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2008-2009 Jacumba Eye Gnat Research Project 2008-2009 Jacumba Eye Gnat Research Project University of California Cooperative Extension San Diego County.

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Presentation on theme: "2008-2009 Jacumba Eye Gnat Research Project 2008-2009 Jacumba Eye Gnat Research Project University of California Cooperative Extension San Diego County."— Presentation transcript:

1 Jacumba Eye Gnat Research Project Jacumba Eye Gnat Research Project University of California Cooperative Extension San Diego County Bryan Vander Mey, Staff Research Associate James Bethke, Floriculture & Nursery Farm Advisor

2 Acknowledgements Community of Jacumba – patients, friendliness, hospitality, trial cooperation John Prock and Josh Waddell, Bornt Farms Tom L. – provided chain to pull me out Julie C. & Beverly - emergence trap participants David W. – various experiments Sonia (Jacumba Spa) – emergence trap and spray trial Bill Pape – gnat influxes and community info Paula W. – helpful and happy

3 Eye Gnat Quiz 1) Eye Gnats are a native species to California? True False

4 1) Eye Gnats are a native species to California? True False

5 2)There are eye gnats in other parts of the United States? TrueFalse

6 2)There are eye gnats in other parts of the United States? TrueFalse

7 3) Eye Gnats hover in large numbers by non-animal objects (trees, telephone poles, etc.)? TrueFalse

8 3) Eye Gnats hover in large numbers by non-animal objects (trees, telephone poles, etc.)? TrueFalse

9 4) Eye Gnats will lay their eggs in manure? TrueFalse

10 4) Eye Gnats will lay their eggs in manure? TrueFalse

11 5) Removing water for 3-4 weeks will kill eye gnat eggs? TrueFalse

12 5) Removing water for 3-4 weeks will kill eye gnat eggs? TrueFalse

13 Who are these guys? Liohippelates Collusor

14 Eye Gnat Facts Life cycle varies greatly- 3 weeks to 6 months (up to 2 months for adults) Prefer light sandy soil with rich organic matter and moist conditions (not swamp) Attracted to people/animals, putrefied eggs, fish meal, freshly tilled land Not attracted to UV light, conventional fly traps, garbage, dung

15 Use lawns/foliage as shelter. Walking around stirs them up. Attracted to movement Require protein for egg production Not strong fliers - low flying & seek shelter when windy –Have been documented up to 4 miles from origin Eggs/larvae overwinter in soil.

16 Have not responded well to pesticide applications –Entrust (Spinosad) has little effect on adult eye gnats “lower than 20% mortality at the highest dosage of 0.08 mg A.I. cm 2 ”- Susceptibility of the adult eye gnat L. Collusor to neonicotinoids and spinosad insecticides, Y. Jiang, M. Mulla No single natural predator; cumulative predators have light to moderate impact.

17 2008 Jacumba Summer Trials Goals – To find out where they are coming from and where they are concentrated 1 st & 2 nd emergence test – Where the gnats are breeding (Do plant stages effect where gnats lay eggs?) 3 rd emergence test – What cultural practices reduce the number of emergence Bait trap trial - Where are the highest populations

18 Emergence Trial – How it works Cages consist of PCV covered with a white mesh (2’W X 2’L X 1’H) Prevents gnats from entering and escaping Set cages on the ground for 3-4 weeks Jars with holes are attached to the inside of the cages and filled with egg bait Emerging adults drown in egg bait Egg bait filtered and eye gnats counted

19 Emergence Traps

20 Emergence Trial #1 Data Trap #Trap LocationAve. MeanGnats/Acre 1Lawn2.5834, Days after planting Red Leaf Lettuce 58, Days after planting Spinach , Days after planting Red Leaf Lettuce ,219

21 Emergence Trial #2 Located at Jacumba Spa and Resort Treated lawn with Tempo Ultra WSP Put trap in treated and non-treated areas Measured number of gnats for two weeks Expect gnats emerging from non-treated area No gnats were caught in either the treated or untreated

22 What did we learn? Eye gnats are not primarily breeding in grass or lawns Most of the gnats are emerging from the soil at the farm 8 day spinach almost always had the highest number of emerging gnats – Soil preference? Higher OM? Why?

23 Emergence Trial #3 Old way (pre 2007 – disc in crop residue) New way (2008) – blade crop on surface and let the organic matter dry up in the sun, reducing organic matter incorporated into soil Expectations- New way should reduce the number of gnats emerging

24 Emergence Trial #3 Data Trap #Trap Location 2-Oct Ave. 6-Oct Ave. 9-Oct Ave. 13-Oct Ave. 16-Oct Ave. 20-Oct Ave. Ave. Mean 1 North Hwy 80 (burned) South Hwy 80 (disc)

25 What did we learn? Soil preference more important than previously thought? South field heavier soil than north side –Should have done soil sample to measure OM during test Believe this practice was the main reason for the lower gnat populations this year

26 Collar Bait Trap Traps put every 1000 ft. around town and at the farm Traps consist of two canning jars attached by a 3-inch ABS coupler. Funnel inside upper jar to prevent gnats from escaping. Left hours and collected Gnats counted in each trap to get a “snapshot” of population distribution

27 Collar Trap

28 Collar Trap Trail #3 (October 28-30, 2008) No. of gnats/48 hours Green = Yellow = Orange = Red =

29 What did we learn? Higher population in town than at the farm.

30 Summer Conclusions Eye gnats are emerging primarily at the farm After hatching, they head to town for : Food? Shelter? What & Why? Return to farm to lay eggs

31 Needed Research Mycotrol O / Botanigard ES –Fungus (Beauveria bassianna) that attacks insects and larvae Gnatrol –Bt (bacteria) that may have effect on larvae Neemix 4.5 –Insect Growth Regulator –Kills larval stages of insects; interferes with the insects ability to molt –Any activity with eye gnats?

32 Needed Research Predatory Nematodes –Small worms that attack larvae in the soil –Test untreated/treated emergence traps Flight Characteristics –Set traps at different heights to see how high the gnats are traveling –How do they migrate? When?

33 Potential Solutions Construct a tree or solid fence barrier with bottle traps along east side of town. –Creates place of shelter –Creates food source/trap –Creates wind/dust barrier between farm and town –Long term/Low maintenance

34 Potential Solutions Hire a commercial applicator to spray community vegetation

35 Potential Solutions Continued work at the farm involving new cultural practices –Reducing organic matter production –Irrigation timings –Weed control –Pesticide applications if proved effective in the lab –Spray oil (applications on crop residue)

36 Trap Design 2 liter or water bottle traps –2 to 3 holes on upper portion and filled with egg bait Collar Traps

37 Angled Entrance Design

38 The “Gnatinator”

39 Eye Gnat Avoidance Products containing DEET Avon’s Skin-So-Soft Absorbine Jr. Dryer sheets (attached to hats, around sunglasses, etc.) Mosquito head net Screened canopies / enclosures Community involvement with trapping

40 THANK YOU! University of California Cooperative Extension, County of San Diego Jim Bethke, Floriculture & Nursery Farm Advisor Bryan Vander Mey, Staff Research Associate, Eye Gnat Project Farm & Home Advisors Office 334 Via Vera Cruz, Suite 152 San Marcos, CA (760)


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