# Spraying Fungicide In Hot Dry Weather



## StevenA (Jun 20, 2020)

I've been dealing with some fungus issues and was waiting on my Propiconazole to arrive. I got it yesterday but the weather in the Midwest (SE Michigan) is hot and humid with no relief forecasted in the 10 day. Most days at or above 90 but mid 60's at night.

My question is would it be a problem to spray my lawn with a fungicide in the hotter weather? I know it is a bad time to spray weeds above 88 F or so. Obviously will go by label suggestions but is there anything else I need to do to prep the lawn or would it be a waste given the current weather?

I was planning on using the Ortho Dial N Spray and put down about 2 gallons of water with 2 oz. Prop / k so I figured I wouldn't really have to water it in. Also planned to spray in evening to avoid evaporation. Let me know if there is a better way to do this or if I should just wait for it to cool off.


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## bernstem (Jan 16, 2018)

Fungicides won't evaporate off the leaves, just the carrier water. You can apply fungicides with a hose end sprayer, but if you have a pump sprayer with a quality fan type spray nozzle that is generally a better option. You will get more even coverage and have more control over the application.

Two gallons/1000 will be fine as a foliar application, but if you want to get to the roots, you should irrigate with 0.1-0.2 inches of water. Propiconazole is a systemic so will be absorbed by roots or leaves. It will move from roots to leaves, but won't move from leaves to roots.

Propiconazole can cause damage to turf in hot weather. The effect isn't from the spray sitting on the leaf, but is possible as long as the fungicide is in the plant, so you can have effects weeks after application if it gets hot. It isn't going to kill the grass, but may result in off color or slight browning. I have applied in hot weather (above 90 on Bluegrass) without much effect, but it is something to be aware of. Propiconazole is also a growth regulator so will slow turf growth after application. In summer, when grass is already growing slowly it can result in very slow growth.


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## StevenA (Jun 20, 2020)

Thank you for the detailed information. This is good to know about potential off coloring and growth regulation moving forward. The only reason I was planning on hose end versus pump sprayer is time and getting some water down at the same time. With 17k sqft to spray and only a 2 gallon pump sprayer even 1 gallon /k would take a long time.

I might try to do it in a couple days an evening before I water in the morning. I really want to take care of some of this fungus before it gets worse.


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