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Discussion in 'Lawn Mowing' started by LAWNMOWERBOY, Apr 20, 2001.
having trouble getting rid of grubs...
Anyone have any suggestions, please??
grubex works ok, if you don't want to spend alot and do it yourself. you might want to call some one in your area that is certified to do this job for you.
Check out the April issue of Landscape Management.
I use Merit for grubs. You need a CPA but it covers season long, no resistance, and low toxicity. There have been some studys done that indicate white grubs can build up an immunity to the organophosphates, especially when they have been used over time at high rates.
I have heard lots of good this about merit and mach2 give them a try. Application time and grub identificaion is very important.
if you wanna go ipm. here is what you do. instead of putting down dursban / merit / diazanon or the milky spore thing. what you can do when you start seeing damage is to keep the lawn watered. this will mask the damage. grubs are root pruning insects and are around in the spring just as much as they are later on in the year. the only reason why we dont see damage in the spring is because it is so wet. so if you can keep moisture levels up in the latter part of the year you should be ok. to actually treat for the grubs you can put down any of the above things. however you should pull a couple of grubs up and check out their rastral patern. if it is a V on their head then you have jap beetle grubs. if you have other kinds then you gotta go look in a book for other treatments.
Daytime watering can certainly help reduce grub damage, mainly by lowering daytime soil temps which can reach over 130 degrees on a 90 degree day. These temps can increase grub feeding, and subseqent turf dammage, significantly.
Grubs are cold blooded, therefore they feed less in the spring because of low soil temps. The grass is also under less stress in the spring and will, often, not show the damage untill later in the summer. This is because the turf's root system has been weakend by grub feeding and is much more suseptable to heat stress and disease in the summer.
A responsible IPM does not mean eliminate spraying or pesticide applications, many times a low rate today can save having to spray a much higher rate later in the season, just read the lable for grub size vs. app rate. As part of a responsible IPM you should have threshold levels for grubs, and then time your applications.
I have seen more damage done by disease brought about by night time overwatering than by grub damage. People start to see their turf yellowing from disease or grub feeding and simply assume it is from lack of water. They doubble the irrigation timer cycle and pythium, dollar spot or a combination of disease wipes out their turf.
I use a threshold of 12 jap beetle grubs/ sf of turf. After that I know that damage and turf loss will occur.
[Edited by greens1 on 04-20-2001 at 11:15 PM]
Simple presence of grubs is not cause of concern, especially in the springtime. Grubs do not feed aggressively in the spring, like late Aug thru Sept. Any damage visible now was caused last fall usually. ID your culprits, and if they are annual grubs, you do not need to do anything now, and if you do try anything it will be very unsuccessful, because the grubs are so large now.
Presence of grubs now is just a warning to watch this area in late summer. Either treat with a preventative, Merit or Mach 2, in early July in your area, or monitor the area closely in Aug/Sept and be ready to treat with Dylox if damaging populations occur. Treatment early in life cycle is the most successful venue.
This article in the February issue of Grounds Mag was very informative. The comments on threshholds, resposnible IPM is all covered on grub control
Hope this helps.
Thank you all very much.