Canola Sclerotinia review West Midlands Group 10-9-13 Rick Horbury – BCS Technical Advisor

Sclerotinia sclerotiorum life cycle Infected leaves rot Apothecia Infected petals drop onto leaves Stems rot and sclerotia produced

Sclerotinia sclerotiorum life cycle Infected leaves rot Apothecia

What about the West Midlands in 2013? Stem infection generally seen in the mid canopy indicating a delayed spore release compared to previous experience from the Geraldton port zone. Ideal timing for fungicide may have been ~30-40% flowering. When leaf infection was observed it was critical to get the fungicide on prior to the 10 day wet period during August or leaf infection resulted in stem infection of up to 30%. -$13.97 -$7.96 $7.67 -$39.98 -$15.33 $11.13

Sclerotinia Risk Factors WA Higher risk factors Grew canola in 2011 History of lupins, canola and pastures with good levels of cape weed. I observed sclerotinia on my farm in the last 2 yrs Big full canopy Heavier soil types Summer rain with average winter rainfall can be enough. Warm moist conditions will also increase risk. Number of rain days ≥50% in the month or the canopy remains wet. forecast lows. Apothecia in the paddock or close by. +5 +10 +0 =40 +10 +5 =55 A risk score of 40 or more should deliver an economic return from the application of a fungicide Presentation • 19 November 2018 • Slide 5

Assessment of flowering stages Flowering stages should be assessed on the main stem: 10% = 10 flowers open 20% = 14-16 flowers open 30% = 20 or more flowers open 40% = 30 or more flowers open 50% = All flowers are open or have opened, crop is at its most intense yellow (full flower) 60% = Flowering intensity is beginning to decline

PROSARO vs ROVRAL direct comparison 2011 Sclerotinia % yield increase over untreated (2.1 t/ha) 11% yield increase over Rovral Liquid (iprodione)

Prosaro 420SC: large scale evaluation / mapping Location: Holbrook, NSW Variety: Thumper Disease pressure: Sclerotinia / High Average ROI*: $327 / Ha (33%) 2.18 t/ha Untreated 2.91 t/ha Prosaro 450 mL/ha @ 20% flowering

So where to from here? Don’t panic as the Geraldton port zone, NSW and Canada show we can still grow quality canola in the presence of sclerotinia. There is no varietal tolerance but good standability and air flow in the canopy can reduce severity. Mark and record paddocks of canola or lupins where Sclerotinia is observed in this years harvest. If we get a warm wet winter in those paddocks in the cereal phase then it is all OK. HOWEVER if we are in canola a fungicide spray may need to be budgeted. In a wet year with a canola rotation in a paddock with history scouting for disease is essential and use the risk assessor tool to make economic decisions. Lengthening the rotation from canola/ cereal won’t necessarily stop the disease with sclerotia lasting for up to 7 years in the soil the window for risk is a long one. -$13.97 -$7.96 $7.67 -$39.98 -$15.33 $11.13

For further information: Email me: rick.horbury@bayer.com Or go to: http://www.bayercropscience.com.au Go to Prosaro and look under the resources tab for Disease Management in Canola - Sclerotinia -$13.97 -$7.96 $7.67 -$39.98 -$15.33 $11.13