (French 1994). During eliminated by exposing only 10% of this period Esenther and Coppel

IPM Practitioner, XXV(1/2) January/February 2003 2 Box 7414, Berkeley, CA 94707 Update

(1964) outlined the termite baiting foraging termites avoided the baits the application of only 500 mg of strategy that is currently being after initial consumption, Esenther mirex, the technology obviously commercialized. They believed that and Beal (1978) suggested that the had promise. The method at that a termite food could be combined baiting technique would be more time suffered, however, because with a slow-acting toxicant to elim- effective if a slower-acting insecti- there was no good way to deter- inate ground populations of sub- cide than mirex could be used. mine initial and final colony sizes, terranean termites. According to Su and Scheffrahn and thus effectiveness could not In the first experiments, (1991), the concentrations (4,000 be quantitatively assessed Esenther and Gray (1968), Ostaff to 13,000 ppm) used in these (Esenther and Beal 1978; 1979). and Gray (1975) and Esenther and experiments were too high, and the Beal (1974; 1978) were able to con- mirex blocks were probably repel- Perimeter and trol Reticulitermes spp. with wood- lent to the foraging workers. Interceptive Baiting en bait blocks soaked in the Since Ostaff and Gray (1975) There are two general types of organochlorine pesticide mirex. showed that termites on a property food baiting that have been used: Since there was some evidence that could be typically controlled with perimeter baiting or interceptive

Box A. Kinds of Termite Damage There are at least 45 different termite species in the Termite Society U.S., and 30 of these are pests. Structural damage due to termite attacks has been estimated at $1 billion to Termites start life as an egg. Eggs hatch into small $2.5 billion per year (Su and Scheffrahn 1990a; Nutting larvae, and the larvae proceed to develop through 6 or 7 and Jones 1990). Termites often differ widely in their stages. At each stage, the outer exoskeleton is shed food and moisture requirements, their appearance and (molting). Time between larval stages typically ranges caste structures, and in the amount of economic dam- from 2 weeks to 2 months. Termites are relatively long- age they do (Light 1946). Due to destructiveness and lived, with typical lifetimes of 3 to 5 years, but progres- widespread distribution in the U.S., the most economi- sion to the 4th larval stage takes less than 6 months for cally important subterranean termites are the eastern R. hesperus (Pickens 1946). This dependence on molting subterranean termite, Recticulitermes flavipes, and the and chitin synthesis to form new exoskeletons makes western subterranean termite, R. hesperus (Synder termites vulnerable to chitin synthesis inhibitors. 1946; Pickens 1946; Light and Pickens 1946). The exotic Formosan subterranean termite, Trophallaxis Coptotermes formosanus, has now become established Although the situation is complicated, the larger lar- in Florida and other southern states (Su et al. 1984; vae generally become foraging workers. According to the Woodson et al. 2001). At least one colony has been needs of the colony, the workers remain undifferentiat- found in California (Haagsma et al. 1995). Due ed or start specialization as soldiers or reproductives. to its size and aggressive foraging behavior, a Soldiers protect the colony, but are unable to forage on colony of Formosan termites does more their own. They eat regurgitated food supplied by damage than single colonies of other U.S. subterranean species, and workers. Small larvae feed on the anal secretions can cause significant structural of workers. [Social transfer of food in this manner damage to a home within 6 is called trophallaxis]. Reproductives, including months (Su and Scheffrahn termite queens whose specialty is egg laying 1990a). must also be fed by foraging workers. Subterranean termites can Developing reproductives sprout wings, and at be distinguished from other ter- the proper moment fly away from the parent mites according to where they live and colony to start a new one (Hickin 1971). Colonies of what they eat. Subterranean termites live in the ground subterranean termites such as R. hesperus grow in size and forage in wood beneath and aboveground. Drywood by consolidation. Isolated colonies merge by tunneling, termites such as Incisitermes spp. or Cryptotermes spp. founding reproductives fight, surviving reproductives spend their entire life cycle inside pieces of dry wood. lead the enlarged colony (Pickens 1946). As the number Dampwood termites such as Zootermopsis spp. prefer to of workers and feeders increases, the surviving queen eat and dwell in wood with a high moisture content acquires the ability to lay larger numbers of eggs, and (Castle 1946). colony building begins in earnest. Subterranean colonies are much larger than dry- Termite development and specialization is determined wood colonies. C. formosanus colonies may contain from by a complex balance of hormones and pheromones. 1 to 7 million foragers, with foraging territories extend- This "caste chemistry" is vulnerable to manipulation by ing up to 100 m (109.4 yds). R.flavipes colonies range insect growth regulators and other artificially produced from 200 thousand to 5 million and can range a linear substances introduced into a colony through the baiting distance of 79 m (86.4 yds) (Su 1994). technique (Jones 1990; Lebrun 1990).

IPM Practitioner, XXV(1/2) January/February 2003 3 Box 7414, Berkeley, CA 94707 Update baiting. If the whereabouts of the Thorne and Traniello (1994) call from each other were attacked termites are unknown, perimeter this initial step diagnostic baiting. about half as often by Reticulitermes baiting is used. Wooden stakes, The percentage attack rate on spp. as those set near areas likely to bait blocks, or plastic monitoring baits tends to be low. Henderson have termite activity. These loca- stations are set around the et al. (1997) found about a 7% tions included areas near air condi- perimeter of a structure either on attack rate in 13 months on pine tioners, spigots, downspouts, tree a continuous circle or in a grid stakes around structures in New stumps, wood piles, mulch beds pattern. Additional baits can be Orleans. However, once baits are and wooden fences (Henderson et placed near wooden fence posts, found, feeding is persistent. On al. 1997). Potter et al. (2001), how- poles, or trees (Ostaff and Gray average 73% of stakes attacked ever, had less luck finding areas of 1975; Esenther and Beal 1978). "were found to harbor termites on preferred placement. Perimeter baiting relies on the cer- the next inspection." Once termites have been locat- tainty that termites foraging at Pine stakes set in patterned ed, either by perimeter baiting or random will eventually discover placement around a perimeter, 10 by observation of shelter tubes or the bait (Su 1994; Atkinson 2000). feet from a building and 20 feet active galleries, interceptive baiting

Box B. Ways to Bait Termites

Hollow wooden stakes capped by a cork can be used in) diameter is cut into 2- or 4-m (6.6 to 13.2 ft) lengths to monitor termites and to place toxic baits. Since cork and placed in the trench. Small holes of 4 mm (0.16 in) is a favorite termite food, termite attack can be moni- diameter are drilled every 100 to 150 mm (3.9 to 5.9 in) tored just by removing the cork. If termites are found, to allow termite access. Corrugated cardboard mois- corrugated cardboard is inserted into the stake, leaving tened with water is inserted inside the pipe. Every 2 to about an inch of the cardboard exposed above the stake. 4 meters, a "T" is attached to connect the conduit. To a The stake can then be covered with a capped plastic pipe vertical pipe (200 mm; 7.9 in) extending out of the "T", filled with treated cardboard (see figure below). The card- an elbow fitting is attached. The elbow is secured to a board extending from the hollow stake directs the ter- plastic bait box which is 300 x 200 x 95 mm (11.8 x 7.9 mites into the treated bait (Ewart et al. 1992). x 3.7 in). The bait box is parallel to the ground and is filled with moistened, treated corrugated cardboard or Pipe-Bait Container treated bait blocks. Trenches are wet with water before the whole apparatus is buried in the ground. Interceptive baiting in or near structures is described by French (1991; 1994). One useful device is the pipe- Galleries and Shelter Tubes bait container. According to French, it is constructed in this way: "Cut 300 mm (11.8 in) lengths of 90mm (3.5 A less involved baiting technique involves just the in) diameter tubular plastic pipe. Into each length, place addition of treated blocks, cardboard, or treated bait two corrugated cardboard inserts (with corrugations tubes to termite shelter tubes or inwards) measuring 60 mm (2.4 in) and 240 mm (9.5 in) galleries. According to French long respectively. Seal the end with the 240 mm (9.5 in) (1991; 1994) "break into the long insert with a plastic petri dish lid into which is fit- galleries or shelter tubes and ted a single filter paper. [The pipe could also be capped, place several treated blocks, and the cardboard periodically moistened.] Wet the card- taped onto corrugated card- board inserts with water prior to placing the whole con- board, over the exposed work- tainer vertically into the soil (to about 50 mm; 2 in) ings. Seal the whole arrange- alongside or near active termite shelter tubes on walls, ment with masking tape." piers or stumps. Also wet the ground around the con- Galleries in trees can be bait- tainer. Inspections are made every week for termite ed by drilling holes (25 mm; 1 in) activity. and the system re-wet if required." Once ter- into the tree and inserting plas- mites are found in the bait tubes, treated pieces of card- tic pipe. To give access to ter- board or treated wood blocks are added to the bait tube. mites, 8 mm (0.3 in) holes are drilled into the pipe and the pipe is filled with corrugated Bait-Box-Conduit cardboard. The conduit can be attached to a bait box (300 x 200 x 95 mm; 11.8 x 7.9 x 3.7 in). Inside the bait Another baiting device box treated blocks can be inserted between layers of is the bait-box-conduit. A cardboard, or alternatively, treated cardboard can be shallow trench (100 to used (French 1994). 150 mm; 4 to 5.9 in deep) Another way to bait trees is to drill and insert a plas- is excavated alongside or tic pipe with "T" fitting. Pipe-baits can then be attached near sheltertubes, diago- to each side of the "T". This method has the advantage nally across the under- that two different bait concentrations, or a toxic bait house area, or around the and untreated bait can be directly compared outside of the building. Plastic conduit pipe of 25 mm (1 (Henderson 1995).

IPM Practitioner, XXV(1/2) January/February 2003 4 Box 7414, Berkeley, CA 94707 Update

can be used (see Box B for Baiting Pinus ponderosa and Douglas fir, Photo courtesy Dow Agrosciences Techniques). Here, actively forag- Pseudotsuga menziesii, while hard- ing termites are intercepted with wood such as Tabebuia guayacan an active bait. Interceptive baiting is repellent (Grace et al. 1989). of galleries and shelter tubes has Artificially constructed baits also the advantage that termites can be show promise. A bait matrix of agar baited more quickly, and if suc- and sawdust was used to attract cessful, colonies are eliminated Mastotermes darwinensis in faster than with perimeter baiting. Australia (Paton and Miller 1980). Su (1994) used a similar matrix of Attractants 80% agar and 20% pine or spruce Although the baiting concept is sawdust. Forschler (1996) used a rather obvious, the devil is in the cellulose powder bait against details. The trick is to find a food Recticulitermes spp. in Georgia. Wood monitoring stakes are being bait that termites can find and Thorne and Traniello (1994) devel- added to a Sentricon bait station. accept, and a slow-acting toxicant oped a bait that R. flavipes termites that is not repellent. One possibility locate significantly faster than pine stakes. At sites showing wide varia- not be damaged if a bait is acciden- is moistened corrugated cardboard. tally ingested. Early researchers This material is attractive to ter- tions in climate and geography, R. flavipes found and fed on the baits used sodium arsenite or mirex mites, and is especially useful when (Randall and Doody 1946; used inside plastic tubes (cut from within 1 to 3 weeks. Esenther and Gray 1968). Arsenic standard PVC plastic pipe) as part Wood that has been partially compounds are too dangerous for of a trapping program (French and decomposed by the fungus Lenzites general use, and mirex has been Robinson 1985; Ewart et al. 1992). trabea (=Gloeophyllum trabeum) is banned in the U.S. (French 1994). Cardboard inside plastic pipe can more attactive to foraging termites Mirex baits are still being used, also be turned into a tamper-proof than sound wood (Esenther et al. however, in Australia (French and bait station (see Box B). 1961). Both R. flavipes and C. for- A number of other wood or cel- mosanus feed and survive better on Robinson 1985; Paton and Miller lulose products also have been wood showing a 5% decay with the 1980). The effective concentration successfully used to attract ter- brown rot fungus, Gloeophyllum tra- range for R. flavipes is 9-15 ppm mites. In areas with low amounts beum. R. flavipes may even require and for C. formosanus is 10-90 of rainfall, toilet paper rolls staked partially rotted wood, as the num- ppm. Colonies are completely killed to the ground with a wire have ber of reproductives increase on in 4-8 weeks (Su and Scheffrahn been effective (French and this diet (Lenz et al. 1991). 1991). Robinson 1980). Toilet paper is Termite physiology and biochem- also a good trapping medium. A istry is being studied to find clues to Boric Acid and its Salts perforated steel drum packed with termite attraction. For instance, ter- The boric acid salt barium metab- wetted toilet paper rolls and par- mites may be attracted toward par- orate was effective in laboratory tests tially buried in the ground allowed tially rotted wood because the in concentrations ranging from 1500 the accumulation of large numbers brown rot fungus produces the ter- to 5000 ppm (Grace 1989; Grace et of Coptotermes acinaciformis mite aggregation pheromone (Z,Z,E)- al. 1990). Jones (1990) field tested a (French and Robinson 1981). 3,6,8-dodecatrien-1-ol (Lebrun sodium octaborate tetrahydrate Further research may lead to 1990). Hydroquinone and amino (DOT) (Timbor®) bait in Arizona. better baits. Field experiments acids have been used as attractants Concentrations of 2500 to 5000 ppm have shown that termites have (Reinhard et al. 2002). Glycol ethers were not repellent and successfully feeding preferences. Pine and can act as trail pheromones (Becker destroyed a colony of the desert sub- eucalyptus bait blocks set next to 1966). The exciting science of ter- terranean termite, Heterotermes the toilet rolls were more readily mite physiology and biochemistry is aureus. Forschler (1996) baited attacked than blocks of white still in its infancy, but profound Reticulitermes spp. with 1000 ppm cypress pine, Callitris columellaris knowledge of feeding attractants is zinc borate hydrate in cellulose (French et al. 1981). Mound sure to develop from further powder, but termites found the colonies of Coptotermes lacteus will research in this area (Lebrun 1990). bait repellent. Esters of boric acid attack and eat cork in preference Bait Toxicants and ethylene glycol are being test- to sound wood (French et al. ed in baits (French 1994). These 1986). Trees such as Aesculus hip- Any non-repellent, slow acting compounds are doubly interesting pocastanum are frequently infest- toxicant or IGR is a candidate for because the ethyl and butyl ed, but Ailanthus altissima is use in termite baits. However, com- ethers of diethylene glycol are ter- rarely infested by Reticulitermes mercial success of a bait is more mite trail pheromones (Becker sp. (Grace 1997). R. hesperus likely if consumers can be assured 1966), and the commercial ter- prefers softwoods such as pine, their pets and their children will miticide Boracare® is a solution

IPM Practitioner, XXV(1/2) January/February 2003 5 Box 7414, Berkeley, CA 94707 Update of DOT in ethylene glycol (Quarles "skin" as part of its normal growth impregnated with hexaflumuron. 1998). pattern. Larval termites must cover At one R. flavipes colony, the bait Boric acid itself at 1500 ppm themselves with a new layer of toxicant concentration was 150 killed 90% of R. flavipes in 7 to 12 chitin every time molting occurs. ppm. At other sites a range of bait days in laboratory feeding tests (Su The time frame for molting is on the toxicant concentrations from 100 et al. 1994). Boric acid and order of 1-2 months. A toxicant to 500 ppm were employed. Boracare can be purchased by the that interferes with molting could Bait stations were inspected general public. After soaking cor- kill an expanding termite colony monthly and replaced with new rugated cardboard in the toxi- over the period of 3 months. The tubes if termites had been feeding cants, homeowners could bait their chitin synthesis inhibitors difluben- and with wooden stakes if they own termites using some of the zuron (Dimilin®), hexaflumuron had not. To increase bait attrac- simpler techniques in Box B. With (Recruit™), and noviflumuron have tiveness, termites from the wooden these techniques and moistened been tested. Laboratory bait block stake were shaken into the bait corrugated cardboard as an attrac- feeding tests with hexaflumuron tube. These termites “tunneled tant, monitoring for termites is and Formosan and eastern subter- through the matrix to enter estab- ranean termites showed that it had also in reach of the typical home- lished foraging tunnels in soil, a wider range of effective concentra- owner. Boric acid termite baits are thus leaving the colony specific tions than mirex. Baits containing 2 also commercially available (see semiochemical clues in the to 62.5 ppm caused better than the next article). matrix.” About twice as much bait 90% mortality to R. flavipes, and Compared to other substances was consumed when this “self- 15.6 to 125 ppm were effective being tested, however, larger recruiting procedure was used ranges for C. formosanus. Termites amounts of boric acid must be compared to foraging in tubes that used to eliminate colonies. For were not repelled and 100% mortal- ity was seen in 3-6 weeks (Su and were merely buried without added instance, about 2 million termites. Formosan termites can be killed Scheffrahn 1993). Noviflumuron equally well when fed 11.5 g of eliminates termite colonies faster IPM Bait Stations boric acid or 0.9 g of hydramethyl- than hexaflumuron (Sheets and non (Su et al. 1994). Karr 2001). Su's successful field trials and Su (1994) developed the baiting other work encouraged Dow Slow Starvation process that led to Sentricon. Agrosciences to register hexaflu- Wooden stakes were buried around muron as the toxicant in their A number of water-insoluble, each monitoring station. Stakes Sentricon baiting system (see fol- slow-acting toxicants or IGRs have that were attacked were replaced lowing article). Termite control with been tested in termite baits (See with plastic bait tubes containing Sentricon is a 3-step process Box C for Active Ingredients). about 80 g of a matrix composed involving detection, elimination, Hydramethylnon and sulfluramid of 80% agar or Methocel and 20% and continued monitoring. Central baits are commercially available (see (w/w) pine or spruce sawdust bait to the technology is the Sentricon the next article). These compounds block the oxidation of food and cause death by starvation. As we see Table 1. Toxicants for Termite Baits* Toxicant Termite LD50 µg/g Effective Bait Oral Acute Toxicity. Reference in Table 1, sulfluramid and hydram- Concentration in ppm LD50 in mg/kg (Species) ethylnon show roughly the same Boric Acid C. formosanus (722) ÐÐÐÐ 2660 (rat) Pestline 1991; Su et al. 1994 toxicity against R. flavipes, however, Boric Acid R. flavipes (264) 1500 2660 (rat) Pestline 1991; Su et al. 1994 Di-iodo-ptolylsulfone C. formosanus 600 ÐÐÐÐ Su et al. 1991 based on the termite LD50, sulflu- Diflubenzuron R. flavipes 7.8-31.3 4640 (rat) Su and Scheffrahn 1993; Tomlin 1997 ramid is about 10 times more toxic Diflubenzuron C. formosanus repellent above 2 ppm 4640 (rat) Su and Scheffrahn 1993; to Formosan termites than it is to R. Tomlin 1997 Fenoxycarb R. flavipes 1120 10000 (rat) Jones 1984; Tomlin 1997 flavipes. In laboratory feeding tests, Hexaflumuron R. flavipes 2-62.6 5000 (rat) Su and Scheffrahn 1993; according to the amount consumed, Tomlin 1997 Hexaflumuron C. formosanus 15.6-125 5000 (rat) Su and Scheffrahn 1993; about 90% of C. formosanus workers Tomlin 1997 are killed in 0.7 to 11.5 days by Hydramethylnon C. formosanus (56) ÐÐÐÐ 1131 (rat) Tomlin 1997; Su et al. 1994 Hydramethylnon R. flavipes (31) ÐÐÐÐ 1131 (rat) Tomlin 1997; Su et al. 1994 sulfluramid, and 3.3 to 9.4 days by Mirex C. formosanus (31.4) 10-90 236 (rat) Su et al. 1994; Su and hydramethylnon. The corresponding Scheffrahn 1991; Pestline 1991 Mirex R. flavipes (4.2) 9-15 236 (rat) Su et al. 1994; times for R. flavipes were 3.3 to 14.7 Su and Scheffrahn 1991; Pestline 1991 days for sulfluramid and 4.4 to 13.5 Silafluofen C. formosanus 10-100 5000 (rat) Tomlin 1997; Grace et al. 1992 days for hydramethylnon. Sulfluramid C. formosanus (4.3) 4-10 543 (rat) Tomlin 1997; Su et al. 1994; Su and Scheffrahn 1991 Sulfluramid R. flavipes (41.3) 18-30 543 (rat) Tomlin 1997; Su et al. 1994; Chitin Synthesis Su and Scheffrahn 1991 Inhibitors *The greater the LD50, the less toxic the material. Acute toxicity data above shows that mirex is the most toxic, and fenoxycarb is the least- toxic. Sulfluramid, mirex, and hydramethylnon are more acutely toxic than boric acid. Silafluofen, hexaflumuron, diflubenzuron, and fenoxy- Chitin synthesis inhibitors target carb are less acutely toxic than boric acid. Long-term chronic toxicity studies may reveal problems with some of these new materials, but as the termite’s need to grow a new long as small amounts are contained in tamper-proof bait stations, they should have low environmental impact.

IPM Practitioner, XXV(1/2) January/February 2003 6 Box 7414, Berkeley, CA 94707 Update plastic bait station. The station tion is available, a computer pro- rain. The western subterranean itself is a cylindrical plastic tube gram indicates how many bait termite, R. hesperus, can probably with side ports for termite access. stations should be used and where be baited year-round but best It is designed to be placed in soil. It they should be placed. results would probably be obtained has a tamper-resistant cap that in June, July and August-right requires a special key to open. The Limitations of Baits before the fall swarm after the first station has a flat round soil cover Termite activity is seasonal, seasonal rains (Pickens 1946). that lies flush with the soil surface. and thus baiting is less effective at Baits work slowly to eliminate a To use the Sentricon system, certain times of the year. Most colony. It can take 2 to 3 months stations are buried in the ground intense feeding occurs while repro- or more. For homeowners needing every 10 to 20 ft (3 m to 6.1 m) or so ductives are being produced and in termite treatments in order to sell around the perimeter of the struc- the period of a few weeks before their house, baits may not do the ture. Stations first contain wooden swarms occur. The best time to job fast enough. monitoring blocks, which are moni- bait R. flavipes is thus in the late tored until termites are found. spring and early summer. During Advantages of Baits Monitoring blocks are then replaced the winter, activity is reduced. Baiting has a number of advan- by bait tubes. Alternatively, if Foraging also drops back during tages over soil applications of pesti- enough information on the infesta- hot weather or periods of intense cides. For instance, smaller

Box C. Bait Active Ingredients If one is searching for a perfect toxicant, the best Other IGRs approach is to find a substance that targets only the pest species. By studing termite biology, researchers felt Su and Scheffrahn (1989) found that the novel IGR that insect growth regulators (IGRs) that interfered with pyridine derivative S-31183 at 300 ppm had no signifi- the hormones and pheromones regulating the termite cant effect on Formosan termites after 12 weeks. caste system were possible selective termite toxicants. However, concentrations of 30-150 ppm were not repel- Because the entire colony must be fed by workers, hor- lent to R. flavipes and led to about 80% worker mortali- monal shifts toward fewer workers and more soldiers ty after 12 weeks. could cause a colony to die. The experiments above and earlier work shows that In lab tests, Jones (1984) fed bait blocks containing IGRs are effective in termite baits, but termite species 1000 ppm fenoxycarb or a derivative, RO16-1295, to R. with soldiers as a small fraction (1-2%) of the popula- virginicus and C. formosanus. The compounds were not tion are more vulnerable than species committing a repellent at this concentration. Fenoxycarb and Ro16- large fraction of the population to the soldier caste. 1295 converted more than half the R. virginicus popula- Thus, IGRs are more effective against Reticulitermes tion to a dependent caste within 4 weeks and killed spp. than Coptotermes formosanus. Although hormonal about 65% of the population in 6 weeks. Subsequent IGRs are definitely worth further study, none of the Reticulitermes field tests with showed a reduction in for- compounds tested so far demonstrates the stability and aging activities after exposure to fenoxycarb baits at wide range of effectiveness seen for other toxicants now 1000 ppm (Jones 1988; 1989). being tested (Su and Scheffrahn 1990b; Su and Formosan termites are more difficult to kill with 1000 Scheffrahn 1993). ppm fenoxycarb than Reticulitermes. Jones (1984) found that although about half of the population was converted to soldiers or intercastes within 4 weeks, the Formosan ter- Novel Compounds mites tested showed little mortality in 6 weeks. Since The novel compound diiodomethyl para-tolyl sulfone Formosan colonies can absorb excess soldiers for long peri- (A-9248) at 600 ppm was not repellent and reduced ods, significant mortality might have been seen if the lab baited Formosan colonies by 65-98% over a 1-year peri- test had been continued for 12 weeks. In fact, Haverty et al. od in Florida. Although colony suppression may be (1989) found that 500 ppm of the IGR methoprene was not slower than with the use of other substances, further repellent to C. formosanus and resulted in 73.7% mortality tests with this compound would seem profitable (Su and and 47.3% dependent castes in 12 weeks. Scheffrhan 1988; Su et al. 1991). A followup study by Jones and Lenz (1996) using a range of concentrations from 10 to 3,162 ppm fenoxycarb Abamectin at 80-200 ppm caused 100% mortality in on two different Formosan colonies showed about a 50% 1-4 days, and 20 ppm caused 50% mortality in 14 days reduction in workers at the most effective concentration to Recticulitermes sp. (Su et al. 1987). Nutting (1983) within 28 days. In one colony the most effective concentra- found that abamectin was repellent in Reticulitermes sp. tion was 100 ppm, and workers were reduced through field tests. Forschler (1996) was able to remove an infes- increased production of intercastes. In the other, the most tation from a structure with 1 ppm abamectin bait in effective concentration was 3,162 ppm, and worker reduc- cellulose powder. However, termites were still feeding tion was due to death of undifferentiated indviduals. near the structure and probably found the bait repellent.

IPM Practitioner, XXV(1/2) January/February 2003 7 Box 7414, Berkeley, CA 94707 Update

amounts of active materials are with physical or chemical barriers. mirex bait suppresses activity of Reticulitermes used. Rather than kilograms of toxic Baits could also be used to replace spp. J. Econ. Entomol. 67:85-88. chemicals applied to soil, only mil- aging chemical barriers. When the Esenther, G.R. and R.H. Beal. 1978. Insecticidal baits on field plot perimeters ligrams of bait are applied. Not only effective lifetime of a chemical bar- suppress Reticulitermes. J. Econ. Entomol. are the amounts applied a thousand rier is reached, rather than 71:604-607. to a million times less, but the toxi- retreating with large amounts of Esenther, G.R. and R.H. Beal. 1979. Termite cant or IGR is fully contained in bait toxic chemicals, baits could be control: decayed wood bait. Sociobiology stations that are inaccessible to ani- installed instead. Conversion to 4(2):215-222. Ewart, D. McG., J.K. Grace, R.T. Yamamoto mals and children. From an envi- least-toxic technology under these and M.Tamashiro. 1992. Hollow stakes for ronmental point of view, bait sta- circumstances would be very con- detecting subterranean termites (Isoptera: tions are a vast improvement over venient and inexpensive. Rhinotermitidae). Sociobiology 20(1):17-22. toxic pesticide barriers. Termite baits also may act as a Forschler, B.T. 1996. Baiting Reticulitermes Another advantage that baits bridge between dedicated chemical (Isoptera: Rhinotermitidae) field colonies with have over current pesticide barri- treatment methods and an IPM abamectin and zinc borate treated cellulose in Georgia. Sociobiology 28(3):459-484. ers is the ability to provide long- approach. PCOs can offer baiting as French, J.R.J. and P.J. Robinson. 1980. Field term protection. Once termite part of a general program of moni- baiting of some Australian subterranean ter- colonies are eliminated, monitoring toring, moisture and food reduc- mites. Z. Ang. Ent. 90:444-449. stations can be left in place. If tion, structural borate treatments, French, J.R.J. and P.J. Robinson. 1981. Baits another colony invades the yard, and when absolutely necessary, use for aggregating large numbers of subter- of termiticides. In many cases, con- ranean termites. J. Aus. Ent. Soc. 20:75-76. baiting can be resumed. Baiting French, J.R.J., P.J. Robinson and N.R. Bartlett. and monitoring can give protection ventional subterranean termite 1981. A rapid and selective field assessment against subterranean termites for treatment methods might be elimi- of termite wood feeding preferences of the the lifetime of a structure. nated altogether. According to the subterranean termite Heterotermes ferox termite experts Thorne and (Froggatt) using toilet roll and small wood- Safety Traniello (1994), "at least in some block baits. Sociobiology 6(2):135-151. French, J.R.J. and P.J. Robinson. 1985. A Since most of the toxicants or circumstances baits will be an technique used on mounds of Coptotermes IGRs used in the new baiting tech- effective stand-alone remedial treat- lacteus to screen potential bait substrates. J. nology have low acute toxicity and ment. It is in that sphere that they Aust. Ent. Soc. 24:111-112. will have the advantage in minimiz- French, J.R.J., P.J. Robinson and D.M. Ewart. concentrations generally used are 1986. Mound colonies of Coptotermes lacteus low, termite baits are relatively ing pesticide exposure to applica- tors and to the environment." (Isoptera) eat cork in preference to sound safe. For instance, if an entire 80 g wood. Sociobiology 11(3):303-309. (0.18 lb) bait tube of 500 ppm French, J.R.J. 1991. Baits and foraging behav- hexaflumuron is eaten, only 40 mg William Quarles, Ph.D. is Executive ior of Australian species of Coptotermes. of IGR is consumed. The acutely Director of BIRC and Managing Sociobiology 19(1):171-186. Editor of the IPM Practitioner. French, J.R.J. 1994. Combining physical barri- toxic dose for a child would be ers, bait and dust toxicants in future strate- about 1250 times this amount. gies for subterranean termite control Manufacturers have safety in mind References (Isoptera). Sociobiology 24(1):77-91. and are designing bait stations Atkinson, T.H. 2000. Use of dyed matrix in bait Gold, R.E., H.N. Howell, Jr., B.M. Pawson, M.S. that are tamper-proof. Such an stations for determining foraging territories Wright and J.C. Lutz. 1996. Persistence and of subterranean termites (Isoptera: bioavailability of termiticides to subter- approach should protect children ranean termites (Isoptera: Rhinotermitidae) and animals from accidental expo- Rhinotermitidae: Reticulitermes spp. and Termitidae: Amitermes wheeleri. Sociobiology from five soil types and locations in Texas. sure. For baits deployed in the 36(1):149-167. Sociobiology 28(3):337-353. soil, since most of the toxicants Becker, G. 1966. Spurfolge-Reaktion Grace, J.K., D.L. Wood and G.W. Frankie. are insoluble in water, very little vonTermiten auf Glykol-Verbindungen. Z. 1989. Behavior and survival of Reticulitermes should leach out into the soil. Angew. Zool. 53:495-498. hesperus Banks (Isoptera: Rhinotermitidae) Castle, G.B. 1946. The dampwood termites of on selected sawdust and wood extracts. J. [Note: Boric acid baits would leach Chem. Ecol. 15(1):129-139. into the soil under wet conditions. the Western United States, genus Zootermopsis. In: Kofoid et al., pp. 273-291. Grace, J.K. 1989. Oral toxicity of barium However, since the amounts Ebeling, W. 1968. Termites: Identification. metaborate to the eastern subterranean ter- involved are so small, there should Biology, and Control of Termites Attacking mite (Isoptera: Rhinotermitidae). J. Econ. be no noticeable damage.] Buildings. Univ. Calif. Agri. Exp. Sta. Manual Entomol. 25(1):112-116. No. 38. 73 pp. Grace, J.K. and A. Abdallay. 1990. Termiticidal Conclusion Esenther, G.R., T.C. Allen, J.E. Casida and activity of boron dusts (Isoptera: R.D. Shenefelt. 1961. Termite attractant Rhinotermitidae). J. Appl. Entomol. 109:283-288. Baiting can provide a safe, from fungus-infected wood. Science 134:50. Grace, J.K., A. Abdallay and J.M. Sisson. 1990. effective method of subterranean Esenther, G.R. and H.C. Coppel. 1964. Current Preliminary evaluation of borate baits and research on termite attractants. Pest Control dusts for eastern subterranean termite con- termite control. Until PCOs trol. Pub. No. IRG/WP/1433, Intl. Res. become familiar with it, the tech- 32:34-38. Esenther, G.R. and D.E. Gray. 1968. Group on Wood Preservation. 7 pp. Grace, J.K. 1991. Response of eastern and nique will probably be used to Subterranean termites in southern Ontario. Formosan subterranean termites (Isoptera: moderate foraging pressure on Can. Ent. 100:827-834. Rhinotermitldae) to borate dust and soil treat- structures that have been treated Esenther, G.R. and R.H. Beal. 1974. Attractant-

IPM Practitioner, XXV(1/2) January/February 2003 8 Box 7414, Berkeley, CA 94707 Update

ments. J. Econ. Entomol. 84(6): 1753-1757. Williams. 1991. Interlaboratory studies on Su, N-Y., M. Tamashiro, J.R. Yates and M.I. Haverty. Grace, J.K., R.T. Yamamoto and R.H. Ebesu. termite-wood decay associations: II. 1984. Foraging behavior of the Formosan subter- 1992. Laboratory evaluation of the novel soil Response of termites to Gloephyllum trabeum ranean termite (Isoptera: Rhinotermitidae). insecticide silafluofen against Coptotermes grown on different species of wood (Isoptera: Environ. Entomol. 13:1466-1470. formosanus Shiraki (Isoptera: Mastotermitidae, Termopsidae, Su, N.-Y., M. Tamashiro and M.I. Haverty. Rhinotermitidae). J. Appl. Ent. 113:466-471. Rhinotermitidae, Termitidae). Sociobiology 1987. Characterization of slow-acting insec- Grace, J.K., J.R. Yates III, C.H.M. Tome and 18(2) :203-254. ticides for remedial control of the Formosan R.J. Oshiro. 1996. Termite resistant con- Lewis, V.R., M.I. Haverty, D.S. Carver and C. subterranean termite (Isoptera: struction: use of stainless steel mesh to Fouche. 1996. Field comparisons of sand or Rhinotermitidae). J. Econ. Entomol. 80:1-4. exclude Coptotermes formosanus (Isoptera: insecticide barriers for control of Su, N.-Y. and R.H. Scheffrahn. 1988. Toxicity Rhinotermitidae). Sociobiology 28(3):365-372. Reticulitermes spp. (Isoptera: Rhinotermitidae) and feeding deterrency of a dihaloalkyl aryl- Grace, J.K. 1997. Influence of tree extractives infestations in homes in Northern California. sulfone biocide, A-9248, against the on foraging preferences of Reticulitermes Sociobiology 28(3):327-335. Formosan subterranean termite (Isoptera: flavipes (Isoptera: Rhinotermitidae). Light, S.F. 1946. Habitat and habit types of ter- Rhinotermitidae). J. Econ. Entomol. Sociobiology 30(1):35-42. mites and their economic significance. In: 81(3):850-854. Grossman, J. 2002. ESA Conference Notes. IPM Kofoid et al., pp. 136-149. Su, N-Y. and R.H. Scheffrahn. 1989. Practitioner 24(7):16. Light, S.F. and A.L. Pickens. 1946. American Comparative effects of an insect growth reg- Haagsma, K., M. K. Rust, D.A. Reierson, T.H. subterranean termites, their classification and ulator, S-31183, against the Formosan sub- Atkinson and D. Kellum. 1995. Formosan distribution. In: Kofoid et al., pp. 150-156. terranean termite and eastern subterranean subterranean termite established in Myles, T. 1996. Development and evaluation of termite (Isoptera: Rhinotermitidae). J. Econ. California. Calif Agric. 49(1):30-33. a transmissible coating for control of subter- Entomol. 82(4):1125-1129. Hamel, M., ed. 1990. Proceedings of the 1st Intl. ranean termites. Sociobiology 28(3):373-401. Su, N-Y. and R.H. Scheffrahn. 1990a. Conf. on Wood Protection with Diffusible Nutting, W.L. 1983. Results of a field test of Economically important termites in the Preservatives, Nov. 28-30, 1990. Nashville, avermectin on Heterotermes aureus in a United States and their control. Sociobiology TN. USDA/ARS/Forest Service Southern southern Arizona desert grassland. Proc. 17(1):77-94. Forest Experiment Sta., New Orleans, LA. 38th Ann. North Central Branch ESA. [cited Su, N-Y. and R.H. Scheffrahn. 1990b. Potential Haverty, M.I., N-Y. Su, M. Tamashiro and R. in Jones 1989] of insect growth regulators as termiticides: a Sociobiology Yamamoto. 1989. Concentration-dependent Nutting, W.L. and S.C. Jones. 1990. Methods review. 17(2):313-328. Su, N-Y. and R.H. Scheffrahn. 1991. presoldier induction and feeding deterrency: for studying the ecology of subterranean ter- Laboratory evaluation of two slow-actingtoxi- potential of two insect growth regulators for mites.Sociobiology 17(1):167-189. cants against Formosan and eastern subter- remedial control of the Formosan subter- Ostaff, D. and D.E. Gray. 1975. Termite (Isoptera) suppression with toxic baits. Can. ranean termites (Isoptera: Rhinotermitidae). ranean termite (Isoptera: Rhinotermitidae). Ent. 107:1321-1325. J. Econ. Entomol. 84(1):170-175. J. Econ. Entomol. 82(5):1370-1374. Paton, R. and L.R Miller. 1980. Control of Su, N-Y., P.M. Ban and R.H. Scheffrahn. 1991. Henderson, G. 1995. Dr. Gregg Henderson, Mastotermes darwiniensis Froggatt (Isoptera: Suppression of foraging populations of the Dept. of Entomology, 402 Life Sciences Mastotermitidae) with mirex baits. Aust. For. Formosan subterranean termite (Isoptera: Bdlg., LSU Agricultural Center, Baton Res. 10:249-258. Rhinotermitidae) by field applications of a Rouge, LA 70803. Pers. comm. Pestline. 1991. Pestline: Material Data Sheets slow-acting toxicant bait. J. Econ. Entomol. Henderson, G., K. Sharpe-McCollum and C. for Pesticides and Related Chemicals. Van 84(5):1525-1531. Dunaway. 1997. Tracking termites. Pest Nostrand/Reinhold, New York. 2097 pp. Su, N-Y. and R.H. Scheffrahn. 1993. Control Technology February: 56,61. Pickens, A.L. 1946. The biology and economic Laboratory evaluation of two chitin synthesis Hickin, N.E. 1971. Termites World problem. significance of the western subterranean ter- inhibitors, hexaflumuron and diflubenzuron, Rentokil/Hutchinson, London. 232 pp. mite, Reticulitermes hesperus. In: Kofoid et as bait toxicants against Formosan and east- Jones, S.C. 1984. Evaluation of two insect ai., pp. 157-185. ern subterranean termites (Isoptera: growth regulators for the bait-block method Potter, M.F., E.A. Eliason, K. Davis and R.T. Rhinotermitidae). J. Econ. Entomol. of subterranean termite control. J. Econ. Bessin. 2001. Managing subterranean ter- 86(5):1453-1457. Entomol. 77:1086-1091. mites (Isoptera: Rhinotermitidae) in the Su, N-Y., M.Tokoro and R.H. Scheffrahn. 1994. Jones, S.C. 1988. Field evaluation of several Midwest with a hexaflumuron bait and Estimating oral toxicity of slow-acting toxi- bait toxicants for subterranean termite con- placement considerations around structures. cants against subterranean termites trol: a preliminary report. Intl. Res. Group Sociobiology 38(3B):565-584. (Isoptera: Rhinotermitidae). J. Econ. Entomol. Wood Pres. No. IRG/WP /1376. 11 pp. Quarles, W. 1995. Least-toxic cockroach baits. 87(2):398-401. Jones, S.C. 1989. Field evaluation of fenoxy- Common Sense Pest Control Quarterly Su, N-Y. 1994. Field evaluation of a hexaflu- carb as a bait toxicant for subterranean ter- 11(1):5-13. muron bait for population suppression of mite control. Sociobiology 15(1):33-41. Quarles, W. 1997. New subterranean termite subterranean termites (Isoptera: Jones, S.C. 1990. Borate baiting systems for treatments. Common Sense Pest Control Rhinotermitidae). J. Econ. Entomol. subterranean termite (Isoptera: Quarterly 13(2):13-19. 87(2):389-397. Rhinotermitidae) control. In: Hamel, p. 128. Quarles, W. 1998. Borates for wood protection. Synder, T.E. 1946. American subterranean ter- Jones, S.C. and M. Lenz. 1996. Fenoxycarb- IPM Practitioner 20(3): 1-12. mites other than Pacific Coast. In: Kofoid et induced caste differentiation and mortality Randall, M. and T.C. Doody. 1946. Poison al., pp. 187-195. in Coptotermes formosanus (Isoptera: dusts. In: Kofoid et al., pp. 463-476. Thorne, B.L. and J.F.A. Traniello. 1994. Rhinotermitidae). J. Econ. Entomol. Reinhard, J., M.J. Lacey and M. Lenz. 2002. Detection and control through baiting ter- 89(4):906-914. Application of the natural phagostimulant mites. Pest Management 13(9):1-13,16-18. Kofoid, C.A., S.F. Light, A.C. Homer, M. hydroquinone in bait systems for termite Tomlin, C., ed. 1997. The Pesticide Manual, Randall, W.B. Herms and E.E. Bowe. 1946. management (Isoptera). Sociobiology 11th ed. British Crop Protection Council, Termites and Termite Control, 2nd ed., rev. 39(2):213-229. Farnham, Surrey, UK. 1606 pp. University of California Press, Berkeley, CA. Sheets, J.J., and L. Karr. 2001. Kinetics of Woodson, W.D., B.A. Wiltz and A.R. Lax. 2001. 795 pp. uptake, clearance, transfer and metabolism Current distribution of the Formosan subter- Lebrun, D. 1990. Termite control: biological of noviflumuron in termites (Reticulitermes ranean termite (Isoptera: Rhinotermitidae) in basis. Sociobiology 17(1):115-127. flavipes). Entomological Society of America the United States. Sociobiology 37(3B):661-671. Lenz, M., T.L. Amburgey, Z-R. Dai, J.K. Conference, Atlanta, GA, 2001. [see Mauldin, A.F. Preston, D. Rudolph and E.R Grossman 2002]

IPM Practitioner, XXV(1/2) January/February 2003 9 Box 7414, Berkeley, CA 94707 Update Termite Bait Update By William Quarles tion can take three months or more enzymes, making it impossible for (see Quarles 1995ab; Quarles and termites to metabolize cellulose ince Dow introduced the Bucks 1995; Su 1993ab; 1994). (Quarles 1998b). All these materials Sentricon™ System in 1995, The current Sentricon bait for- are effective in termite baits because S termite baits have been widely mulation, Recruit II, contains 0.5% they are not repellent at label rates accepted by pest control operators (5000 ppm) hexaflumuron soaked and work very slowly (Su et al. 1994; (PCOs), homeowners, and even envi- into paper towels or sawdust (Potter Su et al. 1987; Logan and Abood ronmental groups. Baits have less of 1997). Dow has developed a new 1990). an environmental impact than the CSI called noviflumuron that will alternative, which is application of a probably replace hexaflumuron. Different Baiting chemical ground barrier. To form a Noviflumuron is 5-6 times more Techniques potent than hexaflumuron and is ground barrier, more than a hun- Sentricon uses a perimeter pre- dred gallons of a pesticide formula- eliminated more slowly by termites. Both hexaflumuron and noviflu- baiting technique. Stations are tion must be added to the soil buried in the ground at intervals of underneath or around a structure. muron are eliminated unchanged, but the half-life for hexaflumuron is about 10 ft (3 m) around a struc- In contrast, baits are targeted to ter- ture, and more than 2 ft away from mites, are contained in bait sta- 8-9 days and for noviflumuron is 1- 6 months. Increased potency and foundations to avoid conflicts with tions, and deploy very small quanti- repellent chemical barriers. These ties of active ingredients. slower excretion leads to quicker buildup of effective doses in all the ground stations are prebaited with The Sentricon System has now pine stakes and used as monitoring been installed in more than a million termites and faster colony elimina- tion. Both hexaflumuron and novi- traps. Monitoring traps are inspect- locations worldwide (Dow 2002b). ed regularly until termites are The expanding market for termite flumuron have low acute toxicity to mammals with LD50s for oral doses found. When termites are found, baits has also stimulated competi- hexaflumuron bait tubes replace tion. Customers now have a choice in rats of about 5000 mg/kg (Sheets and Karr 2001; Sheets et al. the pine stakes in the bait station among six different competing prod- (Potter 1997). ucts, (Dow)Sentricon™, (Ensystex) 2000; Grossman 2002). Exterra and Outpost use the CSI Exterra and Outpost use a simi- Exterra™, (Bayer) Outpost™, (FMC) lar perimeter baiting strategy. Walls Firstline™, (Spectrum) Terminate™, diflubenzuron as the active ingredi- ent. About 0.25% diflubenzuron is of each station are lined with a thin (BASF) Subterfuge™ and TermiRid™ layer of wood. The active bait for- (Bayer 2000, BASF 2001, Dow added to a baiting matrix of paper, in the case of Exterra, or powdered mulation is added to the center of 2002a, Ensystex 2003, Potter 1997; the station when termites begin Cabrera et al. 2002). (see Resources) cellulose, in the case of Outpost. Diflubenzuron was the first regis- feeding on the wood. This strategy minimizes disturbance of feeding Different Active tered CSI and is by far the most widely used around the world. It has termites. However, in areas of Ingredients been registered in the U.S. since known termite activity, wooden pre- Commercial baiting systems have 1976 for forestry, food crops, and baits and the active baits are both different active ingredients, and horticulture applications (Tomlin added when the station is installed. also different baiting and marketing 1997; Farm Chemicals 1999). The Outpost label also recommends strategies. Active ingredients are The active ingredient of Firstline installation of baits in crawl spaces either chitin synthesis inhibitors and Terminate is 0.01% (100 ppm) if termites are seen there (Bayer (CSI’s) such as hexaflumuron and sulfluramid. The active ingredient of 2000). diflubenzuron, metabolic inhibitors Subterfuge is 0.3% (3000 ppm) Subterfuge does not use prebait- such as sulfluramid or hydramethyl- hydramethylnon (Quarles 1998a, ing. Perimeter bait stations are non or a salt of boric acid (disodium FMC 1995; BASF 2001). Sulfluramid installed, and the active bait is octaborate tetrahydrate). and hydramethylnon have both been added immediately. To install the Sentricon uses the CSI hexaflu- used extensively and effectively in baits, holes are drilled into the soil muron. Chitin synthesis inhibitors ant and roach bait stations. They around the perimeter of the build- make it impossible for termites to are metabolic inhibitors that block ing. The outer plastic casing is produce effective amounts of chitin. the oxidation of ingested food. Since inserted into the holes. Then, an If growing termites are unable to food cannot be utilized, termites inner plastic bait tube is inserted, molt, they die. Because termites slowly starve to death (Tomlin 1997). and the powdered bait is poured normally molt every 2 weeks to 6 The active ingredient of TermiRid is into the bait tube. The active bait is months, according to larval stage, sodium borate. Boric acid and supposedly more attractive to ter- hexaflumuron works slowly. Even borates kill termite intestinal mites than other items on their for- with active feeding, colony elimina- microbes and inhibit digestive aging menu, and they are diverted

IPM Practitioner, XXV(1/2) January/February 2003 10 Box 7414, Berkeley, CA 94707 Update from feeding on houses to feeding facturer Ensystex to use it properly. ered by termites, and termite con- on bait stations. Finally, the bait Subterfuge is also sold only to trol was not possible. At the other station is capped to prevent tam- PCOs (Potter 1997, Bayer 2000, 20 locations, termites were eliminat- pering by non-target organisms BASF 2001). ed from structures. An average of (BASF 2001). In most states, property owners 2.7 wooden stakes and 4.1 monitor- The Firstline bait station uses can do their own termite baiting ing stations per structure were dis- either "interceptive" or "directed bait- without hiring a PCO. Terminate covered by the termites (Potter et al. ing" or a perimeter baiting tech- and TermiRid can be purchased at 2001ab). nique. With interceptive baiting, hardware stores, home supply out- In another study, when a large holes are drilled into the ground, lets, or through online suppliers on housing complex of 28 buildings and stations are dropped into place the Internet. If prebaiting is desired, with 205 units was baited with in areas where termites are known HomeChoice bait stations are avail- Sentricon, 9.2% of the 2,041 moni- to be foraging. Active bait is added able online. The do-it-yourself baits toring stations had been discovered immediately. Alternately, perimeter are less expensive than Sentricon or by termites within a 9-month peri- monitoring stations are installed other baits applied by PCOs. od. Some of the foraging was that contain just wood attractants, On the negative side, it is possi- focused, as 25 of 34 stations and active bait is added when ter- ble that the stations may not be around one building were attacked mites appear. In another variant, a installed and inspected properly by (Dow 2002a). Although few stations large bait station (Home Defender™) someone new to the termite control are attacked, feeding by the colony contains simultaneously wood business. Best results come from is usually persistent, and this per- attractants and active baits. proper placement of the stations sistence leads to colony suppres- According to the label, up to 14 bait and introduction of the active bait sion (Henderson et al. 1997; Thorne stations can be used on any one without disturbing foraging ter- and Forschler 2000). property. Visibly infested wood, wood mites. Homeowners who try the do Foraging patterns are hard to mulches, areas near fence posts, it yourself bait may fail to control predict. However, Potter et al. and visible termite tubes are baited their termites, and then think that (2001b) found that Sentricon sta- (see Quarles 1995b; FMC 1996ab). termite baiting does not work. tions were more likely to be Terminate baits are normally Thus, the Terminate approach attacked in bare ground than in installed without a prebaiting cycle. could possibly cause an unfair grass or mulch. Proximity to termite Active baits are applied to the backlash against the new baiting damage or moisture sources did not perimeter or near where termites strategies. increase termite attacks on the sta- have been seen. Terminate is avail- Terminate baits are sold with a tions. A higher percentage of the able as a “Do it Yourself” bait, but money-back guarantee. No money wooden stakes were attacked in the manufacturer recommends that is lost if someone wants to try to mulched areas than in bare ground the structure is first inspected by a bait their own termites. However, if or grass. Attacks on stakes or sta- pest control operator (PCO) (see the attempt fails, the homeowner tions were more likely in shaded Resources). must accept the extra three months areas than in direct sunlight. Another option for the “Do it or so of termite damage, and turn Yourselfer” is to buy HomeChoice to another approach. Field Trials of monitoring stations to operate a Termite Baits perimeter prebaiting cycle. When Termite Foraging and These competing bait technolo- termites appear, then active Bait Discovery Terminate or TermiRid baits can be gies have all been tested in field tri- dropped into the stations (see The key to success with termite als, some of which have only Resources). baits is bait discovery and accept- recently been published. Are these ance. Most likely, termites forage techniques successful, and is one Different Marketing randomly, and baits are discovered approach better than another? by accident as part of the constant These questions can only be Strategies search for food (see below). One answered if the goals and criteria Sentricon differs from the other study measured bait discovery and necessary for success are clearly termite baits in that the manufac- acceptance over a 16-month period. defined. For a homeowner, success turer insists that all PCOs using One group of 24 homes was moni- might simply mean that termites the system be directly trained by tored with 475 pine wooden stakes. are not feeding on or in a structure. the company. In contrast, for states Over this period, 13.7% of the This is the bottom-line result need- where the materials are registered, stakes were attacked. Another 22 ed for any control method, includ- PCOs can purchase Firstline and termite-infested homes were moni- ing chemical barriers. Additional Outpost just by calling a distributor tored with Sentricon stations, and goals possible only with baits are or ordering from the Internet. 20.2% of these stations were suppression and/or elimination of Exterra can be obtained if the PCO attacked. At 2 of 22 locations, moni- subterranean colonies that are signs an agreement with the manu- toring stations were never discov- threatening a structure. Different

IPM Practitioner, XXV(1/2) January/February 2003 11 Box 7414, Berkeley, CA 94707 Update termite monitoring strategies are ter should ultimately repel termites zuron to the 0.5% hexaflumuron necessary according to established from the structural foundations. bait used by Sentricon (Quarles goals (see Box A). But as the poisoned colony begins 1998a). Presumably, choice tests to die, there are also fewer foragers with Outpost bait would produce Choice of Active to deliver the bait to the remaining similar results. Ingredient colony. The result is colony sup- pression instead of elimination. Results with Sulfluramid If the goal is colony suppression Sulfluramid has totally eliminated The final test of a termite bait is or removal of termites from struc- colonies only when applied in the effectiveness in the field. Most of the tures or baited areas, either toxicants trap-treat-release method with a products probably work effectively (Firstline, Terminate, Subterfuge, groomable coating (Myles 1996). to suppress or eliminate termite TermRid) or CSI’s (Sentricon, Su et al. (1984) concluded that populations. Su et al. (1995) con- Exterra, Outpost) would be appropri- field populations of Coptotermes for- ducted field tests with sulfluramid ate. If the goal is colony elimination, mosanus foraged randomly. Workers at three structures. Formosan ter- then CSI’s may be a better choice. In cycle through diffuse galleries, and mites fed at first on boards with 8 fact, up to 1996, the only published move from food source to food ppm sulfluramid, but later avoided cases demonstrating colony elimina- source. Though early experiments them. However, population size was tion involved Sentricon (Su and suggested that Reticulitermes did reduced from 2.7 million to Scheffrahn (1996b). not forage randomly, (Oi et al. 1996; 764,000. A test at a second colony The reason that a CSI might be Thorne et al. 1996), later research led to reduction from 4.1 million to a more suitable choice for colony supports random foraging of each 574,000. Foraging territory was not elimination is due to the termite worker throughout the whole colony affected by the baiting. At a third foraging process. Baits are taken foraging range (Atkinson 2000). This colony foragers were reduced from from bait stations by foragers, then dispersal and trophallaxis insures 1.8 million to 867,000. Foraging transferred to the rest of the colony that the whole colony is exposed to activity or territory was not reduced by trophallaxis (social food an active bait (Su et al. 1995; Grace (Su et al. 1995). exchange). Though termites feeding and Su 2001). at an active station usually move on Chitin synthesis inhibitors such Dr. James Ballard of FMC direct- to another food source within 30 as hexaflumuron (Sentricon) are not ed the Firstline field trials for his days (Atkinson 2000), workers in dose dependent. Any non-repellent company. Ballard assists bait instal- the immediate area of an active bait concentration builds throughout lations and helps to train PCOs who initially tend to accumulate higher the colony. Whether concentrations must replenish, and sometimes concentrations of active materials are high or low in an individual ter- move, bait stations. In trials leading than those foraging elsewhere. mite, results are the same. Death up to registration of Firstline, he Lethal time is dose-dependent for occurs only when the termite tries baited 54 structures. At 45 of these toxicants such as sulfluramid. For to molt. By the time the first ter- sites, conditions were such that example, 90% of C. formosanous mites start dying, the CSI is already control with baiting seemed likely. workers are killed within 16 hours present throughout the colony. As At 15 sites, successful control of after ingestion of sulfluramid at 24 termites are dying uniformly active infestations was achieved ppm, but 11.5 days are required at throughout the foraging area, active within 70 days. Successful control 9 ppm (Su et al. 1994). Repetitive feeding stations do not become is defined as disappearance of ter- foragers at treated stations accu- repellent. In fact, for Sentricon to mites from bait stations and struc- mulate high concentrations and be successful in removing a struc- tures. Heterotermes, Coptotermes, may eventually die near the bait tural infestation, severe colony sup- and Reticulitermes species have all station. Even though the toxicant is pression and perhaps elimination is been successfully baited. slow acting, some termites can die necessary (Su and Scheffrhan Ballard believes that complete within a few days. Others are 1996ab; Su et al. 1995). elimination of a termite colony is exposed to sublethal doses. Those Photo courtesy of Tim Myles Photo courtesy of Tim exposed to sublethal doses avoid Diflubenzuron Repellent? the baits, thus the colony is only suppressed, not eliminated (Su et Early experiments seemed to al. 1995). show that diflubenzuron was repel- Sublethally poisoned termites lent in concentrations greater than also tend to avoid a baited area, 2 ppm (Su and Schefferan 1993). and the area can become repellent. The bait matrix may be a factor, Sulfluramid and hydramethylnon however. According to Ensystex baits, which are toxicants, should company literature, the difluben- be effective in removing termites zuron bait used in Exterra is not from structures if baits are installed repellent in concentrations up to in mud tubes and active galleries. 1%. Ensystex choice tests showed Termites marked with dye can be Toxic baits installed on the perime- termites preferred 1% difluben- used to estimate populations.

IPM Practitioner, XXV(1/2) January/February 2003 12 Box 7414, Berkeley, CA 94707 Update

Box A. Termite Monitoring Strategies

According to Forschler (1996), the primary result of a Foraging termites in the area diminished, but baiting strategy should be prevention or removal of ter- researchers could not determine whether the colony had mite infestations in structures, not necessarily colony been killed or had just moved to another location suppression or elimination. If this approach is taken, ter- (Esenther and Beal 1978). mite activity can be monitored near the baiting sites. When Su (1994) field tested hexaflumuron, he used a Success occurs when foragers are no longer present in mark-recapture methodology to estimate the number of structures or near structures. foraging workers present before and after deploying Another possible goal of termite baiting is colony sup- baits. Wooden stakes were set up to find foragers. At pression or elimination. According to Su and Scheffrahn stakes where foragers were found feeding, monitoring (1996ab), there are three parameters that can be used to stations were established that consisted of plastic cylin- measure colony suppression or elimination: reduced for- ders filled with wooden blocks and buried in the soil. At aging activity, reduced foraging territory, and reduced one station with high activity (5000 foragers) termites foraging population size. One possible way of assessing were captured and marked with Nile Blue A dye, then foraging activity is by counting the number of termites released. One week after release at the monitoring sta- and amount of bait consumed in treated bait stations. tion, termites were again captured at the same station Presence of termites means a colony is present and feed- and the number of dyed termites were counted. ing, but absence of termites could mean that termites Forschler (1994) has used fluorescent paint to mark ter- have been repelled either by the bait or dead termites in mites for mark-recapture population estimates. the area and are foraging elsewhere. Feeding at a number of untreated monitoring stations Counting Jellybeans followed by no activity is good necessary evidence for colony elimination. Reduced activity at untreated moni- Counting termites with mark-recapture is like count- toring stations is one measure of success in colony sup- ing a mixture of white and blue jellybeans in a jar. A pression. If the idea is colony suppression or elimination, known number of blue beans is added to an unknown then termite activity should be monitored at sites away number of white beans, and the jar is shaken. A handful from active bait stations (Forschler and Ryder 1996). is then scooped out. If the handful contains very few blue To insure that monitoring stations are observing the beans, there are very many white beans. Similarly, if very colony that is feeding on the bait, marked termites few marked termites are recaptured, the colony is very should be used to establish foraging ranges. Termites are large. If most of the termites recaptured are marked, the captured, marked, then released. As they show up in colony is small. A statistical formula allows computation other monitoring stations, a map of the foraging territory of the number of foragers in the colony. Mark-recapture can be constructed (Su et al. 1984; Grace 1990; Grace et can estimate a population because "each colony is a al. 1989). closed unit with no individuals moving between colonies, Termite activity at monitoring stations can be mis- and populations do not increase or decrease rapidly" (Su leading if the observation is over a short time interval. 1993a). C. formosanus workers also forage at random, a The amount of feeding is subject to weather conditions condition that is required for valid mark-recapture work and seasonal activity, and the number of termites col- (Su et al. 1984). Thorne et al. (1996) believe that random lected provides only a limited view of activity. Unless a foraging has not been established for Recticulitermes spp. colony is observed for a long period to establish some Errors due to non-random foraging can be minimized by kind of baseline for normal variation, effects of a bait are using a large number of traps (Grace 1990). difficult to assess. Successful use of mark-recapture also requires that Termite populations have been estimated with mark- the dye does not kill termites, that the dye is not trans- release-recapture techniques (see below). Current mark- ferred by trophallaxis, that marked termites are not release-recapture techniques assume that the colony is attacked and killed by their nestmates, that the dye is not merging with another colony, breaking into satellite not lost due to feeding, and that termite fitness is not colonies, or another colony is not involved with a reduced by dye marking under a wide range of field con- takeover of feeding sites (Forschler and Ryder 1996). ditions. Any process that systematically eliminates marked termites gives an overestimation of colony size. Mark-Recapture Technique Preliminary laboratory studies and the triple mark-recap- "Field populations can be estimated into small, medi- ture method minimize errors of this sort (French 1994; um, large, or mega- colonies using mark-release-recap- Thorne et al. 1996). ture studies or simply by the number of stations A major problem with mark-capture-release is low attacked, time to attack and the number of termites recapture ratios. This problem, and the fact that many attacking each station" (Pawson and Gold 1996). assumptions about termite foraging are necessary in However, to successfully conduct field trials with hexaflu- order to fit the model, should lead to cautious interpreta- muron and other bait toxicants, techniques had to be tions of the foraging numbers (Thorne et al. 1996; devised to unambiguously prove efficacy. Earlier baiting Forschler and Townsend 1996). Mark-recapture colony trials with mirex had used wooden stakes to monitor for size estimates are about 10-fold higher than direct counts foraging termites amidst bait blocks soaked in mirex. based on excavated nests (Su and Scheffrhan 1988).

IPM Practitioner, XXV(1/2) January/February 2003 13 Box 7414, Berkeley, CA 94707 Update impractical and unnecessary. What instance, underground telephone similar mortality rates, however. is important is continued monitor- cables in New Orleans are often Even though termites ate less of the ing, and prevention of termite dam- attacked by Formosan termites. higher concentration, the more con- age. If colonies are knocked back to Toxic sprays cannot be used in this centrated toxin had extra potency. the point that no termites are seen situation because toxic vapors in In fact, Formosan termites are so in structures, and no PCO call closed spaces can be very hazardous sensitive to sulfluramid that very backs are necessary, Ballard to personnel involved in repairs. little needs to be ingested for mor- believes that adequate control has Also, cables are close to the water tality (Grace et al. 2000). been achieved. table and groundwater could be eas- Henderson believes that once To bait infestations inside struc- ily contaminated. Since there is no PCOs have become accustomed to tures, Ballard breaks into the lead- real termite food in these areas, the process of monitoring and bait- ing edge of a mud shelter tube and baits are quickly eaten and colonies ing termites, they will readily accept attaches a bait station with tamper- are eliminated (Henderson 1995). the technique. Even if colonies are resistant screws. Termites then At 14 manhole sites baited ini- not totally eliminated, both PCO rebuild the shelter tube around the tially with 10 ppm and then with and client should be better able to bait station. At locations outside, 100 ppm sulfluramid over a two- make treatment decisions if there is Ballard pursues an approach called year period, suppression was com- good information on the type and directed baiting. Baits are placed plete at 36% of the sites, excellent extent of the infestation (Henderson near fenceposts, in wooden at 21%, high at 36%, and low at 7% 1995). mulches, and in other areas where of the sites. "Excellent" meant the termite infestation is likely. total absence of termites for 3 con- Early Results Ballard sees baiting as part of an secutive months, and "high" meant with Subterfuge IPM program involving inspection, a large reduction (Felix and Like other metabolic inhibitors, moisture and food reduction, ter- Henderson 1995). results with hydramethylnon miticide application, use of foam Henderson has also successfully (Subterfuge) are dose-dependent. and sand barriers. Which elements baited active infestations in struc- For example, 24 hr exposure to predominate in the treatment tures. For some of these infesta- 2000 ppm kills 90% within 12 days, depends on the site. For instance, tions, PCOs have called Henderson but 18000 ppm kills this percent- in areas where a well is supplying as a last resort when other methods age within 1 day. Concentration of drinking water, baits would be used of elimination fail. Henderson drills hydramethylnon in the Subterfuge instead of chemical barrier treat- into infested galleries and adds bait is 3000 ppm. Logan and Abood ments. Where treatment is mandat- moistened cardboard soaked in 100 (1990) estimated that an effective ed by a real estate sale, however, ppm sulfluramid. He has found that baiting concentration for R. santo- baits might act too slowly and Formosan infestations centered in nensis should lie between 1250 and another method might have to be attics are more easily eliminated 5000 ppm. Hydramethylnon is not employed (Ballard 1995). than those in basements. Formosan initially repellent to C. formosanus colonies in attics are more desper- in laboratory tests at concentra- Trials in New Orleans ate for water, and thus find the tions up to 1000 ppm (Su et al. moistened baits more palatable. Dr. Gregg Henderson of Louisiana 1987). However, after termites start Henderson was able to completely State University Agricultural Center dying, others start avoiding the eliminate Formosan infestations in in Baton Rouge, LA has baited treated area (Su et al. 1982ab). the Ursiline Convent, which is the Formosan termites with prototype Results with hydramethylnon oldest building in the Mississippi Firstline stations in New Orleans. He have been inconsistent. Early field Valley. Termite infestations also van- started by baiting colonies in cypress tests showed that hydramethylnon ished from St. Patrick’s Cathedral trees. Because the cypress trees are was not repellent and was suppres- after structural baiting with sulflu- surrounded by swamp water, colonies sive to subterranean termites over a ramid. At a Lutheran Church in the are isolated from the ground and two-year period (Anon 1995; Thorne New Orleans area, however, the results from baiting can be more eas- and Traniello 1994), but termite infestation was apparently too large ily determined. Placement of card- colonies were not eliminated (Su for elimination by baiting within a board baits containing 100-1000 and Scheffrahn 1996ab; Su et al. reasonable 4-month time frame. ppm sulfluramid inside trees com- 1982ab). To test repellency, Henderson But Pawson and Gold (1996) had pletely eliminated these colonies fed cardboard soaked in 10 to 100 less success. They did preliminary (Henderson 1995). ppm sulfluramid to laboratory trials with the Subterfuge formula- colonies. Feeding termites were not tion of hydramethylnon (3000 ppm Baiting Structures initially repelled even by the highest and 30 g bait tubes) at four struc- Where the primary purpose of concentration. However, the amount tures. At one structure, about 1 baiting was removal of termites from of feeding was less than on lower tube (1.09) of placebo and 1 tube of structures and other areas, concentrations. High concentrations active material were consumed and Henderson also had success. For and low concentrations produced Reticulitermes termites were not

IPM Practitioner, XXV(1/2) January/February 2003 14 Box 7414, Berkeley, CA 94707 Update controlled over the period of a year. mg of hexaflumuron (Su 1993ab; colonies were eliminated after 3 At a second structure, 1.70 car- 1994). months, the 4th showed activity for tridges of placebo and 1.26 car- 8 months. A further 12 small tridges of active bait were con- Sentricon in Hawaii colonies were studied, without sumed. Apparently, Reticulitermes characterizing colony size or forag- Grace et al. (1996) used sp. found hydramethylnon repellent Sentricon baits at three Formosan ing range. Six of these removed bait and were not controlled. termite sites in Hawaii. Stations and showed no activity at monitor- At a third structure of pier-and- were installed at least 30 cm (11.8 ing stations after 5 months, two beam construction, 13 of 37 stations in) away from foundations at inver- colonies removed bait but were still were attacked, 5.79 tubes of placebo, vals of 4 to 5 m (13 to 16 ft). At one active after 9 months, 3 colonies and 2.02 cartridges of active bait site, a colony of 0.33 million were only briefly monitored and were consumed, and there was par- attacked 4 of 25 bait stations, con- were not baited, 1 colony remained tial suppression. At a 4th structure suming 3.25 bait tubes containing active in a monitoring station, but of slab-on construction, 45 bait sta- 113 mg of hexaflumuron. The did not take the bait. In 93% of the tions were installed. The mixed infes- colony was eliminated. At another colonies where baiting was attempt- tation of Coptotermes formosanus site, a colony of 5.35 million ed, termite activity was eliminated and Reticulitermes sp. consumed attacked 5 of 45 bait stations, con- within a year. In 100% of colonies 3.78 active bait tubes from 33 loca- suming 17 bait tubes containing where bait was taken, the colony tions. Hydramethylnon baits did not 595 mg of hexaflumuron. The was eliminated within a year. control the infestation, and may have colony was eliminated. At the third Studies in California, Iowa and been repellent. Since this early work, site, a colony of 0.94 million other locations have also shown the formulation has been changed to attacked 4 of 27 stations, consum- Sentricon baiting can control struc- make it less repellent (BASF 2001). ing 12 bait tubes containing 420 tural termites (Kistner and Sbragia mg of hexaflumuron. The intial 2001; Prabhakaran 2001). Hexaflumuron colony was eliminated, but the area Field Trials was reinvaded within 8 months by Feedback from PCOs Su (1994) had success with a colony from next door. Baiting Though field trials conducted by hexaflumuron (Sentricon) in was continued, and no activity was entomologists associated with Florida. Three colonies of R. flavipes observed 18 months later. Universities may be necessary to and three of C. formosanus were establish a product’s effectiveness, baited in these initial trials. Three Sentricon in Texas the final approval must come from bait tubes from which 3.9 mg of Pawson and Gold (1996) baited 8 PCOs and their customers. For hexaflumuron were consumed structures with Sentricon using instance, Robert Davis of ABC Pest killed one colony of 400,000 R. standard techniques over a 2-year and Lawn Service in Austin, TX flavipes within three months. period. Bait stations were installed reported success with Sentricon at Another colony of 730,000 was every 3 to 5 m around each perime- the 1999 Entomological Society of killed with 11 tubes and 20.3 mg of ter. Stations were inspected every America meeting in Atlanta, GA. hexaflumuron. The third colony of month for presence of termites and From 1996 to 1999, Davis baited R. flavipes contained nearly 3 mil- 1,276 properties with 35,006 2 amount of bait consumed. Termites lion foragers ranging over 2,361 m were able to locate stations at 6 of 8 Sentricon stations. Over the 3-year (0.58 acre). The colony was killed locations within a month. Altogether, period, 945 of 1,276 colonies were after 4 months with 69 bait tubes termites attacked 18.7% of the mon- eliminated (74%). Of 335 sites treat- and about 1500 mg (1.5 g) of hexa- itoring stations, but they probably ed in 1997, only 20 (6%), still had flumuron. did not continuously forage there. At termites in 1998. At the time of his A C. formosanus colony contain- some bait stations, termites had presentation, 331 clients (26%) had ing about 1 million foragers cover- bought preventive contracts after 2 been present, but were not foraging ing about 1,600 m (0.40 acre) was at the time of the inspection. Control their termites had been eliminated killed with 40 bait stations and was achieved at one of 8 structures. (Grossman 2000). about 233 mg hexaflumuron over a Increasing the number of stations in 9-month period. Another C. for- Texas did not increase the number When are Termites mosanus colony of about 2.5 million of termite encounters (Pawson and Eliminated? infesting a high rise was eliminated Gold 1996). in 7 months with 89 tubes and When baits were first being developed, researchers had to 742.3 mg of hexaflumuron. This Sentricon in Georgia colony had resisted soil termiticides establish efficacy by setting up sep- and one chemical fumigation. Forschler and Ryder (1996) bait- arate monitoring and baiting sta- Another C. formosanus high rise ed four well-characterized tions. Termites were marked and colony was reduced from 1.2 million Reticulitermes spp. colonies averag- released to measure effects of baits to 104,000 in a 4-month period ing 43,000 termites per colony with on populations (see Box A). Pains with 42 bait tubes and about 260 Sentricon. After taking bait, three were also taken to identify colonies

IPM Practitioner, XXV(1/2) January/February 2003 15 Box 7414, Berkeley, CA 94707 Update of termites by dye marking and was completely dead within four 2000; Su et al. 2001). The difluben- cuticular hydrocarbons. In this years. A colony of Formosans zuron bait (Labyrinth™) used in the way, researchers knew whether ter- reduced from 3.6 million to 68,000 Exterra system is also labeled for mites being monitored were part of by the metabolic inhibitor A-9248, use in aboveground stations the original colony, or represented a had rebounded to 743,000 within (Ensystex 2003). reinvasion of a new colony (Getty et four years. Three colonies sup- al. 2000). pressed with sulfluramid from Acute Safety As a practical matter, PCOs and ranges of 1.9-4.1 million to 575,000 All the termite baits contain low their clients must be able to tell to 847,000 remained low for two when termites are no longer a prob- years. Populations then resurged to concentrations of active ingredients, lem. Thorne and Forschler (2000) levels greater than 1 million and which insures their acute safety. suggest the problem is over when were treated either with Sentricon The small amount of toxicant used winged termites disappear, when or soil termiticides. makes them potentially less toxic termites disappear from pre-baiting Elimination of colonies, on the than chemical ground treatments, and post-baiting monitoring sta- other hand "created zones of ter- which use several pounds of formu- tions, and when feeding is vigorous mite-free soil" that lasted from nine lated product. For sulfluramid, the on an active bait, followed by ter- months to more than four years. acute oral LD50 for a rat is about mite inactivity. The manufacturer of Sometimes the territory of the elimi- 543 mg/kg. Since each ground sta- Exterra is using the following crite- nated colony was reinvaded by tion contains 3.54 grams of card- rion of success: “if all termite feed- neighboring colonies, but usually board at 100 ppm (0.01%), only ing and activity in an area has been was not (Su and Scheffrhan 1996a). 0.35 mg of sulfluramid is present in absent from the area for six consec- each station. Thus, a 1 kg rat could utive months and termites fed on Aboveground eat 1550 bait stations before reach- the bait for three months prior to Termite Baits ing the LD50 dose. Since no more the cessation of feeding and activi- than 14 stations are ever installed ty, we presume that colony elimina- Though commercial baiting sys- on one property, the stations have tion has occurred” (Quarles 1998a). tems were all originally installed in more than adequate acute safety Again, as a practical matter, ter- subterranean systems, baits can (Tomlin 1997; FMC 1996a). mites should no longer be foraging also be installed aboveground. Aboveground Firstline stations inside the structure or constructing Aboveground termite baits were contain 0.43 oz (12.7 g) of treated mud tubes. pioneered by the APG Specialty cardboard, containing about 1.3 mg Even if a colony is eliminated, Products Group of FMC Corporation of sulfluramid. Thus, about 418 and signs of an infestation disap- (see Resources). The aboveground aboveground stations, if ingested, pear, the baiting process should bait, called Firstline™ consists of would equal the LD50 for a 1 kg continue in order to maintain pro- cardboard impregnated with 100 rat. Since no more than four above- tection. When colonies are no ppm of sulfluramid. The cardboard ground stations are ever installed in longer feeding on active baits, active is protected by a bait station that is one unit, the sulfluramid above- materials should be removed, and inserted into the leading edge of an ground stations should be acutely active mud tube to control subter- the monitoring process continued safe (Tomlin 1997; FMC 1996d). ranean termite infestations at their with wood or other attractant The Recruit bait used in source (FMC 1995; 1996c). (Bayer 2000; Exterra 2003). Sentricon should cause no prob- Dow distributes an aboveground lems. If an entire 80 g bait tube bait called Recruit AG. The active Recovery of Suppressed containing 0.1% hexaflumuron were ingredient is the same hexaflu- eaten, only 80 mg of active ingredi- Populations muron used in the Sentricon What happens after colonies underground bait station. The com- ent would be ingested. [For compar- have been suppressed or eliminated bination of underground and above- ison, the active ingredient in one by baits? The possibilities are ground baits introduces the active aspirin is about 300 mg.] A 1 kg rat rebound of the colony, invasion by ingredient into underground would have to eat about 62 bait another colony, or total lack of colonies faster than underground stations to reach the LD50. Recruit activity. In any event, monitoring baits alone. Recruit AG is used II, which is currently used, contains must be continued to find out. Su wherever the aboveground infesta- 0.5% hexaflumuron, and about 12 and Scheffrhan (1996a) studied tion is visible and evident. This stations would have to be eaten to colony recovery after suppression, baiting approach is especially use- reach the mammalian LD50 (Su but not elimination, with baits. A ful for aboveground infestations of 1993ab, Su 1994; Tomlin 1997). colony of R. flavipes was baited for Formosan termites (Potter 1997; In the case of Outpost, 200 g of four months with Sentricon, was Josof 1997; Yates and Grace 2000). bait contains 500 mg of difluben- suppressed from 2.8 million to Studies have also shown that zuron. About 100 of the 200g bait 260,000, then was intentionally aboveground stations alone can lead units would have to be consumed allowed to recover. However, recov- to elimination of termites (DeMark to equal the mammalian LD50 of ery did not occur and the colony and Thomas 2000; Yates and Grace about 5000 mg/kg (Bayer 2000).

IPM Practitioner, XXV(1/2) January/February 2003 16 Box 7414, Berkeley, CA 94707 Update

Subterfuge bait stations contain subterranean termites (Isoptera: an average 30 g of bait containing Rhinotermitidae: Reticulitermes spp. and Resources 0.3% hydramethylnon. Each bait Termitidae: Amitermes wheeleri). Sociobiology Firstline Bait (sulfluramid)—FMC 36(1):149-167. Corporation, PO Box 8, station, then contains 90 mg of Ballard, J. 1995. Pers. comm. Dr. James hydramethylnon. Since the LD50 in Princeton, NJ 08543; 800/321- Ballard, FMC Corporation, PO Box 8, 1362; 609/951-3000 rats in 1150 mg/kg, consumption Princeton, NJ 08543; 800/321-1362; of about 13 bait stations would 609/951-3000. HomeChoice (monitoring sta- equal the LD50 for a l kg rat BASF. 2001. Subterfuge termite bait. Subterfuge tions)—www.epestsupply.com; (Tomlin 1997; BASF 2001). label. BASF Corporation, 26 Davis Drive, 877/500-0011 Research Triangle Park, NC 27709. EPA Reg. No. 241-371. Labyrinth Bait (diflubenzuron, Water Solubility Bayer. 2000. Outpost™ Termite Bait Response. Exterra)—Ensystex, 2709 Outpost label, Bayer Environmental Sciences, Breezewood Avenue, PO Box Sulfluramid, hydramethylnon, 95 Chestnut Ridge Rd., Montvale, NJ 07645, 2587, Fayetteville, NC 28303; and hexaflumuron are nearly insol- 800/438-5837. EPA Reg. No. 499-488-3125. 1888-Exterra; Fax 888/368-4789 uble in water, and thus should not Cabrera, B.J., N.-Y. Su, R.H. Scheffrahn and leach out of the bait stations into P.G. Koehler. 2002. Termite baits. University Outpost (diflubenzuron)—Bayer the environment. The little that of Florida Cooperative Extension. Environmental Sciences, 95 does leach out should be strongly DeMark, J.J. and J.D. Thomas. 2000. Seasonal Chestnut Ridge Rd., Montvale, NJ activity, wood consumption rates, and bound to the soil (Tomlin 1997). 07645; 800/438-5837, 214/484- response to aboveground delivery of hexaflu- 6326, Fax 201/307-9700 However, because low solubility muron-treated bait to Reticulitermes flavipes is not insolubility, none of these (Isoptera:Rhinotermitidae) in Pennsylvania Recruit Bait (hexaflumuron, baits should be used in direct con- and Wisconsin. Sociobiology 36(1):181-200. Sentricon)—DowAgrosciences, tact with water (FMC 1996b). The Dow. 2002a. MSDS Recruit II termite bait. 9330 Zionsville Rd., Indianapolis, MSDS’s of hexaflumuron and DowAgrosciences, Indianapolis, IN 46268. IN 46268; 317/337-4379; Dow. 2002b. A cradle-to-grave review of the 800/678-2388 diflubenzuron warn that the materi- Sentricon termite colony elimination system al is toxic to aquatic invertebrates with ESP™ technology. Pest Control Subterfuge Bait—BASF Corporation, (Dow 2002a; Bayer 2000). Technology March: 2002. 26 Davis Drive, Research Triangle Ensystex. 2003. Labyrinth™ Termite Bait. Park, NC 27709; 800/669-2273, Conclusion Labryrinth label, Ensystex Corporation, 2709 973/426-2610 Breezewood Avenue, PO Box 2587, All of these baits can suppress or Fayetteville, NC 28303; 888/exterra. EPA Reg. Terminate (sulfluramid)—Spectrum eliminate subterranean termite No. 68850-2. Industries, St. Louis, MO; colonies if termites find the active Esenther, G.R. and R.H. Beal. 1978. Insecticidal 800/242-1166; www.epestsup- bait and eat enough of it. Choice of baits on field plot perimeters suppress ply.com; 877/500-0011 Reticulitermes. J. Econ. Entomol. 71:604-607. bait depends on goals of homeown- Farm Chemicals. 1999. Farm Chemicals. Meister TermiRid (borate bait)—www.epest- ers and PCOs. Firstline should Publishing Co., Willoughby, OH. supply.com; 877/500-0011 quickly eliminate a structural infes- Felix, J. and G. Henderson. 1995. Debugging tation and tends to repel termites New Orleans' phone lines. Pest Control baiting with hexaflumuron using a prototype from the area of bait installation. Technology 23(10):76,78,151. commercial termite baiting system. J. Sentricon or other systems contain- FMC. 1995. FirstLine™ termite bait. MSDS No. Entomol. Sci. 31(1):143-151. 4151-50-2-4. FMC Corporation, Agricultural ing CSI’s should be the choice if the Forschler, B.T. and M.L. Townsend. 1996. Mark- Products Group, Philadelphia, PA. 4pp. release-recapture estimates of Reticulitermes goal is colony elimination. No matter FMC. 1996a. FirstLine™ termite bait station. spp. (Isoptera: Rhinotermitidae) colony forag- which baiting technology is used, Label, Code 1629, FMC Corporation, ing populations form Georgia, U.S.A. Environ. termite baits require a long-term Agricultural Products Group, Philadelphia, Entomol. 25(5):952-962. committment to termite monitoring PA. 1 p. French, J.R.J. 1994. Combining physical barri- FMC. 1996b. FirstLine™ GT termite bait station. ers, bait and dust toxicants in future strate- in order to prevent structural dam- Label, Code 1743, FMC Corporation, age. The necessary installation of gies for subterranean termite control Agricultural Products Group, Philadelphia, (Isoptera). Sociobiology 24(1):77-91. monitoring stations are the first step PA. 1 p. Getty, G.M., M.I. Haverty, K.A. Copren and V.R. toward implementation of a struc- FMC. 1996c. FirstLine™ GT termite bait station. Lewis. 2000. Response of Reticulitermes spp. tural IPM program for termites. MSDS No. 4151-50-2-6. FMC Corporation, (Isoptera: Rhinotermitidae) in Northern Agricultural Products Group, Philadelphia, California to baiting with hexaflumuron with PA. 4 pp. William Quarles, Ph.D. is Executive Sentricon termite colony elimination system. Forschler, B.T. 1994. Fluorescent spray paint as J. Econ. Entomol. 93(5):1498-1507. Director of BIRC and Managing a topical marker on subterranean termites Grace, J.K., A. Abdallay and K.R. Farr. 1989. Editor of the IPM Practitioner. (Isoptera: Rhinotermitidae). Sociobiology Eastern subterranean termite (Isoptera: 24(1):27-38. Rhinotermitidae) foraging territories and pop- References Forschler, B.T. 1996. Baiting Reticulitermes ulations in Toronto. Can. Ent. 121:551-556. (Isoptera: Rhinotermitidae) field colonies with Grace, J.K. 1990. Mark-recapture studies with Anonymous. 1995. Shots heard round the world: abamectin and zinc borate treated cellulose in Reticulitermes flavipes (Isoptera: a revolutionary termite treatment. Pest Control Georgia. Sociobiology 28(3):459-484. Rhinotermitidae). Sociobiology 16(3):297-303. Technology August:54-55, 58,91,92. Forschler, B.T. and J.C. Ryder, Jr. 1996. Grace, J.K, C.H.M. Tome, T.G. Shelton and R.J. Atkinson, T.H. 2000. Use of dyed matrix in bait Subterranean termite, Reticulitermes spp. Oshiro. 1996. Baiting studies and considera- stations for determining foraging territories of (Isoptera: Rhinotermitidae), colony response to tions with Coptotermes formosanus (Isoptera:

IPM Practitioner, XXV(1/2) January/February 2003 17 Box 7414, Berkeley, CA 94707 Update

Rhinotermitdae) in Hawaii. Sociobiology bait markets. IPM Practitioner 20(10):6-9. Su, N.-Y., P.M. Ban and R.H. Scheffrahn. 2001. 28(3):511-520. Quarles, W. 1998b. Borates for wood protection. Control of subterranean termites Grace, J.K., R.T. Yamamoto and C.H.M. Tome. IPM Practitioner 20(3):1-12. (Isoptera:Rhinotermitidae) using commercial 2000. Toxicity of sulfluramid to Coptotermes Sheets, J.J., L.L. Karr and J.E. Dripps. 2000. prototype aboveground stations and hexaflu- formosanus (Isoptera: Rhinotermitidae). Kinetics of uptake, clearance, transfer and muron baits. Sociobiology 37(1):111-120. Sociobiology 35(3):457-466. metabolism of hexaflumuron by eastern sub- Thorne, B.L. and J.F.A. Traniello. 1994. Grace, J.K. and N.-Y. Su. 2001. Evidence sup- terranean termites (Isoptera: Rhinotermitidae). Detection and control through baiting ter- porting the use of termite baiting systems for J. Econ. Entomol. 93(3):871-877. mites. Pest Management 13(9):1-13, 16-18. long-term structural protection (Isoptera). Sheets, J. and L. Karr. 2001. Kinetics of uptake, Thorne, B.L., E. Russek-Cohen, B.T. Forschler, Sociobiology 37(2):301-310. clearance, transfer and metabolism of noviflu- N.L. Breisch and J.F.A. Traniello. 1996. Grossman, J. 2000. ESA Conference Notes. IPM muron in termites (Reticulitermes flavipes). Evaluation of mark-release-recapture methods Practitioner 22(5/6):15. Entomological Society of America Conference for estimating forager population size of sub- Grossman, J. 2002. ESA Conference Notes. IPM 2001, Atlanta, Georgia (see Grossman 2002). terranean termite (Isoptera:Rhinotermitidae) Practitioner 24(7):16. Su, N.-Y. M. Tamashiro and J.R. Yates. 1982a. colonies. Environ. Entomol. 25(5):938-951. Henderson, G. 1995. Pers. comm. Dr. Gregg Trials on the field control of the Formosan Thorne, B.L. and B.T. Forschler. 2000. Criteria Henderson, Dept. of Entomol., 402 Life subterranean termite with Amdro bait. Doc. for assessing efficacy of stand-alone termite Sciences Bdlg., LSU Agric. Cntr., Baton No. IRGWP/1163. The International Research bait treatments at structures. Sociobiology Rouge, LA 70803. Group on Wood Preservation, Stockholm, 36(1):245-255. Henderson, G., K. Sharpe-McCollum and C. Sweden.[cited in Su et al. 1996a] Tomlin, C., ed. 1997. The Pesticide Manual, 11th Dunaway. 1997. Tracking termites. Pest Su, N.-Y., M. Tamashiro, J.R. Yates and M.I. ed. British Crop Protection Council, Farnham, Control Technology February:56-61. Haverty. 1982b. Effect of behavior on the eval- Surrey, UK. 1606 pp. Josof, L. 1997. Food fight: termite baiting in the uation of insecticides for prevention of or Yates, J.R., III and J.K. Grace. 2000. Effective Crescent City. Pest Control Technology June: remedial control of the Formosan subter- use of aboveground hexaflumuron bait sta- 75,76,80,82,83. ranean termite. J. Econ. Entomol. 75:188-193. tions for Formosan subterranean termite con- Kistner, D.H. and R.J. Sbragia. 2001. The use of Su, N.-Y., M. Tamashiro, J.R. Yates and M.I. trol (Isoptera: Rhinotermitidae). Sociobiology the Sentricon™ termite colony elimination Haverty. 1984. Foraging behavior of the Formosan 35(3):333-356. system for controlling termites in difficult con- subterranean termite (Isoptera: Rhinotermitidae). trol sites in Northern California. Sociobiology Environ. Entomol. 13:1466-1470. 37(2):265-280. Su, N.-Y., M. Tamashiro and M.I. Haverty. 1987. Logan, J.W.M. and F. Abood. 1990. Laboratory Characterization of slow-acting insecticides for trials on the toxicity of hydramethylnon the remedial control of the Formosan subter- (Amdro: AC 217,300) to Reticulitermes santo- ranean termite (Isoptera: Rhinotermitidae). J. nensis Feytaud (Isoptera: Rhinotermitidae) Econ. Entomol. 80:1-4. and Microtermes lepidus Sjöstedt (Isoptera: Su, N.-Y. and R.H. Scheffrahn. 1988. Foraging Termitidae). Bull. Ento. Res. 80:19-26. population and territory of the Formosan sub- Oi, F.M., N-Y. Su, P.G. Koehler and F. Slansky. terranean termite (Isoptera: Rhinotermitidae) 1996. Laboratory evaluation of food placement in an urban environment. Sociobiology and food types on the feeding preference 14(2):353-359. of Reticulitermes virginicus (Isoptera: Su, N.-Y. 1993a. Development of a new termite Rhinotermitidae). J. Econ. Entomol. 89(4):915-921. control bait. Pest Control June:39,42,44,48.s Myles, T. 1996. Development and evaluation of a Su, N.-Y. 1993b. Baits. Pest Control Technology transmissible coating for control of subter- July: 72,73,76,78,80,114. ranean termites. Sociobiology 28(3):373-401. Su, N.-Y. and R.H. Schefferan. 1993. Laboratory Pawson, B.M. and R.E. Gold. 1996. Evaluation of evaluation of two chitin synthesis inhibitors, baits for termites (Isoptera: Rhinotermitidae) in hexaflumuron and diflubenzuron, as bait toxi- Texas. Sociobiology 28(3):485-510. cants against Formosan and eastern subter- Potter, M.F. 1997. Termite baits: status report. ranean termites (Isoptera: Rhinotermitidae). J. Pest Control Technology 25(2):24-26,28,30,35- Econ. Entomol. 86(5):1453-1457. 37, 97, 105, 106, 110. Su, N.-Y., M. Tokoro and R.H. Scheffrahn. 1994. Potter, M.F., E.A. Eliason and K. Davis. 2001a. Estimating oral toxicity of slow-acting toxi- Targeting termites. Pest Control Technology cants against subterranean termites (Isoptera: 29(7):58-63. Rhinotermitidae). J. Econ. Entomol. 87(2):398- Potter, M.F., E.A. Eliason, K. Davis and R.T. 401. Bessin. 2001b. Managing subterranean ter- Su, N.-Y. 1994. Field evaluation of a hexaflu- mites (Isoptera:Rhinotermitidae) in the muron bait for population suppression of sub- Midwest with a hexaflumuron bait and place- terranean termites (Isoptera:Rhinotermitidae). ment considerations around structures. J. Econ. Entomol. 87(2):389-397. Sociobiology 38(3B):565-584. Su, N.-Y., R.H. Scheffrahn and P.M. Ban. 1995. Prabhkaran, S.K. 2001. Eastern subterranean Effects of sulfluramid-treated bait blocks on termite management using baits containing field colonies of the Formosan subterranean hexaflumuron in affected University of Iowa termite (Isoptera: Rhinotermitidae). J. Econ. structures (Isoptera: Rhinothermitidae). Entomol. 88(5):1343-1358. Sociobiology 37(1):221-233. Su, N.-Y. and R.H. Scheffrahn. 1996a. Fate of Quarles, W. 1995a. Least-toxic termite baits. subterranean termite colonies (Isoptera) after Common Sense Pest Control Quarterly 11(2):5-17. bait applications—an update and review. Quarles, W. 1995b. New technologies for termite Sociobiology 27(3):253-275. control. IPM Practitioner 17(5/6):1-9. Su, N.-Y. and R.H. Scheffrahn. 1996b. A review Quarles, W. and C. Bucks. 1995. Non-toxic ter- of the evaluation criteria for bait toxicant effi- mite control. Organic Gardening 42(9):44-50. cacy against field colonies of subterranean ter- Quarles, W. 1998a. New competition in termite mites (Isoptera). Sociobiology 28(3):521-534.

IPM Practitioner, XXV(1/2) January/February 2003 18 Box 7414, Berkeley, CA 94707 Update

IPM Practitioner, XXV(1/2) January/February 2003 19 Box 7414, Berkeley, CA 94707 Update

IPM Practitioner, XXV(1/2) January/February 2003 20 Box 7414, Berkeley, CA 94707 Update

IPM Practitioner, XXV(1/2) January/February 2003 21 Box 7414, Berkeley, CA 94707 Update

IPM Practitioner, XXV(1/2) January/February 2003 22 Box 7414, Berkeley, CA 94707 Update

IPM Practitioner, XXV(1/2) January/February 2003 23 Box 7414, Berkeley, CA 94707