News section

home  |  news  |  solutions  |  forum  |  careers  |  calendar  |  yellow pages  |  advertise  |  contacts

 

Cereal rust update - USA
A ProMED-mail post
ProMED-mail is a program of the International Society for Infectious Diseases

Cereal rust update - USA
Date: 13 July 2006
From: ProMED-mail <promed@promedmail.org>
Source:  USDA Cereal Rust Bulletin 2006: Number 08, 26 Jun 2006 [edited] <http://www.ars.usda.gov/Main/docs.htm?docid=9757>

The small grain harvest has commenced from eastern Pennsylvania to southern South Dakota. Winter wheat is generally in good to poor condition and ahead of normal maturity throughout most of the U.S. Spring-planted small grain crops are ahead of normal maturity throughout much of the area.

Wheat stem rust

There have been no further reports of wheat stem rust since late May, when rust was reported in Baton Rouge, Louisiana and Kinston, North Carolina soft red winter wheat plots. Stem rust observation maps are now available on the CDL website (<http://www.ars.usda.gov/Main/docs.htm?docid=9757>).

Wheat leaf rust

Wheat leaf rust in the upper Midwest is at high severities on susceptible winter wheat and is increasing on susceptible spring wheat. In late June, plots of susceptible winter wheat cultivars such as Jagalene, in east-central Minnesota and east-central South Dakota had 60 percent rust severities, while resistant cultivars had only trace levels of infection on the flag leaves. By late June, spring wheat had leaf rust severities of trace to 1 percent on lower leaves in southern Minnesota and North Dakota fields. Susceptible spring wheat cultivars in southern Minnesota plots had 20 percent rust severities with most infections on the lower leaves. This year leaf rust is widespread, but at lower levels than normal in the upper Midwest on both spring and winter wheat. Lower amounts of rust inoculum than in previous years arrived from the winter wheat region because of the persistent drought-like conditions in the southern plains which reduced rust infections in the winter wheat. Drier than normal conditions in May and June in many areas of the northern Great Plains has further slowed rust development. Some of the spring wheat cultivars currently grown have less effective resistance to leaf rust than those commonly grown 10-15 years ago. Many of the wheat fields in the spring wheat region will be treated with fungicide, which will prevent losses due to leaf rust. More leaf rust was found this year than last year in Ohio. By mid-June, leaf rust was severe on the upper leaves of susceptible cultivars throughout the northern wheat growing areas of Ohio. The 1st report of leaf rust in Ohio was during the 2nd week in May in south central Ohio, where the rust may have overwintered. Moisture conditions throughout this area have been conducive for rust development. As of late June, no wheat leaf rust had been in found New York.

Wheat stripe rust

Wheat stripe rust is widespread in the Pacific Northwest and has stopped throughout the northern plains wheat-growing area. By the 3rd week in June, traces of stripe rust were found on a few winter wheat cultivars in east central South Dakota and east-central Minnesota plots (Fig. 2). Hot weather has stopped rust production in these plots. The only report of stripe rust this year in Ohio was in a wheat breeding line. In 2005, stripe rust was found at a number of locations in Ohio. By mid-June, stripe rust was widespread in eastern Pacific Northwest fields and plots. On 16 Jun 2006, 30 percent severities were reported on susceptible winter wheat entries and 10 percent on susceptible spring wheat entries in disease monitoring nurseries at the Pendleton Experiment Station in Oregon. In nurseries near Walla Walla, Washington stripe rust severities reached 100 percent on susceptible entries in both winter wheat and spring wheat nurseries. Stripe rust was found in commercial spring wheat fields in the Palouse area, where 10 percent of the plants were infected with severities less than 5 percent on lower leaves. The wet and cool conditions the first 3 weeks in June were conducive for rust production. Cool and wet weather the first half of June have been favorable to stripe rust development in Montana winter wheat. In central and east central Montana 15 000 - 20 000 acres of winter wheat have been sprayed with fungicides. There have been sporadic reports of stripe rust spreading to spring wheat, but the severity has been low. It has been dry and warm since the middle of June and stripe rust development has slowed considerably during the latter part of June. In mid-June, wheat stripe foci of 60-80 percent severity were observed in winter wheat nursery plots at Winnipeg, Manitoba, Canada. Infections were noted on lower leaves, indicating that overwintering may have occurred. Very mild winter conditions with adequate snow cover occurred in 2005-2006, and spring temperatures were near normal, which would have been favorable for stripe rust infection.

--
ProMED-mail
<promed@promedmail.org>

[There are 3 main rust diseases of the cereal crop plant wheat (bread wheat, _Triticum aestivum_ and durum wheat, _Triticum turgidum_), all caused by species of the fungus _Puccinia_: wheat stem rust (_P. graminis f.sp. tritici_), wheat leaf rust (_P. triticina_ aka _P. recondita f. sp.
tritici_) and wheat stripe rust (_P. striiformis f. sp. tritici_).

Severe losses due to wheat stem rusts have abated in the USA since the 1960s due to effective resistance breeding. Severe losses are still a possibility with leaf rust. The USDA Cereal Disease Laboratory in St. Paul, Minnesota publishes regular reports on cereal rusts in the USA during the crop season. Each report gives detailed state-by-state information, including a summary map, all in pdf file format (see link to main article).
Information for rusts other than those that infect wheat is not included in this ProMED-mail posting, but others are described in the full report.

This report for late June 2006 confirms that rust is present on susceptible lines and that fungicide treatments are still needed for some commonly grown lines that do not have robust resistance. Climatic reasons are presented to explain lower amounts of leaf rust inoculum than in previous years.

Map:
Puccinia spore pathway
<http://www.ars.usda.gov/Main/docs.htm?docid=11301>

Wheat in USA
<http://www.nass.usda.gov/research/atlas02/Crops/Field%20Crops%20Harvested/Wheat/All%20Wheat%20for%20Grain,%20Harvested%20Acres-chor.gif>

Pictures:
Wheat leaf rust
<http://www.cdl.umn.edu/nomenclature/inf_set.jpg>
Wheat stem rust
<http://www.gov.mb.ca/agriculture/crops/diseases/images/fac15s01.jpg>
Wheat stripe rust
<http://www.utextension.utk.edu/fieldCrops/wheat/Wheat_photos/Wheat_StripeRust.jpg>

Links:
<http://www.ars.usda.gov/Main/docs.htm?docid=9854>
- Mod.JAD]

[see also in the archive:

Cereal rust update - USA (07) 20060707.1861 Cereal rust update - USA (06) 20060601.1528 Cereal Rust Update - USA (05) 20060518.1406 Cereal Rust Update - USA (04) 20060502.1274 Cereal Rust Update - USA (03) 20060418.1144 Cereal Rust Update - USA (02) 20060404.1012 Cereal rust update - USA 20060322.0895]

ISID/ProMED-mail post news item

Other news from this source

16,307

Back to main news page

The news release or news item on this page is copyright © 2006 by the organization where it originated.
The content of the SeedQuest website is copyright © 1992-2006 by SeedQuest - All rights reserved
Fair Use Notice