Japanese Beetle Grub
Can you put grub killer and fertilizer down at the same time?
Yes, there are several fertilizer + grub control products available. There is a difference between curative and preventative products. The curative products work on grubs that are causing noticeable damage and the preventative products will kill newly hatched grubs – hence the term “season-long grub control”.
If you have a severe spring grub problem, then use a curative grub control – Any product that contains carbaryl (Sevin) + fertilizer will work on actively feeding grubs. Curative products need to be applied from March to Mid-May or from September through late October – before the grubs stop feeding.
Preventative products containing Merit (imidacloprid) + fertilizer should be applied between June 1st and July 15th for best results.
Lawn Damage Caused by Grubs?
Last year a section of my lawn started to turn brown in patches. I thought it wasn’t getting enough water so I gave it some extra water. Now that it is spring, it looks worse and I think it might have been grubs. Will I still be able to tell? If it was, should I treat it now or just put down new topsoil and seed?
Good question Marie. It is important to identify a pest and understand its life cycle before treating it.
White grubs are the larval stage of several beetle species. These have a one-year life cycle with the exception of the May beetle – it takes three years for May beetles to complete their life cycle. Grubs overwinter deep in the soil, make their way to the surface and feed a little in the spring, emerge as adult beetles mid-summer, then mate and lay eggs in the soil. The newly hatched larvae feed heavily in late summer through the fall – doing most damage from August through October.
If you have a grub problem, now is not the time to treat it since they stop feeding in Mid-May. It’s a good idea to go ahead and re-seed those dead patches now – then monitor for grubs in late summer.
Grub damage does start out looking like drought stress – they feed on grass roots. You will be able to easily pull up grass plants from the brown patches since the roots will be severed.
Another good clue that you have a grub problem is an invasion of skunks and birds – you may even see increased mole activity however worms are their entree of choice. The animals will tear up the turf looking for grubs to feed on.
To know for sure – roll back a section of sod. The grubs will be just under the soil surface feeding on roots. Consider treating if you find 8 to 12 grubs per ft2. A healthy lawn will be able to handle damage from less than 8 grubs per ft2 and won’t need to be treated.
Can I use the same Grub control product on any type of lawn in St. Augustine, Zoysia, Bermuda?
Yes, the same products will work on any type of lawn. The key is matching the right product for the time of year and grub activity.
“Curative” products should be used in the fall or spring and the “Preventative” grub control products should be applied late May through June – they target newly hatched grubs.