One of the best things you can do for your forage brassica crops at this time of the year is also among the easiest and can have a positive influence on your final yield.
It doesn’t take long once you get into a routine, and it can make a huge difference to how well those swedes, kale, forage rape or turnips perform and ultimately the amount of grazing available to maximise your homegrown feed.
What is this one thing? Checking for weeds and pests as carefully and often as you can.
Regardless of species, young brassicas are very vulnerable to competition from weeds, and predation by a range of insect pests.
Nufarm Territory Manager Mike Cox knows all the ways dry matter yield can be suppressed in the first weeks of brassica establishment, and he’s a big advocate for getting in early, before little problems become big ones.
“If you don’t find anything of concern when you’re checking crops, that’s great. All you’ve done is used a bit of time being proactive. If you do find something, however, you can jump in and deal with it straight away. The big issue with early yield losses in brassicas is they can happen very quickly, and they are permanent.”
Mike says best practice crop care often starts even before brassica seedlings germinate, with post-plant, pre-emergence herbicide. Director® CS (360g/L clomazone, Group 13) kills the main yield-limiting grass and broadleaf weeds in forage brassicas before crops can be adversely affected by weed competition. Once new seedlings are up and growing, the focus shifts to maintaining weed-free status with a robust programme of post emergence surveillance and (if needed) control.
“This is time and money well spent but your window of opportunity is not a long one – after weeds reach a certain size and/or the crop canopy starts to close, herbicides become less effective,” says Mike.
Aim to spray weed seedlings at the correct stage, which is 2-8 true leaves. The crop will typically have 2-4 true leaves at this stage.
Prestige® (150 g/L picloram and 225 g/L clopyralid, Group 4) can be used at this stage in all forage brassicas to control several broadleaf weeds, but is particularly useful against black nightshade and fathen. Prestige® can be tank mixed with SeQuence® (240 g/L clethodim, Group 1) if grass weeds are also present, or SeQuence® can be used on its own. Tank mixing with Bonza® Gold adjuvant improves the performance of both, Mike says.
Insect pests can wreak havoc with brassica seedlings, to the point where he recommends monitoring crops every one or two days in the first few weeks after emergence.
“As the crop matures, weekly checks are usually enough, but whenever you see signs of damage, act fast or risk losing tonnes of dry matter.”
Attack® (475 g/L Pirimiphos-methyl and 25 g/L permethrin, Group 1 and 3) is a broad spectrum insecticide that provides excellent control of springtails, Argentine stem weevil, aphids, leaf miner, Nysius and diamond back moth and white butterfly caterpillars. Alternatively Kaiso® 50WG (50 g/kg lambda-cyhalothrin, Group 3) can be used to control diamond back moth and white butterfly caterpillars.
For insecticide applications later in the season, when the crop canopy is dense, Flume® non-penetrating super spreader will improve spray coverage on forage brassicas, which have waxy leaves that are hard to wet.
Talk to your local Farm Source team or TSR for more tips on growing your best brassicas ever this season.