Raptor (Imazamox herbicides) and rain

[Tap]

I've read about as much of the extensive Raptor herbicide label as my brain can digest and I realize it's rain fast in an hour, but can it be sprayed on wet weeds that have been rained on (as opposed being wet from dew, if that matters)?
Seems like our weather pattern brings the next rain before the previous rain can dry on the foliage.
By the time the rain dries, the timing for spraying before the in-coming rain is a little iffy.
Some of these herbicides are a PIA. Can't spray if the weeds are too mature...Can't spray until emergence...Can't spray more than once a year...Can't spray if it's gonna rain...Can't tank mix with certain other chemicals. Seems like when all the stars and planets align, then for some reason I'm not available to do the chore.
Can I spray Raptor, aka IMOX, aka Clearcast, aka Beyond on wet stuff?
Thanks, Tom.

 

[wsucoug]

I think one of the biggest issues of spraying on wet plants is that the water on the plant will dilute the concentration of the herbicide mixture, so you are no longer getting 4 to 6 oz an acre on the plant foliage (only so much room for water on the plant). Also similar to how a boom sprayer with small droplets can be more effective than a boomless nozzle with large droplets; the water will bead up and run off of the leaves if there is already droplets on the plant leafs. If I was in a pinch and had to spray with moisture on the plants I would make sure I was at the high end of the application spectrum as i would be trying to combat both of the issues above. I do know the herbicide has soil residual, but I doubt it will kill tough established weeds if you had to rely on root uptake vs foliar uptake.

 

[Mennoniteman]

Studies have been done on spraying when it's wet (dew or rainwater is no difference) and there's no evidence that light moisture on the leaves effects the chemical uptake into the leaf for better or worse, but the labels sometimes say don't spray if it's running off wet, that's too much water, like going out and spraying the instant it stops raining or on heavy dew. Early morning when the dew is still wet on the leaf is a favorite time for many farmers to spray, as it's often calm with no wind. Another thing, labels often mention not spraying in the summer in midafternoon heat, leaf cell don't absorb chemicals as well at 90 degrees. This is especially true when using systemic herbicides like Roundup, however, contact herbicides become more active as temperatures increase, but this can also result in crop injury. Contact herbicides are stuff like Atrazine and Gramoxone.