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CROP CRACK - 19-04-08
By WENDY FEARON
Clarendon Agricare - Spring is Here
Spring has arrived at last, and the sound of sprayers, the sight of ploughs and planters throughout the countryside are a very welcome sight on this pleasant Monday morning, but I will not get carried away as I know this can quickly change. The remainder of winter crops received their nitrogen top dressing and the T1 will now be completed on winter barley and winter wheat. The timing for the first growth regulator has passed on early drilled crops but there may still be time to apply either Adjust or Moddus to later drilled crops. Potato and vegetable planting have begun and most of the grassland acreage will have been fertilised over the last few weeks.
SPRING BARLEY
Spring sowings are still a bit stop start as ground conditions are slow to dry in some areas and temperatures are still relatively low. This in effect means weed seedlings will be slow to appear, however once temperatures improve there will be enough moisture in the soil to encourage a rapid weed flush. The most effective time to treat weeds in spring crop is around 2-4 leaves.
IPU may be used on spring barley where annual meadow grass is a problem but this is an off label recommendation and the SOLA should be applied. This may also help with wild oat control. It is important to check for the presence of leatherjackets as crops begin to braird.
WINTER CEREALS
The cool unsettled weather has kept aphid numbers at bay up until now, but this may change as the weather warms up, with a risk from aphids that have over wintered on crops beginning to reproduce. An aphicide treatment at this time should only be considered if over 50% of plants have aphid colonies present. Many crops are still quite yellow and winter wheat has been scorched a bit with frost.
I have seen brown rust on both winter barley and winter wheat especially Alchemy. Opus team applied at T1 will have very good control of rusts and other foliar diseases but is not great on eyespot. If eyespot is a concern prothioconazole should be used. Crops most at risk of eyespot are those sown before the first week of October, crops planted in heavy land and crops were the previous crop was wheat. Septoria levels are variable and very much variety dependant. Foil and Talius may be used at T1 for effective septoria control.
Cleavers and chickweed remain the most dominant weed in winter crops and Starane XL has good activity in cooler temperatures. Ally may be added to control other problem weeds. Winter oats are approaching the growth regulator timing and remaining weed control may be done at this time. Winter oats should also receive their T1 at this time.
Wild oats in winter barley and wheat should be controlled as soon as possible. Wild oat herbicides should be applied alone and a period of at least one week should occur before applying another agrochemical onto the crop.
This may sound unbelievable but I was in winter barley last week and the flag leaf was coming out, so I cannot stress enough the importance to monitor growth stages to ensure the correct timing for growth regulator is observed.
FORAGE MAIZE
Weed control options for maize look a bit different this year. Stomp is probably better than atrazine used to be in drier conditions and more active on black nightshade and grasses. Cadou Star the new pre-emergent from Bayer is a residual herbicide and will require soil moisture. It is recommended that the product is applied before the maize seeds have germinated in a mix with Stomp.Applications should be made within four days of sowing.
It is important to note Stomp carries a SOLA under plastic and is used at the growers own risk, but it will enhance the Cadou Star mix. Other products which may be used on maize crops are Bromotril, Titus and Calaris.It is important to read the literature on these products carefully.
SOIL NUTRITION
Now with most farmers taking soil samples, many crops will receive the correct type of fertiliser required. Whilst the NPK are essential, unfortunately not enough emphasis is put on the importance of essential trace elements when carrying out a test.
Magnesium is essential for chlorophyll and an activator of enzymes needed for the processes of protein production and energy transfer. Copper and manganese are important for photosynthesis, respiration, protein production, hormone regulation and disease resistance. Cereal straw strength, ear development, pollen fertility, and grain fill all depend on adequate copper and manganese levels.
GRASSLAND
Docks, thistles, nettles and other grassland weeds are not quite ready to treat yet. These weeds require active growing conditions to absorb the chemical. Chickweed and ragwort are growing away and should be controlled as soon as temperatures are suitable.
Reseeds where chickweed is a problem and clover is important should be treated with Alistell.Where clover is not important CMPP may be used to control chickweed. It can be difficult to spray for ragwort at this time of year because of the withholding period which can be as long as six weeks. Ragwort becomes very palatable as it begins to rot. Lupo which is an MCPA/2, 4-D mix is very effective or alternatively Depitox may be used.
POTATOES
Potato planting has at last got underway, and with the disappearance of Paraquat and PDQ, weed control options may have to be considered earlier. I will discuss this in the next crop crack.
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