Hairy Chinch Bug

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Hairy chinch bug stages (l to r): egg, nymphs 1 to 5, and adult.
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Typical hairy chinch bug damage to a cool-season lawn.
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Normal winged hairy chinch bug adult (upper) and short winged form (below).
  • Scientific Name: Blissus leucopterus hirtus Montandon.


  • Common Names: Hairy chinch bug


  • Climatic Zone: Temperate


  • Geographic Distribution: Primarily Northeastern North America (the cool-season northeastern states and into southern Canada).


  • Damaging Stage: Adults and nymphs can kill stems.


  • Hosts: Most cool-season turfgrasses, primarily Kentucky bluegrass, perennial ryegrass (without endophytes), bentgrasses, tall and fine fescues (without endophytes), and crabgrass.


  • Damage Symptoms: Irregular patches of turf begin to yellow, turn brown and die. 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. Individual grass blades will often turn purple or reddish before wilting.


  • Description of Stages: These pests are true bugs and have a gradual life cycle with egg, nymphal and adult stages. All the species of Blissus are very similar in form and an expert is needed to separate species and subspecies.

Eggs: The eggs are elongate bean shaped, approximately 0.84mm long by 0.25mm wide, and are roundly pointed at one end and blunt at the other. The blunt end has several small tubercles visible through a dissecting microscope. The eggs are first white and change to bright orange just before hatching.

Nymphs: There are five nymphal instars which change considerably in color and markings. The first instar has a bright orange abdomen with a cream colored stripe across it, a brown head and thorax and is about 0.9mm long. The second through fourth instars continue to have this same general color pattern except that the orange color on the abdomen gradually changes to a purple gray with two black spots. The fourth instar increases to more than 2mm long. The fifth instar is very different because the wing pads are easily visible and the general color is now black. The abdomen is blue black with some darker black spots and the total body length is about 3mm.

Adults: The adults are approximately 3.5mm long and 0.75mm wide. The males are usually slightly smaller than the females. The head, pronotum and abdomen are gray black in color and covered with fine hairs. The wings are white with a black spot, the corium, located in the middle front edge. The legs often have a dark burnt orange tint. Individuals in a population, or in some cases, most of a local population may have short, called brachypterous, wings which reach only half way down the abdomen.


  • Life Cycle and Habits: The hairy chinch bug adults overwinter in the thatch and bases of clumps of grass in the turf. However, the common chinch bug prefers to fly to tall grasses of fields to find overwintering sites. These individuals then migrate in search of grain crops in the spring but may establish in turf instead. The adults become active when the daytime temperatures reach 70 °F. The females feed for a short period of time and mate when males are encountered. Eventually the females begin to lay eggs by inserting them into the folds of grass blades or into the thatch. This usually occurs in May from New York to Illinois. A single female may lay up to 200 eggs over 60 80 days. The eggs take about 20 30 days to hatch at temperatures below 70 °F but can hatch in as little as a week when above 80 °F. The young nymphs begin to feed by inserting their mouthparts in grass stems, usually while under a leaf sheath. The nymphs grow slowly at the beginning of the season because of cool temperatures but speed their development by July. Generally the first generation matures by mid July. At this time considerable numbers of adults and larger nymphs can be seen walking about on sidewalks or crawling up the sides of light colored buildings. If a good hot dry spring is available, turf injury by the first generation can be evident by June. Generally, the major damage is visible in July and August when the spring generation adults are feeding and their second generation nymphs are becoming active. During the hot summer months, the new females lay eggs rapidly and their young may mature by the end of August or the first of September. The second generation adults may lay a few eggs for a partial third generation if the season has been long. However, most of these late nymphs do not mature before winter temperatures drop. When cool temperatures arrive, the mature chinch bugs seek out protected areas for hibernation.


  • Control Approaches: Since chinch bugs have incomplete life cycles, they are relatively easy to control once they are detected. Using endophytic grasses that are known to kille chinch bugs are the best long-term strategy for eliminating the risk of having a chinch bug outbreak.

Cultural Control - Watering the Turf - Since this pest does best in hot dry conditions, irrigation during the spring and early summer may increase the incidence of pathogen spread, especially the lethal fungus, Beauveria spp. The adults can withstand water because of the protective hairs on the body but the nymphs readily get wet and can drown.

Cultural Control - Use Resistant Turfgrasses - Certain perennial ryegrasses and fescues (both tall and fine) that have endophytic fungi appear to be toxic to hairy chinch bugs. Using these grasses can greatly reduce the risk of hairy chinch bug outbreaks. In field tests, Yorktown, Yorktown II and Citation perennial ryegrasses are the most susceptable 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. Check current NTEP results for additional cultivars. Kentucky bluegrass cultivars also have differing susceptibility to hairy chinch bug attack.

Cultural Control - Recovery From Damage - Turf with light to moderate damage will recover rather quickly if lightly fertilized and watered regularly. Heavily infested lawns may have significant plant mortality, because of the toxic effect of chinch bug saliva and reseeding will be necessary. Unfortunatly, this often occurs when summer germinating weeds are most active. Thus, special care must be taken to reduce establishment of these undesireable plants.

Biological Control Several researchers have been trying to develop a usable formulation of Beauveria fungus but at present no practical material is available. Several egg parasites and an adult parasite are known but these do not seem to build up populations rapidly enough to control this pest. Currently no work is being undertaken to augment these parasites. Several predators, especially the bigeyed bugs, Geocoris spp., are noted to kill large numbers of chinch bugs. Bigeyed bugs are often mistaken for chinch bugs because of their similarity in size and shape. Bigeyed bugs usually do not build up large populations until after considerable turf damage has occurred. Use of the insect parasitic nematodes Steinernema spp. and Heterorhabtitis spp. have given inconsistant results when used against these chinch bugs.

Chemical Control - Insecticides -

Preventive Applications. In turf 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 May after the 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 that chinch bugs are indeed present especially if an unusually hot, dry spring has occurred.

Targeted Applicaitons. Chinch bugs are rather easy to detect in turf and targeted insecticide sprays can be applied to reduce populations which appear to be building to damaging levels.

Insecticides and Application. Most insecticides, when applied in liquid form, should not be watered in for chinch bug control, especially with high volume spray equipment. This is because the chinch bugs are surface and thatch residents. Watering in might wash the insecticide into the deep thatch layers without challenging the surface insects. Some of the granulars require some irrigation in order to activate the insecticide (release it from the granule).

Monitoring

Several sampling schemes have been developed for assessing chinch bug populations in turf. The simplest method is to visually inspect the turf by spreading the canopy. 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. A more reliable method is to use the flotation technique, counting the number of adults and nymphs present over a 10 minute span. Populations of 25 to 30 individuals per ft2 warrant control, especially if these numbers are encountered in June and July. More complicated sampling methods use repeated sampling over a long period of time, relating the population numbers to temperature and humidity parameters and predict future populations.