Turf, March 2012

Grubs Billbugs and Chinch Bugs PHOTOS COURTESY OF DR DAVID SHETLAR Embrace new chemistries and proper application timing and you will knock out these tough turf damaging pests This is a Kentucky bluegrass lawn destroyed by the bluegrass billbug Notice the green tufts of perennial ryegrass that have survived because they contain endophytes Oftanol Triumph Turcam Diazinon and Dursban disappeared imidacloprid Merit burst onto the scene This was considered to be a low risk insecticide and it seemed to have pretty good efficacy and good residual action It was also discovered that it had systemic action When white grubs are an issue we know that turf that was damaged last year has on average about an 80 percent chance to suffer grub damage again Merit was first developed for white grub control but it was soon found that it did quite well against billbugs chinch bugs and mole crickets However to be most effective against these other insects it had to be used as a preventive rather than a curative treatment Pyrethroids continued to be the chemistry of choice for curative control Within another decade we had additional neonicotinoids insecticides such as thiamethoxam Meridian clothianidin Arena and the combination product Aloft and dinotefuran Zylam Unfortunately since Merit was the first of this class to be used in turf we have treated each of these neonics as if its a Merit clone In fact each neonic has unique properties In general insects exposed to neonics go into never never land They lose the ability to react to stimuli and they change their normal behavior They by David Shetlar Ph D T heres been a revolution in the types of insecticides registered for control of turfgrass insects over the past two decades These new insecticides have extended residual action different application timing strategies and fewer non target effects In 1996 the U S Environmental Protection Agency U S EPA was directed through the Food Quality Protection Act FQPA to re evaluate all registered pesticides with the goal of greatly decreasing real and potential exposures to people especially children But even prior to the FQPA most of the organochlorine insecticides e g DDT dieldren aldrin etc had been banned or restricted because of their accumulation in the environment and non target affects on animals Under FQPA standards the EPA first evaluated the organophosphates OPs and carbamates because these chemistries have the same mode of action cholinesterase inhibitors It was soon determined that too many of these OPs and carbamates were being used in urban areas Manufacturers were given the choice either keep these pesticides for use in agricultural production areas or spend a lot of money proving that theyre not overly exposing people in urban settings Virtually all the companies opted for the voluntary withdrawal of their OPs and carbamates from urban landscape use Faced with the loss of the major insecticide groups used to manage turf and ornamental plant pests chemical companies got busy developing new chemistries and new modes of action that were lower risk to humans and the environment A group of insect growth regulators were developed but this chemistry is difficult and expensive to make and use Most IGRs also have very narrow spectra of pests controlled There was also a great deal of work on new bio based pesticides derived from bacteria fungi or plants and also biological controls such as insect parasitic nematodes and fungi Neonicotinoids arrive The first major breakthrough was the discovery of the neonicotinoids This class of insecticides blocked the nicotinic receptors of nerves and insects use more of these types of receptors than other animals So as Continued on page A22 A20 TURF Turf Science March 2012