Home Lawn Grub Control Products 2012

 Home Lawn Grub Control Products 2012

Terry Davis  •  D. R. Smitley :

Lawns turned green much earlier than normal this year because of the incredible period of warm temperatures we had in March. Many folks have already mowed 3 or 4 times. It is that time of year again where patches that did not turn green are becoming obvious in some lawns. Sometimes, a flock of birds can be observed working around the dead patches. These patches may be due to grubs. Before doing anything to control grubs, it is important to make sure that the problem is indeed grubs. If you see a dead patch, dig up a few shovelfuls of soil at the edge of the bare spot and look for 1-inch long, C-shaped grubs. These are more than likely the larvae of European chafer if they are found in non-irrigated turfgrass. European chafer can devastate a lawn with little warning because the adult beetles are not visible to the average person. They do not become active until sunset in late June and early July, and can easily be missed as they move out of the soil and congregate in trees. Since they move back into the grass and lay eggs about 11 pm - the average person would never notice them. European chafer grubs can now be found in all locations in the Lower Peninsula of Michigan.

Japanese beetle grubs also feed on turf roots in home lawns, but they are not as much a problem on grass as European chafer. Japanese beetles like to lay their eggs on irrigated turf like golf courses and athletic fields. They will live in home lawns but rarely cause turf damage because they avoid dry soils. Both Japanese beetle and European chafer lay most of their eggs in July, but Japanese beetles continue laying eggs in August.  The eggs hatch about 10 days later. The grubs begin feeding and grow from the beginning of August until late October. By the end of October, they are fully gown. They spend the winter as large grubs (3/4"-long) some 2 - 6 inches below the soil surface.  When the ground warms up in the spring, they resume feeding and can cause damage from the time the grass turns green until they pupate in mid-May. They are big enough that they can cause damage after Labor Day if enough of them are present. Grub damage may appear in home lawns from mid September to November, or from March to early May. However, for low maintenance lawns, even if the turf is not killed from the grub feeding the thinned and weakened turf may be prone to more problems later in the season, including a new round of grub feeding the next year.
It is important to realize that healthy turf, especially if there is plenty of rain in the spring and fall can support a grub population of 5 or more grubs per square foot with no visible turf damage. A lawn should be mowed at 3.5 to 4.0 inches in height and properly fertilized for maximize root growth. But if the grub population is high, or if there is a history of damage in an area, it may be necessary to consider using chemicals for grub control.
I sent Robert, an undergraduate technician working in our lab, to several of the local lawn and garden centers in the Lansing Area to see what kinds of products are available that specifically claim they will work to control grubs. He went to 4 different stores and found 5 - 9 different products at each store. The profusion of different products can be rather mystifying.
The critical issue with any grub control product is the active ingredient. This can be determined by looking at the label on the bag. The active ingredient and % composition information can usually be found on the bottom right or left of the front of the bag. The second major concern is to make sure any product is thoroughly watered into the ground with at least a half inch or irrigation or rain immediately after the chemical is applied. There are 2 main strategies for grub control - preventive chemicals and curative chemicals. There are also products for sale that list grubs on the label - but will not work for grubs.
1)    PREVENTIVE PRODUCTS to prevent grubs next Fall (2012) and Spring (2013)
The interesting question when considering whether to use a preventive grub control product is "do I really need to?" These products should be applied before the grubs are large enough to be easily found. Grub damage, confirmed by the presence of lots of grubs in the spring (or previous fall) may very well indicate a grub preventive would be a good thing. If your neighbors have problems or if there is evidence of skunks or raccoons tearing up the turf to feed on the grubs, these are indications to look in your lawn in the spring, to see if grubs are present. As stated earlier, up to 5 grubs per square foot can be tolerated without there being any evident damage to the turf. If you sample several places in the yard and find that many of the spots sampled have more than 5 per ft², then consider a preventive compound application in the early summer. If you have treated for several years and you do not see evidence of grubs in your lawn or in the neighbor's lawn, it may be time to stop treating.  There is an erroneous philosophy being perpetuated that because we have European chafer and Japanese beetle in the area, it is necessary to treat every year or your lawn will be damaged by grubs. This is not true.
Preventive products work best at controlling grubs.
Products containing imidacloprid, thiamethoxam, halofenozide or chlorantraniloprole WILL NOT CONTROL GRUBS IN THE SPRING. They are preventive products that work very well on newly hatched grubs present in July, but do not work well for large grubs found from September to May. There are different recommended timings for application depending on the ingredient you buy. Although the bag often says apply anytime from May to Aug 15, it is highly recommended that products containing imidacloprid, thiamethoxam or halofenazide be applied and irrigated into the soil during June or July. If applied in the spring or fall, they will have no effect on the grubs currently in the lawn and may degrade or move through the soil by the time the grubs hatch in late July. Preventative applications should target the newly hatched grubs. Therefore, it's best to apply preventative products prior to July 15 so that the material can move into the soil to control the grubs that would be causing damage that fall and the following spring.
Preventive products containing imidacloprid, thiamethoxam, or halofenozide, when irrigated into the ground and applied between June 1^st and mid-July, will consistently give 75%-100% reduction of grubs.
There is a new active ingredient called chlorantraniliprole that is also very effective in preventing grub problems, but it is less water soluble than the three preventive compounds mentioned above. Since it takes quite a bit longer to move down to where the grubs will be, it is best to apply a product containing chorantraniliprole as early in the spring as is possible (no later than early May) for it to be most effective when the grubs hatch in July and Aug.
Chorantraniliprole, when applied in April or early May, and irrigated into the ground, will also give very good grub reductions for the following fall and spring of the next year.

2)  CURATIVE PRODUCTS - 
There are two chemicals, carbaryl and trichlorfon, that are considered curative treatments. They are short lived compounds that kill the active grubs. These are the only options available if high numbers of grubs are found in the fall after Labor Day and in the spring before early-May. Our research indicates they will kill 20-55% of the population. They are not as effective as the preventive compounds in reducing grub numbers. Consider carefully whether it would be best to wait and apply a preventive later. If the need should arise to use a curative compound, make sure to keep the infested lawn watered and fertilized and treat the area again with a preventive application the next summer or the problem will likely reoccur in the fall or the next spring. Current research also shows that watering with ½ inch of irrigation immediately after the application will increase the effectiveness of the insecticides. Our research has indicated that carbaryl has been a little more effective on European chafer grubs than trichlorfon. Both compounds work equally well on Japanese beetle grubs. It will take 10-14 days for the grubs to begin to die. One trichlorfon product called 'Bayer Advanced 24 Hour Grub Control' seems to indicate by the name that it will kill grubs in 24 hours. However, even trichlorfon should not be evaluated for at least 5 days after application (assuming it rains or irrigation was applied), and carbaryl may need 3 - 4 weeks to be effective.  Do not apply any curative compounds in the spring after May 15th as the grubs stop feeding in late May.
3)  INSECTICIDES THAT DO NOT WORK. 
Do not use products containing ONLY lambda-cyhalothrin, gamma-cyhalothrin, bifenthrin, deltamethrin, cyfluthrin or permethrin for grub control.  PRODUCTS CONTAINING ONLY THESE INGREDIENTS WILL NOT WORK FOR GRUB CONTROL because the active compound binds with organic material and will not move down to where the grubs are feeding. These products work well for above-ground feeding insects that live on the grass leaves or soil surface but not for insects that feed on the roots. There are a few combination products that include one of the above mentioned chemicals and one of the preventive compounds listed in section 1 above. These combination products will work to prevent grubs if applied in the early summer because they include a product that will move down to where the grubs are feeding. But I did find one product that said it would control grubs that contained only gamma-cyhalothrin. We tested this product in 2006 and the results were the same as doing nothing at all.

IN SUMMARY:

• Check the bag to determine what active ingredient the product contains
• Do not use products containing only lambda-cyhalothin, gamma-cyhalothrin, bifenthrin, deltamethrin, cyfluthrin or permethrin for any phase of grub control.
• Do not use preventive compounds such as halfenozide, thiamethoxam or imidacloprid now. Use them in June or July to control grubs that would be damaging turf in the fall.
• The preventive compound chlorantraniliprole should be applied in late April or Early May to control grubs that would be damaging turf in the fall, as it will take longer for the material to move to where the grubs will be feeding in July.
• To kill grubs in the spring ­(or fall) use carbaryl or trichlorfon and irrigate. Make sure the turf is watered with ½" of irrigation (see what is a ½" below) and fertilized.
• Always wear rubber gloves and rubber boots when applying insecticides to turfgrass.  Make sure to irrigate the lawn with at least ½ inch of water and allow the grass to dry before allowing anyone (or pets) into the treated area.
• Store insecticide products in a locked cabinet not accessible to children.

What is a ½" of irrigation?  A ½" of irrigation is when lawn sprinklers are run until a coffee mug (or several mugs) fills to a level ½" up from the bottom of the cup.

PRODUCTS AVAILABLE:
A short list of products now being sold for grub control as of 4/20/2012 in the 4 stores checked in the mid-Michigan area.
Gardentech Sevin Lawn Insect Granules
carbaryl 2.0%
Apply in spring or fall to active grubs.

(local distributors name) Lawn Insect Control and Fertilizer
carbaryl 4.3% and fertilizer
Apply in spring or fall to active grubs.

Bayer Advanced 24 hr Grub Killer Plus
trichlorfon 9.3%
Apply in spring or fall to active grubs.

Scotts Grub-Ex
chlorantraniliprole 0.08%
Apply between April 15 and May 15 for best results.

Bonide Grub Beater
imidacloprid 0.5%
Apply between June 1 and July 15 for best results.

ImiGold 0.5% G
imidacloprid 0.5%
Apply between June 1 and July 15 for best results.

Imida Pro 2SC
imidacloprid 21.4% (must be diluted in water and sprayed)
Apply between June 1 and July 15 for best results.

Bayer Advanced Season Long Grub Control and Turf Revitalizer
imidacloprid 0.25% and fertilizer
Apply between June 1 and July 15 for best results.

Bayer Advanced Complete Insect Killer
cyfluthrin 0.05% and imidacloprid 0.15%
Apply between June 1 and July 15 for best results.

(local distributors name) Premium Grub Control (Do not confuse with "Premium Insect Control")
imidacloprid 0.2%
Apply between June 1 and July 15 for best results.

Spectracide Triazicide Insect Killer Once and Done Granules
gamma-cyhalothrin 0.05%
Will not kill grubs at any rate.
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