Consider seed treatment choice
Overlooking seed treatment as just part-and-parcel of the seed bundle could mean missing out on valuable protection at the most vulnerable time of crop development. Farm Business investigates why it could pay to ask questions about the specific properties of the treatment, or treatment combination.
There is no doubt that treating seed delivers commercial benefit, with HGCA data demonstrating how common seed borne diseases, such as Bunt and Fusarium seedling blights in wheat can be effectively controlled from the outset.
“It is clearly beneficial,” says Certis’ account manager Morley Benson. “Evidence from trials, designed to analyse the efficacy of various products on Fusarium seedling blight in winter wheat, demonstrates that plant emergence in treated seeds was over twice that of untreated.”
He adds that with at least a three to four month gap between sowing and the first spring fungicide foliar spray, the choice of seed treatment can be vital.
“This is particularly significant when early sowing and mild conditions increase pest and disease pressures, or when the soil and weather limit spray opportunities.
“Unpredictable weather is something that has seriously interfered with the timing and effectiveness of many autumn and spring spray programmes in recent years; the fact that seed treatment application is independent of difficult weather conditions is a key selling point for these products.”
However, he points out that a ‘one size fits all’ Single Purpose Dressing (SPD) may not provide adequate protection in all situations. “When purchasing something like a seed treatment, which is almost routine, it’s often the case that loyalty to one brand or formulation takes precedence over fully analysing the broader market.
“But, where factors like rotation, soil type and geography raise the risk of pest attack, such as wheat bulb fly, it’s worth finding out if the treatment employed provides the necessary protection.
“This is where it’s important to ask questions of the seed merchant or treatment firm,” he advises.
Wheat bulb fly is most prevalent in eastern England, the East Midlands and north-eastern regions, favouring rotations after potatoes or sugar beet in particular. But, economic damage is only evident where egg populations are above 250 eggs/m2 in autumn-drilled wheat crops, although HGCA advice is that egg numbers above 100 eggs/m2 justify the use of seed treatment on the latest-drilled crops of wheat or barley.
Morley advises that an SPD may be combined with an additional insecticidal seed treatment such as Signal (cypermethrin), a treatment that Certis have recently taken over from Chemtura. This delivers added protection against hatching wheat bulb fly larvae in the early part of the following calendar year.
Beware emergence risk
Seed treatment choice is also important to ensure it doesn’t hinder the emerging seed from getting off to a good start. “It’s worth considering that there are certain active ingredients that have been known to delay emergence, which can be a particular issue in later drilled crops where conditions are far from ideal for establishment.”
In addition to Signal, Certis have also taken on the marketing of seed treatments Anchor (carboxin and thiram), Rancona iMix (ipconazole and imazalil) and Rancona 15ME (ipconazole); all of which do not hinder emergence. In fact, trials have revealed that Anchor exhibits a ‘growth promotion effect’, which aids emergence and establishment in a range of conditions, including late and early drilled crops or dry seed beds, with no detriment to the seedling.
Morley Benson adds that there are innovations within the seed treatment sector, with products including Rancona i-Mix being derived from a next generation, micro-emulsion formulation. As well as offering robust, broad spectrum control in the ground, the solution itself mixes very well with other products and binds well with the seed.
“This binding factor is a key advantage” says Morley. “Users can clearly identify products that have strong adhesion to the seed because there is minimal dust residue in the bag. This is obviously preferable from a handling point of view – however it is also the case that there is less risk of the treatment leaching into the soil and thus potentially reducing efficacy.”
He adds that growers have made a very deliberate choice when choosing which varieties they want to grow and this can also dictate their seed treatment options. “Rancona i-Mix contains ipconazole and imazalil and in addition to a range of seed-borne diseases, it offers leaf-stripe protection which is particularly valuable for winter barley seed; this formulation also has enhanced fusarium control.”
He describes how some milling wheat varieties are very prone to fusarium and growers will often apply a foliar fungicide to the ear at the back end of the season. “In these instances, seed treated with Anchor or Rancona i-Mix could provide additional early insurance as part of a more planned and programmed approach.”
"As a result, it is essential that growers work closely with their agronomists to identify individual variety needs and the most suitable treatments for their specific circumstances," says Morley. "Doing this as early as possible is key in order to secure the most appropriate seed package ahead of their target drilling window."
Choice of active ingredient and consideration of the wider foliar fungicide programme are also important. “Using Rancona i-mix as a seed treatment which contains ipconazole makes sense as it is not used as a foliar treatment unlike many other active ingredients.”
When considering disease prevention and control, Morley encourages growers to think of an integrated approach and to consider the crop's protection right through to the mature crop, rather than just the seed. "A seed treatment is an investment and not just an extra cost," he affirms. “It also provides risk management so growers don’t have to be too quick off the mark with the first foliar spray.”