How to Manage Pests

UC Pest Management Guidelines

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 has caused serious damage on occasion. This damage is easily confused with cavity spot symptoms.

MANAGEMENT

Manage for palestriped flea beetles by removing weeds along field margins and deeply discing plant residue in infested fields after harvest. Do not direct seed or transplant artichoke crops near alfalfa fields.

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 true leaf stages. Treat if you find several damaged plants in multiple rows; spot treatment of outside rows or borders may be sufficient. Baits are not effective.

No economic thresholds are available, but treatments, especially on young plants, should be considered if damage reaches a moderate level. Insecticide treatment should rarely be required, but if it is, one application should suffice. Once plants have several true leaves, they can tolerate several beetles per plant without damage. Older plants are even more tolerant. Chemical treatment may disrupt biological control of aphids and whiteflies.

Common name		Amount/Acre**	R.E.I.+	P.H.I.+
(trade name)			(hours)	(days)
When choosing a pesticide, consider information relating to impact on natural enemies and honey bees and to the environment.
A.	PERMETHRIN*
	(Ambush)	6.4–19.2 oz	12	0
	MODE OF ACTION GROUP NUMBER1: 3
	COMMENTS: Limited to 1.5 lb a.i./acre/season.
B.	ESFENVALERATE*
	(Asana XL)	5.8–9.6 fl oz	12	1
	MODE OF ACTION GROUP NUMBER1: 3
	COMMENTS: Apply no more than 0.15 lb a.i./acre between bud formation and harvest. Highly effective against adults and larvae. Mixing with methidathion (Supracide) enhances efficacy.
**	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.
*	Permit required from county agricultural commissioner for purchase or use.
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/.

PUBLICATION

UC IPM Pest Management Guidelines: Artichoke
UC ANR Publication 3434
Arthropods
M. A. Bari, Artichoke Research Foundation, Salinas
E. T. Natwick, UC Cooperative Extension, Imperial County
Acknowledgment for contributions to Arthropods:
W. E. Chaney, UC Cooperative Extension, Monterey County
W. L. Schrader, UC Cooperative Extension, San Diego County
L. Handel and T. K. Shannon, Kleen Globe, Inc., Castroville, CA

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