Cropside: Comparing ‘set-up’ residual herbicides for glyphosate tolerant corn

AGRONOMIC INFORMATION FROM ONTARIO'S CROP SPECIALISTS

Mike Cowbrough, Weed Specialist, Ontario Ministry of Agriculture and Food and Ministry of Rural Affairs

With François Tardif, Clarence Swanton, and Peter Sikkema

ON AVERAGE THERE is a 4% yield advantage to incorporating a pre-emergent residual herbicide in glyphosate tolerant corn. The yield benefits are much higher when the in-crop glyphosate application has been delayed due to unavoidable circumstances. There is also the benefit of having additional herbicide modes of action that, provided they control the weeds in your field, will delay the selection of herbicide resistant weed populations. It is therefore important to know what weeds are controlled by the “set up” herbicide to be used. This past season, a number of set-up treatments were compared. The summary of weed control data is provided below.

Rates for each of the above treatments can be found on page 153 and 154 in the Guide to Weed Control, OMAFRA Publication 75.

TABLE 1: AVERAGE AND RANGE OF VISUAL CONTROL OF WEEDS WITH SEVERAL RESIDUAL ‘SET-UP’ TREATMENTS IN GLYPHOSATE TOLERANT CORN.

 

Velvetleaf Ragweed Pigweed Lambsquarter Smartweed Foxtail
Marksman 73
(51-94)
82
(71-96)
99
(98-100)
94
(79-100)
99
(98-100)
57
(48-71)
Integrity 86
(79-92)
75
(75)
100
(100)
81
(64-100)
88
(76-100)
97
(93-100)
Converge XT 90
(81-99)
91
(78-99)
98
(96-100)
88
(65-100)
83
(66-100)
93
(81-100)
Primextra II Magnum 52
(43-61)
71
(46-96)
98
(96-100)
81
(49-100)
83
(65-100)
83
(58-100)
Prowl + Marksman 79
(73-85)
77
(65-98)
100
(100)
98
(92-100)
98
(95-100)
94
(97-100)
Aatrex 57
(33-81)
73
(40-91)
100
(100)
98
(93-100)
83
(65-100)
71
(58-83)
Battalion 98
(96-100)
95
(91-98)
94
(89-99)
Primextra + Callisto 97
(95-98)
94
(88-98)
100
(100)
99
(96-100)
87
(79-100)
79
(58-100)
Primextra + Broadstrike Rc 92
(85-99)
84
(75-99)
100
(100)
98
(95-100)
82
(63-100)
100
(100)

This project was funded in part by the Grain Farmers of Ontario. The assitance of OMAFRA through the OMAFRA/University of Guelph Partnership is also acknowledged. •

About Mike Cowbrough 9 Articles
Weed Specialist, Ontario Ministry of Agriculture and Food and Ministry of Rural Affairs