Drying soils and longer days will hasten the resumption of crop protection programmes this spring. But growers have been urged to pay close attention to detail on product choice and timing in order to get the most out of every application, says Bayer CropScience, following trials with its flagship herbicide Atlantis WG.
“With workloads tight for many people, there is always the temptation is to try to do too many jobs at once,” says the company’s Ben Giles. “A multi-way tank-mix might appear to save time, but any mix containing several products runs the risk of achieving far less than the sum of its parts.”
With Atlantis WG (mesosulfuron + iodosulfuron) to control black-grass likely to be many growers’ first spray this spring, Bayer has conducted extensive research into the effect of tank-mixing. The safest mixtures are simple ones, with only one or two products.
For early spring Atlantis WG applications that could be a residual partner like Liberator (flufenacet + diflufenican) at 0.3 L/ha, or another herbicide to widen the broad-leaved weed spectrum. Mixes with other types of products, for pest or disease control, can lead to losses in efficacy and, in the worst cases, crop damage. Keep a close eye on the latest growth stage or date cut off for the herbicide mixture partners as many of these are early to mid-tillering of the crop.
“A loss of control between two and four per cent may seem quite small and possibly nothing to worry about. But with black-grass being a numbers game, just a few per cent can make the difference between staying in control and a growing black-grass population,” Mr Giles points out. “The thing to keep in mind is how many seeds those extra plants will produce.”
For example, with a two per cent drop in control, growers could be faced with an extra four plants remaining from a typical population of 200 plants/m2. Each of those plants could shed up to 6,000 seeds, which means there’s the potential for an extra 24,000 seeds to be returned to the field.
“In fields where black-grass is difficult to control, every per cent counts,” Mr Giles emphasises. “Multi product tank-mixes can lose some of the control you’ve paid for when you selected Atlantis WG.
“So when workloads are high, it’s a good idea to prioritise the worst fields and not to overcomplicate the tank-mix for applications of post-emergence herbicide.”
Mr Giles says in less problematic fields, there may be scope to add additional products into the tank without compromising the overall black-grass control programme.
“If you to decide to mix products with Atlantis WG, check the Bayer tank-mix guide to see whether the products are compatible. We test a number of products and only list those mix partners that are safe for the crop and which lead to a minimal reduction in efficacy.
“Where weather allows, farmers should get their post-em on as soon as possible. This will leave a sufficient gap before returning with T0s,” says Mr Giles.
