Sulfonylureas (SUs), such as Ally Max and Cameo Max, are all ALS herbicides and are the backbone for broadleaf weed control in spring cereals. However, hormone-based chemicals and others like Galaxy and Foundation, as well as HBNs such as Oxytril, are still needed with sulfonylureas to fill gaps in their weed control spectrum.
Some straight products such as Finy/Empire/Thor are available. But the majority of growers have switched to products with mixes of actives such as Ally Max SX and Harmony Max SX which are widely available from merchants (see Table 3, right). They can offer good value for money as they contain more active ingredients over older straight products like Ally or Cameo.
The mixing and increased concentration of these SU actives in one product brings increased control of a broader range of weeds than using an SU product on its own.
Many have become standard treatment for spring crops and offer better insurance for fields where you do not know the weed history. They tend to be more expensive and so many growers use them at reduced rates of 80pc. But rates can be reduced to less than 50pc if used in the correct circumstances.
All the SU products have different strengths and weaknesses in terms of the control of weeds.
Generally, SU should be mixed with a hormone-type product (CMPP-P, HBN, fluroxypyr or Foundation) or Galaxy to achieve full control of a wide variety of weeds and to prevent weed resistance.
Table 1 (top left) outlines some of the strengths of some of the available products.