Eucalyptus Tortoise Beetle
( Trachymela sloanei )


2010-0704-01080149-COL00242-Trachymela_sloanei[1312h37s,F,A,tree-leaf]{EXD}-G.jpg

PHOTO COMMENT

IDENTIFICATION
Identification:Trachymela sloanei
(Blackburn ,1896 )
Common Name:Eucalyptus Tortoise Beetle
Life Stage:(A) adult

PHYLOGENY

Phylum:Arthropoda
Class:Insecta
Superorder:Holometabola
Order:Coleoptera
Suborder:Polyphaga
Family:Chrysomelidae
Subfamily:Chrysomelinae
Tribe:Chrysomelini
Genus:Trachymela
Taxon Code:COL00242
ITIS/TSN:720041

LOCATION DETAILS
Location Name
Sycamore Grove/Veteran's Park, Sycamore Grove/Veteran's Park, 5211 Arroyo Road, Livermore
County:Alameda County
ECI Site#:CA01080149

RECOGNITION
Description
Feeding by adult beetles is a signal the beetle is present. Leaves on eucalyptus trees have irregular notches. Adult: Dark brown with blackish mottling, resembling a large lady beetle. Larva: Light to dark green (similar to the foliage of the host) to reddish brown with a black head and pronotum. Larvae true color is sometimes obscured by plant matter that covers its exterior. Larvae resemble caterpillars, but like most members of the family, they have 6 visible legs and no prolegs on the abdomen.
Body Length
6-9 mm.
Similar Taxa
The Eucalyptus Leaf Beetle (Chrysophtharta m-fuscum) is similar in biology, form and size. It is more lightly colored (gray to reddish brown) than T. sloanei and does not possess its mottled coloring. It was discovered in Orange County in 2003 and has spread to at least four nearby counties.

BIOLOGY
Female Trachymela sloanei lay 5 to 40 or more eggs side by side on leaves or under loose bark. The eggs are pinkish or light brown at first and become orange or dark brown to purplish as they age. Larvae superficially resemble caterpillars but can be distinguished by their appendages. Leaf beetles have three pairs of true jointed legs with no prolegs on the abdomen. Trachymela sloanei larvae are dark green to reddish brown with a black head and prothoracic shield (black area on the top and sides of the first segment behind the head). Larva color resembles the host foliage. There are four immature stages before pupation beneath loose bark, or soil or litter at the base of the host tree. In warm weather, development from egg to adult may be as short as 5 weeks. There are several generations per year from late winter through fall. Trachymela sloanei larvae and adults hide under loose bark during the day and feed primarily at night.
Host
Eucalyptus
Importance
The beetles can eat away most of the leaf surface, leaving only the midvein, and they occasionally feed on new terminal growth. Heavy infestations can cause a tree to lose most of its leaves. Feeding by this insect, alone, is not enough to kill trees. However, feeding, combined with other stressors, such as drought, can lead to tree death. T. sloanei is one of more than a dozen new eucalyptus pests introduced into California during the last 30 years. Adult beetles and larvae chew semicircular holes or irregular notches along the edges of eucalyptus leaves.
Distribution
America, north of Mexico: California; found in Riverside County (1998) and now occurs throughout most areas of California where eucalyptus grows. Introducted from Australia.
Importance
The beetles can eat away most of the leaf surface, leaving only the midvein, and they occasionally feed on new terminal growth. Heavy infestations can cause a tree to lose most of its leaves. Feeding by this insect, alone, is not enough to kill trees. However, feeding, combined with other stressors, such as drought, can lead to tree death. T. sloanei is one of more than a dozen new eucalyptus pests introduced into California during the last 30 years. Adult beetles and larvae chew semicircular holes or irregular notches along the edges of eucalyptus leaves.
Development
Females lay 5-40+ eggs side by side on leaves or under loose bark. Eggs are pinkish or light brown, turning orange, dark brown or purplish as they age. There are four instars. Pupation occurs beneath loose bark or in soil or litter at the base of the host tree. Time to maturation may be as short as 5 weeks, in warm weather. There are several generations per year from late winter through fall. Feeding stages hide under loose bark during the day and feed primarily at night.
Introduced_from
Introducted from Australia. First record in North America is in California (1998)

CREDITS
Photographer
Eddie Dunbar
Insect Sciences Museum of California

References
Species Trachymela sloanei - Australian Tortoise Beetle. (bugguide.net/node/view/13061). Accessed January 2, 2017. .
ITIS.
Pest Notes: Eucalyptus Tortoise Beetle. UC ANR Publication 74104. Produced by UC Statewide IPM Program, University of California, Davis, CA 95616 . Acknowledgements Staff-only pages Subscribe (RSS) Contact UC IPM. Agriculture and Natural Resources, University of California. © 2014 Regents of the University of California Division of Agriculture and Natural Resources Nondiscrimination Statement. April 25, 2014.


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