Onion Maggot Biology and Management

Transcription

1 Onion Maggot Biology and Management Updated March 2007 Brian A. Nault Department of Entomology Cornell University NYSAES Geneva, NY 14456

2 Onion Maggot Life Cycle * * days total Adult - Lives 2 to 4 weeks Puparium Egg - In soil for 2 to 4 weeks -Lays hundreds of eggs -Hatch in 2 to 5 days Larva - Feeds for 2 to 3 weeks

3 Seasonal Activity of Onion Maggot Flies In New York Number of flies/trap * 3 generations/year 4/26 5/18 5/31 6/13 6/30 7/12 7/25 8/8 8/22 Date Elba, NY -2005

4 Onion Crop in June

5 Onion Crop in September Undamaged Damaged

6 Onion Maggot is a Serious Problem in New York and Other Regions Infestations can be difficult to control Continuous onion production in same fields exacerbates development of high onion maggot populations Only two insecticides recommended (Trigard and Lorsban) Widespread resistance to Lorsban and possibly beginning resistance to Trigard

7 General Pest Management Tactics Chemical Cultural Plant Resistance Biological

8 Chemical Control For Control of Maggots: In-furrow treatments - chlorinated hydrocarbons, organophosphates and carbamates (up until 1970s and 1980s) In-furrow treatment - chlorpyrifos (Lorsban) (1970s present) Seed treatment cyromazine (Trigard) (1996 present) For Control of Flies: Foliar applications pyrethroids or other inexpensive broad-spectrum materials

9 Insecticides Currently Recommended At- Planting for Onion Maggot Control Product Active Ingredient Class Lorsban 4E chlorpyrifos Organophosphate Trigard 75WP cyromazine Triazine

10 Benefits of Seed Treatments as an Alternative to In-Furrow Treatments Easy to use Require less active ingredient (e.g., Trigard reduced amount of a.i. by 85% compared with Lorsban) Precise amount of crop protectant applied to each seed Safer for workers Taylor et al. (2001)

11 Onion Coatings Used for Seed Treatments Pelleted Untreated Film coated Encrusted E. M. Chirco

12 Promising New Insecticide Seed Treatments for Onion Maggot Control Trade Name Active Ingredient Rate Mundial 500* fipronil 2.5 g a.i./ 100 g of seed Entrust spinosad 0.2 mg a.i./seed Poncho 600 clothianidin 0.18 mg a.i./seed *Note: Mundial 500 formerly was called Regent

13 Objectives Compare efficacy of new seed treatments with efficacy of Lorsban and Trigard for controlling onion maggot Identify optimum rates of Entrust and Poncho 600 for onion maggot control

14 Untreated control

15 Onion Seedling Loss Due to Onion Maggot in Orange County, New York in 2005 (n= 4) Untreated a Lorsban Trigard bc ab Entrust (1.25 g) bc Entrust (2.5 g) Entrust (5 g) Poncho (1.25 g) Poncho (2.5 g) Poncho (5 g) Regent (2.5 g) d d d d cd d (*Note: 2.5 g a.i./100 g of seed is equivalent to 0.2 mg a.i./seed of spinosad and 0.18 mg a.i./seed of clothianidin) Mean Cumulative Seedling Loss (%)

16 Onion Seedling Loss due to Onion Maggot in Wayne Co., New York in 2005 (n=6) Untreated Lorsban (drench) Trigard Trigard+Lorsban e cde bc a Entrust (1.25 g) Entrust (2.5 g) bcd bc Entrust (5 g) Poncho (1.25 g) Poncho (2.5 g) Poncho (5 g) Regent (2.5 g) de de cde bc b (*Note: 2.5 g a.i./100 g of seed is equivalent to 0.2 mg a.i./seed of spinosad and 0.18 mg a.i./seed of clothianidin) Mean Cumulative Seedling Loss (%)

17 Lorsban (drench) Trigard Trigard+Lorsban Entrust (1.25 g) Entrust (2.5 g) Entrust (5 g) Poncho (1.25 g) Onion Seedling Loss due to Onion Maggot in Yates Co., New York in 2005 (n=6) Untreated Poncho (2.5 g) Poncho (5 g) Regent (2.5 g) e e cde bcd b bcd bcd de bc bcde Mean Cumulative Seedling Loss (%) a (*Note: 2.5 g a.i./100 g of seed is equivalent to 0.2 mg a.i./seed of spinosad and 0.18 mg a.i./seed of clothianidin)

18 Summary High rates of Entrust and Poncho were consistently effective against onion maggot and control was similar to levels provided by Regent and Trigard + Lorsban. Trigard alone and Lorsban alone were generally less effective than the high rates of Entrust, Poncho, Regent and Trigard + Lorsban.

19 Insecticide Sprays to Control Onion Maggot Flies

20 Limitations and Detriments Direct contact with insecticide required to kill flies Timing of spray is critical (dawn and dusk only) Sprays predicted to contact 10-20% in May/June and 0.2 to 4% in September Cost of insecticide, fuel and time May kill beneficial organisms that attack onion maggot and onion thrips and may accelerate insecticide resistance in onion thrips populations

21 Attract and Kill Using Insecticide-Baited Devices Starker Wright Prokopy et al. (2004). Fruit Notes.

22 Objectives 2006 To determine efficacy of spinosad-baited spheres for onion maggot fly control during entire season To determine the rate of spinosad that is most effective against onion maggot flies

23 Treatments Duration in Field 1. 1 month 2. 1 month 3. 1 month 4. 2 months 5. 2 months 6. 2 months 7. 3 months 8. 3 months 9. 3 months months months months Rate of Spinosad 1.0% 0.5% 0 1.0% 0.5% 0 1.0% 0.5% 0 1.0% 0.5% 0 * Split-plot experimental design ; each treatment replicated 6 times

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25 Cage Setup Sphere Water Food -20 flies released (50:50 sex ratio) -Mortality recorded over 3 days

26 Conditions of Spinosad-Baited Spheres after Various Periods in Onion Field 1month (mid May to mid June) 2 months (mid May to mid July) 3 months (mid May to mid August) 4 months (mid May to mid Sept)

27 Onion Maggot Fly Mortality After Exposure to Spinosad- Baited Spheres Mean % Mortality a b b a b Elba, NY 2006 b a b Control 0.50% 1.00% 1 month 2 months 3 months 4 months Season Average b a b b Duration of Spheres in Field a b b

28 Onion Maggot Female Mortality After Exposure to Spinosad-Baited Spheres 100 Elba, NY 2006 Mean % Mortality a a a a 0 1 month 2 months 3 months 4 months Duration of Spheres in Field

29 Onion Maggot Male Mortality After Exposure to Spinosad- Baited Spheres 100 Elba, NY 2006 Mean % Mortality a c ab bc 0 1 month 2 months 3 months 4 months Duration of Spheres in Field

30 Onion Maggot Fly (Both Sexes) Mortality After Exposure to Spinosad-Baited Spheres 100 Elba, NY 2006 Mean % Mortality a b ab ab 0 1 month 2 months 3 months 4 months Duration of Spheres in Field

31 Total Amount of Rainfall in Elba, NY in Rainfall (inches) st month 2nd month 3rd month 4th month Duration of Spheres in Field

32 Mean Number of Onion Maggot Flies Captured per Sticky Card Number of Flies/Card Male Female 1st month 2nd month Elba, NY rd month 4th month Season Total Period of Capture

33 Estimated Mean Number of Onion Maggot Flies Killed by a Single Spinosad-Baited Sphere Estimated Number Flies Killed/Sphere 200 Elba, NY total month 2 months 3 months 4 months Season Total Duration of Spheres in Field 36

34 Summary Flies attracted to spinosad-baited spheres (can include additional attractants like Delia lure) Spinosad is a safe biologically based insecticide Effective for entire onion-growing season (e.g., 16 weeks) and estimated to kill 55% of flies that visit One sphere estimated to kill 182 flies during season (36 females and 147 males) Spinosad-baited spheres can be hung along onion field edges Preliminary cost estimated to be $5 to $6 per trap

35 Cultural Control Crop rotation plant as far away as possible from last year s onion crop (Martinson et al., 1988) Sanitation remove volunteer and cull onions (Finch and Eckenrode 1985) Avoid mechanical injury during season and during lifting (Eckenrode and Nyrop, 1986; Finch et al., 1986) Delay planting date reduce time plants are exposed to flies (Doane and Chapman, 1952; Nault et al. unpublished)

36 Plant Resistance Allium cepa (onion) Allium fistulosum (Japanese bunching onion) hybrids *In all cases, some varieties have some tolerance to onion maggot under low pressure (Ellis and Eckenrode, 1979)

37 Biological Control Predators Bembidion quadrimaculatum carabid beetle (Grafius and Warner 1989) Aleochara bilineata staphylinid beetle (Tomlin et al. 1985) Parasitoid Aphaereta pallipes braconid wasp (Tomlin et al. 1985) Nematode Heterorhabditis bacteriophora (Yildrim and Hoy 2003) Fungi Entomophthora muscae- (Carruthers and Haynes 1986); Tu and Harris 1988) Paecilomyces fumosoroseus (Majchrowicz et al. 1990)

38 Other Tactics Non-woven fiber barriers- ethylene vinyl acetate, which operates as a physical barrier for oviposition (Hoffmann et al., 2001) Sterile male release radiation induced sterility (McEwen et al. 1984) Ovipositional deterrents cinnamyl derivatives and monoterpenoids (Cowles et al. 1990)

39 Conclusions Insecticide use will continue to be the principal management tactic for onion maggot in onion Seed treatments Cultural controls are effective, but further adoption must be encouraged Crop rotation, sanitation, delay planting date, etc. Host plant resistance is not a viable strategy at this time Biological control may have greater impact in future if broad-spectrum insecticide use on onion wanes