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Words by Bill Cabout, Ruralco Assistant Retail Manager

Autumn Sown Arable Crops:

Autumn Sown Cereal Crops

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-April will now not be protected from aphids. Aphids can carry the Barley Yellow Dwarf Virus (BYDV), if your crop gets BYDV at an early stage, this will severely damage the 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. Depending on what the aphid numbers do (Dependent on weather, cold and wet means less aphids) will determine if we need to follow up 3 weeks later with another spray. A good way to check up on aphid numbers is to check the Lincoln Suction Trap data on the FAR website www.far.org.nz.

Diazinon granules at drilling will provide up to 5 weeks’ protection from grass grub so this protection will also be wearing off. If you find grass grub is close to the soil surface, your crop may need spraying to control these with Dew 600. This is ideally put on during rain so it washes into the soil where the grubs are. If you have drilled with Suscon green you should be covered for the life of the crop.

Slugs have been an ongoing issue in crops throughout the autumn. 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 ideal to clean this up while the weeds are small. Talk to your Ruralco Account Manager for the best weed control options.

For the control of brome grass, we can use Rexade, it has the same active ingredients as Simplicity (Pyroxsulam) plus the addition of 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 can be applied from GS13 to GS31. If applying to control brome it can be applied twice otherwise once only. The rate used is 100g/ha plus 250ml non-ionic surfactant /100lt water and is available in a 2kg pack.  Please check the withholding periods for planting following crops as it is up to 12 months currently on some crops. This product is for wheat and triticale only.

If you are planting wheat and barley during the winter month’s you can use Firebird or Invado pre-emergent up to the 30 July. After this date, it doesn’t work as effectively as the weeds grow too fast.

White Clover Seed Crops

Kerb 500F or Fiera can be applied to white clover seed crops the winter months from June to August for the control of grass weeds and some broadleaf weeds. Weeds not controlled by kerb can be controlled by various products depending on weed spectrum during July and August.

Ryegrass Seed Crops

As most ryegrass seed crops were in the ground early this year an early post emergence spray is worth looking at to control any weeds that have appeared in the paddocks. In early spring herbicide is recommended to control wild oats.

Barley Grass Control:

For control of Barley Grass in your pastures, apply Nortron/Claw at 4lts per ha. Timing is important when applying these products, the recommended timing of the herbicide application should be after the main germination has occurred following autumn rains. There is residual activity from about 8-10 weeks, therefore timing is essential to ensure that the residual activity is effective during the period of spring germination of the weed. Ideally apply during the last week in June or first week in July.

Weed Control in Lucerne:

It is highly important to control weeds in lucerne during the winter dormancy period, before the onset of spring growth so there is no crop damage or suppression.  Paraquat is the ideal broad-spectrum weed control for lucerne as it provides excellent control of annual and many perennial broadleaf weeds, plus most grass weeds. Paraquat can be mixed with a residual herbicide, such as atrazine, to provide season-long weed control. Atrazine should not be applied to stands less than 12 months old. Terbuthylanzine (Asset) can also be used but limited to stands older than 24 months. Stands 6-12 months old can be sprayed with paraquat only. Any weeds not controlled by this can be looked at again in the spring.

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. Temperature and moisture content are key 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.

For further information on all the above, get in contact with your Ruralco Team.