Keep Reseeds Clean this Spring to Restore Silage Stocks

Silage stocks are running low on many farms this spring, after last year’s awkward grass growing season meant less conserved forage was made.

This means farmers are looking for ways to make as much silage as possible this year – starting with a large first cut.

Some autumn-sown leys are now filling up with germinating weeds

Some autumn-sown leys are now filling up with germinating weeds

“There was a large amount of reseeding of poor performing grass fields last autumn,” explains Dr Nicola Perry, weed biology specialist for Corteva Agriscience (formerly Dow AgroSciences).

“Now is a good time to check whether a herbicide spray is needed to clean these fields up. Getting rid of annual weeds such as chickweed or seedling perennial weeds such as docks and thistles, is vital to ensure the investment in reseeding realises its full potential.”

Perennial weed control
Recent Teagasc trials in Ireland held from 2010 to 2015, have shown that long-term control of docks can be achieved best by applying a suitable herbicide onto small docks shortly after reseeding. This will give almost complete control of the docks. Even those that do emerge in following years, rarely establish due to strong competition from the established grass.

Leystar, a new selective herbicide from Corteva Agriscience has three effective active ingredients, fluroxypyr, clopyralid and florasulam, which combine to control a wide spectrum of annual weeds, such as fat hen, red shank and mayweeds, as well as seedling docks and thistles.

Leystar can be applied from 1 February to 31 August in new sown leys in 200 litres of water, so can be used on autumn-drilled and spring-sown grass reseeds. It has good grass safety, but will kill clover or any broad-leaved weeds that have not germinated when the herbicide is sprayed.

Best results
“For best results apply to weeds that are small and actively growing, and when the grass has reached the three-leaf stage,” says Dr Perry.

“Allow an interval of four weeks after application before cutting grass to optimise the effect of the herbicide. Do not roll the grass for ten days before or seven days after application. If the fields are to be grazed, animals can return just seven days after application.”

Farmers must be certified to use professional use herbicides on their fields. Those that do not hold the appropriate certification need to book a qualified contractor to come and spray their new leys.


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