More Preventive Strategies

NORTHERN LAWNS. Primary Target - Sod Webworms. Sod webworms rarely require a preventive control strategy. However, when drought conditions occur in consecutive years, sod webworms can cause unacceptable damage and a preventive control may be warranted. Some sod webworm species, especially the cranberry girdler, can cause damage in September and October. This species has one generation per year and controls applied two to three weeks after peak adult flight (mid- to late-July), are effective in preventing the
later larval damage.

SOUTHERN LAWNS. Primary Target - Other Pests. Damage to billbugs, especially to Bermudagrass or zoysia, is commonly misdiagnosed as disease, drought or winter damage. Hunting and Phoenician billbugs cause turf to die in patches and delay spring green up. A preventive approach can eliminate such damage. Application of imidacloprid or thiamethoxam in May or June appears to kill both billbug adults and subsequent larvae. Application of halofenozide in
June controls billbug larvae. Either of these applications should also control the secondary targets, white grubs and/or mole crickets. Application of carbaryl, diazinon or bendiocarb in July or August will also reduce billbug larval populations that can damage Bermudagrass during fall and winter dormancy. White grubs present when these applications are made will also be controlled.

At present, there are no registered insecticides that claim to provide long-term control of southern chinch bug. However, our view is that preventive programs in which imidacloprid or thiamethoxam are applied for control of primary targets such as mole crickets or grubs should suppress development of first generation southern chinch bugs. Suppression of at least this generation would likely impact development of succeeding generations; how many remains to be seen.

Research in Florida has indicated that entire lawns treated in May to July with acephate or a pyrethroid reduce southern chinch bug populations for most of the season. Where smaller lawns are chronically reinfested from untreated surrounding lawns, a preventive program can be used whereby insecticide is applied every three to four weeks until cool weather arrives in late fall.

Populations of southern chinch bug resistant to certain insecticides, especially organophosphates and/or carbamates, have been identified in Florida and Texas and can likely occur where this pest is active all year. If an insecticide application does not appear to be effective, switch to another insecticide, preferably one in a different chemical category. In order to reduce the development of resistance, attempt to reduce the number and frequency of insecticide applications in a season. An effective preventive control program for southern chinch bug in St. Augustinegrass has been to use resistant cultivars, such as ‘Floratam’ and ‘Floralawn’ though ‘Bitterblue,’ ‘Sevelle,’ and ‘Floratine’ have fair resistance. Localized populations of southern chinch bug have overcome the resistance factors of ‘Floratam.’

It has been our experience that where irrigation systems reach all parts of
the lawn and irrigation is applied on a daily or every-other-day basis,
natural Beauveria fungal infections appear to suppress chinch bugs below
damaging levels.

While common in Bermudagrass and St. Augustinegrass, spittlebug is primarily
a pest of centipedegrass. Where spittlebug is a chronic problem, a
preventive program of applying acephate, carbaryl or a pyrethroid at the
time of spring green up has been effective in eliminating hatching nymphs.

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