How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

Adults are small, glossy black sawflies about 0.2 inch long. The newly hatched larvae are white with a yellowish brown head. Almost immediately after hatching, the larva exudes an olive green coating that covers its body and gives it the appearance of a slug. The head end is wider than the rest of the body and a fully mature larva is about 0.5 inch long. Cherry slugs overwinter as pupae in the soil. There are two generations a year with adults emerging in July to lay eggs of the next generation that overwinters.

DAMAGE

Cherry slugs are a pest of cherries in coastal areas. Larvae skeletonize leaves and may remove all tissue except for the fine network of veins. High populations may reduce fruit size.

MANAGEMENT

Inspect foliage in spring, and treat if high numbers are found.

Common name		Amount to Use**		R.E.I.+	P.H.I.+
(trade name)		(conc.)	(dilute)	(hours)	(days)
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and honey bees. When choosing a pesticide, also consider information relating to environmental impact. Not all registered pesticides are listed. Always read label of product being used.
A.	SPINOSAD
	(Entrust)#	1.25–2.5 oz	0.31–0.6 oz	4	7
	MODE OF ACTION GROUP NUMBER1: 5
B.	SPINETORAM
	(Delegate) WG	4.5 oz	1.125 oz	4	7
	MODE OF ACTION GROUP NUMBER1: 5
C.	DIAZINON* 50WP	3 lb	1 lb	4 days	21
	MODE OF ACTION GROUP NUMBER1: 1B
	COMMENTS: Avoid drift and tailwater runoff into surface waters. Where cherries are grown adjacent to waterways, do not use this material.
**	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.
#	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/.

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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