West: Keep a close eye on final leaf three

Since last writing the weather has finally warmed up and crops have started to grow, but not before winter had her final say and a few more marginal winter crops were written off.

According to my records we are currently about three weeks behind in terms of growth stage in most crops. T1 on wheat is usually about the 15th April down here, but this year the majority of crops were only receiving their T0 fungicide on this date, with T1 still a good fortnight to three weeks away.

One thing that is certain is that the crops are going to make up time and grow extremely quickly with the likelihood that most wheat crops will drop a leaf in order to make up time. We need to keep a close eye on the wheats to ensure that the T1 timing is correct, as final leaf three is likely to be emerging at growth stage 31 rather than growth stage 32 this year. On the plus side at least fungicide timings should be fairly tight rather than extended this year.

Weed control in cereals is proving to be a bit of a challenge this year as many crops have some large overwintered weed that requires controlling soon. At the same time we have a raft of spring germinating weeds that are slowly emerging as the weather warms up. As the crops are not yet uncompetitive, these late germinating weeds will prove to be a problem and will need dealing with.

In some cases two applications of herbicide may be required, but hopefully in most instances a well timed broad spectrum herbicide or herbicide “cocktail” should do the job. Wild oats are also proving tricky this year in that they have not yet put in an appearance, even in fields with known large populations. At present I can see most wild oat control taking place between T1 and T2 or possibly as late as the T2 timing itself. 

The winter rape crop – or what is left of it – has now started to grow. The one certainty this year is that growing too large a canopy is not going to be a problem. In the past I have often heard farmers comment that their worst looking field of rape turned out to be the best yielding. This gives me some optimism that we might yet get a reasonable yield this year. In fact, on that basis we should have a record year if there is any truth in the saying.

At the time of writing the flower buds are now visible above the leaf, but I have yet to see a crop in flower, which again is incredibly late for this part of the world. Stem extension fungicides will be chosen on the basis of their lack of growth regulatory properties. If the crop should start to look overly large as it develops we can always slot in a growth regulatory fungicide at the Sclerotinia control application.

The spring barley crops are by and large all emerging at the same time, irrespective of drilling date. The early drilled crops have taken 6 to 8 weeks to emerge, whereas the later drilled crops are coming through in two weeks. The delay in emergence does not appear to have had any detrimental effect. There is also very little evidence of any slug activity in the spring barleys which is a pleasant surprise, given all the problems experienced with this pest through the winter months.

At the time of writing the soil temperature is bouncing along between 8-11C. This of course has opened the debate over whether to drill maize or not. At these temperatures I would be quite relaxed to see maize drilled on favourable sites with lighter soil types, but more marginal sites or sites with a heavier or wetter soil drilling should be delayed until we can see a more upward progression in the soil temperature.

I have seen alot of fields destined for maize that have ploughed up very “slabby”. Care will need to be taken in these fields to ensure that they are not allowed to dry out in this condition or it will be nearly impossible to work a sufficiently good seed-bed for the crop, which in turn will have an adverse effect on crop establishment.

As an overview I would say that the season thus far has proved challenging, but that in general the crops that are left are generally good enough to produce a good yield. It is therefore all left to play for and with careful management and a half decent summer we should be able to achieve this. 

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