Sugarcane Breakout - Jeff Hoy_ LSU AgCenter

8/4/2019 Sugarcane Breakout - Jeff Hoy_ LSU AgCenter

1/17

DISEASE UPDATE

Jeff Hoy

Plant Pathology and Crop Physiology


2/17

Orange rust: Is it coming our way??


3/17

Orange rust spore shower detected - 2010

Spore trapping conducted during 2010 at Houma, St.

Gabriel, and Jeannerette.

Orange rust spores detected at multiple locations on

.

Have spore showers occurred in previous seasons?Almost certainly.

NO ORANGE RUST HAS BEEN DETECTED INSUGARCANE IN LOUISIANA.

Orange rust may not tolerate cold weather.


4/17

What have we learned about

brown rust? Temperature of 26 or below will kill entire plant.

Disease requires minimum temperature above 63 F. Leaf wetness period minimum of 7 hr per night.

Mean daily ambient temperature above 90 F will curtaile idemic.

Limiting temperatures determine start and end ofepidemic.

Leaf wetness determines severity during epidemic.

May be possible to forecast outbreaks time fungicideapplications.

Rust inhibited by nickel and copper.

Inoculation method for seedlings works will apply.


5/17

Rust Inoculation System


6/17

Brown rust outlook for 2011 ~80% of acreage in susceptible varieties

6 of 11 varieties susceptible.

We are vulnerable to brown rust.

, .

Low natural infection prevents ID of susceptible

experimental varieties.

2008-2009 winter freezes: 17 days, 63 hours, 27 F low2009-2010 winter freezes: 27 days, 177 hours, 19 F low2010-2011 winter freezes: stay tuned


7/17


8/17

What can we do to prepare for

billet planting? Continue screening varieties for tolerance.

Not possible to select for tolerance.

Basic breeding for red rot resistance is possible.

ur er eva ua e e ec s o arves er se ngs on

billet quality and performance.

Evaluate benefits of seed-treatment chemicals.

Look at starter fertilizer again?


9/17


10/17


11/17

Primary shoot population in 2011

Syngenta test at St. Gabriel

Treatment 96-540 99-226 99-233

Control 11.6 B 17.7 14.0

Insecticide 12.0 B 17.1 14.5

Fungicide 14.6 AB 18.4 13.5

All 15.6 A 20.4 14.2

Whole stalk 13.3 AB 15.7 17.3


12/17

Harvester application of Syngenta

chemicals to 99-226 billets


13/17

Fall shoot population in 2011

Syngentachemical harvester test

Treatment PopulationWhole stalk 71.4 C

.No chemicals 81.2 B


14/17

Smut Update Still growing varieties with moderate susceptibility:

95-988, 97-128, 99-226, 99-233, 01-299 Biggest problems with 128

Possible to buffer seedcane sources of susceptible

varieties with 540 (299 most susceptible)

Healthy seedcane program helps keep smut atacceptable levels


15/17

Healthy Seedcane Tissue culture based programs have provided

control of RSD, smut, leaf scald, yellow leaf, andmosaic

Allows variet selection ro ram to avoid a l in

strict resistance standards (increases odds of comingup with improved agronomic performance)

Some interest in heat-treatment

What is heat-treatment controlling?

Heat treatment was never effective for total

industry


16/17

RSD testing will be available Sample oldest stubble fields.

Lowest complete internode from 20-30 stalks.

Can deliver to WBR Extension office or St. Gabriel.

o c arge or es ng.


17/17

Red Stripe Top Rot in 00-950

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Sugarcane Breakout - Jeff Hoy_ LSU AgCenter