Pests in turf can be looked at in a number of ways. The most obvious is that they’re pests, which can raise objectionable feelings in the viewpoint of the customer. Another is that they need to be removed from a lawn by somebody — and that somebody is you. Since you can’t hope them away, it’s wise to accept the fact that they arise and infest lawns, and strategies are necessary to keep them at bay. In terms of insect pests, the steps are to find them, identify them, learn a little about their biology and life cycles and then select control options that are both effective and soft on the environment.
Once identified, the next step in effective insect control is scouting — a regular and thorough inspection of the turf, looking for the presence of above and below ground activity. Simple tools are required for scouting. A pocket knife, sod spade, hand lens, plastic bucket and sampling bags will do the job nicely. Actually, one additional tool, a hari-hari knife is quite useful as well for quick and easy digging in close quarters.
Monitoring is best thought of as a series of scouting activities. For most pests, it’s best to scout for various insects, identify ones that are present, consider if they are numerous enough to pass pre- determined thresholds and make an appropriate insecticide application if needed. As with all pesticides, it’s critical to read and follow all label directions to obtain maximum efficacy paying close attention to dilution rate, pH of water, needed adjuvants, pre- and post-watering instructions, timing and interactions with other pesticides.
What are the top five worst turf insects?
In residential lawns, business park and campus grounds, there are many insects that cause damage, including sod webworms, chinch bugs, billbugs, cutworms and armyworms. However, by far, the ones that cause the greatest number of complaints as well as efforts for control are the white grubs — the northern and southern masked chafers, May/June beetles, black turfgrass ataenius and Japanese beetles.
Chuck Monico, owner of CM’s Lawn Care in Omaha, Nebraska, says: “Our treatment of grubs is on a proactive basis because our customers do not want the problem to occur. For many years, we relied on halofenozide (Mach II) for control. For the last 10 years, we have used imidacloprid (Merit). We are probably due for a chemistry change to chlorantraniliprole (Acelepryn) because of its longer window and broader spectrum. For late- season breakthroughs we will apply trichlorfon (Dylox).
“It is important to educate our customers on the types of grubs that may be present in any given season as well as to the concept of treatable thresholds,” Monico says. “Healthy yards can withstand mild infestations of grubs. Weaker stands of turf are compromised quite easily. Sometimes we receive calls from people who have outbreaks because they did not treat on a preventive basis. We encourage them to not peel back the turf but to have us treat the impacted areas with trichlorfon and to fertilize and water to stimulate root growth and recovery which often happens. Overseeding can also help. Foraging mammals (raccoons and skunks) cause more damage than the grubs themselves. Raccoons and skunks don’t care about treatable thresholds.”
When applying rescue treatments, it’s most effective to water thoroughly a day before treatment to drive the grubs upward in the soil profile, and then apply a granular insecticide followed by 1/2 to 1 inch of water to move the product through the thatch layer to reach the intended target. Core aeration before product application should also be considered, particularly when dealing with thick thatch layers and on slopes to reduce runoff. In heavy thatch situations, the use of added surfactants to lower the surface tension of the water should also be considered.
In other regions, chinch bugs and aphids can be quite persistent, requiring many applications of insecticides such as bifenthrin for control. Where feasible, scouting for insects two weeks before and after an application will provide fine-tuning as to the best application timing, as well as specific control information.
Success with insects.
Plant pathologists, weed scientists and entomologists have made recommendations in recent years to prevent pesticide resistance including identification of the pest, proper plant care and selection to reduce the need for applied insecticides, rotating among the various modes of action and making sure that the formulation reaches the site of pest activity. Using the recommended label rate as opposed to half doses is another technique that will lessen the likelihood of control failure and tendency for resistance.