How to Manage Pests

UC Pest Management Guidelines

Cherry

Cribrate Weevil

Scientific Name: Otiorhynchus cribricollis

(Reviewed 11/09, updated 11/09)

In this Guideline:

Description of the Pest

Adults are dark brown compact weevils up to about 0.5 inch long with longitudinal striations. They are flightless and nocturnal, hiding at the base of fruit or under dirt clods during the day and crawling up the tree at night to feed. Larvae are white, legless grubs that feed on tree roots. Adult emergence often begins in May, and adults are present all summer. There is one generation per year.

Damage

Adults feed on foliage, notching out the edge of the leaves, giving them a ragged appearance. Under high population pressure, only the midvein of the leaf will remain. Adult feeding on the bark of young twigs may cause dieback. Mature trees can withstand attack without significant damage; however, feeding before harvest may damage fruit stems. Replanted trees may be severely defoliated and die. No damage has been associated with larval feeding.

Management

To reduce damage on young trees that are infested, apply a 3- to 4-inch band of sticky material on the trunk of young trees to trap crawling adults in May when the first adult feeding is observed. Apply Stickem or Tanglefoot over a special tape or painted areas of the trunk of young trees to prevent bark damage. Reapply the sticky material when it becomes dirty or loses its effectiveness. Alternatively, some growers have had success with an insecticide treatment applied at night when the insects are exposed, but research has not been done to verify this.

Common name		Amount to use**		R.E.I.‡	P.H.I.‡
(trade name)		(conc.)	(dilute)
				(hours)	(days)
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, the pesticide's properties, and application timing. Not all registered pesticides are listed. Always read the label of the product being listed.
A.	CARBARYL*
	(Sevin) 4F	3-4 qt	0.75-1 qt	12	1
	MODE-OF-ACTION GROUP NUMBER1: 1A
	COMMENTS: Apply at night when insects are active and exposed may provide control; research data is lacking.
**	For concentrate applications, use the amount given in 80-100 gal water/acre, or lower if the label allows; for dilute applications, amount is per 100 gal water to be applied in 300-400 gal water/acre, according to label.
‡	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: Cherry
UC ANR Publication 3440

Insects and Mites

• J. A. Grant, UC Cooperative Extension, San Joaquin County
• J. L. Caprile, UC Cooperative Extension, Contra Costa County
• W. W. Coates, UC Cooperative Extension, San Benito County
• R. A. Van Steenwyk, Insect Biology, UC Berkeley
• K. M. Daane, Kearney Agricultural Center, Parlier

Acknowledgment for contributions to Insects and Mites:

• J. Colyn, Mid-Valley Ag. Services
• M. Devencenzi, Devencenzi Ag. Pest Mgmt. and Research
• P. McKenzie, Mid-Valley Ag. Services

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