PEST MANAGEMENT

By Geoffrey Rinehart

Integrated pest management ( IPM ) is a process of integrating several approaches to the management of insects with the goal of keeping damaging populations below threshold levels . For insects , these threshold levels are usually expressed as “ individuals found per square foot ” or “ per trap ” over a given period of time .

Some popular scouting techniques include soap flushes ( helpful for cutworms , sod webworms and cranefly larva ) and pitfall traps ( for adult billbugs ). It ’ s important to realize that many beneficial insects are at work regulating pest populations by way of predation and parasitism . Thus , successful IPM programs seek ways to preserve these beneficials by using targeted threshold levels and applying products that minimize off-target impacts .

Broad-spectrum products such as pyrethroids provide quick knockdown of pests that come into contact with the product , but these products can also knock back beneficial populations . Active ingredients such as chlorantraniliprole , tetraniliprole , spinosad and Bacillus thuringensis are more targeted to pests and have relatively little impact on beneficials within the turfgrass system .

Some varieties of tall fescue , fine fescue and perennial ryegrass contain symbiotic fungi called endophytes . Endophytes grow between cells of the turfgrass plant and can be transmitted via seed . These fungi help to impart some degree of drought tolerance , but , more notably , render the plant unpalatable to surface-feeding insects . Examples of surface-feeding insects include chinch bugs , billbugs , sod webworms , armyworms and cutworms ( note : grubs are a “ root-feeding ” insect ). It ’ s important to be aware that testing for endophytes may be inconsistent among seed companies , and those varieties that have been shown to possess endophytes often have their potency dissipate with time if seed is stored at high temperatures or for long periods of time .

Sound turfgrass cultural practices are the foundation for integrated pest management . In an increasing number of jurisdictions , pesticide usage on school grounds is being restricted , so it is especially incumbent

Billbug . Photo by Geoffrey Rinehart

upon field managers to implement proper cultural practices . Except for grubs and — at certain life stages — craneflies , most of the notable insect pests of coolseason fields are surface feeders . With this in mind , using turfgrass varieties that contain endophytes will go a long way toward preventing insect damage .

The population threshold levels represent ranges of pest populations . Typically , the turfgrass should be able to sustain populations in the higher part of that range if root growth is good and the sward consists of healthy plants . Cultivating to control thatch ; aerifying to relieve compaction and allow better soil oxygen exchange ; irrigating properly ; ensuring adequate fertility for the species and use level of your field ; and mowing at the high end of the mowing range ( based upon the species and desired function of the field ) all go a long way to encouraging a well-maintained , durable field that is more tolerant of pests . Overwatering , over- or underfertilizing , mowing too low or not cultivating can lead to unthrifty turfgrass swards that are most susceptible to insect pest pressures .

An important factor in limiting insect pest populations is the presence of beneficial predators . Beneficials are insects and other arthropods that provide natural control of pests when present in sufficient populations , and can be specific or generalists . Since many beneficial

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