Agriculture: Spinach Pest Management Guidelines

Herbicide Treatment Table

Herbicide Amount per acre REI‡ PHI‡
(Example trade name)   (hours) (days)
Not all registered pesticides are listed. The following are listed alphabetically. When choosing a pesticide, consider information relating to environmental impact, resistance management, the pesticide’s properties, and application timing. Tank mixes may be necessary to achieve desired control; see Susceptibility of Weeds to Herbicide Control for information on specific weed control. Always read label of product being used.
 
PREPLANT FUMIGANT
 
A. METAM SODIUM* 213–319.5 lb a.i.    
  (Vapam, Sectagon 42) 50–75 gal 48 NA
  COMMENTS: Used on 80-inch wide beds with densely planted stands of spinach where cultivation is not possible.
  . . . or . . .
  METAM POTASSIUM*
  (K-Pam HL) 30–60 gal 48 NA
  COMMENTS: Used on 80-inch wide beds with densely planted stands of spinach where cultivation is not possible.
 
PREPLANT FOLIAR
 
A. GLYPHOSATE 0.5–1 lb a.i.(Roundup)
0.375–0.94 lb a.i. (Touchdown)
   
  (Roundup) 0.5–1 qt See label NA
  (Touchdown) 0.5–1.25 qt 12 NA
  WSSA MODE OF ACTION GROUP NUMBER1: 9
  COMMENTS Apply to emerged annual weeds before sowing crop or before it emerges. Observe label restrictions for application.
 
B. PELARGONIC ACID
  (Scythe) 4–13 oz/1 gal spray solution 12 NA
  WSSA MODE OF ACTION GROUP NUMBER1: 27
  COMMENTS Apply to emerged annual weeds before sowing crop or before it emerges. Apply in a minimum spray volume of 75 gal/acre, or spray-to-wet. Do not apply by air. Observe label restrictions for application.
 
PREPLANT INCORPORATED (Before weeds emerge)
 
A. CYCLOATE 3–4 lb a.i.    
  (Ro-Neet 6E) 0.5–0.66 gal 12 NA
  WSSA MODE OF ACTION GROUP NUMBER1: 8
  COMMENTS: Apply to weed-free soil surface. Incorporate mechanically to a depth of 2 inches. Production of this product was suspended in 2008; availability limited to stocks on hand.
 
AFTER PLANTING (Before irrigation and crop emergence)
 
A. CYCLOATE 3–4 lb a.i.    
  (Ro-Neet 6E) 0.5–0.66 gal 12 NA
  WSSA MODE OF ACTION GROUP NUMBER1: 8
  COMMENTS: Apply to weed-free soil surface. Incorporate with sprinklers to a depth of 2 inches. Production of this product was suspended in 2008; availability limited to stocks on hand.
 
B. S-METOLACHLOR 0.28575–0.47625 lb a.i.    
  (Dual Magnum) 0.3–0.5 pt 24 50
  WSSA MODE OF ACTION GROUP NUMBER1: 15
  COMMENTS: Apply to weed-free soil surface. Incorporate with sprinkler irrigation to a depth of 2 inches. Has a 12-month plantback restriction for lettuce. The 50-day PHI is difficult to achieve on clipped spinach grown during summer, which can mature in as few as 28 days.
 
AFTER CROP EMERGES
 
A. PHENMEDIPHAM 0.4875–0.975 lb a.i. (single application)
0.4–0.4875 lb a.i. (split application)
   
  (Spin-Aid) 3–6 pt (single application)
2.5–3 pt (split application)
12 21
  WSSA MODE OF ACTION GROUP NUMBER1: 5
  COMMENTS: Apply the 0.975 lb a.i. rate only on well-established crops (4–6 true leaves) that are not under stress. Split applications may be made when spinach is at the 2-leaf stage followed by a second application 4 to 6 days later. Use only on spinach grown for processing or seed. Use only when temperatures are below 75° F.
 
B. SETHOXYDIM 0.1875–0.28125 lb a.i.    
  (Poast) 1–1.5 pt 12 15
  WSSA MODE OF ACTION GROUP NUMBER1: 1
  COMMENTS: Apply with a crop oil concentrate to actively growing grasses. Does not control annual bluegrass.
 
C. CLETHODIM 0.0985–0.12125 lb a.i.    
  (Select Max) 13–16 fl oz 24 14
  WSSA MODE OF ACTION GROUP NUMBER1: 1
  COMMENTS: Controls annual bluegrass in the 2- to 3-leaf stage as well as other annual and some perennial grasses. Do not apply through any type of irrigation system. Always apply with a crop oil concentrate. Use higher rate on perennial grasses.
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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 Group numbers are assigned by the Weed Science Society of America (WSSA) according to different modes of action. Although weeds may exhibit multiple resistance across many groups, mode of action numbers are useful in planning mixtures or rotations of herbicides with different modes of action.
NA Not applicable.
Text Updated: 12/09
Treatment Table Updated: 12/09