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UC Pest Management Guidelines


Potato flea beetle adult.

Cole Crops

Flea Beetles

Scientific Names:
Palestriped flea beetle: Systena blanda
Striped flea beetle: Phyllotreta striolata
Western black flea beetle: Phyllotreta pusilla
Western striped flea beetle: Phyllotreta ramosa

(Reviewed 6/07, updated 9/09)

In this Guideline:


DESCRIPTION OF THE PESTS

Flea beetle adults are small (about 0.125 inch or 1 mm long), shiny, hard beetles with enlarged hind legs that allow them to jump like fleas. Different species vary in color and markings. Adults do most of the damage; flea beetle larvae may mine leaves or feed on roots, but this activity is not of economic concern.

DAMAGE

Flea beetles feed on the undersides of leaves, creating small pits or irregularly shaped holes. Large populations can kill or stunt seedlings. Older plants rarely suffer economic damage although their older, lower leaves may be damaged.

MANAGEMENT

Flea beetles occasionally infest cole crop seedlings. They are most common in spring but can occur any time, especially in fields that are weedy or surrounded by weeds. Remove weeds along field margins and deeply disk plant residue in infested fields after harvest. Regular monitoring of seedlings for these pests will help detect problems and treatment needs.

Organically Acceptable Methods
Cultural control is acceptable in an organically certified crop. Insecticidal soaps applied at cotyledon stage may provide partial control.

Monitoring and Treatment Decisions
Check newly emerged seedlings twice weekly for flea beetle damage until plants are well established. Relatively low populations can cause economic damage when plants are in the cotyledon or first-leaf stages. Treat if you find several damaged rows; spot treatment of outside rows or borders may be sufficient. Baits are not effective.

If populations are high, treat infested fields just before thinning to prevent post-thinning damage. Once plants have 5 leaves they can tolerate several beetles per plant without damage. Older plants are even more tolerant. One insecticide treatment should be all that is required.

Common name Amount/Acre R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
When choosing a pesticide, consider information relating to natural enemies and honey bees as well as the environmental impact. Not all registered pesticides are listed. Always read label of product being used.
 
A. CARBARYL*
  (Sevin) 4F or XLR 1–2 pt 12 3
  (Sevin) 80S 0.67–1.25 lb 12 3
  MODE OF ACTION GROUP NUMBER1: 1A
  COMMENTS: For broccoli, Brussels sprouts, cabbage, cauliflower.
 
B. CHLORPYRIFOS*
  (Lorsban Advanced) 2 pt 24 21
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Foliar application for Brussels sprouts. Avoid drift and tailwater runoff into surface waters.
  . . . or . . .
  (Lorsban Advanced) See label see comments see comments
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Soil application. Check label for rates, which vary according to crop and row spacing. REI is 24 hours, except for cauliflower, which is 3 days. PHI for cauliflower is 30 days, and 21 days for broccoli, Brussel sprouts, and cabbage.
 
C. DIAZINON*
  (Diazinon) 50W 0.5–1 lb 4 days 0
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Avoid drift and tailwater runoff into surface waters.
 
D. ESFENVALERATE*
  (Asana XL) 2.4–5.8 fl oz 12 3
  MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: For broccoli, cabbage, and cauliflower.
 
E. INSECTICIDAL SOAP#
  (M-Pede) Label rates 12 0
  MODE OF ACTION: A contact fungicide with smothering and barrier effects.
  COMMENTS: For broccoli, Brussels sprouts, cabbage, cauliflower. Provides partial control of flea beetles when plants are in the cotyledon stage.
 
F. CRYOLITE
  (Cryolite) 96W 8–16 lb 12 7
  MODE OF ACTION GROUP NUMBER1: 9A
  COMMENTS: For use on broccoli, Brussels sprouts, and cauliflower. Must be ingested by the insect. Apply when early insects are present. Can be used in an insecticide resistance management program.
 
+ Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
# Acceptable for use on organically grown produce.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cole Crops
UC ANR Publication 3442
Insects and Mites
E. T. Natwick, UC Cooperative Extension, Imperial County
Acknowledgments for contributions to Insects and Mites:
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
W. E. Chaney, UC Cooperative Extension, Monterey County
N. C. Toscano, Entomology, UC Riverside

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