A new maize herbicide hits the market this year. Principal Forte was launched in the UK last year and is now available in Ireland. It contains dicamba, nicosulfuron, rimsulfuron and a safener. The product comes in a 5ha pack at a rate of 480g/ha.

So far, Principal Forte was trialled on 20 different varieties and has been used to treat approximately 9,000ha in the UK and 300,000ha in Europe with no issues.

A wide spectrum of broad-leaved weeds are on the label, including fat hen, groundsel, cleavers and many more.

Blackgrass

If blackgrass is a problem on the farm, then this may be a good option. Blackgrass and annual meadow grass, as well as bromes, oilseed rape and voluntary cereals are all listed on the label.

Application

Advice from Corteva is to apply from two to nine leaves unfolded (BBCH 12-19), between 1 May and 3 July. It should be applied with at least 200l/ha of water. A 5m buffer zone is required from water sources.

It should be applied with an ionic surfactant or an oilseed adjuvant. Speaking at a briefing on the product recently, Hugh Guinan of Corteva (the producer) said there have been no issues with application in trials or in tank mixing. No crop damage was reported, even when the product was applied late. Growers should check the label to make sure tank mixes are safe.

Following crops

Winter cereals can be planted following use of the product on a maize crop. It is recommended to plough first. If there are 90 days between application and planting, the need to plough can be removed, according to Corteva.

Ryegrass can be planted after the maize crop without any issues. Other crops can be planted in spring.

If a cover crop is being planted after the maize crop, then 80 days need to be left, although this is unlikely in Ireland, given the late harvest date of maize.