Managing winter oilseed crops in the North this autumn

Yields of winter oilseed rape in Scotland this year appeared to be higher than in England and one contributing factor to this success could be due to the inclusion of the fungicide and growth regulator, Sunorg Pro (metconazole) into the management programme, according to Derek Robertson of Agrovista, South West Scotland.

"Winter oilseed rape has the potential to produce high yields in Scotland providing the crop is established well and receives the correct inputs throughout the autumn and into the spring. In the West of Scotland every year is a challenge to get the crop in, as it is either too wet or too dry. This year however winter rape has established well and so needs to be looked after in order to fulfil its potential," says Derek.

Derek recommended Sunorg Pro for the first time last year and found it worked very well, both as a growth regulator and as a fungicide. "Treated crops had better root development and deeper rooting which gave the crop much better anchorage – something that is essential up here in the North. Treated crops also had a much richer green colour and a more even plant stand."

"The autumn treated crops also stood less proud and had less excessive vegetative growth. A crop that has a better rooting system and sits closer to the ground can withstand the more extreme weather conditions in the winter. We are also often subjected to gales at and around harvest and so it is important to keep the canopy closer to the ground to avoid losses through pod shatter. The process of growth manipulation needs to start in the autumn and continue in the spring."

Sunorg Pro was applied at 0.3 l/ha to winter oilseed crops in November around the 6 leaf stage. It was mixed with 3 kg/ha of MultiTrace B which contains a number of trace elements including boron, 0.25 l/ha of flusilazole, together with 0.5 l/ha of Transcend. "Transcend is specifically designed to enhance triazole fungicide performance by improving plant coverage and increasing fungicide uptake. In the spring the same mixture was applied around the beginning of April," explains Mr. Robertson.

"Last year late drilling and poor weather conditions led to some crops being treated later than the ideal timing, at around 8 leaves. The two-spray programme of Sunorg Pro resulted in the production of a nice tight mat of racemes in the canopy which were able to make the most of the light and also be harvested efficiently. Yields of around 5 t/ha were not uncommon."

"But Sunorg Pro is not just a growth regulator : its disease control is also excellent. Our crops suffer from Light Leaf Spot, White leaf Spot and Phoma. We never seemed to see much Phoma here in the past, but now it is common. Metconazole appears to control these diseases well. We need a fungicide that offers effective growth regulation and disease control at the same time."

"I have every intention of recommending Sunorg Pro again this year. The only circumstances that would prevent me from using a highly active growth regulator fungicide are when the crop is slow to develop or if it was particularly uneven. Most crops are around 3-4 leaves at the moment and reasonably even, so I will be looking to treat them when they get to 6-8 leaves which will be

sometime in November," says Derek.

Using Sunorg Pro (also available as Caramba) in the autumn is fundamental to setting up and protecting yield and it is just as valid in Scotland as it is in the rest of the UK, according to Dick Dyason, Agronomy Manager in Scotland for BASF. "According to experts, 70% of the oilseed rape yield potential is determined in the autumn as this is when the rooting and branching is determined. The growth regulatory effects of Sunorg Pro have been well documented and researched and are due to changes in plant hormone levels. In Scotland the timing for growth regulation and Phoma control is generally earlier than that for Light Leaf Spot. This year many crops are very forward and so the Sunorg Pro window is rapidly approaching."

"Sunorg Pro has been proven to improve rooting which results in better anchorage, improved nutrient utilisation and less lodging. It has also been shown to improve axillary bud formation which will result in a more even crop: this will mean a more even canopy, even flowering and even ripening. In the cold and windy North there is a definite need to strengthen the crop by increasing its root length, diameter and mass and to slow down the production of leaves," says Dick.

"Sunorg Pro also shortens the main stem which improves hardiness and reduces the risk of direct Phoma infection. It also protects the growing point from the weather," explains Dick.

"When it comes to disease control, Sunorg Pro offers good control of Phoma and additional cover of Light Leaf Spot. In the North of Scotland where Light Leaf Spot is the major disease, growers should be looking at a two-spray programme starting with Sunorg Pro for regulation and Phoma control, followed by a second spray of a non-PGR product from mid-November onwards specifically for Light Leaf Spot. It is the benefit of effective growth regulation combined with additional disease control that makes Sunorg Pro a key input in oilseed rape and an essential one to maximise yields," concludes Mr. Dyason.