Crop Watch – Farmers Weekly
Crop Watch - Farmers Weekly ...
In the South West, February proved to be an extraordinarily dry month, but so far March has been the exact opposite, with higher-than-average rainfall. This has caused a few problems.
Spring plantings have fallen behind schedule, field applications of fertiliser and sprays have been delayed and, most importantly, foliar disease has continued to build in already well-developed and heavily diseased crops.
T0 applications on both wheat and barley are now behind schedule. Unlike last year, when nearly every day was a spray day, this year is already proving a lot more tricky. The chances of applying everything in one go have been slim and we now have to look at grabbing every spray window, no matter how small, to get the applications made. This may mean having to get only a field or two done at a time, but it will be preferable to further delays.
Rhynchosporium is the primary disease in winter barley, and septoria continues to dominate in wheat, with even quite resistant varieties showing disturbingly high levels of the disease for this time of year.
Growth regulators
Many wheat and barley crops have a much higher biomass than is normal in March, so applying any planned plant growth regulator is also going to be critical, leaving aside the need for the T0 fungicide.
OSR crops continue to look promising and have relatively low levels of disease. At the time of writing, most crops are at early stem extension with green flower buds, and it is looking like we will have some yellow fields in early April, unless the cold temperatures return.
Maize is always an important crop for us in the South West, and with a larger-than-usual acreage of the crop predicted to be planted, growers should be beginning to think about the list of jobs that need doing before planting, such as glyphosate applications (if not already done), monitoring soil temperatures and getting organic manures applied.
It is probably worth reiterating that in the vast majority of circumstances, the earlier the crop is planted (subject to seedbed conditions and soil temperature being correct), the better the yield, quality and earliness of harvest.
With this in mind, we could be drilling in as little as two weeks’ time. With fertiliser prices high, there will be a temptation to overly rely on or overestimate the amount of nitrogen delivered by organic manures. I would urge all growers to approach the nitrogen input to this crop as scientifically as possible, because getting it wrong can prove to be very expensive.
By the time I write my next article, T1 applications should have been made. There is a lot of work to do and I hope it all goes well.
Each year in early spring do a rough fungicide plan for every wheat variety (obviously subject to change due to weather) and workout a basic idea of how much each variety is going to cost to keep clean.
More so this year than in previous years, the plan has highlighted significant differences in control and the associated cost needed to keep individual varieties in good condition.
The difference between the varieties with a lower overall spend and those with a higher cost is more than £50/ha. These differences have been exaggerated by:
Varietal resistance (or lack thereof) to septoria and rusts, and the growing difference between more resistant new varieties and older varieties on the Recommended List with lower resistance Inflation of fungicide prices this season.
While we can’t alter the varieties currently in the ground, it does give food for thought about future variety selection. There is a lot of independent data to show that the return on fungicide spend from a technically sound programme outweighs the cost of application.
To that end, T0 plans here in the region are written and, in a few cases where growth stage allowed, T0s were applied on Monday. Recent wet weather has seen newer leaves knocked down to sit on older – and in some cases septoria-infected-leaves, allowing spore transfer up the plant.
T0 spray
In varieties susceptible to the disease, folpet will be applied at T0, and if wet conditions persist and the disease appears on newer leaves, a fungicide with mefentrifluconazole orfenpicoxamid will be planned for the T1.
Although temperatures have been relatively low over the past few weeks, crops that had fertiliser applied early have been growing well.
OSR has begun stem extension – rapidly in some cases. Where a certain number of plants have been lost to either flea beetle larvae or frost, in among healthy plants, an application of plant growth regulator will be needed to reduce apical dominance and encourage the growth of side branches to spread out and cover the area once occupied by now dead plants. Trinexapac-ethyl or metconazole will be applied to achieve this.
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