timing for application of season long grub control

Hello,

I bought my grub control (Bayer Advanced Season Long Grub Control) a while ago and it was too early to apply. My recollection is that I put this down in early June but when I put in my garden a few days ago I found a few grubs. They were about 4 inches below the surface. I seem to remember that if they are too deep, the grub control isn't effective but I don't know how deep is too deep. My lawn looks great at this point and I would rather not lose half of it to grubs. Should I put the grub control down now or wait a bit still.

I live in the Boston area, so spring is a bit of a hit or miss season. It has been 90 degrees already, but has also been in the 40s the last few nights.

LMHmedchem

Don't wait any longer.

I found this writeup from our state extension lab,
https://ag.umass.edu/fact-sheets/current-insecticide-approaches-for-white-grub-control

According to this, imidacloprid based preventatives should be applied starting in mid June. This is to time the application to when the adult beetles are starting to lay their eggs. Imidacloprid is very water soluble and if it is applied to early it will disperse too quickly and will not be at an effective concentration when the eggs hatch. Chlorantraniliprole based preventatives need to be applied much earlier because it is far less water soluble and takes up to 60 days to disperse into the soil. So if you are using GrubEx, it should be applied in mid April, and Merit based products should be applied in Mid June (at least for our zone).

I found a couple of write-ups for Michigan that said the same thing, so I guess that this advice would apply to zones 4 and 5 as well.

LMHmedchem

I learned many years ago to try ID the type of bugs I had visiting my plants both indoors and out, tried to get the damage descriptions right too. Like the edges only of the leaves being eaten, or the small circles in the middle of the leaves. Yellowing leaves, or flower buds opening up and half the bud nibbles yet the leaves all in tact.
It did take a few seasons of hard work, guess and trial and error.

I found that like all animals, insects etc all work on a seasonal pattern, Therefore the problem I experience with my lawn insect wise, is the daddy-long-legs, they lay there eggs very early spring, the grubs hatch spring with warmer soil, these grubs are about an inch long and live /eat the tender grass roots, the grass dies off and is easy to pull up, maybe with a few grubs attached, Flocks of Starling birds arrive in time ( June / July ) to feed on the emerging grubs that are awaiting their wings to harden up allowing flight, it's a fascinating sight to see all those birds devouring hundreds of grubs. But you learn this is that insects cycle so you can prepare for it early spring.By the way I should mention these grabs are More prolific in coastal areas, or where there is light (weight) sandy soil; etc. ALL the things I have.
The same can be said for Red Spider Mites Black flies on the bean tops, white flies on Roses, you look up the habits of the bugs and when they lay eggs etc and it helps you to take action Before you have to resort to chemical methods etc. Also when you understand the bugs cycle, you understand they will only reproduce when there is plenty of the right type of food for the youngsters when they emerge as Mother aint always around.

Take notes or start a diary this year OF you can, then add to it each year with further info, times, weather or damage, when to feed, when to dead-head, when to prune such and such, that way you are well ahead of the pack (bugs etc).
Good luck.
Kindest regards.
WeeNel.

The grubs here are highly likely a beetle larvae. The beetle has one generation per year. Adults are active toward the end of summer, laying eggs for next year. Eggs hatch as it warms up, and the larvae feed on the tender growth (roots, youngest stems) that are also growing at this time of year. By about June (varies with the climate) the grubs are getting larger and dig themselves in deeper to be protected while they pupate. They turn into adults and breed...

Control is aimed at the grubs when they are as young as possible, so as to minimize the amount of pesticide to use (smaller grubs and they are closer to the surface).
The actual timing can vary with the climate, the species (there are several beetles with minor variations on this life style) and the pesticide. A longer lasting one could be applied earlier, in hopes of killing the first larvae to hatch, and last longer to kill the somewhat later larvae. A short acting pesticide might have to be applied twice to get similar action.

If you have a patch of garden that warms early, and you do not mind digging it up, then this could be a place to monitor the grub population. Plant a few sacrificial plants and when you see the little ones in this area you know the other warm spots should be treated now, and the slightly cooler areas of the garden will be hatching soon, so be ready to treat them soon.

I read some similar articles that I linked in this thread:
http://davesgarden.com/community/forums/t/1340255/

One of those says that the only chemical that will kill established grubs is Dylox and 24 Hour Grub Killer from Bayer was the only thing I could find locally with Dylox:
http://www.bayeradvanced.com/find-a-product/insects-pests/24-hour-grub-killer-plus

That paper says that Dylox cannot be used on playgrounds so if you have children or pets on your lawn you might not want to use it.

I tried the natural Milky spore about 3 years ago but I was still seeing grubs in the lawn last season. That combined with how much I've been spending on grass seed led to my using the Bayer product with Dylox just to be sure I was not also fighting a grub problem.

Our lawn looks the better than it has in the last 10 years now. Lots of reseeding, fast acting lime, and good fertilizer/weed control.

I think I'm going to put down another application of Milky spore since I bought nearly twice as much as I needed and see how that goes. I don't plan to put down the Dylox product every year.

This message was edited Jun 22, 2015 9:53 PM

This message was edited Jun 24, 2015 3:30 PM