Lawn pests driving you buggy? Before you run out and buy a can of pesticide, there are two very important things you need to understand about insects and lawn pests.
Let's look at these points in a little more detail. In my experience in gardening and lawn care, insect pests arrive when there is an imbalance in the growing conditions that weaken the plants. For example, if a lawn is fed too much nitrogen, the grass grows very green and lush. This very lushness is a signal to some insects: “Lunch time!” The sugar content of the plant changes in response to the extra nitrogen and makes the plant that much more delicious to eat.
Some researchers believe that plants give off hormones and electronic vibrations that either attract or repel insects. When the plant is weakened, it sends a different signal than when it is growing strongly. Insects are able to interpret these changes and attack the weakened plants. How often have you seen a plant growing in your garden and blamed the insects for making it grow poorly? In reality, it was likely growing poorly and the insects were attracted to it. It is the same for the lawn. The lawn is simply a lot of individual grass plants growing together, and when they get sick, they send out different signals and the bugs come running.
To have a healthy pest-free lawn, you have to solve the underlying problems that are stopping the grass plants from achieving optimum health. Fix them and the pest population will decrease accordingly. Constant spraying with garden chemicals does not fix the underlying cause; it only puts a temporary bandage on the problem. Also, as we'll see, garden chemicals can create more problems than they cure.
Should a homeowner become upset when insects are roaming freely over the lawn? Not necessarily. As we all understand, there is a balance in nature, and the vast majority of insects are harmless to grass plants. In fact, many of the insects out on the lawn are just waiting to pounce on and eat the odd insect that likes to eat grass. We call these good guys beneficial predators or simply beneficials. The term used in the turf industry to determine whether pests are causing problems is threshold. For example, what is the threshold number of grubs on a lawn before spraying is necessary?
Please understand that to have the beneficials out there eating and protecting your lawn, you have to have something for them to eat. You have to create a balance in which the good guys can keep the bad guys in check (and the subsequent damage to your lawn minimal). If you spray a lawn to kill the odd bad bug, you'll be killing the beneficials as well. It is an unfortunate fact that the grass-eating pests can usually reproduce faster than the beneficials. When you kill off the beneficials, the first population to regrow to its former level is the pests. And there are no beneficials around to stop them from munching on your grass plants.
I once encountered a homeowner who wanted my advice. He stated quite clearly that he didn't want insects of any kind in his backyard and asked what spray he could use to kill everything. He and his wife didn't want worms, ladybugs, ants, beetles, or flies—nothing. They wanted to get rid of them all so they could sit out without being bothered by the wildlife. Hmmmm. My first suggestion was pavement, but he demurred. With my tongue firmly in my cheek, I suggested that he explode a personal nuclear device and that he could likely get one at his nearest discount store. Gardening is about creating balances with nature, and lawns are simply one thing that we homeowners do outside where we have to find that balance.
In human medicine, doctors refer to a disease cycle. This means that there are five separate things that have to occur in a progressive order that leads to disease. In both diagnosis and treatment, you have to start at the bottom of the cycle and work toward the top, you just can't start at the top. Turfgrass management has exactly the same cycle when a pest becomes a problem for our lawn. This is the lawn pest cycle.