Options for Managing Striped Cucumber Beetle and Bacterial Wilt on Organic Farms Abby Seaman, NYS IPM Program With information from Ruth Hazzard, Meg McGrath, and Mike Hoffmann
Bloodnick Farm
Blue Heron Farm Blue Heron Farm
Porter Farm
Slack Hollow Farm
Squash Pests Striped cucumber beetle (AUDPC) Organic Conv. Sig. 26.95 7.48 * Squash bug (AUDPC) 18.69 12.91 ns Aphids (AUDPC) 8.04 12.88 ns Powdery mildew (AUDPC) (top leaf surface) Powdery mildew (AUDPC) (bottom leaf surface) 7.60 10.15 ns 6.41 10.45 ns
Striped Cucumber Beetle Parasitism Species Management Early Late Average Syrrhizus diabrotica Organic 16.2 (±8.9) 11.6 (±7.8) 13.9 (±8.5) Conventional 4.4 7.7 6.2 (±6.8) (±8.9) (±7.8) Celatoria setosa Organic 5.1 5.0 5.0 (±4.8) (±6.2) (±5.5) Conventional 5.5 2.6 3.9 (±5.9) (±5.3) (±5.5)
Courtesy Michael Hoffmann, Cornell University
Striped cucumber beetle life cycle Adults migrate to fields Overwinters as adult in field borders Summer adults emerge in early August Eggs laid at base of plants - larvae feed on roots
Courtesy Michael Hoffmann, Cornell University
Management Options Transplanting Trap Cropping Row Covers Chemical
Attractiveness to beetles varies with crop type and variety Susceptibility to wilt varies with crop type and variety Plants past the five-leaf stage are less susceptible to bacterial wilt
Induced Resistance Zhender et al. have found reduced SCB feeding and wilt incidence on plants treated with PGPR BioYield and other approved products may be able to cause induced resistance Do microbially active soils elicit an induced resistance response?
Transplanting Reduces direct plant loss from beetle feeding Reduces time plants are in susceptible stage
Cost of Transplants vs Direct Seed (winter squash or pumpkins at 2x6 spacing) Direct seeded Transplanted $260/A $1630/A* *@ $0.45/plant to produce and establish
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Cucumber Beetle Density, Feeding Injury, and Bacterial Wilt Incidence for Pumpkin, 1999 Merlin Magic Lantern Howden Harvest Moon 3 b 13 b 22 b 2 # Beetles/10 plants Feeding Damage (%) Wilt on 25 Aug (%) 4 4 4 7 8 8 89 a 9
Cucumber Beetle Density, Feeding Injury, and Bacterial Wilt Incidence for Pumpkin, 2000 Merlin 2 Magic Lantern Howden Harvest Moon # Beetles/plant Feeding Damage Wilt on 22 Aug (%) 6 5 3 58 b 3 6 53 b 6 3 on 3 July (%) 97 a 98 a
Cucurbit Crop Types and Cultivars Cucumber (Cucumis( sativus) Calypso, Dasher II, County Fair (wilt resistant) Muskmelon (Cucumis( melo) Eclipse, Saticoy, Athena Watermelon (Citrullus( lanatus) Crimson Sweet Gourd (Cucurbita( maxima and C. pepo) Turk's Turban, Pear Bicolored Pumpkin (Cucurbita( pepo) Magic Lantern, Merlin, Howden,, Harvest Moon Squash, Summer (Cucurbita( pepo) Multipik, Goldbar,, Sunray Squash, Winter (Cucurbita( pepo and C. moschata) Golden Delicious, Blue Hubbard, Burgess Buttercup, Waltham Butternut, Table Ace Squash, Zucchini (Cucurbita( pepo) Seneca, Ambassador
Number Cucumber Beetles/10 Plants, 1999 Winter squash Pumpkin Gourd Watermelon Muskmelon Cucumber Zucchini squash Yellow squash 2 e 4 de 6 cd 6 cde 5 de 9 bc 12 b 20 a
Incidence of Bacterial Wilt on 3 Aug 1999 Winter squash Pumpkin Gourd Watermelon Muskmelon Cucumber Zucchini squash Yellow squash 0 c 7 c 14 c 12 c 13 c 33 b 48 b 68 a
Number Cucumber Beetles/10 Plants, 2000 Winter squash Pumpkin Gourd Watermelon Muskmelon Cucumber Zucchini squash Yellow squash 10 e 15 de 21 cd 20 d 20 d 29 b 26 bc 39 a
Incidence of Bacterial Wilt on 2 Aug 2000 Winter squash Pumpkin Gourd Watermelon Muskmelon Cucumber Zucchini squash Yellow squash 6 d 11 d 12 d 32 c 40 bc 38 bc 50 b 97 a
Trap Cropping Choose attractive, wilt tolerant variety for trap crop Surround entire planting, two rows are better than one Arrange main crop such that attractive or susceptible varieties are surrounded by less attractive/susceptible Reduce attractiveness of main crop Surround, BioYield
Trap Cropping Reducing second generation beetle production in trap crop Disc up? Apply nematodes to roots? Steinernema riobravis (Ellers-Kirk et al., PA) Heterorhabditis bacteriophora strain GPS-11 (Miller and Welty, OH) Nothing?
Costs for Trap Cropping To produce and establish transplants One row - $185 for a square 1A field Two rows - $370 Plus any cost of managing beetles on trap crop
Row Cover Must be removed at flowering Provides excellent control plus growth enhancement But: Interferes with cultivation Cost: ~ $415/A hoop system ~ $435/A entire field system
Insecticide Options Per application - cost of materials only Pyganic 5.0 @4.5-18 oz/a - $23.75-95.00/A Reliable kill or just knockdown? Surround @ 6.25-25 lb./a - $6.25-25.00/A Greatly reduced if transplants treated in flats
Surround-treated transplants
Scouting and Thresholds? Twice weekly scouting during invasion season, keep an eye on maturing fruit later Depends on crop susceptibility to wilt and reliability of control (0.5-2 beetles/plant) Current approved insecticides do not provide reliable control Relying on insecticides alone will not work for organic farmers Integrate a variety of approaches.