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Adult Chinchbug

Chinchbugs

(crown & thatch inhabitant)

Several varieties of chinch bugs have been known to attack American turfgrasses. The hairy chinch bug (Blissus leucopterus hirtus Montandon) is the most common pest of northern turfgrasses, although the common chinch bug (Blissus leucopterus leucopterus Say) is occasionally found in cool season lawns.

The common chinch bug is normally found from South Dakota across to Virginia and south to a line running from mid-Texas across to mid-Georgia. The hairy chinch bug cohabits some of the northern range of the common chinch bug but also extends throughout the northeastern states and into southern Canada.

The hairy chinch bug prefers turfgrass species such as fine fescues, perennial ryegrasses, Kentucky bluegrass, bentgrass and zoysiagrass. The common chinch bug prefers grain crops such as sorghum, corn and wheat but will attack turfgrasses such as Bermudagrass, fescues, Kentucky bluegrass, perennial ryegrass, zoysiagrass and crabgrass.

Infestations of southern chinch bug are often related to drought conditions or non uniform irrigation. Populations can often be brought under control by correcting the watering distribution problems and beginning regular irrigation during the drought. Population decline and turf recovery are usually the result of a combination of chinch bugs being infected with the fungus disease, Beauveria, and vigorous turf growth.

Types of damage

Chinch bug damage is usually first detected when irregular patches of turf begin to turn yellow then straw colored. The straw colored areas may be completely dead. These patches continue to become larger in spite of watering.

Apparently, feeding by chinch bugs blocks the water and food conducting vessels of grass stems. By blocking the water, the leaves wither as in drought and the manufactured food doesn't get to the roots. The result is plant death. Damage generally occurs during hot, dry weather from June into September.

Control tactics

Chinch bugs are relatively easy to control if they are detected early. There is no preventative pesticide controls.

Cultural Control: Option 1

Since this pest requires hot dry conditions for optimum survival and reproduction, irrigation during the spring and early summer may increase the incidence of pathogen spread, especially the lethal fungus, Beauveria spp. Adults can withstand water because of the protective hairs on the body but the nymphs can be damaged by large water droplets.

Cultural Control: Option 2

The hairy chinch bug seems to prefer perennial ryegrasses and fine fescues, especially if these are in the sun and have thatch layers greater than 1/2". Bentgrass is also attacked but this turf is rarely used in lawns. Bluegrass lawns with 50% or more ryegrass and/or fine fescue are the most likely to be attacked. In field tests, Yorktown, Yorktown II and Citation perennial ryegrasses are the most susceptible to chinch bug build up, while Score, Pennfine and Manhattan are avoided. Jamestown and Banner fine fescues are more commonly attacked than FL-1, Mom Frr 25 and Mom Frr 33. In general, perennial ryegrasses, fine fescues and tall fescues with endophytes are highly resistant to this pest.

Cultural Control: Option 3

Slightly damaged turf will recover quickly if lightly fertilized and watered regularly. Heavily infested lawns may have significant plant mortality because of the toxic effect of chinch bug saliva—re-seeding will be necessary. Unfortunately, this often occurs when summer germinating weeds, especially crabgrass, are most active. Thus, additional controls for weeds may be necessary to reduce establishment of these undesirable plants.

Chemical Control: Option 4

Areas where chinch bugs have been a perennial problem, early insecticide sprays have been used to reduce the beginning spring population. This works well if applications are made in April or early-May after adults have finished spring migrations and the young nymphs are just becoming active. It is highly recommended that preventive sprays be used only if sampling has been done to determine chinch bugs are indeed present.

Chemical Control: Option 5

Chinch bugs are easy to detect in turf and targeted insecticide applications can be applied to reduce populations which appear to be building to harmful levels.

Sampling methods

The best place to look is in hot, dry places on your property. These are the conditions chinch bugs prefer and where their populations are more likely to rapidly grow. However, they are very sensitive to vibration and will scurry if they sense your footsteps. Step lightly when approaching areas you suspect of harboring the bugs. If no damaged areas are currently present, it's pure luck to actually find the chinchbug.

Several sampling schemes have been developed for determining chinch bug populations in turf:

Visually inspect the lawn by spreading the blades back. Chinch bug nymphs tend to hide in the deeper thatch and careful inspection is necessary. Unfortunately, eggs and small chinch bugs are easily missed using this technique.

If lawn areas are already damaged, inspect for the chinchbugs early in the day and in the green grass areas surrounding the dead looking areas.

A more reliable method is to use the flotation technique, counting the number of adults and nymphs present over a 10 minute span. To use the flotation technique, cut the top and bottom lids out a large coffee can. Twist the sharp edge of the can down through the turf into the underlying soil. Fill the can with water. Refill if the water soaks into the ground before the 10 minute period.

Sliding-foot method. Slowly sliding your foot through the sod and watching for the bugs to crawl across your shoe. That sounds easy enough. I have also noticed the distinctive, pungent odor of chinch bugs when I mow. It's not as reliable as other methods, but it has alerted me to stop and check for the bugs.

Integrated-turf-management workers advise that a level of 10 — 15 adult chinch bugs per square foot is a treatment threshold. I have never seen such a high count except when chinch bugs were already damaging the turf. Thus, to prevent visible damage, you may need to use a lower treatment threshold. Avoid treating without first verifying the presence of chinch bugs through sampling.

Insecticides and application

Most insecticides, when applied in liquid form, should not be watered in for chinch bug control. This is because chinch bugs are surface and thatch residents. Watering in will wash the insecticide into the soil and avoid working on these surface insects.

Some granular-type insecticides require irrigation to activate. Check instructions for current information.