How to Manage Pests

UC Pest Management Guidelines

Carrot

Palestriped Flea Beetle

Scientific Name: Systena blanda

(Reviewed 1/09, updated 1/09)

In this Guideline:


DESCRIPTION OF THE PEST

Flea beetle adults are small (about 0.12 inch long), shiny beetles with enlarged hind legs that allow them to jump like fleas. The palestriped flea beetle has a broad white stripe down each brown wing.

DAMAGE

Adult flea beetles do most of the damage by feeding on the undersides of leaves, leaving small pits or irregularly shaped holes on the leaves. Large populations can kill or stunt seedlings. Older plants rarely suffer economic damage although their older leaves may be damaged. In the Imperial Valley, larvae feeding on roots have caused serious damage on occasion. This damage is easily confused with cavity spot symptoms.

MANAGEMENT

Cultural Control

Remove weeds along field margins and deeply disk plant residue in infested fields after harvest.

Organically Acceptable Methods

Cultural controls are acceptable for use on organically grown produce.

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.

Once plants have several true leaves, they can tolerate several beetles per plant without damage. Older plants are even more tolerant. Insecticide treatment should rarely be required, but if it is, one application should suffice. However, chemical treatment may disrupt biological control of aphids and whiteflies.

Common name Amount per acre** R.E.I.‡ P.H.I.‡
(example trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
 
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
 
A. ESFENVALERATE*
  (Asana XL) 5.8–9.6 fl oz 12 7
  MODE-OF-ACTION GROUP NUMBER1: 3
  COMMENTS: Lower rate should suffice. Do not exceed 0.5 lb a.i./acre per season.
 
B. CARBARYL*
  (Sevin 4F, XLR Plus) 1–2 pt 12 7
  (Sevin 80S) 0.66–1.25 lb 12 7
  MODE-OF-ACTION GROUP NUMBER1: 1A
 
C. DIAZINON*
  (Diazinon 50W) 0.5–1 lb 24 14
  (Diazinon AG600WBC) 0.5–1 pt 72 0
  MODE-OF-ACTION GROUP NUMBER1: 1B
  COMMENTS: Avoid drift and tailwater runoff into surface waters.
 
** See label for dilution rates.
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.
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 Groupgroup numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.
* Permit required from county agricultural commissioner for purchase or use.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Carrot
UC ANR Publication 3438

Insects

  • E. T. Natwick, UC Cooperative Extension, Imperial County
  • D. R. Haviland, UC IPM Program, Kern County
  • C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
Acknowledgment for contributions to Insects:
  • W. E. Chaney, UC Cooperative Extension, Monterey County

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