Fall Armyworm in NZ Maize: Four Years of Research
Four years since it was first detected in New Zealand, researchers and growers now know much more about management of maize pest fall armyworm (FAW).
In the 2014-15 growing season the national average trial programme yield was 23.77 tDM/ha, compared to 20.76 tDM/ha 10 years ago. In Waikato the 40 silage product advancement trials (PAT) had an average harvest of 25.38 tDM/ha with only one of these below 20 tDM/ha. In the lower North Island and Taranaki there were 42 PAT crops that averaged 23.07 tDM/ha with only five harvests below 20 tDM/ha.
In the last five years 279 silage plots have yielded more than 30 tDM/ha, 29 plots have yielded more than 35 tDM/ha and a handful have produced over 40 tDM/ha.
It is clear maize yields are high and increasing, so how can local farmers ensure they get the best from their maize silage crops this season?
Soil test and apply the appropriate nutrients. While applying too little nutrients can limit crop yields, applying too much fertiliser is costly and can lead to higher nutrient losses. Always take a 150mm soil test and ask your local fertiliser representative for an appropriate crop nutrient management plan.
Select the right hybrid. Hybrid genetics play a huge role in determining crop yields. Maize breeding is in part a numbers game. The more genetic combinations tested, the greater the odds of developing improved products faster. There are more than 50 Pioneer maize breeding centres around the world so the company's overall breeding effort is huge. Here in NZ we evaluate about 100 hybrids each year and this allows us to identify and commercialise new, higher yielding products.
When selecting a maize hybrid always ask for statistically significant yield information collected from multiple trials over several seasons. Never buy a bag of maize seed simply because it is cheap.
Plant at the recommended population. Modern maize hybrids are better able to produce a cob under moisture and density stress. When plant density optimums are exceeded, yields tend to level off rather than drop abruptly. Planting at the plant populations recommended in the Pioneer brand 'Maize for Silage' catalogue will allow you to achieve higher yields in favourable growing seasons while minimising yield risk in a dry year. It is important to plant at the population recommended for the hybrid and yield environment.
Control insects. While planting at a right population is critical, it is equally important that every seed you plant has the chance to grow into a high-yielding plant. Insects can be a problem especially when maize is planted in paddocks which have recently come out of pasture. This season AgResearch scientists are predicting a bumper black beetle population. The best way to protect your crop is to plant Poncho treated maize seed.
Eliminate weeds. Weeds compete with maize plants for sunlight, water and nutrients. They can harbour insects which attack maize plants and some weeds can reduce silage palatability and even create toxicity problems. In my experience weedy maize crops fare particularly badly in dry seasons. To achieve good weed control, spray out the paddock completely and use a pre-emergent spray to kill grass and broadleaf weeds. Inspect crops regularly post-emergence and apply additional weed-specific herbicides as required.
Your local merchant, contractor or Pioneer brand products representative can provide you with more tips on how to maximise maize silage yield and quality.
• Ian Williams is a Pioneer forage specialist. Contact This email address is being protected from spambots. You need JavaScript enabled to view it.
