Drywood _ Dampwood - Manatee County Extension Office

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Drywood and Dampwood Termites1
F. M. Oi, R. Scheffrahn, W. Kern, and K. C. Ruppert2

     In Florida, structurally damaging termites                                        All termites are true social insects, which means
generally belong to one of three groups: drywood                                  they live in cooperative societies called colonies.
termites, dampwood termites, and subterranean                                     Drywood and true dampwood termite colonies
termites. This document focuses on the first two                                  contain reproductives, soldiers (which defend the
groups. Drywood and dampwood termites belong to                                   colony) and nymphs and immature forms called
the family Kalotermitidae. These termites live inside                             pseudergates or "false workers" (which perform most
the wood they eat. Subterranean termites (families                                of the work in the colony).
Rhinotermitidae and Termitidae) usually live in the
soil and travel to wood to eat. More information on                                                 Signs of Infestation
subterranean termites can be found in ENY-210,
                                                                                                        Drywood Termites
Subterranean Termites (
IG097).                                                                                A telltale sign of drywood infestation is the
     It is important to know what termite you are                                 accumulation of six-sided fecal pellets. Fecal pellets
                                                                                  are also known as “frass.” Termites inside the
dealing with because control measures can be
                                                                                  infested wood push frass out through pencil-tip sized
significantly different in cost, application method and
                                                                                  “kick-out holes” (1-2 mm diam.) in infested
product selection. Drywood termites most commonly
                                                                                  material. Frass can resemble “sawdust” or “coffee
infest dry, sound (non-decayed) wood and are a
                                                                                  grounds.” The pellets have a gritty texture when
problem more commonly associated with older
                                                                                  rolled between your fingers and can be from light
homes. They can infest wood flooring, framing
members, window sills, doors, fascia boards, and                                  brown to almost black in color. The color is not
                                                                                  related to the age or the color of the wood. Pellets
furniture. They are also known to infest attics where
                                                                                  usually collect into piles on the floor and other
the temperature of the wooden members can exceed
                                                                                  surfaces. A sign of advanced infestation is surface
                                                                                  blistering or warping. Drywood termites sometimes
                                                                                  tunnel just under the surface of the wood giving it a

1. This document is ENY-211 (IG098), one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of
   Food and Agricultural Sciences, University of Florida. Frist published: April 1993. Revised: February 2008. Please visit the EDIS Website at
2. F. M. Oi, assistant extension entomologist, Entomology and Nematology Department, Cooperative Extension Service, Institute of Food and Agricultural
   Sciences, University of Florida, Gainesville, 32611; R. Scheffrahn, professor and W. Kern, associate professor, Entomology and Nematology Department,
   University of Florida, Ft. Lauderdale REC, Davie, FL 33314; and K. C. Ruppert, associate extension scientist, Florida Energy Extension Service,
   Cooperative Extension Service, IUniversity of Florida, Gainesville, 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and
other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex,
sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service,
University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry
Arrington, Dean
Drywood and Dampwood Termites                                                                                       2

blistered, uneven appearance. Infestations may be         generally there will be significantly fewer wings and
detected by tapping the wood every few inches with        termites if they are coming from indoors. Swarming
the handle of a screwdriver or by probing with a sharp    is a seasonal event, happening once, perhaps twice a
tool. Damaged wood sounds hollow - a papery,              year. Thus, the opportunity to find infestations based
rustling sound indicates tunnels just beneath the         on the presence of wings or swarmers is limited.
surface.                                                  Table 1 contains a comparison of the characteristics
                                                          of the three major termite pest groups in Florida.

                                                               Description of Drywood and
                                                              Dampwood Termites in Florida
                                                              Drywood termites

                                                             • The West Indian drywood termite
                                                               (Cryptotermes brevis) soldier is easy to identify
                                                               by its distinctive head, which resembles a burnt
                                                               match (Figure 1). This type of head is termed
                                                               “phragmotic.” The head is used to block the
Figure 1. Drywood termite (Cryptotermes brevis soldier         tunnels in the termite gallery system thus
with brown head and cream colored body; head                   protecting the colony from intruders, especially
“phragmotic” and can plug kick-out holes. Credits:             ants. This termite typically infests picture
University of Florida                                          frames, furniture, boxes and structural
                                                               woodwork. Interestingly, this species is never
               Dampwood Termites
                                                               found in natural environments but only in wood
     Dampwood termites are found only in wood                  in human-made structures. (See also:
with high moisture content. In structures they need   The alates of
sources of “free water,” such as roof leaks, to                related species, Crytotermes cavifrons, will come
survive. Dampwoods are considered a minor                      to lights, but it infests only dead tree branches.
structural pest, but they can do substantial damage if
                                                             • Southeastern drywood termite (Incisitermes
left unchecked. Correcting moisture problems and
                                                               snyderi) colonies are generally larger than those
wood replacement are effective controls. They are
                                                               of the West Indian drywood termite and occupy
commonly found infesting large trees. Dampwood
                                                               larger pieces of wood. These termites are found
fecal pellets are often stuck together along the bottom
                                                               in both natural and human-made environments
or sides of the tunnels or may dissolve into a muddy
                                                               and are the most common drywood in the state.
paste. Infested wood usually shows no external
                                                               The development of the colony is slow, but
damage because openings in the wood are plugged
                                                               structural damage can be extensive if multiple
with fecal material. If the wood is sound, dampwood
                                                               colonies are present in the same structure. This
termites eat along the grain. However, if the wood is
                                                               termite usually swarms from May through
decayed they consume irregular galleries similar to
those of the drywood termite.
                                                             • The Western drywood termite (Incisitermes
     Another sign of infestation for both drywood and
                                                               minor), is a non-native termite. It has been found
dampwood termites is the presence of wings or
                                                               in many parts of the state. This is the number
winged termites (also known as “swarmers” or
                                                               one drywood termite pest in the western U.S. It
alates) inside or around the structure. The termites
                                                               usually swarms from the end of August through
shed their wings after short flights. These wings are
                                                               November. (See also:
commonly found around window sills, and on floors
and countertops. There is a possibility that termites
may be flying into the structure from the outside, but
Drywood and Dampwood Termites                                                                                           3

Table 1. Comparison of the three termite pest groups.

       Termite       Usual Location           Damage                 Frass                  Control Methods

 Drywood            Dry, sound wood      Along and across   Six-sided pellets, dry     • Wood replacement
                                         wood grain                                    • Spot treatment
                                                                                       • Fumigation
 Dampwood           Saturated or         Along or across    Elongated pellets, moist   • Elimination of moisture
                    decayed wood         wood grain                                    • Removal of infested wood
                                                                                       • Spot treatment
 Subterranean       Soil                 Along wood grain   Sticky, incorporated       • Structural modification
                                                            into mud tubes and         • Liquid or granular chemicals
 (For control                                               galleries                  • Baits
 purposes, the                                                                         • Physical barrier
 species are
 included here)

   • J. schwarzi has been limited to south Florida. It                     Preventive Measures
     usually swarms between April and June.
                                                                   Used lumber, furniture and other wooden articles
   • J. milleri is found in the Keys. It ususlaly             should be carefully inspected for termite infestations.
     swarms around April-May.                                 Drywood termite reproductives may enter a building
                                                              through the attic or foundation vents, under or
     Dampwood termite swarmers are generally
                                                              directly through shingles or under eaves, or even
larger (average length 1/2 inch or 14 mm) than
                                                              open doors and windows. All vents, doors, and
subterranean and drywood termite swarmers (average
                                                              windows, especially those in the attic, should be
length about 1/3 inch or 10 mm or less). (See also:
                                                              screened with 20 mesh screen. A good coat of paint
                                                              on exposed wood will provide some protection
   • Neotermes castaneus is the largest termite               against termite entry. Before painting, all cracks and
     (winged individuals are over 1/2 inch or 15.5 mm         crevices should be filled with putty or plastic wood.
     long) in the southeastern U.S. but it is not an          Pressure treated wood is resistant to termite attack.
     economically important pest. Sometimes it is             Certain woods are also naturally resistant to termites;
     found in living trees. N. castaneus swarms during        among these are heart wood of redwood,
     August through early December.                           bald-cypress, mahogany, and Spanish cedar;
                                                              however, these woods can be more expensive and
   • Neotermes jouteli infests drier wood compared            will become susceptible after several years when
     to other dampwood species. It is known only as           subjected to aging and weathering.
     an incidental pest in structures with excessive
     moisture problems. N. jouteli swarms from                          Submitting a Sample for
     March to early June, then again in August to                           Identification
     early November.
                                                                   Drywood and subterranean termites require
   • Neotermes luykxi is also an incidental pest in           completely different control methods. Therefore,
     structures. N. luykxi swarms from the end of June        correct identification of the termites is extremely
     to early October.                                        important. If in doubt, take several swarmers to your
                                                              County Extension Office for identification. Soldiers
   •                                                          can also be submitted but most people do not find
                                                              these unless they break open infested wood. Soldiers
                                                              and winged specimens, which tend to dry and shrivel
                                                              up fairly quickly, should be preserved in rubbing
Drywood and Dampwood Termites                                                                                       4

alcohol. Termite identifications can also be made         treatment that will kill all termites in the structure,
with just the wings. Samples consisting of only           when done correctly.
termite nymphs (workers) are difficult to identify and
require a specialist. Pellets can also be submitted for        Sulfuryl fluoride gas is used to create a toxic
identification.                                           atmosphere within a confirmed space; under a tarp,
                                                          within a sealed structure or inside a fumigation vault.
                      Control                             Once the structure is cleared after the fumigation is
                                                          complete, no sulfuryl fluoride remains in the
     Most drywood termite infestations are not cause      structure. Thus, there is no product left to prevent
for panic and immediate treatment. The best course of     termites from re-entering the structure. Because
action is to take some time to research the pest          sulfuryl fluoride is odorless and colorless,
control companies in your area and find the best          chloropicrin ("tear gas") is used as a warning agent.
treatment option for your home or construction type.      This is the odor that can be detedted sometimes after
Soil treatments, either with liquid insecticides or       the fumigation is completed and cleared for re-entry.
termite baits, would be ineffective because drywood
and dampwood termite colonies are inside the wood,             Fumigation is usually the only alternative when
not in the ground.                                        the infestation is widespread or colonies are in areas
                                                          that are difficult to treat locally. Fumigation can only
     If detected in the early stages and damage is        be performed by a PMP licensed in the fumigation
localized, a drywood termite colony may be                category. Contact several companies for an inspection
controlled by removing and replacing the damaged          and cost estimate for treatment. Ask for references of
wood. It is very important to carefully inspect all       previous fumigation jobs.
woodwork in the building for pellets and/or damaged
wood, especially in attics, baseboards, windowsills,           For non-chemical control, construction should be
floor joists, and furniture. Localized treatments for     designed to eliminate moisture and water leaks.
drywood termites include directly treating the            Remove and replace infested or damaged wood.
infested wood. Products registered for wood               Microwaves, electroguns, and liquid nitrogen have
treatment are usually liquids. The product is applied     limitations and require thorough wood access. Heat
by brushing or spraying it onto the wood surface.         threatment can be used for whole structure of
Wood can also be treated by injecting insecticide         compartment treatments. The following link provides
directly into a termite gallery through holes made        additional information on drywood control options:
with a drill or into the kick-out holes. Applications
can also be made to cracks and crevices such as the       Control.pdf.
spaces between wooden pieces or between different
                                                              Additional information posted by the Florida
building materials, such as wood and concrete, if
                                                          Department of Agriculture and Consumer
there is evidence of an infestation. Use a product
labeled for indoor surface treatments, if treating
indoors, and outdoor treatment if treating termites          • Consumer Information on Drywood Termites:
found outdoors.                                      
     Homeowners can usually find registered
products for local wood treatments (Table 2). More           • Consumer Service Aid for the Homeowner and
often, the skills of a pest management professional            Buyer Relating to Termites and Other
(PMP) are required. PMPs have the equipment                    Wood-Infesting Pests:
needed to get the product to its target site (Table 3).
If the infestation is too extensive and advanced for
local treatment, it will be necessary to tent and            • Consumer Information Bulletin: Alternative
fumigate the entire building. Although this method             Methods of Treatment for Drywood Termites:
can be very expensive and disruptive, it is the only 
Drywood and Dampwood Termites                                                                                            5

   • Important Information for Home Buyers –
     Understanding Wood Destroying Organisms
     Inspection Reports:

Table 2. Examples of Insecticides Labeled for Homeowner Use. These insecticides are generally intended as a supplement
to a professional treatment. As with all pesticides, read and follow the label. The label is the law.*

           Trade Name                  Common Name           Formulation        Signal                  Pests
          (Manufacturer)                                                        Word

 Bayer Power Force Carpenter         Beta-Cyfluthrin       Emulsifiable       Caution        Wood destroying pests
 Ant & Termite Killer Plus                                 Concentrate
 Ortho Ortho-Klor Termite &          Bifenthrin            Emulsifiable       Caution        Wood destroying pests
 Carpenter Ant Killer                                      Concentrate
 Bayer Advanced Home, Home           Cyfluthrin            Ready-To-Use       Caution        drywood
 Pest Control Indoor & Outdoor
 Insect Killer
 Spectracide® Carpenter Ant &        Permethrin            Concentrate        Caution        Termites
 Termite Killer Insect Spray

 * Not intended as a comprehensive list, or product endorsement.
Drywood and Dampwood Termites                                                                                                     6

Table 3. Examples of Insecticides Labeled for Professional Use. As with all pesticides, read and follow the label. The label is
the law.*

         Trade Name                    Common Name               Formulation          Signal                 Pests
        (Manufacturer)                                                                Word

 Bora-Care                         Disodium Octaborate         Solution            Caution         drywood
 Tim-Bor                           Tetrahydrate
 DeltaDust                         Deltamethrin                Dust                Caution         dampwood, drywood
 Demon TC                          Cypermethrin                Concentrate         Caution         drywood

 Phantom                           Chlorfenapyr                Suspended           Caution         Southeastern drywood
 (BASF)                                                        Concentrate

 Premise 0.5 SC                    Imidacloprid                Emulsifiable        Caution         dampwood, drywood
 Premise 2                                                     Concentrate
 Premise 75
 Premise Foam                      Imidacloprid                Foam                Caution         drywood
 Optigard ZT                       Thiamethoxam                Suspended           Caution         drywood
 (Syngenta)                                                    Concentrate

 Termidor SC                       Fipronil                    Suspended           Caution         drywood
 (BASF)                                                        Concentrate

 Termidor 80WG                     Fipronil                    Wettable            Warning         drywood
 (BASF)                                                        Granule


 Dow;                              Chlorpicrin                 Warning Agent       Danger          drywood

 Vikane                            Sulfuryl fluoride           Fumigant            Danger          drywood
 (Dow AgroSciences)

 Zythor                            Sulfuryl fluoride           Fumigant            Danger          drywood
 (Ensystex II)

 * Not intended as a comprehensive list, or product endorsement.

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