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Xylosandrus compactus (Eichoff) |
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Black twigborer |
Hosts | Distribution | Damage | Biology | Behavior | Management | Reference |
Authors
Victoria L. Tenbrink, Research Associate
Arnold H. Hara, Entomologist
Beaumont Research Center
Hilo, Hawaii
Updated by: J.M. Diez April 2007
HOSTS
Recorded hosts of the black twig borer exceed 200 plant species and include:
Cattleya, Dendrobium, Epidendrum, Vanda, anthurium, avocado, citrus, coffee, cacao, brushbox (Tristania conferta),
turpentine tree (Syncarpia glomulifers), paper-bark (Melaleuca
leucadendron), red-ironbark eucalyptus (Eucalyptus sideroxylon),
blackbutt eucalyptus (E. pilularis), robust eucalyptus (E.
robusta), Koa haole (Leucaena glauca), guava, vervain
(Stachytarpheta jamaicensis), Christmasberry (Schinus
terebinthifolia) floral red ginger, litchi, macadamia, mango,
mahogany, hibiscus, kukui, star jasmine, pikake, periwinkle,
Surinam cherry. (Davis, 1963; Davis, 1969; Dixon & Woodruff,
1982; Hara & Beardsley, 1979; Mangold et al., 1977; Marsden,
1979; Nelson & Davis, 1972).
DISTRIBUTION
The black twig borer is native to Asia, but has spread to
coffee growing areas of the world. Considered a serious coffee
pest in French Guinea, it is also widely distributed the tropical
areas of West Africa, coffee growing areas of East Africa,
Madagascar, Mauritius, Seychelles, India, Malaysia, Java,
Sumatra, and Fiji. (Davis, 1963; Nelson & Davis, 1972). In
Japan it attacks tea (Hara & Beardsley, 1979). New World
locations include Brazil and Cuba (Dixon & Woodruff, 1982).
In the U. S. it is established in Hawaii and the Southeastern
states (Mangold et al., 1977). It was discovered at Kailua, Oahu
in November of 1961 and is now widespread in the Islands (Nelson
& Davis, 1972). A ban on shipment of woody plants to Hawaii
Island failed to prevent its introduction into the coffee growing
areas of that Island (Davis, 1963).
DAMAGE
Female black twig borers tunnel into woody twigs, leaving
pin-sized entry
holes. Once inside they excavate galleries and lay eggs. This
excavation, along with the introduction of pathogens, is the
cause of
damage to the host. Damage is not caused by feeding, since
the beetle larvae feed on ambrosia
fungus introduced by the female. Infestation by one to three
females is sufficient to kill the twig or branch. Infestation
becomes apparent when die-back of twigs and branches occurs. A
severe infestation can kill host plants, including large trees
(Nelson & Davis, 1972; Hara & Sewake, 1990). The black-twig bore has become a serious pest of coffee in the Kona-area.
BIOLOGY
The black twig borer belongs to the tribe Xyleborini, all of
which feed on ambrosia fungus and are called ambrosia beetles.
The black twig borer is somewhat unique in that it attacks living
plants rather than dead or dying ones. There is some evidence
that stressed plants are more susceptible to infestation (Hara & Beardsley, 1979). The life cycle of the black twig borer is
completed in about a month. Males spend their entire lives inside
the brood gallery. Females mate inside the brood gallery and then
leave to produce new galleries. Females can reproduce without
mating, in which case the offspring are all males
Eggs
Eggs
are laid in galleries in the twigs. The tiny eggs (less than 1 mm
long) are smooth, white ovals laid over a period of several
weeks. They hatch three to five days after being laid (Hara &
Beardsley, 1979).
Larvae
Larvae
are grubs, white and legless. There are two larval instars.
Larvae feed on ambrosia fungus in the gallery and pupate after
about 7 days (Hara & Beardsley, 1979).
Pupae
The pupae are initially white, changing to light brown with
black wings (female) near maturity. This process takes at least 6
days (Hara & Beardsley, 1979).
Adults
Female
adults, initially light brown, turn shiny black in 3 to 4
days; females are 1.6-1.8 mm long (about 1/16 in).
Males are about half as long and incapable of flight. After
emerging from the pupal stage they turn from light brown to
reddish brown in 3 to 4 days. (Hara & Beardsley, 1979).
BEHAVIOR
Black twig borers spend the majority of their lives inside the
host plant. The exception is the adult female, which leaves the
gallery by way of the parentŐs entrance hole and establishes a
new gallery elsewhere.
Cultural control
Pruning and destruction of beetle-infested plant material is
essential. Good tree care to promote tree vigor and health will
help in resisting infestation or recovering from infestation.
Physical control
Mass-trapping of adult beetles is an option currently (2006) being investigated, using various types of traps and attractants.
Biological control--Parasitoids
Literature on natural enemies indicates the black twig borer
is parasitized by at least one species of eulophid wasps of the
genus Tetrastichus (Davis, 1963). Nine species of this genus, all
accidentally or purposely introduced, are in Hawaii; whether any
are parasitizing black twig borer is not recorded (Nishida,
1992). Three braconid wasps were imported by the Hawaii
Department of Agriculture in the 1960Ős but did not become
established (Heu, unpublished data).
Biological control--Predators
Biological control of black twig borer is being looked into, to determine if there are any predators present in Hawaii.
Chemical Control
Chlorpyrifos provided 83% mortality of all stages of the black
twig borer infesting flowering dogwood in Florida (Mangold et
al., 1977). Hata & Hara (1989) reported 100% mortality of
adult females with chlorpyrifos. Marsden in 1972 recommended
malathion (not to be applied to blooming orchids). Consult the
University of Hawaii Cooperative Extension Service for up to date
recommendations. Note that these recommendations are not for coffee.
There no listing for malathion and chlorpyrifos is not labelled as of April 2007.
Davis, C. J. 1963. Notes and Exhibitions. Proc Hawaiian Entomol Soc. 23 (2): 197.
Davis, C. J. 1969. Notes and Exhibitions. Proc Hawaiian Entomol Soc. 20 (2): 262.
Dixon, W. N. & R. E. Woodruff. 1982. The black twig borer, Xylosandrus compactus (Eichhoff) (Coleoptera: Scolytidae). Florida Dept. Agric. & Consumer Serv. Division of Plant Industry. Entomology Circular No. 250.
Hara, A. H. & J. W. Beardsley, Jr. 1979. The biology of the black twig borer, Xylosandrus (Eichhoff), in Hawaii. Pro. Hawaiian Entomol Soc. 18 (1): compactus 55-70.
Marsden, D. A. 1979. Control of the black twig borer. Hawaii Cooperative Extension Service, Farm and Home Insect Pests, Entomology Note # 5. University of Hawaii at Manoa: Honolulu.
Mangold, J. R., R. C. Wilkinson, & D. E. Short. 1977. Chlorpyrifos sprays for control of Xylosandrus compactus in flowering dogwood. J Econ. Ent. Soc. 70: 789-790.
Nelson, R. E. & C. J. Davis. 1972. Black twig borer, a tree killer in Hawaii. USDA Forest Service Research Note PSW 274. U. S. Dept of Ag.: Berkeley, CA.
Nishida, G. M., ed. 1992. Hawaiian Arthropod Checklist. Bishop Museum Press: Honolulu.
DEC/1994. Last updated 3 July 2006, MGW