2018 Crop Protection Guide for Tree Fruits in Washington

Chemical Weed Control

Friday, March 22, 2019

Temporary Weed Control on Stone Fruit

See General Recommendations for guidelines on table use. Read all product labels carefully.
Grass and broadleaf weeds



Except where noted, rates are amount per acre (active ingredient per acre) 
1.7-2.7 pt (0.64-1.0 lb AI)

24 h

28 d

Gramoxone Inteon
2.5-4 pt (0.63-1.0 lb AI)

24 h

28 d


3 pt (1.425 lb AI)
48 h

40 d


0.33-0.67 pt (0.125-0.25 lb AI)
12 h

30 d


1-4 fl oz (0.0013-0.0053 g AI)
12 h

0 d

glyphosate -- 1-3 qt (--)4 h17 d9  

Firestorm: WSSA Group 22: photosystem I electron diverter

See entry for Gramoxone Inteon. 28 day PHI applies to all stone fruit but peach; PHI for peach is 14 days.

Gramoxone Inteon: WSSA Group 22: photosystem I electron diverter

Foliage applied, contact herbicide used to control annual broadleaf and grass weeds and to suppress perennial weeds. Apply as a directed spray. May be used at any time, but most effective when weeds are no more than 4–6 inches tall and growing actively. Thorough spray coverage is required to ensure control. Keep off tree foliage, fruit, and green bark. Often tank-mixed with soil residual herbicides to control established weeds. Paraquat is corrosive to aluminum. This is a restricted-use herbicide. Use this product only if you carefully read and follow PPE directions on the lable. Use a full face shield, gloves and apron when filling and mixing. Do not ingest or inhale spray mist when spraying. 28 day PHI applies to all stone fruit but peach; PHI for peach is 14 days. Grazing of livestock is prohibited.

glyphosate: WSSA Group 9: EPSPS inhibitor

Glyphosate is a broad-spectrum, systemic herbicide. It is one of the most commonly applied herbicides and is sold under many trade names. Some of the products containing glyphosate are identical to the original product, others vary in their additives (such as wetting agents) and amount of active ingredient. The parent acid, the "active ingredient," is formulated with ammonium, potassium, or isopropylamine and varies in content per gallon from one product to another. The active ingredient is called "acid equivalent" in glyphosate products, and can range from 3 to 5 pounds per gallon, depending on the product. If you switch products, compare the acid equivalent of the two, and make rate adjustments, if necessary. Repeated use of glyphosate has led to the development of glyphosate resistance in many species common to perennial systems in the West Coast; rotate with other foliar-applied herbicides. Water quality and quantity can affect glyphosate performance; high pH, presence of cations, or dirty water can reduce efficacy. See label regarding adjuvant use. Grazing of livestock is prohibited.

Saber: WSSA Group 4: synthetic auxin

Multiple trade names: Saber, Orchard Master (not on apricots and nectarines), Weedar 64, Amine 4 and 2,4-D. Kills most annual and many perennial broadleaf weeds. Apply as directed spray to weeds. Avoid contact with foliage, limbs and trunk. Do not apply during windy periods. May be used at any time except during bloom but most effective when weeds are small and growing actively. Can be absorbed by tree roots and cause serious injury. Best results are obtained when applied within 2 days following an irrigation and the weeds are growing actively. In sprinkler-irrigated orchards, apply only after irrigation and never to dry or bare ground. Do not apply to trees established in orchard for less than 1 year. Do not make more than 2 applications per year. Do not harvest within 40 days of application. Grazing is prohibited.

Stinger : WSSA Group 4: synthetic auxin

Controls many difficult to control weeds in the sunflower, buckwheat (or knotweed), nightshade and legume families. Apply to actively growing weeds in a minimum of 10 gallons of water per acre. Apply to Canada thistle after a majority of basal leaves have emerged, but prior to bud stage. Up to two applications may be made during the crop year, but do not exceed a total of 2/3 pint of product per sprayed acre per year. Do not apply within 30 days of harvest.  

Venue: Group 14: protoporphyrinogen oxidase (PPO) inhibitor

A contact herbicide that is active on annual broadleaf weeds. Use as a directed spray when the weeds are less than 4 inches tall or 3 inches across. Thorough coverage is required for control. Apply during the dormant season and prior to bloom. Addition of a crop oil concentrate or non-ionic surfactant will enhance control. Keep off green stems and foliage; will burn off young green crown and root suckers. Use lower rates for small weeds and higher rate for larger weeds. Tank mixing can increase the weed spectrum that is controlled. 


Tree Fruit Research & Extension Center, 1100 N Western Ave, Washington State University, Wenatchee WA 98801, 509-663-8181, Contact Us