At this point in the season you may be considering applying nitrogen to your cereal crop to boost yield potential or spraying fungicides, particularly with recent reports of stripe rust outbreaks in the mallee, mid North and Yorke Peninsula. When making these decisions however, it’s important to have a good understanding of plant growth stages when applying fungicide sprays or nitrogen.

The Zadoks growth stage scale is the most commonly used method of determining plant growth stages in cereals. It is a decimal code with ten distinct phases of plant development, with each phase segregated into ten separate stages. Quite often there is uncertainty in determining some stages, especially between stem elongation and up to the end of ear (head) emergence. Growth and development of cereals changes considerably during this period, and depending on conditions, the changes can occur quite rapidly.

Some growth stages occur simultaneously, although Zadoks scale focuses on the major developmental phases. For example, the flag leaf (final leaf) emerges during the major developmental phases of stem elongation and booting, and although not a developmental stage in itself, knowing when the flag leaf has fully emerged is critical for management decisions. The following table shows a section of Zadoks growth stages, from stem elongation to the end of flowering. There are a number of publications available that outline the whole Zadoks growth stage scale.

*Number of weeks after sowing depends on earliness of district, sowing time and variety sown

AUTHOR:  Charlton Jeisman, Sustainable Ag Systems Consultant, Rural Solutions SA

CONTACT: Charlton Jeisman, Rural Solutions SA Jamestown, Telephone, 08  8664 1408, Mobile, 0401 122 098 Email, jeisman.charlton@saugov.sa.gov.au