Onion handout only2006

Weed Control in Onion: 

Weed Control in Onion Bernard Zandstra MSU

Review of 2006: 

Review of 2006 1. Early season was dry; preemergence herbicides were not very effective 2. In general, postemergence herbicides were effective and good weed control was maintained to harvest Most fields that were harvested before rains came in September were free of weeds at harvest

New Labels in 2006: 

New Labels in 2006 1. Outlook had Section 3 (Federal) label 2. Chateau had Section 3 label 3. Prowl H2O and GoalTender available and widely used

Onion Weed Control Research Priorities in 2006 : 

Onion Weed Control Research Priorities in 2006 1. Develop methods for use of Chateau on onion 2. Compare Prowl H2O and GoalTender to Prowl and Goal

Prowl H2O: 

Prowl H2O 1. Prowl H2O 3.8 ACS or CS (aqueous capsule suspension) 2. Water-based flowable 3. Label includes all crops on Prowl 3.3 label 4. Less yellow color, staining, and odor

Prowl 3.3 EC: 

Prowl 3.3 EC 1. Petroleum solvent-based formulation 2. Strong odor; stains everything 3. There are several generic pendimethalins 4. Solvents and adjuvants in the formulation may increase activity of other herbicides in tank mix

How to use Prowl 3.3 EC and Prowl H20: 

How to use Prowl 3.3 EC and Prowl H20 1. Use Prowl 3.3 EC or generic pendimethalin PRE 2.4 qt/a 2. Use Prowl EC POST alone, or with GoalTender Use Prowl H2O POST (2 qt/a) in tank mixes with GoalTender, Chateau, and/or a grass herbicide (Fusilade, Poast, Select Max)

GoalTender 4SC : 

GoalTender 4SC 1. Flowable-type, water-based formulation (suspension concentrate) 4 lb/gal 2. Very thick; less odor than Goal 2XL 3. Use half as much volume as Goal 2XL Little improvement over Goal 2 XL in crop safety, but use in tank mixes to avoid crop phytotoxicity

Goal 2XL: 

Goal 2XL 1. Petroleum-based formulation; strong odor 2. Causes spotting and curling of onion leaves 3. It may reduce onion yields slightly if applied in tank mixes 4. Under warm, dry conditions, it is safe POST on onions at 0.031–0.063 lb/a (2-4 fl. oz) There is generic oxyfluorfen

How to use Goal 2XL and GoalTender: 

How to use Goal 2XL and GoalTender 1. Never use oxyfluorfen before onions emerge 2. GoalTender is safer on small onions (< 3 leaves) 3. Use GoalTender in tank mixes with preemergence herbicides (Chateau, Outlook, Prowl) 4. Use GoalTender when higher rates (0.125 lb ai/acre) are needed to control larger weeds 5. Use Goal 2XL alone at low rates (0.031-0.063 lb; 2-4 fl oz) on onions with 3 or more leaves 6. Use GoalTender in tank mixes with a grass herbicide plus an adjuvant

Dual Magnum on Onion: 

Dual Magnum on Onion New Michigan 24c (SLN) label for Dual Magnum; growers must agree to indemnify Syngenta for liability; www.farmassist.com; print label after agreement; membership in MVC no longer required for use 2. Rate is 0.67-1.3 pt/acre (0.53-1.2 lb ai) Use at 2 leaf stage or later; Max. of 2 applications/year For control of yellow nutsedge, eastern balck nightshade, pigweeds, and annual grass

Outlook on Onion: 

Outlook on Onion 1. Section 3 Supplemental label for USA 2. Max. rate of 21 fl. oz/a (0.98 lb ai) 3. 1 app. after 2 leaf stage up to 30 day PHI 4. Tank mixes with Goal 2XL may injure onions 5. Most effective at 2 leaf stage to suppress YENS 6. Controls annual grasses and broadleaves

Chateau on Onion: 

Chateau on Onion 1. Section 3 Supplemental label for USA 2. Apply between onion 3-6 leaf stage; 45 day PHI 3. Use 1 oz product (0.032 lb ai)/a; 3 oz max/season Do not tank mix with Prowl EC, Outlook, Dual Magnum, Goal XL, Poast, Fusilade, Select, adjuvants 5. Chateau has PRE and POST activity on pigweeds, nightshades, COLQ, smartweeds, chickweed, PRSP, and wild mustards

Nortron on Onion: 

Nortron on Onion 1. Label pending for 2007 2. 1 pt (0.5 lb ai)/acre POST 3. Max. 4 applications/year; 30 day PHI 4. Controls chickweed, nightshade, and pigweed 5. Suppresses yellow nutsedge 6. Use for specific weed problems

An Onion Weed Control Plan for 2007 (1): 

An Onion Weed Control Plan for 2007 (1) 1. April 1-15: Plant onion and barley (0.75 bu/acre) 2. May 1-10: (just before onion emergence): Apply Prowl EC 2.4 qt + Buctril 4EC 0.3 pt 3. May 20-30: Kill barley at 4-6 inches with Fusilade, Poast, or Select + COC 4. June 1-6 at 2 leaf stage: Apply Prowl H2O 1.9 qt + GoalTender 1-2 fl. oz; or Outlook 21 fl. oz. (alone) if nutsedge is a problem

An Onion Weed Control Plan for 2007 (2): 

An Onion Weed Control Plan for 2007 (2) 5. June 15-20 at 3 leaf stage: Apply Chateau 1-2 oz to control nightshade, mustard, chickweed, groundsel, pigweeds, and lambsquarters 6. July 1-5: Apply Prowl H2O 1.9 qt or Dual Magnum 1.3 pt + GoalTender 2 fl. oz + grass herbicide 7. July 15-20: Apply Prowl H2O 1.9 qt or Dual Magnum 1.3 pt + GoalTender 1-2 fl oz. 8. July 10-20: Apply Chateau 1 oz.

An Experimental Weed Control Plan for Small Area – No Nutsedge: 

An Experimental Weed Control Plan for Small Area – No Nutsedge 1. At onion 2 leaf stage, apply Prowl H2O 1.9 qt + GoalTender 1 fl. oz. + Chateau 1 oz 2. Repeat the same application 4 weeks later, ± July 1 3. July 15-20: Repeat the application (45 day PHI) 4. Add Poast or Fusilade to another mix for grass control no adjuvant; do not apply with Chateau

An Experimental Plan – With Nutsedge Present: 

An Experimental Plan – With Nutsedge Present 1. At 2 leaf stage (± June 1-5) apply Outlook 21 fl. oz. alone 2. 2 weeks later, apply GoalTender 2 fl. oz. + Chateau 1 oz. 3. July 1-10: Apply Dual Magnum 1.3 pt 4. July 15-20: Apply Prowl H2O 1.9 qt + GoalTender 1-2 fl. oz. + Chateau 1 oz. 5. Apply grass herbicides in tank mixes without an adjuvant; do not apply with Chateau

New Labels for Green Onion: 

New Labels for Green Onion 1. Dual Magnum – apply at 2 leaf stage 2. Prowl H2O – label pending for 2007 3. Outlook – label pending for 2007

Onion Weed Control Summary: 

Onion Weed Control Summary 1. Maximum onion yield is a function of good weed control and lack of crop injury 2. A few weeds can cause yield reduction 3. Onions can overcome early season stunting, but injury in mid-season often causes yield reduction 4. Select onion herbicides based on the weed and crop situation for each application

Acknowledgement: 

Acknowledgement Onion research supported by: Michigan Onion Research Committee (The Growers) MSU (Project GREEEN, MAES, MSUE) BASF Syngenta Valent IR-4