Despite the loss of several key herbicides in recent years, leek growers can still achieve effective weed control by using a combination of the remaining active ingredients, with the addition of aclonifen to tank mixes ensuring the full spectrum of annual broad-leaved weeds are accounted for.
That is according to ProCam agronomist, John McCulloch, who explains that effective weed control in leeks comes down to three factors: applying safe doses of multiple active ingredients, leaving a suitable interval between repeat applications and ensuring plants have developed a surface layer of wax prior to being treated.
Emerger (600 g/L aclonifen) is predominantly known as a pre-emergence herbicide for the control of annual broad-leaved weeds in potatoes, but its EAMU means it can also be used as a treatment in a range of vegetable crops. John is however keen to point out that, as with any product licensed under an EAMU, the use of Emerger on leeks is at the grower’s risk.
Applying too much of the active ingredient too early in the crop’s development can be to the detriment of the crop as well as weeds, John explains, “but by following a few simple rules, there’s no reason why aclonifen can’t be used successfully and safely in leeks.”
John’s first recommendation is to use aclonifen at a low initial rate: “Applying Emerger in combination with Lentagran WP (45% pyridate) and a nutrient growth promotor such as Hadron will provide effective control of a very broad spectrum of weeds including key targets such as fat-hen, bindweed, redshank and pale persicaria,” he explains.
John’s third recommendation is to make multiple herbicide applications at suitable intervals: