When planning your potato crop there are many things which should be considered, with arguably the most important component being the seed potato.
The contracting and purchase of good quality certified seed – that is both cosmetically sound and of the correct physiological age - is one of the most important decisions that a grower will make. It is very valuable for commercial growers and seed growers to have open discussions throughout the season, ensuring that each party understands “what they want the seed to do” in the commercial phase.
It is important to consider what the physiological, as well as the physical, age of your potato seed is when choosing potato seed. There are many factors that can affect the physiological age of your seed tubers, including growing season stress, storage temperature and time. Temperature is very important because warmer storage temperatures will speed the ageing process of the tubers.
One of the things to look for when you receive seed potatoes are excessively sprouted tubers; these may lead to performance problems and any broken sprouts could produce excessive and weaker stems. You should also look for mechanical damage to the seed as bruising or damage is an indication of rough handling during harvest and transport, which can cause physiological ageing and increased levels of disease.
Inspecting seed for disease symptoms and general condition, as soon as you receive it from the seed supplier is also important. Some disease symptoms can be easily treated using fungicides applied to the seed piece (e.g. MAXIM®) or fungicides applied in furrow (e.g. AMISTAR®), but the presence of others, above certification standards, could be grounds to reject the seed.
You then need to decide whether you are going to plant whole seed or cut seed. Properly cut seed pieces feed correctly in the planter and provide uniform plant stands. Mechanical cutters can handle large volumes of seed and cut tubers into two or more pieces. Alternatively, hand cutting minimises the number of blind pieces, but is slower and more labour intensive. Remember, the size of a potato seed piece can have an impact on early plant vigour and larger seed pieces usually emerge faster than smaller ones.
Disinfect all equipment before each seed cutting session and between seed lots and keep the seed cutter blades sharp and straight to prevent ripping the potato surface (any damage from the cutting process provides an ideal area for disease).
When you are ready to plant, you then need to consider what fungicide treatment to use to minimise disease. Whether seed treatments are directly applied to the seed piece or as an ‘in-furrow’ application, it will be one of the most important decisions to be made by growers for the early management of their commercial potato crop.
Because disease pressure differs from one growing region to another, both seed and commercial growers should carefully select the seed and/or in-furrow treatment that best meets their needs.
A variety of fungicides are available to growers that provide effective control of multiple diseases. Fungicides can be applied either to seed pieces prior to planting, at planting, or as in-furrow treatments, and you should speak to your agronomist about the best options for your operation.