Cereal Killers:

What you need to know about

controlling small grains

disease

Alyssa Collins

Director, PSU SE Research & Extension Center

Assistant Professor, Plant Pathology & Environmental Microbiology

http://www.extension.psu.eduhttp://www.extension.psu.edu

Use of fungicides in small grains

• Fungicides can be effective in reducing

some yield-limiting leaf diseases

• Fungicide use is one tool in the approach to

reducing vomitoxin in the harvested product

Major Wheat Diseases

Rusts

Powdery mildew

Leaf spots

Head scab

Leaf Rust

Puccinia pathway

Stripe Rust

Powdery Mildew

• Present almost every year

• Environmental conditions determine yield impact (likes cool weather, humidity, high N situations)

• Favored by wheat following wheat or barley, no till

• Some resistant varieties available

Other leaf diseases

Stagonospora glume blotch (Phaeosphaeria nodorum)

Septoria leaf

Blotch (Septoria tritici)

• To determine the impact of early, late, and

early + late applications of fungicides on

the overall yield of soft red winter wheat.

• Conducted with grower cooperators in the

PA On-Farm Network, and at SEAREC

Wheat Fungicide & Timing Study

Wheat Fungicide & Timing Study

Treatments• Untreated Control

• Headline at GS 5, (6 oz/acre)

• Headline GS 5 (3 oz/acre), followed by Twinline GS 9-10 (9oz/acre)

• Twinline GS 9-10 (9 oz/acre)*

• Quilt GS 5 (10.5 oz/acre)

• Quilt GS 5 (10.5 oz/acre), followed by Quilt GS 9-10 (14 oz/acre)

• Quilt GS 9-10 (14 oz/acre)*

Sites: Lebanon Berks York Lancaster Armstrong

Franklin

*

*

Effect of Fungicide and Application

Timing on Wheat Yield

83.1

85.7

89.2

90.4

85.7

88.288.4

78.0

80.0

82.0

84.0

86.0

88.0

90.0

92.0

Untreated Headline Early Headlinefollowed by

Twinline

Twinline Late Quilt Early Quilt followedby Quilt

Quilt Late

Bu

sh

els

per

Acre

A

B

AB

AA

A

A

B

Treatments bearing the same letter

are not significantly different at

P=.05

Tukey’s Studentized LSD

Wheat Fungicide Yield Results

• Disease pressure less than in 2009

• All later fungicide treatments yielded slightly better than untreated control (avg 5.9 bu/A)

• Does not appear to be an advantage to multiple applications, early applications

• At most sites, single late applied strobilurin/triazole mix yielded highest

• Does the yield increase warrant fungicide cost?

Treatment

Yield

response

Cost of

treatment Average net return per acre

bu/A $/A at $5/bu at $7/buUntreated Control

0.00 0 0.00 0.00

Headline early (6 oz/acre) 2.80 *9.30 to 13.98 0.02 to 4.70 5.62 to 10.31

Headline (3 oz/acre),

followed by Twinline

(9oz/acre) 6.02 *14.91 to 17.25 12.86 to 15.21 24.91 to 27.25

Twinline late (9 oz/acre) 7.29 † 10.26 26.18 40.76

Quilt early (10.5 oz/acre) 0.96 14.49 -9.67 -7.74

Quilt (10.5 oz/acre),

followed by Quilt (14 oz/acre) 4.29 33.81 -12.38 -3.81

Quilt late (14 oz/acre) 4.24 19.32 1.87 10.35

* Range given the maximum $100/gal rebate

† Cheapest effective treatment

• Leaf diseases significantly lower in

treatments that include a late application

• No differences were observed among

treatments in head scab

Wheat Fungicide Disease Results

Fungicide economics

Grain price ($/bu) $4 $5 $6 $7 $8 $9 $10

Yield (bu/a) gain to

recoup investment

7.5 6.0 5.0 4.3 3.8 3.3 3.0

Assumes $30/acre based on cost of fungicides and application. Actual cost will vary.

Does it help to throw in

a fungicide at greenup?

• Fungicide at Feekes 5 followed by a flowering application

• Usually not enough to make it worth it

• Profitability: 1% increase at $3/bu, 3% at $5/bu, and 5% at $7/bu grain priceso Sylvester et al. 2017

Head scab

• F. graminearum (also causes

Gibberella ear rot of corn)

• Produces mycotoxins

(Deoxynivalenol=vomitoxin)

• Favored by no-till, wheat

following wheat, cool & wet

weather

• Fungus infects through

flowers

• Tends to be worse in wide

row wheat

Vomitoxin prevention approach

• Select a resistant variety (seriously!)

• Track conditions to target fungicide

applications

• Best variety + Best fungicide = 70%

control

Based on ND Combo trials 03-05

Management: FHB

• U.S. Wheat

and Barley

Scab Initiative

• Prediction tooI

• www.wheatscab.

psu.edu

What should I spray?

• Best reduction of scab & DON: Caramba,

Prosaro, Proline

• Some reduction of scab & DON: Tilt, Folicur

• NEVER strobilurins once wheat reaches

boot!

o Headline, Quadris, Evito ALL can increase

DON

What if it’s going to rain?

• Prosaro/Caramba rainfast within 15-30

minutes

• Bottom line: If the growth stage is right, go

for it even if it’s about to pour

What if I can’t apply at flowering?

• Good conditions for scab

development = bad

conditions for spraying

• Best time to spray is at

the beginning of flowering

• Can go 4-6 days later and

still get decent control

• Better to go late than

early!

How long does my fungicide last and

Would it help to spray again?

• Half life of these fungicides is about 7 days

• But scab and DON can continue to

develop after flowering

• Now exploring a Feekes 10.5 Prosaro or

Caramba followed by a generic

tebuconazole 4 days later if weather

conditions persist

Using a fungicide for Scab prevention• Be prepared to spray when prediction tool forecasts

“medium” to “high” risk for your area

• Start treating within 5-6 days of the start of flowering

• Fungicides applied before flowering do not provide

control

• Wheat that is 5 days or more beyond initial flowering

cannot be treated

• Do not use strobilurins (Headline, Quadris, Twinline, Quilt,

Stratego, etc.) at or after heading (there is evidence that

these chemicals can increase toxin levels)

Miravis™ (pending EPA approval)

• Syngenta

• Adepidyn™, new chemical group within

carboxamide chemistry (FRAC 7)

• Corn, soybean, wheat, among other crops

• Leaf spots and blights

• Field testing ongoing in multiple states and

environments for Fusarium head blight

(wheat)

Things to Know for Barley• Barley is not wheat (dif. in flowering

and resistance)

• In barley, some factors that make varieties less susceptible to scab include: o Hulless

o Two-row

o Nodding head types

• Can’t always see barley anthers—spray for scab once heads are emerged

• Barley has a better ability to prevent spread of the fungus following infection than wheat.

• Be aware that grass forages and cover crops can harbor and serve as an alternate host for many wheat and barley pathogens like Barley Yellow Dwarf Virus and Cephalosporium Stripe.

• A fungicide at flowering for scab will also give you nice control of flag leaf diseases

• Manage your previous crop residue when planting wheat or barley.o Uniform residue = uniform seedling emergence

= uniform tillering and heading time = easier to time fungicide in the spring

Things to Know for Barley

• Mid-atlantic will probably always be

challenged by DON

• How do we make that work?

• It’s always been about risk management

for farmers, but now we have to teach

maltsters

• Much more research needed, but for

now, moderately resistant varieties is

key

Things to Know for Malting Barley

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Resources

collins@psu.edu717-653-4728

@PACropDoc