Options for Managing Striped Cucumber Beetle and Bacterial

Wilt on Organic Farms

Abby Seaman, NYS IPM ProgramWith 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)

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)7.60 10.15 ns

Powdery mildew (AUDPC)

(bottom leaf surface)6.41 10.45 ns

Organic Conv. Sig.

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(±6.8)

7.7(±8.9)

6.2 (±7.8)

Celatoria setosa Organic 5.1(±4.8)

5.0(±6.2)

5.0(±5.5)

Conventional 5.5(±5.9)

2.6(±5.3)

3.9 (±5.5)

Courtesy Michael Hoffmann, Cornell University

Striped cucumber beetle life cycle

Overwinters as adult in field borders

Adults migrate to fields

Eggs laid at base of plants - larvae feed

on rootsSummer adults emerge in

early August

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 $260/A• Transplanted $1630/A*

*@ $0.45/plant to produce and establish

http://www.nysaes.cornell.edu/recommends/

Harvest Moon

Howden

MagicLantern

Merlin

# Beetles/10 plants Feeding Damage (%)Wilt on 25 Aug (%)

Cucumber Beetle Density, Feeding Injury, and Cucumber Beetle Density, Feeding Injury, and Bacterial Wilt Incidence for Pumpkin, 1999Bacterial Wilt Incidence for Pumpkin, 1999

77

22 b22 b99

44

3 b3 b

44

44

22

89 a89 a

13 b13 b

88

88

Harvest Moon

Howden

Magic Lantern

Merlin

# Beetles/plant Feeding DamageWilt on 22 Aug (%)

Cucumber Beetle Density, Feeding Injury, and Cucumber Beetle Density, Feeding Injury, and Bacterial Wilt Incidence for Pumpkin, 2000Bacterial Wilt Incidence for Pumpkin, 2000

66

98 a98 a55

33

33

22

58 b58 b

53 b53 b

97 a97 a

33

66

66

on 3 July (%)

Cucumber (Cucumber (Cucumis sativusCucumis sativus))Calypso, Dasher II, County Fair (wilt resistant)Calypso, Dasher II, County Fair (wilt resistant)

Muskmelon (Muskmelon (Cucumis meloCucumis melo))Eclipse, Saticoy, AthenaEclipse, Saticoy, Athena

Watermelon (Watermelon (Citrullus lanatusCitrullus lanatus))Crimson SweetCrimson Sweet

Gourd (Gourd (Cucurbita maxima Cucurbita maxima andand C. pepo C. pepo))Turk's Turban, Pear BicoloredTurk's Turban, Pear Bicolored

Pumpkin (Pumpkin (Cucurbita pepoCucurbita pepo))Magic Lantern, Merlin, Howden, Harvest MoonMagic Lantern, Merlin, Howden, Harvest Moon

Squash, Summer (Squash, Summer (Cucurbita pepoCucurbita pepo))Multipik, Goldbar, SunrayMultipik, Goldbar, Sunray

Squash, Winter (Squash, Winter (Cucurbita pepo Cucurbita pepo andand C. moschata C. moschata))Golden Delicious, Blue Hubbard, Burgess Golden Delicious, Blue Hubbard, Burgess Buttercup, Waltham Butternut, Table AceButtercup, Waltham Butternut, Table Ace

Squash, Zucchini (Squash, Zucchini (Cucurbita pepoCucurbita pepo))Seneca, AmbassadorSeneca, Ambassador

Cucurbit Crop Types and CultivarsCucurbit Crop Types and Cultivars

Number Cucumber Beetles/10 Plants, 1999Number Cucumber Beetles/10 Plants, 1999

Winter squashWinter squash

PumpkinPumpkin

GourdGourd

WatermelonWatermelon

MuskmelonMuskmelon

CucumberCucumber

Zucchini Zucchini squashsquash

Yellow squashYellow squash

9 bc9 bc

6 cd6 cd

20 a20 a

4 de4 de

6 cde6 cde

2 e2 e

12 b12 b

5 de5 de

Incidence of Bacterial Wilt on 3 Aug 1999Incidence of Bacterial Wilt on 3 Aug 1999

Winter squashWinter squash

PumpkinPumpkin

GourdGourd

WatermelonWatermelon

MuskmelonMuskmelon

CucumberCucumber

Zucchini squashZucchini squash

Yellow squashYellow squash

14 c14 c

12 c12 c

48 b48 b

7 c7 c

0 c0 c

68 a68 a

13 c13 c

33 b33 b

Winter squashWinter squash

PumpkinPumpkin

GourdGourd

WatermelonWatermelon

MuskmelonMuskmelon

CucumberCucumber

Zucchini squashZucchini squash

Yellow squashYellow squash

29 b29 b

26 bc26 bc

21 cd21 cd

20 d20 d

10 e10 e

15 de15 de

39 a39 a

20 d20 d

Number Cucumber Beetles/10 Plants, 2000Number Cucumber Beetles/10 Plants, 2000

Incidence of Bacterial Wilt on 2 Aug 2000Incidence of Bacterial Wilt on 2 Aug 2000

Winter squashWinter squash

PumpkinPumpkin

GourdGourd

WatermelonWatermelon

MuskmelonMuskmelon

CucumberCucumber

Zucchini squashZucchini squash

Yellow squashYellow squash

11 d11 d

40 bc40 bc

50 b50 b

12 d12 d

6 d6 d

97 a97 a

32 c32 c

38 bc38 bc

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/AReliable kill or just knockdown?

Surround @ 6.25-25 lb./A - $6.25-25.00/AGreatly 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.