Tillage Update 3rd June 2021
Rainfall in May was above normal everywhere and has led to increased disease pressure in all crops. Ciaran Collins, Teagasc Crops Specialist notes that high levels of rhynchosporium has been reported in recent days, in early sown Spring Barley. Ciaran has more here in this week's Tillage update
(Image above: Rhynchosporium in RGT Planet, Spring Barley, in Wexford)
Rainfall in May was above normal everywhere with Cork Airport and Oak Park recording values in excess of 100% of normal May rainfall. The high rainfall in May has led to increased disease pressure in all crops, particularly in early sown spring barley where high levels of rhynchosporium has been reported in recent days.
Most spring barley has received its first fungicide in the last week thanks to a welcome dry spell. Crops have benefited from the increased temperatures but heavier land and compacted areas are still showing typical yellowing symptoms due to excessive moisture.
While the majority of crops have low disease levels, some early sown crops that are at flag leaf emerging have very high levels of rhynchosporium. Most reports of rhynchosporium are in Gangway and RGT Planet and there are reports of net blotch in RGT Planet.
Due to lack of opportunities, many fungicides were applied later than planned which may affect control but it is important that the final fungicide is applied at the correct timing of flag leaf to awn emergence even if the time from first fungicide is relatively short.
Another issue that is very apparent this year is sulfonylurea resistant chickweed. We can assume that the majority of chickweed is resistant to sulfonylureas at this stage. Control is generally dependent on a partner herbicide that has activity on chickweed such as fluroxypyr but the issue this year is that much of the weed control was late and the rate of the partner product was not high enough to control large chickweed.
A recent visit to a DAFM trial site highlighted the value of varietal disease resistance. Some of the poorer varieties in the untreated trails have septoria on the flag leaf and there will not be much of the crop left by mid-June. On a positive note, the upper canopy is relatively free of septoria in the treated trials and the new chemistry is performing well. However, we cannot expect this to last when we combine varieties with poor septoria resistance and high disease pressure. The lack of new varieties with high septoria resistance is a concern.
Another observation from the trials is the impact of sowing date on disease pressure. There is a large difference in an untreated crop sown in mid-October when compared to an early November planting date.
For more Agronomy information check out https://www.teagasc.ie/tillagemonth/
The Teagasc Tillage Crop Specialists issue an article on a topic of interest to Tillage farmers every Thursday here on Teagasc Daily