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Crop Crack 11.07.09
By Wendy Fearon
The rain over the last week has been welcome as crops were beginning to show signs of stress, especially on lighter soils. Most spring crops have greened up well as the moisture has improved uptake of any applied nitrogen, and are flying through the growth stages at the moment. Winter crops that managed to receive good herbicide & fungicide programs are also looking very well but there is also considerable variability where spray programs got pushed back because of the very difficult weather during all of May.
Previous fungicide treatments and the end use of the crop will determine the T3 treatment onto spring wheat crops. Where the T2 treatment will be the final treatment, its application should be delayed to ear emergence to protect the head also, and rates increased to provide protection right through to ripening. Spring barley crops should now all have received a fungicide treatment.
The continued warm weather has encouraged high populations of aphid in all crops. While rain will wash them onto the soil, dry weather following sees them quickly move back up onto the ears. As the grains begin to fill they feed at its base, drawing off the sugars that should be filling the grain if left unchecked. Growers need to continue checking crops for aphid’s right up to milky ripe stage (GS73), and spray if present in numbers.
Pre Harvest Glyphosate
With the recent sunshine hastening the ripening of winter barley, a continuation of this decent weather will see harvesting begin within the next few weeks.
Thoughts will now turn to grain quality, moisture levels, and ease of harvesting. This year in particular grasses and other weeds are a real problem in many fields, the long wet winter and spring playing havoc with weed control. With no spray-window for the herbicide application appearing until mid March, annual meadow grass (AMG) was much too well established to be adequately controlled at this time. In spring cereals the very wet weather during late April and all of May allowed AMG to establish particularly well this season and so many of these fields have a lot of grass also.
Broad-leaved weeds are also a problem in some fields.
Pre harvest application of glyphosate is an essential tool to improve the efficiency of harvesting, giving a range of benefits:
1. Harvest management
all green tissue removed – ripens any green stems, leaves and pickles so allowing cutting to start earlier in the day & continue for longer
no green pickles reduces overall grain moisture meaning lower drying costs
less grain lost over straw walkers caused by green material during threshing
faster straw clearance reduces length of weather window required
limits sprouting in laid crops
2. Scutch & general weed control
the most effective time to control scutch in tillage ground
desiccates any other green grass & broad-leaved weeds present, facilitating lower grain moisture, faster harvesting and sooner baling of straw
Note however, do not use glyphosate on any crops where seed may be saved for re-sowing.
Independent trials carried out over a number of years in GB looking at the effect of using Roundup in various replicated treatments consistently show moisture contents being reduced by 2.0-2.5% at harvest compared to plots where no treatment is applied.
With a wide range of glyphosate products available, which offers the best performance in the field, and best value for money? First off, it is not the price per can that should be compared. With different formulation types having different strengths of active per litre and therefore different rates of use, it is the price per acre treated that should be compared, and what level of performance is being obtained from each. ETA formulations available which include Clinic Ace, Glyfos & Gallup Hiactive use ethoxylated tallow amine as the surfactant (wetter) and an isopropylamine (IPA) glyphosate salt, whereas ROUNDUP ENERGY uses a much safer transorb surfactant and a potassium salt.
ETA products de-wax the leaf surface and cause cell damage, whereas the ROUNDUP ENERGY wetter does not damage the leaf surface, so the uptake of glyphosate into the leaf is much more effective than with the ETA product, and the level of long-term kill achieved from ENERGY is significantly greater.
The potassium salt is also taken up significantly faster than the IPA salt; as a result ENERGY is rainfast within 1 hour of application and cultivation can commence as soon as 2 days after application whereas the IPA glyphosate products need a minimum of 6 hours to be rainfast and 5 days minimum before cultivating.
Application should be made once the grain moisture gets down to 30% or below, ideally 10-14 days (and not less than 7 days) before cutting. An easy and reliable test to estimate this 30% moisture level is to press the thumbnail into a number of grains; if the indentation holds on all the grains the crop is ready for spraying.
Grain Store Hygiene
Now is the time to make grain stores ready for the coming harvest. Pest problems in stored grain arise from within the store itself, so a good clean-out is essential to minimise the carry-over of grain beetles, weevils and mites. The store should be empty and thoroughly cleaned before any treatment is carried out, removing all traces of grain and dust that might harbour insects or mites.
Apply using a knapsack to spray all surfaces including underside of roof and floor, concentrating especially on areas where dust can collect – cracks, light fittings, around equipment etc.
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