Phyllotreta cruciferae Goeze.
Taxonomic placing: Insecta, Homometabola, Coleoptera, Chrysomelidae.
Common name: Cabbage flea beetle.
Morphology: The body of the adult is shiny dark, with green-blue hues, about 3 mm long, the head, thorax and elytra densely punctate. The larva is apodous, about 5 mm in length, whitish, head and thorax dark.
Geographical distribution: North America, Europe, parts of Asia and Africa, CABI Pest map 434 (1982).
Host plants: Various Brassicaceae (Cruciferae).
Life history: Females place their eggs (about 50/female) on the ground and the emerging larvae enter the soil wherein they feed on cruciferous roots and pupate. The adults climb to the surface and feed, especially on the leaves of various Brassicaceae, but also on bean and beet foliage. These beetles are strong, nervous jumpers that leap when their habitats are disturbed. They are mostly active during warm days, being abundant throughout spring and summer, rare in autumn and winter.
Economic importance: The cabbage flea beetle is a serious pest of seedlings and young plants, especially cabbage and radish. In the USA it is a major pest of canola (Brassica napus L.). Its feeding on the host foliage results in small and large leaf “windows”, which reduce photosynthetic activity and causes retarded growth and reduced yields.
Management
Monitoring: Yellow sticky traps are used for monitoring population levels, especially in young plants. The presence of leaf “windows” in the foliage of susceptible crops indicates the pest’s presence. A threshold for pesticide applications, at 15–20% leaf area damage, was recommended in Montana, USA, in order to reduce damage.
Plant toleranceand resistance: Some Brassica species and cultivars are little affected by the beetle. Bigger seeds of canola and of mustard (Sinapis alba L.) enhance the resistance of their seedlings to P. cruceferae, and result in increased seedling survival.
Chemical control: Spinosad and a carbamate provided most consistent damage reductions. Seed treatments with a neonicotinoid also gave good control.
Biological control: Several predators, such as chrysopids and geocorids, feed on flea beetles, but their effect is unclear. Entomopathogenic fungi applied with pinene or a pyrethroid controlled the beetles. Entomopathogenic nematodes killed almost 75% of the beetles in laboratory experiments.
References
Andersen,C.L., Hazzard, R., Van Driesche, R. and Mangan, F.X. 2006. Alternative management tactics for control of Phyllotreta cruciferae and Phyllotreta striolata (Coleoptera: Chrysomelidae) on Brassica rapa in Massachusetts. Journal of Economic Entomology 99: 803-10.
Bodnaryk, R.P. and Lamb, R.J. 1991. Influence of seed size in canola, Brassica napus L. and mustard, Sinapis alba L., on seedling resistance against flea beetles, Phyllotreta cruciferae (Goeze). Canadian Journal of Plant Science 71: 397-404.
Brown, J., McCaffrey, J,P,, Brown, D.A., Harmon, B.L. and Davis, J.B. 2004. Yield reduction in Brassica napus, B. rapa, B. juncea, and Sinapis alba caused by flea beetle (Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae)) infestation in northern Idaho. Journal of Economic Entomology 97: 1642-1647.
Reddy, G.V., Tangtrakulwanich, K., Miller, J.H., Ophus, V.L. and Prewett, J. 2014. Sustainable management tactics for control of Phyllotreta cruciferae (Coleoptera: Chrysomelidae) on canola in Montana. Journal of Economic Entomology 107: 661-666.
Sabbour, M. M. and Abdel-Rahman, A. 2007. Evaluation of some terpenes and entomopathogenic fungi on three sugar beet insect pests. Egyptian Journal of Biological Pest Control 17: 125-130.
Tangtrakulwanich1, K., Reddy, G.V.P., Wu, S., Miller, J.H. Ophus, V.L. and Prewett, J. 2014. Developing nominal threshold levels for Phyllotreta cruciferae (Coleoptera: Chrysomelidae) damage on canola in Montana, USA. Crop Protection 66: 8–13.
Tansey, J.A., Dosdall, L.M., Keddie, B.A. and Sarfraz, R.M. 2008. Differences in Phyllotreta cruciferae and Phyllotreta striolata (Coleoptera: Chrysomelidae) responses to neonicotinoid seed treatments. Journal of Economic Entomology 101: 159-67.
Trdana, S., Vidriha, M., Valiča, N. and Laznika, Z. 2008. Impact of entomopathogenic nematodes on adults of Phyllotreta spp. (Coleoptera: Chrysomelidae) under laboratory conditions. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science 58: 169-175.
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