Phyllotreta striolata

(Fabricius, 1803)

Striped Flea Beetle, Turnip Flea Beetle

Phyllotreta striolata is a small (1.5–2.5 mm) in the , to Eurasia and now distributed worldwide. It is a major pest of Brassicaceae , causing substantial yield losses through feeding on aboveground parts and larval feeding on roots. The exhibits strong positive with peak sensitivity to wavelengths (350–430 nm). It has been recorded from diverse including open prairie, forest, and agricultural systems across North America, Europe, and Asia.

Phyllotreta striolata P1290538a by
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Phyllotreta striolata P1210443a by
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Phyllotreta striolata P1210435a by
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Pronunciation

How to pronounce Phyllotreta striolata: /ˌfɪloʊˈtriːtə ˌstraɪəˈleɪtə/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from by the wavy (not straight) amber longitudinal stripes on the . is similar but typically has straighter elytral stripes. The combination of small size, jumping hind legs, and striped elytra separates it from non- . In North America, it overlaps with P. cruciferae in distribution and ; microscopic examination of or elytral punctation patterns may be required for definitive identification.

Images

Habitat

Agricultural fields, especially Brassicaceae systems; open prairie with cruciferous weeds; forest clearings and edges; parkland regions. inhabit aboveground parts. , , and develop in soil. Laboratory colonies maintained successfully on horseradish, Napa cabbage, canola, and Chinese flowering cabbage.

Distribution

to Eurasia; now . Europe (widespread including UK, Scandinavia, Mediterranean); Asia (China, Japan, Korea, India, Southeast Asia, Russia Far East); North America (Canada: Alberta, British Columbia, Manitoba, Ontario, Quebec, Saskatchewan; USA: California to eastern seaboard, Texas, Wisconsin); recorded from Africa. In India: Tamil Nadu, Karnataka, Odisha, Madhya Pradesh, Uttar Pradesh (recent invasion in south India). In China: severe pest in Guangdong Province and southern regions.

Seasonality

emerge from sites in spring. In temperate regions, peak activity occurs during seedling stages (late spring–early summer). Multiple possible in warmer climates; laboratory rearing achieves continuous generations without . In Canada, follows typical cycle with overwintering adults. In Indonesia (Bogor), adult longevity averages 119 days with preoviposition period of 3 days.

Diet

on Brassicaceae. feed on tender shoots, stems, leaves, flowers, , and fruits. feed on roots in soil, penetrating root cortex. Preferred include Brassica oleracea (cabbage), B. napus (rapeseed/canola), B. campestris/rapa (turnip, Chinese flowering cabbage), B. juncea, B. nigra, Raphanus sativus (radish), Sinapis arvensis and S. alba. Adults attracted to but do not necessarily feed on all hosts; laboratory feeding shows preference hierarchy within Brassica.

Host Associations

Brassica oleracea - Preferred ; cabbage
Brassica napus - Canola/rapeseed; major
Brassica rapa - Turnip, Chinese flowering cabbage
Raphanus sativus - Radish; severe root damage reported
Sinapis arvensis - Wild mustard; less preferred
Armoracia rusticana - Horseradish; supports laboratory colonies
Brassica campestris - Field mustard

Life Cycle

with distinct aboveground () and belowground () stages. laid in soil near plants; incubation at 26°C requires several days. through three : first two instars adopt C-shape, feed on roots; third instar emerges, ceases feeding, crawls to site. Pupation occurs in soil. Adult follows; adults feed on aboveground tissues. Laboratory development: 25–33 days from egg to adult; adult longevity 17–55 days (laboratory) to 119 days (field). Multiple annually in favorable climates.

Behavior

Strong positive with action spectrum peaking at 350–430 nm ( light); sensitivity shifts diurnally with reduced short-wavelength response in afternoon/evening. jump when disturbed using enlarged hind legs. Congregates on leaf surfaces to feed. Parasitized adults emerge earlier from sites than unparasitized individuals. Adults attracted to plants through olfactory and visual cues; feeding discrimination does not always match attraction responses.

Ecological Role

Major of Brassicaceae in agricultural and natural systems. Feeding wounds on roots and foliage facilitate entry of including bacterial soft rot and black rot. Serves as for Microctonus vittatae (), which manipulates host timing. can substantially reduce yields. Genetic studies show high and low population structure across southern China, suggesting effective .

Human Relevance

Significant agricultural pest of cruciferous vegetables and oilseed worldwide. Listed as II important pest by Guangdong Province (2021). Yield losses from direct feeding and secondary . Subject to extensive use, with documented to multiple chemistries including pyridaben; P450 genes CYP6TH1/CYP6TH2 implicated in metabolic . Target for research using ( bassiana, spp., Cordyceps javanica). Neonicotinoid have been used for control, though efficacy and cost-effectiveness remain debated.

Similar Taxa

Phyllotreta cruciferaeOverlapping distribution and ; P. cruciferae typically has straighter elytral stripes versus wavy stripes in P. striolata; both major canola pests
Phyllotreta vittulaSimilar size and coloration; stripe pattern differs
Alticini tribe membersShared jumping leg ; elytral pattern distinguishes P. striolata

More Details

Genetic structure

Lack of genetic structure across southern China with high (FST < 0.05) suggests effective long-distance . 44 mitochondrial haplotypes identified with one haplotype widespread.

Laboratory rearing

Two established methods: (1) Napa cabbage and canola diet supporting full with 62–90% -to- survival; (2) canola-only diet for mass adult production with 6–9 fold increase per . Chinese flowering cabbage identified as optimal for due to minimal interference with fungal activity compared to radish, which contains sulforaphane with fungistatic effects.

Invasion history

Recent invasion documented in south India (Tamil Nadu, Karnataka) with severe root damage on radish (74–92.6% damage reported). Range expansion in North America includes prairie, forest, and parkland in Saskatchewan.