Turfgrass Insect Pests

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Turfgrass Insect Pests

• Biology, Diagnosis, and Control

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Biology, Diagnosis, and Control

• Importance and Nature of Injury
• Plants Attacked
• Distribution
• Distinguishing Characteristics
• Life History and Habits
• Management

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Surface Feeders Chewing

• Armyworms
• Sod Webworm

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Importance and Nature of Injury

• Both the True and Fall Armyworm are generally
  considered minor pests, but they have the
  potential for explosive outbreaks

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Importance and Nature of Injury

• True Armyworm
• Larger larvae chew whole turf plants down to the
  crown
• Larvae are gregarious and feed in a large group

• Fall Armyworm
• Large larvae devour entire turf plants down to
  the crown
• Uniform, militant (i.e., army) style feeding, but
  less gregarious than true armyworm

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Feeding Damage
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Plants Attacked

• True Armyworm
• ALL common turfgrasses

• Fall Armyworm
• Most turfgrasses including bermugagrass, creeping
  bentgrass, bluegrass, ryegrass, and fescue
• Bermudagrass is most often attacked

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Distribution

• True Armyworm
• Native species that is found throughout the
  United States

• Fall Armyworm
• Essentially a southern species which extends its
  range into the temperate regions (i.e., Great
  Plains and Midwest)

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Distinguishing Characteristics

• True Armyworm

• Fall Armyworm

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Life History and Habits

• True Armyworm
• Incapable of overwintering in northern U.S.
• There are up to three generations/year with the
  first in June
• Most larval feeding occurs at night

• Fall Armyworm
• Overwinters in southern states and migrates to
  north by late summer
• One generation/year
• Larvae feed both day and night

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Management

• Although quite unpredictable, armyworm outbreaks
  are more likely in years with a mild winter, a
  cool, moist spring, and early arrival of summer
• Because the occurrence of armyworms is erratic,
  preventative treatments are rarely justified

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Management

• Monitor adults with pheromone traps
• Monitor larvae with soap drenches
• Armyworms are easily controlled by spot or
  target-treating on an as needed basis

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Control Options

• Almost any surface insecticide will provide good
  control
• Liquid applications work best
• Irrigation and mowing should be withheld for 24
  hours after application
• Granular formulations are less effective

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Control Options

• Because armyworm damage can literally occur
  overnight, few alternative control strategies are
  effective
• Endophyte enhanced turfgrasses may provide
  meaningful resistance

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Sod Webworm

• Several sod webworm (SWW) species occur in the
  temperate-region
• Bluegrass sod webworm
• Larger sod webworm
• Striped sod webworm
• Western Lawn moth

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Importance and Nature of Injury

• Sod webworms hide in silk-lined burrows in the
  thatch and soil, emerging at night to feed on
  turf leaves and stems
• Initial damage appears as thinning brown patches
  of turf
• Severe infestations and damage coalesces into
  large irregular patches of brown, closely-cropped
  grass

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Feeding Damage
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Plants Attacked

• Sod webworms damage nearly all cool-season
  turfgrasses including Kentucky bluegrass,
  perennial ryegrass, fine-leaf and tall-fescues,
  and creeping bentgrass
• Endophyte-infected turfgrasses provide meaningful
  resistance

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Distribution

• Sod webworms are common across North America

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Distinguishing Characteristics

• Most sod webworm adults and larvae look similar
• Sod webworm adults have a characteristic
  elongated mouthpart that forms a snout and their
  wings are folded about the body in a resting
  position
• Most sod webworm larvae have characteristic dark,
  circular spots and coarse hairs scattered over
  the body

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Distinguishing Characteristics
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Life History and Habits

• All species of sod webworms have multiple
  generations/year
• Larvae make tube-like, silken tunnels in the
  thatch or soil surface where piles of green fecal
  pellets are often found
• Older larvae feed mainly at night

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Management

• Mere presence of SWW moths does not mean
  subsequent larval damage will occur, however
  watch for moth activity on turf near dusk to
  determine larval sampling program
• Close visual inspection is the best way to
  confirm a sod webworm infestation
• Sample with a soap flush to confirm

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Management

• Controls should be directed against feeding
  larvae
• SWW larvae are fairly easy to control on a
  curative basis
• Almost any surface insecticide will provide good
  control
• Liquid applications work best
• Irrigation and mowing should be withheld for 24
  hours after application
• Granular formulations are less effective

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Surface Feeders Piercing/Sucking

• Chinch Bugs

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Chinch Bugs
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Importance and Nature of Injury

• Chinch bugs damage turfgrass by sucking juices
  from leaves, stems and crowns, gradually causing
  yellowing
• As feeding progresses, the turf dries out and
  turns brown
• Ultimately, as sever chinch bug damage can result
  in drastic thinning or even death of the turf
  stand

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Importance and Nature of Injury

• Damage is usually the most prevalent in sunny
  locations during hot, dry periods and often
  mistaken for drought stress

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Feeding Damage
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Plants Attacked

• Chinch Bug
• Cool-season turf such as creeping bentgrass,
  Kentucky bluegrass, ryegrass, and fine-leaf
  fescues
• Zoysiagrass grown in the cool-season zone

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Distribution

• Chinch Bug
• Throughout the United States and Southern Canada

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Distinguishing Characteristics

• Nymphs or immatures resemble adults, however
  nymphs are wingless

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Distinguishing Characteristics
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Life History and Habits

• They overwinter as adults in turf
• There are typically 2 generations/year
• Most severe damage coincides with periods of heat
  and drought stress in July and August

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Management

• Chinch bug infestations can be sampled
  effectively with the flotation method
• Cut off both ends of a coffee can, insert the
  edge of one end into the turf to be tested, flood
  the can with water to the brim, maintaining the
  water level above the foliage.
• If present, chinch bug nymphs and adults will
  float to the surface within a few minutes

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Flotation Method
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Management

• Sound cultural practices that maintain turf in
  optimum condition are the best defense against
  chinch bugs
• Turf that is irrigated during dry periods is
  better able to tolerate chinch bug damage
• Endophyte infected turfgrasses (Perennial
  ryegrass and tall fescues ONLY) will provide
  meaningful resistance

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Endophyte Infected Turfgrass
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Management

• Various short-residual insecticides will
  effectively control chinch bugs
• For maximum efficacy, apply control product to
  the leaves, stems, and thatch
• Both granulars and liquids are effective
• Irrigation may be necessary depending of
  formulation and label requirements