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How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About 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 6/07)

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)
When choosing a pesticide, consider information relating to the impact on natural enemies and honey bees and environmental impact.
 
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) 4E* 2 pt 24 see comments
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Preharvest interval for cauliflower is 3 days, cabbage and broccoli 30 days, and Brussels sprouts 21 days. Avoid drift and tailwater runoff into surface waters.
  ...or...
  (Lorsban) 50W 2 lb 24 21
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: For broccoli, Brussels sprouts, cabbage, cauliflower. Avoid drift and tailwater runoff into surface waters.
 
C. DIAZINON*
  (Diazinon) 50W 0.5–1 lb 24 see comments
  (Diazinon) AG 500 0.5–1 pt 24  
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Avoid drift and tailwater runoff into surface waters. Preharvest interval is 7 days for broccoli, Brussels sprouts and cauliflower and 21 days for cabbage. See label for other cole crops.
 
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, brussel 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
W. E. Chaney, UC Cooperative Extension, Monterey Co.
E. T. Natwick, UC Cooperative Extension, Imperial Co.
Acknowledgments for contributions to the insects section:
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
N. C. Toscano, Entomology, UC Riverside

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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