Phyllotreta pusilla

Horn, 1889

Western Black Flea Beetle

Phyllotreta pusilla, commonly known as the western black flea beetle, is a flea beetle in the Chrysomelidae. It is distributed across Central America and North America, with documented presence in regions including Alberta, Canada and Colorado, USA. The species is recognized as an agricultural pest of canola and mustard crops, where it causes plant injury through feeding damage. Research has identified significant variation in plant susceptibility among different canola and mustard varieties.

Chaetocnema aridula (09) by Die Käfer des Deutschen Reiches. (1908). Used under a Public domain license.

Pronunciation

How to pronounce Phyllotreta pusilla: //ˌfɪloʊˈtriːtə ˈpjʊsɪlə//

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

Images

Habitat

Agricultural fields and surrounding areas, particularly those cultivated with Brassica crops. Documented in greenhouse and field conditions in Colorado, USA. Fields and field borders that have been kept clean of weeds during the previous season are less subject to damage.

Distribution

Central America and North America. Documented presence in Alberta, Canada; Colorado, USA; and broader regions of Middle America and North America per GBIF records.

Diet

Feeds on canola (Brassica napus) and mustard (Brassica juncea) plants. Specific cultivar preferences have been documented: spring mustard (ZEM1), winter mustard (Debut), and spring canola (CO1) showed significant attraction and susceptibility; spring canola (Helios) demonstrated with high injury but low ; spring mustard (W1-23) showed reduced susceptibility.

Host Associations

Brassica napus - primary canola, multiple varieties
Brassica juncea - primary mustard, multiple varieties

Behavior

Jumps readily when approached or disturbed. In fall, may infest field borders and gradually move across fields, feeding on and killing plants as they advance. Feeding activity results in skeletonized leaves that give injured plants a bleached appearance before wilting and death.

Ecological Role

Agricultural pest causing plant injury and potential yield losses in canola and mustard crops. role beyond agricultural contexts has not been documented.

Human Relevance

Recognized pest of canola and mustard production. Subject of research on and strategies. Neonicotinoid have been evaluated for control, though research suggests reduced treatment rates may maintain efficacy while lowering environmental load.

Similar Taxa

Phyllotreta cruciferaeSimilar appearance, , and range; both are black flea beetles feeding on Brassica crops and can co-occur in agricultural settings
Other Phyllotreta species-level shared characteristics including flea beetle and jumping ; -level differentiation requires detailed examination

More Details

Host Plant Resistance Research

Studies in Colorado (2000-2002) evaluated relative plant preferences among various canola and mustard varieties, identifying significant differences in susceptibility that may inform breeding programs for cultivars.

Pesticide Efficacy Context

Research on neonicotinoid for Phyllotreta spp. control found that reducing treated seed proportion by one-third maintained efficacy under low-to-medium feeding pressure, suggesting potential for reduced application rates.