The best time to tackle dock infestations in silage crops is before first cut according to Andy Bailey, grassland agronomy specialist for Dow AgroSciences.
“There are three good reasons for spraying docks in grass in early to mid-April,” says Mr. Bailey.
“Firstly killing them now allows the grass time to spread into the gaps they leave which will maximise silage yields at first and subsequent cuts.
“Secondly it improves the quality of the silage. Docks only have 60% the feed value of grass so the fewer of these that make it into the clamp the better.
“Thirdly, when using modern translocated herbicides like DoxstarPro, leaving three to four weeks between treatment and harvest gives the active ingredients plenty of time to reach right down into the roots for thorough and long-lasting control.”
Mr. Bailey suggests farmers plan a potential spray date now by working back at least three weeks from the expected cutting date, and noting this in the diary or booking the contractor if spraying is out-sourced.
“Weed growth has been slow so far this spring due to the cold nights and dull days. But recent warm weather may spur them into action, especially in fields that have had fertiliser as they respond very well to nitrogen.”
DoxstarPro controls mature and seedling docks – both broad-leaved and curled. For best effect, weeds should be sprayed when they are actively growing and at rosette stage, 15 to 20cm across or high. The dose rate for one spring application is 2l/ha, applied in a water volume of 300l/ha; or 400l/ha if dock numbers are particularly high or the grass sward is dense.