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University of Florida Research Update

University of Florida Research Update. Eileen A. Buss Entomology & Nematology Dept. University of Florida/IFAS. Southern Chinch Bugs ( Blissus insularis ). Southern Chinch Bugs. 1 generation occurs about every 6-8 wks Multiple generations per year

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University of Florida Research Update

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  1. University of Florida Research Update Eileen A. Buss Entomology & Nematology Dept. University of Florida/IFAS

  2. Southern Chinch Bugs(Blissus insularis)

  3. Southern Chinch Bugs • 1 generation occurs about every 6-8 wks • Multiple generations per year • Adults may live up to 2 months, and each female can lay ca. 300 eggs • Populations are very aggregated; greater competition may lead to dispersal, lower survival, longer development, & fewer eggs • In colony, >70% RH is needed for survival, & development is faster at higher temperatures

  4. Resistance Management for the Southern Chinch Bug • Determine the mechanism(s) of resistance • Penetration of cuticle, enzymatic, metabolic, behavioral • Evaluate cross resistance • Develop rotation strategies based on the cross resistance profile • Test different insecticides for ovicidal activity • Assess the effect of nitrogen on chinch bug survival, development time, and fecundity • Determine how to adjust St. Augustinegrass fertilization practices

  5. Fertilization • Horn & Pritchett. 1962. Fla. Turfgrass Assoc. Bull. 9:3-5. • Excessive fertilization of lawns with quick-release inorganic N resulted in less chinch bug damage. • Slightly less fertilization actually increased chinch bug damage. • Busey & Snyder. 1993. Int’l Turf. Soc. Res. Jour. 7:353-357. • Chinch bug populations were greater on small plots fertilized with ammonium nitrate, IBDU, or milorganite compared to non-fertilized plots.

  6. Nitrogen Rate Test 2006 • St. Augustinegrass pots will be treated monthly with either 0, 0.5, 1.0, or 2.0 lbs soluble N/1000 sq. ft. • 12 L:12 D, 70-80% RH, and 29-31C • RCBD, 5 replicates • 1 attached runner from a pot will be inserted into a clear plastic container with 30 chinch bug eggs. • Length of time from egg hatch to adult emergence, percent survival, percentage of adults with long vs. short wings, ratio of males to females will be recorded. Tibial leg length, which is correlated with female fecundity, will be measured with an optical micrometer.

  7. Nitrogen Effects on Fecundity • Twenty fifth instars of similar age will be placed on each 3-inch long, attached runner. • Pots and chinch bug arenas will be maintained in the greenhouse under 12 L:12 D, 70-85% RH, and 31-33C. • Containers will be checked daily after nymphs have molted to adults, and eggs will be removed and counted daily for two months.

  8. Natural Enemies • Big-eyed bugs (Geocoris spp.) • Scelionid egg parasitoid (Eumicrosoma benefica) • Anthocorids (Xylocoris vicarius, Lasiochilus pallidulus) • Nabids (Pagasa pallipes) • Earwigs (Labidura riparia) • Several ant species • Spiders (Lycosa spp.) Reinert, J. A. 1978. Ann. Entomol. Soc. Am 71: 728-731.

  9. Effect of Pesticides on Beneficials • Geocoris uliginosis • Pesticides: • Bifenthrin (TalstarOne): 0, 1, 10, 100, 1000 ppm • Label rate (low to high): 47 – 94 ppm • Carbaryl (Sevin SL): 0, 100, 1000, 10,000, and 100,000 ppm • Label rate (low to high): 5,472 – 7,265 ppm • No. replicates: 50 unsexed adults, <7 days old

  10. Response of G. uliginosis to Bifenthrin Treatment Rate 72 Hours Post-exposure to Sprig (ppm) (% AI) % Moribund and/or dead 0 --- 0 1 1/10,000 12.5 10 1/1000 25.0 100 1/100 87.5 1,000 1/10 100.0 Current no. reps = 8 LC50 = 16.5

  11. Billbug Biology • Objective: Describe the adult and larval billbug activity periods in northern and southern Florida • 2 golf courses in Gainesville, 1 in Miami, and 1 in Key Largo • Four linear pitfall traps were placed in bermudagrass roughs on each course in Jan. ‘06 • Adults collected weekly in 24 hr samples • Soil cores taken monthly to collect larvae and pupae • Partial funding was provided by the FTGA, FGCSA, and GCSAA

  12. Billbugs on Florida Golf Courses (Sphenophorus spp.) S. apicalis S. cariosis S. inaequalis S. minimus S. venatus vestitus Photos by Ta-i Huang

  13. Cultural Control of Billbugs • Objective: Evaluate the impact of overseeding with endophytic ryegrass on billbug populations. • 2 rates of 2 commercial varieties of endophyte enhanced perennial ryegrass will be overseeded onto a golf course in fall 2006. Control= endophyte-free ryegrass. • Plots: 10 x 10 ft. Five replicates, in a RCBD. • Evaluations: Five 4-inch cupcutter samples will be sifted in January and March 2007 for billbugs. Turf color and density (0-9 scale) and amount of endophyte present will be assessed.

  14. Biological Control of Billbugs • Objective: Determine the effectiveness of several biopesticides against billbug larvae. • Treatments: • Heterorhabditis bacteriophora • H. indica • Steinernema carpocapsae • S. riobrave • Untreated control • Plots: 10 x 10 ft. Four replicates, in a RCBD. • Evaluations: Five 4-inch cupcutter samples will be sifted 4 and 8 weeks post-treatment for billbugs. Turf color and density (0-9 scale) will be assessed.

  15. Chemical Control of Billbugs • Objective: Evaluate preventive and curative insecticides against larvae and adults • Treatments: • Allectus 0.81 SC (2 rates), Arena, Merit 2F, Merit 0.5G, several rates of thiamethoxam, TalstarOne, Talstar G, Dylox, and an untreated control • Plots: 10 x 10 ft. Four replicates, in a RCBD. • Evaluations: Five 4-inch cupcutter samples will be sifted 4 and 8 weeks post-treatment for billbugs. Turf color and density (0-9 scale) will be assessed. • Partial funding provided by Bayer ES and Syngenta

  16. Greenbug Aphids • Pest of grains & grasses • In Florida, main host is seashore paspalum • Feeding causes yellow or red leaf spots, tip “burning” • Females reproduce without mating • One generation takes only 7-9 days at temps of 60-80°F

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