growing fall cucumbers efficacy and economics of downy ... · 2016 season hot dry, drought...

Growing Fall CucumbersEfficacy and economics of downy mildew resistant

varieties

2018 CCE ENYCHP Winter ConferenceFebruary 21, 2018

Susan B. ScheufeleUMass Extension Vegetable Program

[email protected]

September 26, 2017

Many pests have been building up…

Suddenly, plants appear scorched

Cucurbit downy mildew

Cucumber


Acorn squash Butternut

Photos from cdm-ipm-pipe.org


Melon

Watermelon

Photos from cdm-ipm-pipe.org


5 strains infect different host crops+ Highly compatible host interaction

— incompatible or very slightly compatible host interaction

https://www.apsnet.org


• Oomycete

• Produces many sporangia

• Wind dispersed great distances

• Living host to survive

• Does NOT overwinter

Where does it come from?

• Blows up from FL each year

• Usually arrives in mid-August (MA)

cdm.ipm-pipe.org

Need to spray every 5-7 days once disease present and conditions favorable!!• Broad spectrum: Bravo, Copper, Mancozeb

+

• Oomycete-specific: e.g. Tanos, Ranman, Forum, Gavel, Previcur Flex, Zampro

• Organic: Copper, Oxidate, Biofungicides??

Control of Downy Mildew

Market for cucumbers all year round but…

So much time and $$ spraying

Bravo is harmful to bees

Affects fungal gut symbiont

More susceptible to fungal parasite Nosema

Organic spraying effective?

Need new resistant varieties

So, what’s the problem?

Photo by K. Keatley Garvey, UCANR

XReduce need for fungicides Save time Save money Work for organic and conventional

alike Durable solution New varieties coming on the

market

Role of Resistant Varieties

X How effective are new resistant varieties?

Can we extend the cukeseason?

More profitable than spraying?

More profitable to plant resistant variety AND spray?

Research Questions

Resistant Variety Trials

Cultivar 2016 2017Straight Eight (Susceptible control) X X

SV4719CS X XGreen Bowl X X

Bristol X XDMR401 X XNY264 X X

Diamondback XPython X

Straight 8 – Susceptible to EVERYthing!!

PROS

• Heirloom variety

• High yielding

CONS

• Susceptible to everything

• Monoecious

SV4719CS – New standard of DM resistance

PROS

• Good resistance to DM, PM, other leaf spots, viruses

• Widely available

CONS

• Not very vigorous plants, brittle

• Attractive to beetles and so bacterial wilt

Green Bowl – Great DM resistance, poor yields

PROS

• Strong resistance to DM, PM

CONS

• Very poor yield

• Off flavor

• Will not be marketed…

Bristol – Great DM resistance, good yields

PROS

• Strong resistance to DM, PM, fungal diseases and viruses

• Vigorous, high yields

• Good looking and tasting

CONS

• Susceptible to anthracnose

DMR401 – Great DM resistance, some off shapes

PROS

• Strong resistance to DM, PM, leaf spots, virus

• Vigorous


CONS

• Misshapen fruit--tapered, hooked, broken ends

• Not widely available: CommonWealth Seeds

NY264 – Best DM resistance, short fruit

PROS

• Strongest resistance to DM, PM, virus

• Vigorous. Plants are huge, many flowers


CONS

• Not widely available

• Longer DTH (75)

• Unconventional shape, color

Diamondback – Strong DM resistance

PROS

• Good resistance to DM, PM

• Strong yields


CONS


Python – Strong DM resistance

PROS

• Good resistance to DM, PM

• Strong yields


CONS


2016 Season

Hot

Dry, drought

Unfavorable conditions

Disease came Aug 17

Low DM pressure

Virus affected control plots

2017 Season

Cool

Wet

Favorable conditions

Disease came early Aug 2

Very high DM pressure

**use white mulch when planting in July!!

a

b

d

bcc

e02468

1012141618

2016 Downy Mildew over Time (AUDPC)

p < 0.0001

a

b

cc

b

c

b b

0

500

1,000

1,500

2,000

2,500

3,0002017 Downy Mildew over Time (AUDPC)

P < 0.0001

d

ccd

ab

bc

a

0

10,000

20,000

30,000

40,000

50,000

60,0002016 Marketable Yield (lb/A)

p = 0.0005

cd

abc

d

aba

ab

bcdabc

0

5,000

10,000

15,000

20,000

25,000

30,0002017 Marketable Yield (lb/A)

p = 0.0087

2-Sep

9-Sep

9-Sep

9-Sep

9-Sep

30-Sep

24-Jul 3-Aug 13-Aug 23-Aug 2-Sep 12-Sep 22-Sep 2-Oct

Straight Eight

SV4719CS

Green Bowl

Bristol

DMR401

NY264

Diamondback

Python

Last Harvest Date 2016

22-Aug

29-Aug

22-Aug

4-Sep

4-Sep

11-Sep

1-Sep

4-Sep

24-Jul 3-Aug 13-Aug 23-Aug 2-Sep 12-Sep 22-Sep

Straight Eight

SV4719CS

Green Bowl

Bristol

DMR401

NY264

Diamondback

Python


Variety Trial Conclusions

NY264 Susceptible

NY264 (Commonwealth Seeds)

Bristol (Seminis)

DMR401 (Commonwealth Seeds)

Does it help to spray the resistant varieties?Can we extend the season further?

What is the most profitable approach?

Next Questions…

$$$

Fungicide Efficacy and Economics Study

Susceptible (Straight 8) Resistant (SV4719CS)

———— No Spray ————

—— Conventional Spray ——

———— Organic Spray ————

Fungicide Efficacy and Economics Study

2016 Season

Hot

Dry, drought

Unfavorable conditions

Disease came Aug 17

Low DM pressure

Virus affected control plots

6 sprays

2017 Season

Cool

Wet

Favorable conditions

Disease came early (Aug 2)

Very high DM pressure

9 sprays

a

c

bb

dcd

0

5

10

15

20

25

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org

2016 DM over Time (AUDPC)

p = 0.0135

a

d

abbc

d

c

0500

1000150020002500300035004000

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org

2017 DM over Time (AUDPC)

p = 0.0050

bb b

aa a

0

5,000

10,000

15,000

20,000

25,000

30,000

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org

2016 Marketable Yield/A

p = 0.0025

c

a

c

bc

abb

02,0004,0006,0008,000

10,00012,00014,00016,00018,000

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org


p = 0.0239

2-Sep

9-Sep

9-Sep

16-Sep

20-Sep

20-Sep


Susc; Unsprayed

Susc; Conv

Susc; Org

Resist; Unsprayed

Resist; Conv

Resist; Org


22-Aug2-Oct

8-Sep

15-Sep

22-Sep

22-Sep


Susc; Unsprayed

Susc; Conv

Susc; Org

Resist; Unsprayed

Resist; Conv

Resist; Org


Calculating Sales & Profits

Cost of Materials

6 sprays in 2016 $411 (C) $37 (O)

9 sprays in 2017 $702 (C) $40 (O)

Price/lb

Conventional: Retail $2.00/pound

Organic: Retail $2.50/pound

Cost of Spraying… $24/hour

1.0 hours /A to mix, spray, clean up

Tractor maintenance, repair, depreciation = $20/acre(http://www.beetclock.com/NOFA_workbook.html)

http://www.beetclock.com/NOFA_workbook.html

bb b

aa a

0

5,000

10,000

15,000

20,000

25,000

30,000

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org


p = 0.0025

$0$2,740 $1,525

$15,415 (C)$19,268 (O)

$19,910

$25,611

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org

2016 Profit/A

c

a

c

bc

abb

02,0004,0006,0008,000

10,00012,00014,00016,00018,000

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org


p = 0.0239

$0

$31,283

$3,629

$13,861 (C)$17,326 (O)

$20,674$22,651

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

Susc;Unsprayed

Susc;Conv

Susc;Org

Resist;Unsprayed

Resist;Conv

Resist;Org

2017 Profit/A

Economics Study Conclusions

Conventional fungicides are very effective, if you use them choose high yielding variety

Resistant varieties yield better even if lower yield potential

Resistance to other diseases more reliable, consistent yield

Spraying can improve yield and profitability

Choose a better yielding resistant variety e.g. NY264 or Bristol and spray to get maximum benefit

Thanks!!!

Thanks to my colleagues in the UMass Extension Vegetable Program: Katie Campbell-Nelson

Lisa McKeag

Genevieve Higgins

Michele Meder

Ben Jankowski

Farm Crew: Neal Woodard and Zack Zenk

Sue’s Contact Info:

[email protected]

This project was supported by the Specialty Crop Block Grant Program at the U.S. Department of Agriculture

mailto:[email protected]

growing fall cucumbers efficacy and economics of downy ... · 2016 season hot dry, drought...

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