Formerly NE North Dakota, now NW MN | It's not really the flat temperature you have to watch, it's the delta T (a random number that is derived from temperature and relative humidity). If your delta T is too high, your product will evaporate before the plant really has a chance to absorb it. Here's a link to a delta T chart. If you are going to spray in high delta-T situation, Up your water and down your pressure so you can get a lot of big drops that will be resistant to evaporation. A.I. tips and a good (emphasis on good) drift reducing adjuvant (we use Crosshair from Wilbur Ellis. Have tried a few others with no luck. We've not tried interlock, people seem to like that one too).
http://www.spraymaster.net.au/system/product/specs/0000/0170/Delta_...
There's also the question of if your plants will be shut down and therefore less likely to intake the fungicide. Based on little more than information I've gleaned from what people say about how to make herbicides work... I've always used 85 degrees as a cutoff point.....however, that's probably pretty conservative for soybeans. Strobi's like quadris aren't true trans-locating systemic fungicides anyways, they only move in a trans-laminar fashion (at least this is what I'm meant to understand?) so I'm kinda thinking you should be able to bend that plant shut down rule a little and still get good results. If the plant is flipping leaves from the heat, that would be an obvious sign that it's shutdown, and I would not make the application then.
On the flip side, I've made quite a few fungicide applications to very dewy dry beans and had pretty good results. That 7 to 10 am time frame when the plants are still wet, but are awake and respiring has given me some very good results in the past. That was using true, trans-locating fungicides, so I don't know how relevant that is to strobularins but I would suspect the results would be similar.
Whatever time of day, we've seen having a good adjuvant load makes as big a difference as anything else. |
Spraying when its 100°
