Slugs in lawn
I thought the problem with a dead area of my lawn was caused by grubs but no sign of grubs. It is in a shady area all summer.... but I just found a fat slug in the grass in that area and think that the slugs are what is causing the grass to die. Please provide some solutions.... Bug Geta and beer are not the answer.... I"ve tried many of those slug control products with no results. Is there a spray or granular treatment that will kill the slugs and because it is so damp and wet from the recent rains this is just making the problem worse. Sarah Hodge - Englewood
Arapahoe County Colorado
Slugs are not likely the cause of lawn dying; they like to feed on other plants more than grass plants.
If you notice that grass plants are eaten down to the ground, that could be from rabbits
Slugs are more of an annoyance in lawns because they leave a slimy mucus on the grass blades. Slugs like moist, humid shady areas.
It's more likely that your lawn is thinning out due to shading - KY bluegrass is not very tolerant of shade.
Here's some good information on slug biology and control/suppression:
Thank you for your response... but since I wrote I am pretty convinced that grubs are the problem altho' no sign of them in July or Sept. after lifting turf... maybe too deep down. Unfortunately I know you cannot name products, but maybe you can advise which is the best insect control to use.... one contains beta cyfluthrin and imidacloprid (kills up to 3 mos.).. one is "season long" with ingredient of imidacloprid and the third product uses chlorantraniliproil...... all three recommend using in early spring April to May but second one says "spring thru summer"... which is the best to use and when?
Grub controls you listed are best applied when young grubs are visible at soil surface, just under dead grass, as in photo. Dead grass would "roll up" easily, almost like rolling up a carpet. If grubs were the cause of your dead grass, you might see some skunk damage to the lawn as they dig to search for grubs. You might even see some crows and sparrows pecking at the lawn in search of grubs.
If/when grubs burrow more deeply into soil with cooler weather, insecticides become much less effective on grubs, as the greater soil volume and organic matter in the soil tend to "bind" insecticides before they reach grubs. Insecticides are much more effective on smaller (early-season) grubs close to the soil surface than on larger grubs deeper in the soil.
Given these factors and the fact that you have not seen or found any grubs, suggest you skip insecticide treatments now. If you find grubs/damage next season, chlorantraniliprole (Grub-Ex, Acelepryn) is a good choice.
An alternative grub treatment is insect-parasitic nematodes (genus Heterorhabditis).
Another possibilty for your lawn damage is cranberry girdlers; larvae (caterpillars) can damage lawns in Sept/Oct. Caterpillars are near the soil surface, about 1.25 inches long, with tan body and orange heads; see photos. Insect-parasitic nematodes in the genus Steinernema are fairly effective on cranberry girdlers. http://extension.colostate.edu/topic-areas/insects/insect-parasitic-nematodes-5-573/
Thanks once again for your response. I've given up until next spring and this time I want to get a complete analysis of my lawn before using any product for any disease or other problem. Do you have any publications about FUNGUS in the lawn.? since I have never seen any grubs (but admit I did not look in early June or May when they are supposedly just beneath the soil surface and not deep in the ground), I'm thinking that now it could be a matter of fungus that is causing the lawn to die out in areas - a lawn company will only come and use fertilizers, weed controls and preventives, but I've yet to find one that treats fungus or insects damage.. One company came and dumped a load of Revive on the lawn... another one told me I was not watering enough.... not true... so I'm looking for someone to give me an honest assessment who is NOT associated with a lawn maintenance company!!
Here are the most common diseases of lawns caused by fungi in the Denver area, with link to publication
Powdery mildew http://extension.colostate.edu/docs/pubs/garden/02902.pdf
Leaf spot/melting out http://planttalk.colostate.edu/topics/lawns/1524-leaf-spot-melting/
Necrotic Ring Spot http://extension.colostate.edu/docs/pubs/garden/02900.pdf
Ascochyta leaf blight https://extension.colostate.edu/docs/pubs/garden/02901.pdf