Shropshire Innovation Centre site update – 21st May 2021
The recent rain has been much needed for development of winter crops and the recently planted spring crops. It came just in the nick of time for the winter wheat crops before they suffered irreversibly from the dry, cold weather in April. Temperatures remain low for the time of year which has slowed the development of disease but there is plenty of Septoria tritici on lower leaves in susceptible varieties.
The heavy rain we have been getting as well as the wind will be spreading disease up through the canopy by rain splash but also by direct contact of infected leaves. Many growers reduced their inputs when crops were stressed and development was very slow, in some cases crops have had reduced T1 applications meaning disease has a chance to infect leaves further up the canopy which had less protection. It is important that the T2 timing is targeted at a fully emerged flag leaf to give the best protectant activity from the fungicides available, a persistent SDHI such as solatenol should be considered during high risk periods as well as newer available chemistry. A multi-site fungicide should also be included to help prevent disease reaching the flag leaf but also to help with resistance management.
At our Shropshire Innovation Centre we have a wide range of fungicide trials looking at a number of new and existing actives against Septoria tritici, and we are also looking at novel ways to help reduce disease build up using cultural control methods. The commercial crop of September drilled KWS Barrel, which is very susceptible to Septoria tritici, is now approaching its T2 application timing with the flag leaf 10% emerged at the last visit. The lifecycle of the disease can take between 14-28 days; depending on temperatures, between the infection of a leaf and it being visible. We have been using rapid DNA sampling tests to assess disease levels in the leaf before symptoms become visible. As we would expect different varieties are carrying varying levels of disease with the likes of Graham and KWS Extase having much less infection than varieties such as KWS Barrel and Wolverine. We are also looking at the cultural control measures that can be implemented to reduce disease risk, drill date being a major factor for Septoria tritici susceptibility, the mid October drilled plots are carrying much less disease inoculum than the equivalent September drilled plots. Trials looking at variety blends and mixing different susceptibilities together is currently showing very little difference, but we will monitor disease levels to capture potential benefits. A trial looking at intercropping with legumes is trying to provide evidence whether mixing canopy structures and increasing soil cover under the wheat crop may help reduce rain splash of disease up through the canopy.
We are also looking at trials with disease control in winter barley at the site, primarily Rhynchosporium and Net blotch but Ramularia may also be an important disease later on. All sprays have now been applied to trials in the commercial crop of September drilled KWS Tower. The final fungicides were applied this week at GS49-55 with ears emerging, this allows good protection of the ear and awns which are important for building yield in barley. Disease levels are currently moderate with 10% leaf area infected on final leaf 3 and below with Rhynchosporium; which as with Septoria will be spread up through the canopy by rain splash. Other trials at the site are looking at seed treatment options with some good differences in rooting between Vibrance Duo treated crops and single purpose dressings. Barley yellow dwarf virus has been an important factor for growers this year with some symptoms being picked up generally on single plants from primary aphid infection but insecticide applications or autumn temperatures slowing any further infections.
We have also drilled a range of alternative spring cropping options to help with discussions around extending rotation for soil health and reducing pest incidence. All plots have emerged very well with some unusual additions such as green lentils and chickpeas. A strip of Operation Pollinator Bees ‘n’ Seeds mix has also been established along one side of the trial site; under fleece initially due to cold weather, to highlight our subsidiseded mixtures that are available.