Department of Entomology Cornell University New York State Agric. Exp. Stn. 630 W. North Street Geneva, NY Department of Entomology Cornell University New York State Agric. Exp. Stn. 630 W. North Street Geneva, NY Cucumber Beetle Management Using Seed Treatments January 20, 2008 Brian A. Nault Associate Professor Brian A. Nault Associate Professor

Spotted and Striped Cucumber Beetles Identification Adults are 8-10 mm in length and 3-4 mm wide Spotted cucumber beetle, Diabrotica undecimpunctata Striped cucumber beetle, Acalymma vittatum

Striped cucumber beetle (Acalymma vittatum) Lifecycle Overwinters as an adult in protected areas and becomes active in early spring Lays eggs at base of host plant; two generations per year

April May June July Aug Sept Oct Cucumber Beetles Adult Activity

Types of Cucumber Beetle Damage Defoliation Pollination interference Feeding scars Rindworms

Bacterial Wilt Disease Causal Organism - Erwinia tracheiphila, which is transmitted by cucumber beetle adults Causal Organism - Erwinia tracheiphila, which is transmitted by cucumber beetle adults C. Welty

Cucumber Beetles - Bacterial Wilt Worst damage caused by bacterial wilt, not beetle damage Diagnosed by cutting stem and looking for stringy sap No cure for controlling bacteria; must control vector Beetle may not be present during wilting Susceptibility of crop to wilt: Melons > cucumbers > squash > watermelon

Managing Cucumber Beetles Plant Resistance Plant Resistance Behavioral Control Behavioral Control *Cultural Control Biological Control General Approaches Taken to Manage Cucumber Beetles *Chemical Control

Chemical Control - Sampling activity with yellow sticky traps - Established thresholds (direct counts on plants): - 1 beetle / plant for melons, cucumbers, and young pumpkins - 5 beetles / plant for watermelon, squash, and older pumpkins Foliar Sprays

Chemical Control At-plant Treatments - Apply in-furrow or via drip irrigation - Drench transplants e.g., 4 ml (0.14 oz) of Admire diluted in water to treat a flat of 200 plants

Chemical Control Seed Treatments - thiamethoxam - Cruiser 5FS - FarMore DI clothianidin + imidacloprid - Sepresto (registration package submitted summer 2008) cucumberpumpkinsquash

Collaborative Effort to Evaluate Seed Treatments Researchers New York – Alan Taylor, Brian Nault, Robert Hadad & Charles Bornt Ohio – Celeste Welty Maryland - Jerry Brust Virginia – Thomas Kuhar Delaware – Joanne Whalen IR- 4 Project - Keith Dorschner

Objective Evaluate neonicotinoid seed treatments for early-season cucumber beetle control in cucumber and pumpkin

Treatments Seed Treatments - * Cruiser 0.75 mg ai/seed - * 1 mg ai/seed - * Admire 1 fl oz of Admire Pro mixed with 1 fl oz of water to treat 1 lb of seeds At-plant Treatments - Admire 7 fl oz/acre -* 8 fl oz/acre Crops - cucumber (var. ‘Vlaspik’) - pumpkin (var. ‘Gladiator’) * Not labeled in New York

Approach In the field: Visually record number of dead beetles per 10 plants per plot each week for 5 weeks (NY) In the lab: Sample foliage from field plots and conduct assays in laboratory to assess beetle mortality (NY, VA and DE)

Number of Dead Beetles/ 10 plants Total Mean Number of Dead Beetles per 10 plants over 5-Week Period in the Cucumber Field – Eden, NY 2008 a a b b R. Hadad

Petri Dish 10 beetles per dish (NY); 5 beetles per dish (VA & DE) 2-, 4- and 7-leaf stage (NY); 4-leaf stage (VA & DE) Record # dead at 72 hr (NY) and 96 hr (VA & DE) Laboratory Assay Stage of Plant Sampled 2-leaf4-leaf7-leaf

Beetle Mortality (%) Mortality (after 72 hr) on Excised Pumpkin Leaves Collected from Field Plots – Geneva, NY 2008 a b b b c ab B. Nault

Beetle Mortality (%) Mortality (after 72 hr) on Excised Pumpkin Leaves Collected from Field Plots – Geneva, NY 2008 a c b b c c B. Nault

Beetle Mortality (%) Mortality (after 72 hr) on Excised Pumpkin Leaves Collected from Field Plots – Geneva, NY 2008 c a c bc ab B. Nault

Beetle Mortality (%) Mortality (after 96 hr) on Excised Cucumber Leaves Collected from Field Plots – Painter, VA 2008 a a b b b T. Kuhar

Beetle Mortality (%) Mortality (after 96 hr) on Excised Cucumber Leaves Collected from Field Plots – Georgetown, DE 2008 a a a a b J. Whalon

Summary Cruiser and Sepresto seed treatments had similar or better activity against cucumber beetle than Admire and Platinum at-plant treatments Efficacy of Cruiser and Sepresto seed treatments did not extend beyond 4-leaf stage (20 to 26 days after planting)

Benefits of Seed Treatments Saves time – just plant treated seed Less exposure to active ingredient (a.i.) Precise amount of a.i. applied to seed Often use considerably less a.i. per acre Less risk of killing non-target organisms

Future Work Repeat study in 2009; more on-farm trials with extension educators Potentially assess efficacy of Cruiser 5FS/ Farmore DI 400 and Sepresto on other insect pests

Acknowledgements Collaborators: Alan Taylor, Robert Hadad, Tom Kuhar, Joanne Whalon Technical Assistance: Mary Lou Hessney (Entomology, NYSAES) Grower: Laura Pedersen (Geneva, NY) Funding: IR-4 Project Federal Formula Funds

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