Pest Profile

Photo credit: Whitney Cranshaw, Colorado State University, Bugwood.org (Left); Luke Tembrock, USDA APHIS PPQ ITP, Bugwood.org (Right)

Common Name: Western Striped Cucumber

Scientific Name: trivittatum

Order and Family: Coleoptera, Chrysomelidae

Size and Appearance:

Length (mm) Appearance Egg  Oval in shape  Yellow to orange in color  Laid at the base of host plants

Larva/Nymph  Off-white to yellow in color 8-13 mm  Brown head and legs

Adult  Bright yellow in color with 3 uniform black stripes across the back  Central stripe is divided on either side of the wing cover 8-9 mm  Wing covers are also covered in small indentations

Pupa (if applicable)  White to yellow in color 6 mm  Look like soft-bodied adults without wings  Pupate in the soil

Type of feeder (Chewing, sucking, etc.): Larvae and adults both have chewing mouthparts.

Host plant/s: Roots and fruits of cucurbits and leaves, stems, blossoms, and fruit of corn, potatoes, tomatoes, beans, and peach fruits.

Description of Damage (larvae and adults): Larvae only cause minor damage by chewing on the roots and sometimes even the rind of young cucumbers and melons.

Adults often feed on young, tender plants which can lead to stunting, scarring, malformation or even death of young seedlings. Their feeding also results in holes and chew marks in the leaves as well as leaving pits that reduce marketability of the crop. Adult may also cause indirect damage from vectoring plant pathogens such as cucumber mosaic virus, and Erwinia tracheiphila, the causal agent of of cucurbits.

References:

Alston, D. G., & Worwood, D. R. (2012). Utah pests fact sheet: Western striped , western spotted cucumber beetle (calymma trivittatum and undecipunctata undecipunctata) No. ENT-118-08PR). Logan, Utah: Utah State University Extension and Utah Plant Pest Diagnostic Laboratory.

Cranshaw, W. (2004). Garden of North America: The ultimate guide to backyard bugs Princeton University Press.

Natwick, E. T., et al. (2012). UC IPM pest management guidelines: Cucurbits. Retrieved January 24, 2016, from http://www.ipm.ucdavis.edu/PMG/r116300511.html