ISSUE 3 May 17, 2001
STATE LABEL GRANTED FOR RONILAN ON CRAMBE
A state label for the use of Ronilan on crambe for control of Sclerotinia stem rot was granted in January. The label rate and timing is the same as for canola.
SECTION 18 GRANTED FOR EMINENT ON SUGARBEET
A section 18 was granted for the use of Eminent on sugarbeet for control of Cercospora leafspot. Eminent is to be applied at 13 fl oz/A. It must be alternated with a non-triazole fungicide. If the alternate fungicide is known to provide protection for up to 14 days, applications of eminent should be no more than 28 days apart. Do not make more than 3 applications of Eminent in a growing season.
SECTION 18 GRANTED FOR LSP ON LENTIL
A section 18 was granted for the use of Gustafson LSP and Mertect LSP for treatment of lentil seed to control Ascochyta blight. It is to be applied at 1.7 to 3.0 fl oz/cwt of seed. Research in Washington state has shown LSP to be highly effective against seedborne Ascochyta.
SECTION 18 GRANTED FOR TILT ON DRY BEAN
A section 18 was granted for the use of Tilt on dry bean for rust control. Although many popular pinto, navy and dark red kidney beans are resistant to the prevalent races of rust currently present in our area, new races may arise from time to time. Thus, even varieties reported to be resistant should be monitored for rust. If rust appears to be developing more than expected on a variety considered to be resistant, a fungicide may be needed. Before using a fungicide, collect a few leaves with rust, allow them to air dry, place them in an envelope and send them to the bean pathologist, Dr. Luis del Rio, Plant Pathology Department, NDSU, Fargo, ND 58105-5012. Keep in mind that all pink beans, all small red beans, and some pinto beans are susceptible to rust. Variety reactions are reported in NDSU Extension Circular A-654, North Dakota Dry Bean Performance Testing, 2000.
SECTION 18 GRANTED FOR FOLICUR ON SUNFLOWER
A section 18 was granted for the use of Folicur on sunflower for rust control. The section 18 allows the application of 4 fl oz/A of Folicur, with a maximum of 8 fl oz/A per year. In many cases only one application will be needed unless an application is required in the bud stage. The greatest damage and yield losses from rust occur when rust develops in the bud stage or the bloom stage. If more than 3% rust appears on the upper four leaves, then an application of Folicur will be economic. NDSU Extension Circular PP-998, Sunflower Rust, has illustrations of various levels or severities of rust.
Folicur should not be applied within 50 days of harvest. Usually this occurs at about ray petal wilt, which is the stage at which there is no longer an economic return from the use of a fungicide.
Sunflower rust is a hot weather disease. If cool weather occurs, this disease will progress very slowly, and may not cause much damage. If hot weather develops and persists, this disease is capable of exploding and becoming devastating.
ANOTHER USEFUL WEB SITE
Be sure to put a bookmark in the Web site for the NDSU
Pesticide Program. This site, in addition to information on pesticide laws and
certification, also contains information on useful publications and provides a
search for pesticide labels. It posts the labels of pesticides that have a
section 18 in North Dakota, as well as those which have a state label. This site
is located at:
Extension Plant Pathologist
LATE PLANTING AND SMALL GRAIN DISEASES
One of the recommendations we make to avoid the risk of some small grain diseases is to plant early. Planting early hasnít been an option for many growers in the region this year, so does the late planting mean a higher risk of some diseases? The answer obviously is - maybe.
Late planting of wheat, barley, and oats puts these crops at potential risk to exposure of higher spore populations of leaf rust. However, these spore populations have to develop first in small grain crops growing in states to our south, and currently the leaf rust levels in these states is very low. Hot weather in states such as Kansas this week has hastened the development of the crop, and limited the development of wheat leaf rust and stripe rust. Recent dry weather also has slowed the development of oat crown rust and barley leaf rust. Late planting also puts small grains at risk of increased exposure while in early growth stages to grain aphids and barley yellow dwarf virus (BYDV). The grain aphids that carry the virus move into the state on southerly winds, but little aphid activity or BYDV symptoms have been reported from southern wheat states. Kansas reports BYDV commonly found in wheat fields, but only at very low incidences, from a trace to 2 percent.
Other diseases, such as leaf spot diseases and head scab, will be more dependent on weather conditions as the crop approaches heading stage, rather than on planting date. The biggest vulnerability of crops for these diseases is that much of the crop, at least in the Red River Valley, is being planted in a very short time frame and may head out all at once. Hopefully, no long period of fog and heavy dews will occur at the time of heading and flowering.
Extension Plant Pathologist