Hi Patty,

Water it right away at 1/2 inch, then call Bayer customer service, tell them what happened and see what they say. I'm not familiar with that Bayer product but I have read that some grub control products lose their effectiveness if exposed to too much sunlight. I would imagine this is particularly a concern if the grass is mowed short like yours is, but that is just a guess.

Sure, usually you don't want to water at night, but I would do it this one time. But after you start watering, do see what the Bayer folks have to say. Maybe they will say it is still like 80% effective. Who knows. But whatever they say, worst case is you need to apply it again, and IMHO that is a small price to pay if the alternative is potentially massive grub damage. I've been there, and try to avoid it now at all costs.

Good luck!
Paul

Thanks for the answer Paul, It rained on my way home from work and according to the folks at Bayer it should be ok, it was mostly cloudy since putting the product down. Sunlight definately affects the performance. They advised that we watch for damage.

It's a little late to be applying grub control. Ideally should be applied in June when the weather is warming and grubs are making their way up to feed on your turf's roots. The whole "season long" thing is just marketing hype. Sure, the chemical residuals stick around in the soil all season, but is it controlling grubs right now???? It would be if there were any, but there aren't. They've already hatched. Have you noticed japanese beetles around yet? You need to read the labels from pesticide and herbicide containers. They will tell you how and when to apply without having to rely on internet forums.

Here's the life cycle chart, so you still may be able to control the biginning of the next cycle for the next 2 months or so.

{{gwi:105713}}

Again, thanks for the helpful advice. jtcm05, as a student pursuing a degree in horticulture I have a healthy respect for pesticides and am fully aware of the need to read labels and follow directions. According to the label the product should be applied "anytime between May thru mid-August". Further as you've pointed out, they have already hatched but according to the research that I did, they mate, feed and lay eggs very quickly and in very hot weather the development of the first and second instar begin feeding in as few as 17 days. We thought it best to try to control the future generation. My question did not concern when or how to apply the product, simply the window on rainfall. You may not realize that you came across as a condecending jerk.

Jerk or not....but I'm not the one relying on a forum for my lawn care questions.