WAIT OR IT’S TOO LATE (Lawn & Garden)

In almost 35 years of answering yard and garden questions, I often joke I spend most of my time telling people to wait or that it’s too late to do anything for now.

During March, I’ve been telling people to wait to begin many lawn and garden practices. This is due to cold soils, and we are not past our average frost free date.

When it comes to controlling pests, timing is critical. When a control method is used at the correct time it can prevent or reduce plant damage. If used at the wrong time money is wasted, the environment may be harmed, and plant damage still occurs.

This is especially true when pesticides are used to control weeds, insects and diseases. As living organisms, all have a life cycle. There are only certain times in the life cycle when a pesticide is effective in controlling the pest or reducing plant damage.

Pesticides can be an important management tool but need to be used responsibly. Making an application when it will reduce plant damage is the main goal and the start of responsible use. I could use every plant pest as an example, but following are some common ones.

Responsible and effective pesticide use for crabgrass is an application of a preemergence herbicide in late April or early May. When applied at this time, only one application is needed and more crabgrass is controlled. It’s also the best time for the first fertilization leading to dense turf that competes with weeds.

If applied earlier in spring, a second application will likely be needed or some crabgrass will escape. The amount of herbicide applied is increased due to two applications, along with the cost of control and increasing the risk of herbicide resistant weeds.

We often see white grubs at this time of year when working in yard and garden soils. However, the grubs we see now will not cause damage and are very difficult to control with insecticides. This is the wrong time in this pest’s life cycle to attempt control.

It is the next generation that hatches in August that might cause lawn damage. Pesticides applied at a time of year will control young grubs shortly after hatching and before they damage the lawn. We cannot eliminate insects, we can only reduce their numbers enough to prevent damage.

Then there are different insecticide formulations. For grubs, we have preventive products applied before eggs hatch, typically June up to mid-July. And there are insecticides that work only if applied after eggs hatch and grubs are still small, typically mid to late August.

And we also battle the idea that if grub control is not used, lawn damage will occur. Insecticides only need to be applied to lawns that had damage last season. In the last 18 years, I’ve applied grub control only once and have had no damage.

Summer patch is a fungal disease that infects grass roots. Symptoms of this disease appear in July and August after plants are heat stressed. This is when homeowners want to apply a fungicide for control.

However, most fungicides work if applied at the time the fungus is infecting a plant which is always before symptoms appear.  For summer patch, the infection period is May. Once symptoms appear in July and August, it is too late for fungicides to be effective.

 As we move into the growing season, follow these steps for responsible pesticide use. Positively identify the cause of damage before using a pesticide. Determine if control is even needed. Then select the best control methods and use them at the correct time; which may not be until the next growing season.  

By: Kelly Feehan, Extension Educator
Release: March 29, 2017