Turfgrass Insects

Primary Cultural Practices (PCP): 

Primary Cultural Practices (PCP) Mowing Fertility Irrigation Cultivation Pest Management

Turf Insects: Life Cycles: 

Turf Insects: Life Cycles Metamorphosis - series of changes during life cycle Molt - shedding of exoskeleton; increase in mass Instar - time interval between each molt Black turfgrass aetenius

Turf Insects: Metamorphosis: 

Turf Insects: Metamorphosis Simple: aphids, chinch bugs Egg-->nymph -->adult wingless nymphs resemble adults; may be > 1 nymph stage Complex: beetles, moths, flies Egg-->larva-->pupa-->adult Larva is always feeding stage; adults may/may not feed on turf grubs - beetles; caterpillars – moths; maggots - flies Adult = reproductive stage Mole cricket growth stages

Feeding mechanisms (mouth types): 

Feeding mechanisms (mouth types) Chewing: insect consumes plant tissue directly Piercing-Sucking: = plant juice sucking; toxins Both types can cause severe damage to turf shoots, roots, or crowns Highly maintained turf (mowed, H2O, fert.) is succulent & preferred Billbug with piercing-sucking mouth

Root Feeders: White Grub: 

Root Feeders: White Grub May & Japanese beetles North.,south. masked, European chafer Black turfgrass ataenius Aphodius beetles Golf course turf Characteristics C-shaped; white-grayish, brown heads; 6 sm. anterior legs 0.5-1.0” long (except atenius/aphodius: rice-grain sized) 1-yr. life cycle (except May beetle: 3 yr)

Grub Species Identification: 

Grub Species Identification Raster pattern: Arrangement of abdominal hairs unique to species May beetle raster Japanese beetle raster

White Grubs: Life Cycle: 

White Grubs: Life Cycle Larvae feed on roots, esp. late summer/fall; not adults Overwinter stage: larvae, deep in soil (except atenius/aphodius:adult). Resume spring feeding, pupate, adults in mid-summer

Diagnosing White Grubs: 

Diagnosing White Grubs Large areas dead turf: compounded w/ drought/heat stress Skunk, bird, mole damage Turf can be peeled back like carpet: no roots Grubs on soil

White Grub Control: 

White Grub Control Spp. ID impt! - how? why? Damage thresholds (# grubs/ft2) differ among spp. Susceptibility differs during season due to growth stage Chemical efficacy differs - esp. biocontrol Bt = (Bacillus thuringiensis): milky spore disease Chemical contact difficult and essential...how to achieve? Light, frequent irrigation for adventitious roots

Root and Shoot Feeders: 

Root and Shoot Feeders Bluegrass billbug = Kentucky bluegrass Adult lays eggs in shoots; larvae burrow to crown, later feed on roots. Pupate in fall; adults seen on pavement; overwinter Annual bluegrass weevil similar; feeds on shoots

Billbug Diagnosis: 

Billbug Diagnosis Brown patches of turf in summer Hollowed shoots easily pulled from crown Sawdustlike frass at feeding sites Larvae small, white w/ black head, legless

Mole Crickets: 

Mole Crickets #1 insect pest in south Hard to control: few chemicals Tawny mole cricket and damage to bermudagrass fairway Mole cricket infestation

Shoot Feeders: 

Shoot Feeders Sod webworms Larvae of lt. brown/tan lawn moths Chew leaves near base of leaf sheath Turf loss occurs during summer stress periods Female moths randomly drop eggs on turf at night Larvae live in thatch, feed at night

Sod Webworms: 

Sod Webworms Larvae: 0.75” long, tan-colored with spots. V. small anterior legs. 2 generations per season! Overwintering stage: larvae Diagnosis Large irregular brown areas of turf Chewed-off leaf blades at edge of patches Green frass in thatch of damaged turf Moths fly around turf; random egg drop

Cutworms (armyworms problem in warm season areas): 

Cutworms (armyworms problem in warm season areas) Black, legged caterpillars; 1.5-2” long Moth larvae Larvae feed at night on grass leaves; rest in thatch during day. Tunnels in turf Move from high cut turf to low cut turf Infested turf can be symptomless

Cutworms: 

Cutworms Usu. minor problem except on greens often cause damage around cups 1-4 generations/yr Overwintering stage: pupae or eggs in soil

Chinch bugs: 

Chinch bugs Nymphs & adults suck fluids from shoots Toxins cause chlorosis & death Life cycle Simple metamorphosis Adults lay eggs in leaf sheaths. Egg hatch is temp. depend.,10-30 days. 5 instars; 5-14 days/instar = 1-5 generations/yr Wet weather: fungus (Beauvaria) disease suppresses population

Chinch bugs: 

Chinch bugs Overwinter as adults: small (0.2” long) black w/ white folded wings Diagnosis Turf loss during hot, dry weather, esp. in sunny areas Use liquid soap or pyrethrin to float adults to surface

Aphids (greenbugs): 

Aphids (greenbugs) Serious pest only since 1970’s on KBG in midwest esp. shaded turf Piercing-sucking mouthparts; release toxins Adults birth live young! can reproduce w/out mating Incomplete life cycle Diagnosis Turf turns chlorotic, orange, then brown, usu. in summer See aphids infesting turf shoots Aphid damage under dripline of tree

Insecticides: 

Insecticides Chlordane/chlorinated hydrocarbons=BANNED! Current chemicals have short term persistence (sev. wks-months) Organic phosphorous compounds except bendiocarb, carbaryl,dicofol Diazinon canceled after 2003; Casualty of Food Quality Protection Act 1996

Insecticides: 

Insecticides Biocontrols becoming more common; efficacy poor (< 50% ctl) Biorationals Greater specificity Lower non-target toxicity, short environmental life Spinosad – insect growth regulator Imidacloprid (Merit) and halofenzide (Mach-2) -white grub control Trichlorfon (Dylox) and carbaryl (Sevin)

Insecticide Strategies: 

Insecticide Strategies Timing of applic. w/ suscept. life stage is critical! Positioning/retention of chemical also vital Irrigate immediately w/ 0.5” water for root-feeders use granules for root-feeders; less volatilization, photodecomposition or sticking to leaf surface Foliage-adhering sprays for shoot feeders apply late afternoon since feeding is at night

Insecticide Strategies: 

Insecticide Strategies Maintain healthy turf using cultural controls--insecticides last resort Chemically-resistant pops. can occur w/ frequent applic.