Date: 01 July 2018

A recent report out of the University of Illinois agricultural economy section indicates a significant number of US farmers will be operating at or below break-even costs – despite a strong stock market and high prices for soybean and corn. This, of course, has farmers looking at ways to trim costs off of their operating budgets by bringing back overheads. One area of intense interest is seed treatment as a cost cutting measure for the often expensive exercise of disease mitigation and loss of yield.

Seed treatment describes both products and processes. Using specific products and specific techniques can improve the growth environment for the seed, seedling and young plant. Seed dressing – where the seed is dressed with either a dry formulation or wet treated with a slurry or liquid formulation of the seed treatment chemicals - is the most common method of seed treatment. Seed treatment comprises priming, coating, pelleting, phytosanitary treatment and microbial inoculation. These seed treatment techniques continue to evolve.

Across the seed industry interest is increasing and sees regular collaborations to take advantage of innovations in both biology and chemistry of new seed treatment technologies, for instance the use of biologicals and inoculants in seed treatment may well be the next revolution in agriculture. In areas where land swapping is common and growers don’t necessarily know the history of the plot often an inoculant is a good idea. Although not common yet in New Zealand, we expect this to become far more common in due course – especially as the process of fumigation becomes the norm and soils require reestablishment of a microbial population.

Several presentations at the recent International Spinach Conference were in and around the topic of seed health and focused, not only, on the testing of seed crops for fungal oospores of mildew and bacterium of Pseudomonas spp., but also the application of seed treatments to ensure these diseases were not carried on seed presented to growers. Seed treatment for seed borne diseases is a major issue facing the industry as production areas free of disease become few and far between, and seed companies expect post-harvest testing and treatments of seed crops to become the norm.

Likewise the lettuce industry, particularly in Europe, is in the midst of an issue with fusarium hitting crops. Fusarium wilt in the field is destroying vast production areas in England and mainland Europe and, given most lettuce seed that is sold is done so as an untreated pellet, pre-sowing treatment is difficult. While research is still under way as to the source of infection, in areas where the disease is already present in the soil, the only way forward may well be seed treatment.

One of the primary reasons and advantages for using seed treatment is adverse planting conditions. More often than not planting coincides with early, cold and often wet conditions making plant establishment slower; plants that are sitting in these conditions, growing slowly, are more susceptible to disease (or that infection is brought on by damage to the young plant from hail/heavy rain typical during these periods). Pythium spp. and Rhizoctonia spp. are two prime examples of this. The application of, especially systemic, fungicides can greatly improve the defences of the young seedling and prevent early mortality. Even with the advances in GPS technology and targeted spray application the ability to place pre-treated seed in to the ground is a far more cost effective and efficient way to protect a young crop.

So, as a grower you may ask: ‘Why isn’t all of my seed that I buy pre-treated for me to cover off all diseases?’ There are several reasons… Firstly, when seed is sent from the supplier the country of origin (or perhaps even prior to this – the country of production) may have very different regulations on which chemical may be applied to seed. New Zealand’s very own MPI may have different regulations as to which chemicals can be applied to imported seed. At the crop stage, often specific growing areas have different pests and diseases (or priorities thereof), in Ohakune for instance Rhizoctonia crocorum (Violet Root Rot) is a major issue for carrot production – and while it is an issue throughout the rest of the country severity is rarely as advanced as seen in the central North Island. In Pukekohe, white rot is the number one issue with early onion production due to humid conditions while later in the season, as heat increases insecticides tend to become more important.

Another issue is seed health. Putting chemical on seed can, in some cases, shorten shelf life – perhaps the most obvious example is the application of imidacloprid. While germination testing shows very little impact on short term impact on seed health we, at Seed Innovations, remind growers that storage of imidacloprid treated onion often exhibits a significant drop in germination if seed is held over from one season to the next and recommend a pre-sowing germination test in the case of stored seed.

Much investigation has been put into the return on investment that seed treatment can deliver. In the soybean industry in the US for instance, fusarium (which results in Sudden Death Syndrome – SDS) is present in nearly all US soybean growing areas. Its severity is dependent on weather. Fusarium seed treatments can provide both foliar and root protection from SDS which can cost growers up to 2-4 lost bushels per acre of yield. In addition, biological seed treatments have seen 2 bushel per acre yield increases due to similar root protection. The cost of some biological treatments equate to ½ a bushel but returning 2.

Again, in the soybean industry, 80% of growers utilise a fungicide on their seed and 55% use an insecticide. What the industry is seeing more and more of is seed companies matching a seed treatment with particular varieties as a package. In this case the package is matched to maximise the genetic potential of the variety. This is especially the case with hybrids where – for instance – a biological that promotes root growth may be ideal for a hybrid onion suited to dry climates but not so for a hybrid line grown in wet conditions where an extensive root system to source water is not a major requirement and in fact a fungicide is of a higher priority.

So as fresh ground becomes less available and disease and adverse weather conditions become the standard while we look to increase our yields and provide our workers with a Health and Safety compliant workplace – seed treatment becomes a more and more cost effective option for growers as a way to best invest in their business.

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