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AgAlerts 2001 From Griggs County
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Issue # 1, April 30th, 2001
If you need to get a copy of a pesticide label or MSDS materials, go to the CDMS site. This site updates labels and MSDS when ever there are any changes made. It is current and easy to use. The site address is http://www.cdms.net
To control quackgrass in the spring, it is necessary to wait until stems are 6 to 8 inches tall. Spraying at an earlier growth stage will only control top growth and will have little effect in killing the root system. When the plant reaches this height a change in the plant occurs. At this time the leaves become productive and start to replenish the nutrients in the roots. Since glyphosate is translocated, the product is moved to the roots causing increased control. A fall application followed by tillage kills more of the underground root system than spring applications. In either application, it is important to delay tillage for at least 3 days after treatment to allow the product to be moved into the roots. Ammonium sulfate is recommended for increased control. Since there are several formulations of glyphosate available, follow labeled rates.
Aside from the universally recognized need to
place seeds into moist soil to enable germination, the particulars of seed
placement remain somewhat under-rated in importance. Recommendations often
give crop seeding depth as a range. For example, 1.5 - 3" in depth
with 1.5 - 2" being optimum. Unfortunately, recommendations stated
like this may leave the false impression that sowing at 3" will have the
same result as sowing at 1.5", this simply is not the case. A seed
placement study conducted by Jack Moes, P. AG Manitoba Agriculture, Brandon, has
shown that seeding depth is an important (and free) step in attaining the
highest economic yield.
The emergence response curve for wheat is typical of many
crops: as sowing depth increases, emergence is progressively slower and less
complete. Larger seeds (within the variety) are affected to a lesser
degree. The duration of emergence (from first to last plants emerged) also
increases with sowing depth. Late emerging plants growing from deeper in
the soil produce fewer tillers and lower yield per plant. Not only was
tillering reduced for deep-sown plants, but crown root development was also
greatly reduced. Deeper sowing increased seedling to seedling variability
in wheat emergence, and the effect was greater at lower temperatures. In
other work at the University of Manitoba, wheat sown at 2" and 3"
yielded 3% and 6% less than wheat sown at 1" under conditions where 1"
was adequate. Semi-dwarf varieties have a shorter coleoptile than
conventional height varieties can emerge from deeper depths.
Summary
The following problems may manifest themselves if sowing is
deeper than absolutely necessary:
*Delayed and reduced emergence, poor non-uniform stand.
*Reduced tillering of cereals.
*Reduced competitiveness of crop.
*Increased root disease risk
*Delayed, non-uniform maturity and reduced yield.
Crop
Temp.
Crop
Temp.
Wheat
40
Durum
40
Barley
40
Oats
40
Canola
40
Sunflower 45
Flax
48
Corn
50
Soybeans
50
Dry Beans 52
Weeds
Early Emerging (35-40 degrees)
Kochia
Milkweed Wild
Mustard
Cocklebur Wild
Oats Wild
Buckwheat Frenchweed
Russian Thistle Canada
Thistle Tansy
Mustard Shepherdspurse
Absinth Wormwood
Common Lambsquarter Quackgrass
Late Emerging (50 degrees or higher)
Redroot Pigweed Wild
Sunflower Volunteer
Sunflower Field
Bindweed
Nightshades
Lanceleaf Sage Foxtails (pigeongrass)
Ragweeds
(click on to enlarge)
Black knot, caused by the fungus Dibotryon
morbosum, affects at least two dozen species of cherries, plums and
other members of the genus Prunus. This disease is easily
recognized by the characteristic hard black elongated swellings or
"knots" that develop on the smaller branches. Some of
these knots may be a foot or more long. Eventually they girdle and kill
branches on heavily infected trees. The black knot fungus produces spores
on knots that are one or two years old. The spores are released about the
time the leaf buds are in the green tip stage. Spore release is heavy at
blossom time and is completed about the time the shoots have finished
growth. Spores are carried by the wind, infecting new shoots in wet
weather, especially when the temperature is between 55 and 77 degrees F. A
few infections show up in the fall, but most infections do not show symptoms
until the following spring. New infections appear in the spring as soft
knots with an olive-green velvety surface. Later, the knots become hard
and black, and may continue to grow for several years, finally girdling the
branch.
This pictures illustrate new infections and branch deformity. (click on to
enlarge)
Control
Control requires the removal of all developing knots from affected trees before bud-break in the spring. Prune 4-5 inches below the knot. Apply a wound dressing to large wounds. Promptly destroy all pruned knots by burying or burning. Annual spring pruning may have to be done for several years before the disease level drops because of the long period before the disease symptoms show. Best controls is achieved by using fungicides in conjunction with pruning. Before bud-break, use a dormant spray of lime sulfur at the rate of 10 tablespoons per gallon of water or Bordeaux mixture (see label for rate). Pre-bloom spray when most blossoms show color and before blossoms open use Captan 50% WP 1/2 tbls. + benomyl 50% WP 1/2 tbls.
Please Contact Our Office For Additional Information
E-mail: griggs@ndsuext.nodak.edu
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