European Crane Fly


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European Crane Fly

  1. 1. European Crane Fly Tipula paludosa Tom Cook Dept. of Horticulture Oregon State University Updated Feb 2008
  2. 2. European crane fly first arrived in the Vancouver, BC area in the 1960’s. Since then it has moved south and is currently found throughout western Washington and most of western Oregon. Isolated outbreaks have been observed in the Spokane, WA area and in the Bend-Redmond area in Oregon. This is an unusual insect in that it causes most of its damage in late winter and early spring as larvae feeding on all parts of the plant. While we think of it as a turfgrass pest it is also active on many ornamental perennials. The historical pattern for this insect is to move quietly into an area where it may develop to very high populations within a year or two. Suddenly, out of the blue people start observing damage in the spring. Since no one was looking the initial damage from this insect can be quite severe. After a few years, reports of damage decrease and we typically see just an occasional flare up during a ‘good year’ for larval development. This slide show depicts the life cycle for this European crane fly and points out the times of the year to monitor for activity and when to use control strategies. Understanding the natural cycle for crane fly will help you avoid needless use of insecticides.
  3. 3. European Crane Fly Adult Male Crane fly adults emerge over about a two month period from late August through October. The adult forms are harmless to turf. J F M A M J J A S O N D T Cook photo
  4. 4. European Crane Fly Adult Female Female crane fly adults are larger than the male adults. The female body is longer than the wings and tapers to a pointed ovipositor used to disseminate eggs. T Cook photo
  5. 5. Crane flies mate shortly after emerging from the pupae Adults mate shortly after hatching out. Adult crane flies live for only a few weeks at the most so they have to work fast! T Cook photo
  6. 6. Females lay eggs in thatch Gravid females are not able to fly very far so they tend to lay their eggs by walking over an area and depositing eggs in the lower thatch layer via the long ovipositor. Each female can lay several Ovipositor hundred eggs. The female dies shortly after egg lay. T Cook photo
  7. 7. Crane fly eggs European crane fly eggs are tiny; just slightly larger than grains of sand. They have to remain constantly moist for the 10-14 days needed to hatch. Drying during the incubation period will kill a high percentage of the eggs.
  8. 8. Crane fly development European crane fly develops through four instar stages prior to pupation. This photo shows each of the first three instar stages. The first and second instars last only about a month each and neither instar causes any damage to the turf. The third instar appears generally in December and may be active through April. This is the stage that causes damage by feeding on shoots and roots. The third instar is commonly referred to as a leather jacket. Damage is most likely to occur in February through March in most years. 2nd Instar 3rd Instar 1st Instar J F M A M J J A S O N D J T Cook photo
  9. 9. J F M A M J J A S O N D J 3rd or 4th instar larvae in soil beneath turf Crane fly larvae live their entire lives in the zone from 0 to 3” deep. The fourth instar is similar in appearance to the third instar but it does not actively feed and is not associated with damage though it often is the stage we see after damage has occurred. The fourth instar 3” is active through July. 4th instar T Cook photo
  10. 10. European crane fly pupa The fourth instar molts into the pupal stage by August. Pupation takes about 4 weeks after which adults emerge to start the cycle over. Crane fly pupae appear to be modeled after King Tut’s sarcophagus! T Cook photo
  11. 11. European crane fly adults emerge in fall It’s fun to watch crane fly emerge from the pupa. First the head and legs break through the tip of the pupal casing. The legs are then positioned and the struggle to emerge begins. During emergence, the body stretches to about 1.5 times its normal length. After emergence, the body shrinks back to normal and its short life begins in earnest. Emergence appears to occur primarily in morning or late afternoon. T Cook photo
  12. 12. Pupal casings are easy to see during the fall hatch period. Pupal casing on putting green just after emergence T Cook photos
  13. 13. Tipula paludosa Life Cycle J F M A M J J A S O N D Adults Eggs 3rd 4th 1st 2nd 3rd Larvae Pupae Produces one generation per year Injury may occur If you put it all together the life cycle for European crane fly looks like this. People tend to freak out in fall when adults are active and miss the early spring period when damage actually occurs.
  14. 14. Crane fly 3rd instar larvae feed primarily on the foliar parts of the plants Carne fly damage starts out with simple thinning of turf. You may notice that growth seems to slow down when it should be increasing. You may also notice increased starling activity as they look for larvae. T Cook photo
  15. 15. As feeding progresses, turf thinning becomes more pronounced As feeding continues, the turf gets much thinner and weaker. If you do nothing, a heavy infestation can literally remove all of the turf. On the other hand, a modest infestation may thin turf about 50% with no lasting damage to the turf. This is about like a good dethatching. T Cook photo
  16. 16. End point without treatment In this case nothing was done and severe turf injury occurred. The larvae in this picture are all 4th instar larvae. The damage was done by the 3rd instar larvae, which then molted into the 4th instars. Applying an insecticide now will serve no purpose since the damage is already done. T Cook photo
  17. 17. Practical monitoring for 3rd instar larvae Monitoring for larvae is the best way to determine the potential for turf damage in any given year. 6” spade Simply remove a 6” x 6” chunk of turf about 3” deep. Break up the soil and count larvae. Multiply the total count by 4 and you will have the number of 3rd instar larvae per square foot. Monitoring should start in mid-January. If you are finding larvae repeat on two week intervals during February. T Cook photo
  18. 18. Monitoring Schedule No History: Start in January Prior History: Start in December SAMPLE EVERY TWO WEEKS
  19. 19. Curative Control Existing Turf Treatment threshold for 3rd instar larvae: WSU: 15-25 larvae /sq ft OSU: 25-50 larvae /sq ft plus visible turf thinning Over time we have established empirical thresholds for when you need to do something to avoid significant damage to lawns. WSU uses a conservative threshold of 15-25 larvae per sq ft. In Oregon I use 25-50 larvae per sq ft and visible signs of turf thinning. My rationale is that it doesn’t matter how many larvae you find If there is no sign of damage. Healthy lawns can tolerate very large numbers of larvae and show no signs of damage. Since the Beavers beat WSU this year in football, the smart move is to use the OSU threshold!
  20. 20. A few crane fly larvae in an otherwise healthy lawn do not require treatment T Cook photos
  21. 21. High larval populations and turf thinning indicate that treatment is needed to save the lawn. In this case larvae reached 60 /square foot. T Cook photos
  22. 22. Cultural control of crane fly 1.Maintain healthy turf 2.Stop irrigation after Labor Day Dense healthy turf will rarely show damage from crane fly larvae. I have observed that healthy lawns can tolerate as much as 50% thinning and recover completely by early summer. People who want really nice lawns often tend to over irrigate their lawns in general and specifically going into fall. Since moisture during egg lay ensures large crane fly larval populations, wet lawns often have the worst infestations. In much of the PNW we can shut water off after labor day without any impact on the appearance of our turf. By drying out the turf during the egg lay period we can kill a large percentage of the eggs. Fewer eggs means fewer larvae and less chance of turf damage. As long as the fall period is dry this approach can help us avoid turf damage and reduce the likelihood that we will need to apply insecticides to control larvae in spring.
  23. 23. Curative Control Chemicals Target 3rd Instar larvae (December-April) Dursban (Golf only) Sevin Talstar Deltaguard
  24. 24. Preventive Control Chemicals Target 1-2nd Instar larvae (Sept-October) Merit (Sept) Dursban (Golf only) Sevin Talstar Tempo Preventive control works very well, but it is based on a false premise that you are definitely going to have a problem with crane fly. In perennial trouble spots this might make sense, but in the vast majority of lawns crane fly do not attack the same site every year. I think we can control crane fly just fine by using the monitoring approach. Of the products listed above Merit definitely works better applied as a preventive chemical than it does once the larvae get larger.
  25. 25. Crane Fly Control in New Lawns Target 1-2nd Instar larvae (Sept-October) Dursban (Golf only) Sevin Talstar Tempo Several years ago I started getting calls from the Tillamook area about crane flies destroying new lawns planted in the fall. When you think about it, if you plant a lawn around the time the crane fly are laying eggs it will be a perfect environment for larvae to develop in because you will be irrigating it frequently. If you plan on planting during this period you may have to treat preventively to avoid losing your lawn. Options include planting in spring through midsummer in coastal areas so your lawn will be more mature come fall. I haven’t seen much problem with this in other parts of Oregon.
  26. 26. What about other crane fly species? There are many different species of crane fly. The majority do not affect turf at all. One that is frequently found in lawns is the common crane fly, Tipula oleracea. It cause quite a stir when it was first observed because it apparently produces two generations each year so we now see adults emerging in spring as well as fall. The following slides denote the differences between the appearance of the European crane fly and the common crane fly. I have also developed a life cycle chart that shows how each species overlaps during the year. We normally find both crane fly species in most lawns.
  27. 27. European crane fly Common crane fly Tipula paludosa Tipula oleracea
  28. 28. Differences between European crane fly and Common crane fly Tipula paludosa wings (A) are shorter than the abdomen (B). A B T Cook photo
  29. 29. General Observations: 1. European crane fly out number common crane fly approx. 9 to 1 2. No documented damage from common crane fly 3. European crane fly control efforts will also control common crane fly
  30. 30. T. oleracea & T. paludosa Combined Life Cycles J F M A M J J A S O N D Adults Eggs Larvae Pupae Based on two generations per year for T. oleracea TO spring T O fall TP and one generation for T. paludosa I have never seen damage from the summer generation of common crane fly. The fall generation can generally be controlled by following procedures for European crane fly. I don’t consider the common crane fly as a big problem.
  31. 31. Final thoughts: 1. Crane fly damage is worse when they first invade a new area. 2. Crane fly damage is more likely in wet or otherwise stressed areas. 3. Damage is usually sporadic in a given area. 4. Monitoring can reduce insecticide use up to 80%