Side PanelExpand side panel Cereal Disease Control 2024 Part 2. Disease Control Strategies in Barley
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Rhyncosporium secalis Leaf blotch of Barley – Leaf Scald 1- Whats it suited to? 2- What does it look like? 3- How does the primary infection occur? 4- How long is the disease cycle? 5- Whats a major gene in disease resistance? 6- Whats very important?
1- Suited by cool maritime conditions 2- Pale grey-green water soaked lesions Mature lesion shows grey centre and dark brown edging , lesions coalesce into larger necrotic tissue areas 3- Primary infection from splash dispersal of spores from crop debris 4- 14 day disease cycle in optimum weather conditions – cool wet humid weather 5- Disease resistance is impt – Polygenic and major gene Resistance rating of 6/7 needed 6- Azole fungicides (Proline) very impt
Just have a look at slide 3,4,5
Disease Control and Fungicide Programmes for Spring Barley 1- What are fungicides used for? 2- What do fungicides improve? 3- What are widely used products? 4- Whats the contact product?
1- * Fungicides are used to control disease, to increase grain yield and to improve grain quality 2- * Fungicides improve grain quality by increasing the grain size (1000 grain wt.) and by improving grain- fill (hectolitre weight) and by reducing small grain % (screenings) 3- * Widely Used Products Siltra , Ascra Pro, Proline, Revystar, Priaxor, Elatus Era etc 4- * Contact product - Arizona (Folpet)
Disease Control and Fungicide Programmes for Spring Barley 1- Whats the key target: 2- When is portection against diease needed? 3- whats the standard approach? 4- Whats the cost? Whats the yield responce?
1-* Key target are foliar disease - Rhyncosporium, mildew, net blotch, ramulaira and rust diseases 2-* Protection against disease is needed for a period of 50-60 days from late-May to end July 3-* standard approach is a two-spray fungicide programme 4- * Cost is Euro 40-80/ha, requires 5-10% yield increase to cover costs 5- * Yield response to fungicide use varies greatly depending on variety and season and is in the range 10-40% (0.5 to 2 t/ha)
Fungicide Programmes for Barley: (3)
• Two-spray treatment , sometimes three e.g. winter barley • Early-season - GS 30-31 • Mid-season - GS 39 (45)
What is the frequent approach in both winter and spring crops if high levels of disease?
• Frequently a three-spray approach in both winter and spring crops if high level of rhynco on early-sown crops
What is the Target is for high levels of wet weather disease control
• Rhynco, Net blotch, Ramularia, Ear Fusarium • Less focus on mildew and brown rust
Fungicide Programmes for Spring Barley 1- How many times are they sprayed, How many sprays and what gs? 2- When does most grain yield response happen when spraying?
1* Standard - two-spray programme : with applications at GS 24-30 (T1)and GS 37-39 (T2) • T1 spray - reduced rate application (30-40% of total) to give 20-25 days protection • T2 spray - main spray (60-70% of total) to give 30-40 days protection 2- Most of the grain yield response to fungicide is expected from the second spray (main spray) which protects the crop during the grain filling period
Barley Diseases and Weather Unpredicability 1- Wet weather diseases: 2- Dry weather diseases 3- What can be a problem in ireland?
1- Wet weather diseases – Rhyncosporium (RHYNCO) and Net Blotch – The spread and infection of Rhyncosporium and Net blotch are favoured by high rainfall and high humidity (rain splash diseases) 2- Dry’ Weather Diseases – Mildew and Rust diseases favoured by relatively dry warm weather but do require moisture and humidity (in small quantities) 3- In a changeable Irish spring and summer both wet and dry weather diseases can be problems
Background – ‘novel’ Barley Disease - Leaf Blotch- just read over
Incidence around the world - mid-1980’s reported in Austria, New Zealand (Ovulaira leaf spot) - late-1990’s Germany, Scotland, Ireland, Denmark, Czech Rep., Austria and also field trial research in New Zealand the New Zealand research has reported that even at low levels of infection the disease has a marked effect on the grain yield of barley 2000 to today – a disease threat in winter and spring barley in western Europe in every season - Very effectively controlled by Chlorothalonil at T2 up to 2020 - Now best options are contact (Folpet) plus Azole fungicides (variable) - Lack of useful genetic resistance ( low-moderate Variety ratings)