Fungicides are applied so that the green surface area is not reduced by colonising fungi, so the grower maximises the ability of their crop to catch available sunlight.
The one variable that cannot be manipulated is the amount of sunlight that is available to the crop.
Much was made of the high yields achieved in 2011 and the factors that were involved in achieving these high yields.
While growers and advisors went to great lengths to explain their role in the success of these high yields, the predominant factor in 2011 was the weather, and more importantly, weather during the critical grain-fill period.
In the summer of 2011, we experienced the rare combination of bright and cool weather during June and early July: the critical grain-fill period for cereals in Ireland.
A bit like an athlete in training, the most important work to get ready for a good outcome is all preparatory. On the day however, other factors come into play and no matter what the potential, an athlete may not perform to their ability. In cereal production, seeds are sown, fertiliser is spread, pesticides are applied.
This is all on the basis of getting the plant 'match fit' for the crucial grain-fill period.
If the sun doesn't shine or the temperature is too high or too low, the potential of the plant to trap more sunlight and convert it to yield is not fully realised.
It is in this context that the yield potential of crops currently in the ground can be viewed.
Early maturing crops, such as winter barley or winter oilseed rape, are most of the way through their grain fill period, and the weather to date would suggest that record breaking yields are unlikely.
Winter barley crops are generally standing well, a fact in itself that might not bode well in some quarters.
However, both these crops are notoriously difficult to predict in terms of their reaction to growing conditions and a few bright days might make all the difference.
Later maturing crops, particularly winter wheat and spring barley, are still in the midst of grain fill and there are number of weeks left that will determine the outcome of these crops.
As crops move towards maturity and the time for desiccation, take stock of the ground conditions before commencing.
Pre-harvest desiccation of cereals has benefit in terms of better kill of perennial weeds, removal of green grain from the sample, and a drier crop to harvest, which can result in better harvesting conditions.
However, running a machine through wet tramlines and particularly wet headlands may not be in the best interests of the crop or the field.
Post-harvest perennial weed control can be just as successful as pre-harvest, especially where applied early.
Also, keeping machines out of the fields for as long as possible may help the drying out process of wet areas, assuming of course that better weather is in front of us.
Dr Richard Hackett is a crop consultant and member of the ITCA. Email: firstname.lastname@example.org