With May’s weather continuing to be up and down, humidity control is a problem in the greenhouse, meaning Powdery Mildew (PM) is too. This pest is rearing it’s ugly head in crops like Kalanchoe and Dahlia.
We won’t cover the basics of PM here: biology, spread and prevention were covered in a previous post. Instead, we’ll focus on monitoring, and which control products to use once you’ve found an infection.
This post was written with help from Plant Pathologist Ann Zemke of the Chase Research Group.
That’s right! As of today, flower growers have 2 new weapons against fungal diseases at their disposal. Heritage MAXX (azoxystrobin) and Medallion (fludioxonil) are now registered for use in outdoor and greenhouse ornamentals.
Heritage (a Group 11 fungicide) is asystemic fungicide, and is appropriate for control of Pythium, Grey mould (aka Botrytis blight)and Rhizoctonia.It can also be used for foliar diseases such as Powdery Mildew, Downy mildew, Rust, Anthracnose and Alternaria Leaf Spots. You can find the new label here: HeritageLABEL2016.
Medallion (a Group 12 fungicide)is a contact fungicide, and is appropriate for control of root rots such as Fusarium, Rhizoctonia, and Black Root Rot (Thielaviopsis) when applied as a drench. It can be applied foliarly for Grey Mould, Anthracnose Leaf Spot and Rhizoctonia Stem Rot. MedallionLABEL2016.
Both are broad-spectrum fungicides that can be used curatively or prophylactically.
As with any chemical control product, make sure to read and follow the label carefully prior to use.
(Also, 1000 points each to the team that helped push these label expansions forward:Cary Gates, Flowers Canada; Jim Chaput, OMAFRA; Jennifer Llewellyn, OMAFRA and Graeme Murphy, formerly of OMAFRA).