Dylox grub-killer near tomatoes - pennlive.com - PennLive

George Weigel

Lawn damage of this type is less likely this year due to a light Japanese beetle population. Dylox at this point is unnecessary.

Q:

I recently applied a grub-killer with Dylox to my lawn. Prior to application, I read the entire label on the package, and there were no precautionary comments as to vegetables. Is there any threat with getting Dylox too close to the vegetable area of my lawn? Most specifically near my wonderful, prolific tomato plants?

A: Dylox runoff won't kill or harm your tomato plants. More of a concern is potential exposure on something you plan to eat.

Dylox is one of the more potent and toxic insecticides, and it's not labeled for use on edibles. It's highly toxic to birds, fish and wildlife (humans, too, if you ingest it or absorb enough of it through the skin).

Since this is a granular product, there's little risk of any direct contamination of the tomato fruits. It's possible that minute amounts of Dylox could get into the tomato plants by root absorption if the tomatoes are downward from the lawn. Even then, it's unlikely that enough would get into the fruits to do much health damage. On the other hand, I try not to eat ANY of anything that I know is toxic.
Dylox is usually used as a "rescue" treatment on a lawn that's being decimated by grubs. It kills pretty quickly, but the tradeoff is that it's markedly more toxic than chemicals that prevent grubs (such as imidacloprid or halofenozide). If you're concerned about grub damage and lean toward chemical controls, one of those are the ones to use now. Dylox is something usually recommended when it's too late to use the less-toxic preventers, i.e. in September or early October.

In any event, this year is turning out to be a perfect example of why it's not really necessary to apply any grub control every year "just in case." Most people are reporting hardly any Japanese beetle infestations, which means we're likely to have a very light grub problem later this summer and fall. Unless you have zero tolerance for grubs, a good strategy is to wait until July to see how the beetle population is shaping up. If it's bad, mid-July is not too late to apply imidacloprid (i.e. Grub-Ex) or halofenozide (Mach 2). Even if you miss that, Dylox or Sevin (carbaryl) are options if you start seeing really bad lawn damage in September.

Personally, I hardly ever even use a preventer and never Dylox. It's just too toxic for my taste. I'd rather spend money on grass seed if a grub problem turns out to be so bad that patches die off.

Here's a web page with a detailed rundown on Dylox (trichlorfon) from Cornell University: http://pmep.cce.cornell.edu/profiles/extoxnet/pyrethrins-ziram/trichlorfon-ext.html.