Over the last two weeks, you may have asked your playing partners if we have aerified some of the approaches and fairways. While we have yet to take any machinery to these areas and punch holes, we have had some natural help with aerification.
The picture above displays voids in the turf similar to mechanical aerification. These areas are a direct result of this litter critter below:
Earthworms have long been associated with natural aerification of the sub-surface. In fact, we will find roots in the channels created by worms as they move about the soil. However, when we experience a lot of activity on the surface from these invertebrates, the result is detrimental to playing surfaces in which the game of golf is played upon.
Above is a close-up of the earthworm cast. During the nighttime hours, worms move upward in the soil to emerge on the surface to feed on almost anything they can find. Worms have been used for years in organic gardening to produce natural compost. As the worm emerges from the soil to the turf canopy, they bring a little amount of soil to the top, represented above.
The following day, traffic from golf carts, mowers, etc. will flatten the worm casting, spreading the mound over a wider area. This eventually will collapse the turf and the void in the surface is created. If you look closely at the picture above, you will see an area where the earthworm cast was compacted by traffic the previous day and in the same exact spot, an earthworm left a casting (small mound in voided area) overnight.
Above represents the wide scale damage from the activity we have experienced this fall. To the right of the golf ball you may be able to pick out the earthworm casting. What can we do to eliminate this eye sore?
The answer may lie in an approach designated as Integrated Pest Management (IPM). IPM refers to programs that combine not only chemical control but also biological, cultural and mechanical/ physical control.
Everyday we implement cultural programs to the course. An example of this is daily mowing of the playing surfaces.
A cultural control program for earthworms that has shown to be effective is the use of sand topdressing to the playing surfaces. Earthworms do not like to move in sandy soils. This is the reason we do not see any activities on the greens.
Can we simply incorporate a sand topdressing program to our fairways? Yes we can, HOWEVER, it is considerably expensive undertaking to battle earthworms. Yes there are advantages to topdressing fairways such as firmer playing surfaces and topdressing fairways helps with drainage, but this type of program is one that will take a few to several seasons to see the results for this type of investment.
Numerous golf courses throughout the area are seeing similar earthworm activity this time of year. It is a natural phenomenon. It should be noted that it is illegal to apply any chemical controls specifically for earthworms.