European crane fly (T. paludosa)
Pest description and crop damage European crane fly (ECF) is a native of western Europe which was introduced to eastern Canada and found in British Columbia in 1965. The mild winters, cool summers and relatively abundant rainfall in the PNW is ideal habitat for this insect and its range now extends as far south as central California. It has been documented east of the Cascades in Spokane WA and Bend, OR. The adult is a large two-winged fly that is often compared to a large mosquito. ECF have one generation per year. The larvae are wormlike, with leathery skin, 1 to 1.5 inches long. Larvae hatch in late summer (Aug.-Sept.) and feed through winter and into spring, causing the most damage in the spring (April and May). European cranefly larvae feed on turfgrass shoots, crowns, and roots. Affected turf areas often thin out severely in early spring when normal turf starts vigorous growth. Starlings and other birds are attracted to affected turf and may damage it as they search for larvae.
Biology and life history ECF overwinters as a third-instar larva in the soil. Adult emergence may begin anytime from July to mid-October. Adult males are 14 to 19 mm long, adult females are 19 to 25 mm long. Adult crane flies do not feed-they only drink water-and their life expectancy is 2 to 14 days. They usually mate and lay eggs within 24 hours of emergence. Eggs are laid in turfgrass. Eggs and early instar larvae require a very moist atmosphere or high mortality will occur; therefore, populations are greatest in turfgrass adjacent to saturated soils. Eggs hatch in approximately 11 to 15 days. The young larvae develop rapidly through to the third instar, known as leatherjackets, in which state they overwinter. At this stage the larvae feed on the turfgrass through the winter months into the spring, causing the most damage in the spring months of April and May.
Scouting and thresholds Monitor turf areas starting in November. A common clue that ECF are present is a high level of bird activity on the turf. Scout in the top 2 inches of the soil using a shovel. The action threshold for well-maintained turfgrass is 25 larvae per sq ft.
Management-cultural control
Observations indicate that drought stress at the time of egg lay may significantly reduce larval populations. In the Willamette valley of Oregon, turning off turf irrigation systems shortly after Labor Day will often create enough drought stress to reduce larval populations without causing damage to turf. Unfortunately, around Labor Day is when most of the overseeding and seeding of new lawns is done. If there has been a history of a high population of ECF larvae in the past on your newly seeded site, it would be advisable to apply a preventative application at the time of seeding to limit the feeding of ECF larvae on the newly developing grass plants.
Management-biological control
Research indicates larvae are not affected by endophytic fungi common in some varieties of perennial ryegrass, fine fescue, and tall fescue. Research in the PNW has indicated limited efficacy of beneficial nematodes (55% reduction in larvae at best). Applied biological controls in general have not been shown to be effective on this pest, although birds and mammals such as raccoons and skunks may be highly effective.
- beneficial nematodes-Nematodes may only achieve 50% control, but this may be an acceptable level of control in some situations. Read label carefully for application procedures, timing and appropriate soil temperatures for best efficacy.
Management-chemical control: HOME USE
Do not permit children or pets on the treated turfgrass until it has been watered to wash the insecticide into the turf and the grass is completely dry. Most insecticides are toxic to bees exposed to direct treatment or to residues on blooming weeds/ flowers in lawns: mow and remove clippings prior to applying insecticides.
- azadiractin (as a mix with other active ingredients)-Some formulations OMRI-listed for organic use.
- bifenthrin (often as a mix with other active ingredients)
- carbaryl
- chlorantraniliprole
- clothianidin (as a mix with pyriproxyfen)
- fenvalerate
- imidacloprid
- indoxacarb
- lambda-cyhalothrin
- plant essential oils (cedarwood, clove, mint, rosemary, etc.)-Some formulations are OMRI-listed for organic use.
- pyrethrins (as a mix with insecticidal soap)-Some formulations are OMRI-listed for organic use.
Management-chemical control: COMMERCIAL USE
When pest densities exceed thresholds, apply insecticides in the spring. Where serious prior infestations have occurred or when spring applications were missed, apply in mid-November to December. Most applications need irrigation or rainfall after treatment to get the insecticide to the thatch/soil interface layer where larvae are present. Do not permit children or pets on the treated turfgrass until it has been watered to wash the insecticide into the turf and the grass is completely dry. Most insecticides are toxic to bees exposed to direct treatment or to residues on blooming weeds/ flowers in lawns: mow and remove clippings prior to applying insecticides.
- azadiractin (Azaguard Botanical Insecticide/Nematicide)-For early larval instages in early fall for best results. OMRI-listed for organic use.
- bifenthrin (Talstar S Select Insecticide, multiple trade names)-Restricted use. Not all labels allow for applications to golf courses. Treatments should be timed from August to February; applications to late season larvae may provide suppression only. Mow the lawn first and remove the clippings. REI 12 hr. Bifenthrin is highly toxic to bees and other pollinators exposed to direct treatment or residues on blooming crops or weeds. Do not apply bifenthrin or allow it to drift to blooming crops or weeds if bees or other pollinating insects are foraging in the treatment area. Extremely toxic to fish and aquatic invertebrates. Do not apply if rain is expected within 24 hr or whatever time is necessary for product to dry.
- bifenthrin + imidacloprid (Allectus GC SC Insecticide)-Restricted use. Highly toxic to bees and other pollinators exposed to direct treatment or residues on blooming crops or weeds. Do not apply or allow to drift to blooming crops or weeds if bees or other pollinating insects are foraging in the treatment area. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
- bifenthrin + zeta-cypermethrin (Talstar XTRA Granular)-Not for use on golf course turf. Treatments should be timed from August to February; applications to late season larvae may provide suppression only.
- carbaryl (Sevin SL Carbaryl Insecticide, other trade names)-Treatments should be timed to early spring (April). Mow the lawn first and remove the clippings. Highly toxic to bees. Keep children and pets off the lawn until it has been thoroughly watered after treatment, and the grass is completely dry.
- chlorantraniliprole (Acelepryn Insecticide, Acelepryn G Insecticide)-Apply between September and November.
- clothianidin (Arena 0.25G Insecticide, Arena, 50 WG Insecticide, Arena 50 WDG Insecticide)-Apply in spring when larvae are mature bug prior to pupation, or apply in fall prior to egg hatch. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
- clothianidin + bifenthrin (Aloft GC SC Insecticide, Aloft LC G Insecticide, Aloft LC SC Insecticide)-Restricted use. Highly toxic to bees and other pollinators exposed to direct treatment or residues on blooming crops or weeds. Do not apply or allow to drift to blooming crops or weeds if bees or other pollinating insects are foraging in the treatment area. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
- cyantraniliprole (Ference)-Apply between mid-summer and fall.
- dinotefuran (Zylam)-Apply in spring when larvae are mature but prior to pupation, or apply in fall prior to egg hatch. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
- esfenvalerate + prallethrin + piperonyl butoxide (Onslaught FastCap Spider and Scorpion Insecticide) - Not for use on golf course turf.
- imidacloprid (Avatar PLX Insecticide, Lesco Bandit 2F Insecticide, Malice 0.5G, other trade names)-Apply at oviposition (Early September) for best results. Applications made later will not be successful. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
- indoxacarb (Provaunt)-Restricted use.
- lambda-cyhalothrin (Scimitar, other trade names)-Better results when applied at earlier instars. Not as effective as bifenthrin at later larval stages.
- thiamethoxam (Meridian 0.33G Insecticide, Meridian 25WG Insecticide, Flagship 25WG Insecticide)-Effective only when applied at oviposition. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
For more information: Cranefly pests of the PNW-http://whatcom.wsu.edu/cranefly/index.htm