Words by Bill Cabout, Ruralco Chemical Manager
We will look at the following this month: Autumn sown Crops, Gibberellic Acid on pasture, and monitoring stored grain.
Autumn Sown Crops
Cereals: Most autumn sown crops have already been planted by now. Seed treatment only persists for a certain amount of time after planting until the start of tillering (GS21) Those crops drilled before mid-May will now not be protected from aphids. Aphids can carry the disease barley yellow dwarf virus (BYDV) which if your crop gets at this early stage will severely damage yield. It is a good idea to apply an approved insecticide even if numbers of aphids are low as this often proves to be good insurance. Whether a follow-up spray is required three weeks later will depend on aphid numbers. Weather conditions will play a key role, with cold and wet conditions typically resulting in lower aphid numbers. A good way to check up on aphid numbers is to look at the Lincoln Suction Trap data on the FAR website.
This year there are large numbers of grass grub about, and this can decimate a crop before you realise. Diazinon granules at drilling will provide up to 5 weeks’ protection from grass grub so this protection will also be wearing off. Check your crops and if grass grubs close to the soil surface are found your crop may need spraying to control these with liquid Diazinon. This is ideally put on during rain, so it washes into the soil where the grubs are.
Slugs have been an ongoing issue in some crops. Monitor your crops closely and if need be, apply more slug bait.
If you have some early weed strike not controlled by your pre-emergent spray, it is best to clean this up while the weeds are small. Which product to use is determined by what weeds are present. Talk to your Ruralco Representative for the best options.
For the control of Brome grass, we can use Rexade (Pyroxsulam + Arylex). This combination controls wild oats, rye grasses and brome grass as well as many significant broadleaf weeds such as fumitory, chickweed, cleavers, field pansy, speedwell, shepherds’ purse, white clover, and volunteer linseed. It is for wheat and triticale only and can be applied from GS13 to GS31. If you are applying to control brome it can be applied twice, otherwise apply once only. It is available in a 2kg pack, and the rate used is 100g/ha plus 250ml non-ionic surfactant /100lt water. Please check the withholding periods for planting following crops as it is up to 12 months currently on some crops. This year we have also have a generic Pyroxsulam (Merito) available which we can use instead of Rexade, at a rate of 500ml/ha.
This season we have a new pre-emergence herbicide for wheat and barley from Adama called Tower. It contains a new active ingredient for the New Zealand market called Chlortoluron, it also contains Pendimetalin and Difluenican. It controls a wide range of broadleaf weeds and selected grass weeds and is suitable for use in both autumn sown and spring sown crops. The rate used is 2.5lt/ha. Please contact your Ruralco Representative for further information.
Clover: After drilling Armada/Preside gives good control of certain weeds without concern about clover size. Propyzamide (Kerb) can be applied to white clover seed crops during the winter months from June to Aug for the control of grass weeds and some broadleaf weeds. Weeds not controlled by Propyzamide can be controlled by various products depending on weed spectrum during July and August. Contact your Ruralco Representative for options.
Ryegrass Seed Crops: With the good growing conditions this year an early post emergence spray is worth looking at to control any weeds that have appeared in the paddocks. What to use will depend on your weed spectrum. We can also start looking at applying wild oat sprays such as fenoxaprop over the next month or so. Contact your Ruralco Representative for options.
Pasture Gibberellic Acid
Late winter and early spring pasture growth can be increased through the use of gibberellic acid. For the best response, there must be adequate fertility and moisture available to support the additional growth. It is often applied alongside liquid nitrogen to help maximise the response.
Both granular and liquid formulations of gibberellic acid are available. For optimum results, apply 3–5 days after grazing and graze again 3–4 weeks after application to capture the maximum growth response.
Fodder beet
Sowing time for fodder beet is fast approaching. For a high yielding crop, good weed control is essential and if possible, the use of the stale seedbed technique before planting is a good idea. Poor plant numbers mean a reduction in yield so for good germination of fodder beet a well-prepared seedbed is essential. For further information on growing fodder beet please contact your Ruralco Seed Team.
Monitoring Stored Grain
Monitoring grain during storage is a valuable tool in maintaining quality. This becomes more important the longer the grain remains in storage because deterioration in seed quality early in storage is slower and insects are sparse and not easily noticed. Temperature and seed moisture content are important indicators of grain quality that influence insect and mould activity. Once grain is in storage, monitoring for insects and mould once a month will give early notice of any problems occurring and action can then be taken to control these problems.
With all the above scenarios talk to your Ruralco Representative for the best options for you and your situation.