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AgAlerts 2007 From Griggs County
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Issue #3, June 1, 2007
Although rainfall amounts in most areas of
Griggs County were not high enough to cause many areas of saturated soils or
standing water, areas west of the county are having some problems. The
question to "how long a crop survive in flooded conditions is
environmentally dependant. Under cool cloudy conditions, soybeans: about 3
days, drybeans: about 1 day, corn: 2 to 3 days. Under sunny and warm
conditions, soybeans: 1.5 days, drybeans: 1/2 day, and corn: 1 to 1.5
days.
Soybeans become nitrogen deficient and also susceptible to
iron chlorosis under flooded conditions. Phytophthora root rot in
susceptible varieties is frequently associated with flooding damage.
Flooding causes anarobic conditions (lack of oxygen) which will cause root
damage. as waters subside, plants may start to appear normal but will be
stunted that could cause yield losses.
Eastern forest tent caterpillar (EFTC)
causing defoliation of trees in North Dakota has been reported since 1997.
Since defoliation is early in the year, health trees will usually develop a
second flush of leaves and tree health is usually not affected. However,
the insect can become a nuisance during early to mid June.
EFTC feeds on ash, aspen, basswood, birch, cottonwood, elm,
maple, oak, poplar, and other hardwoods. As the larvae enlarge,
keyhole-shaped spots along their backs and bluish lateral bands become
evident. These markings make identification relatively simple.
Controls: Bt products work well to control young
caterpillars, while permethrin, pyrethrins or other insecticides are needed for
older larvae. Or if infestations are low, you can trim the infected area
out. Insecticide treatments work well for young trees but become harder to
apply to older trees.
Eastern Forest Tent Caterpillar infestation (click to enlarge)
In past years, alfalfa harvest was determined by flowering stage. Recent research has shown that plant height has more influence on forage quality than maturity stage. In order to achieve prime alfalfa hay, harvest must occur around 25 to 28 inches of growth. Plant maturity stage will vary, but it could be as early as late vegetative to very early bud. If winger injury was severe, forage quality should be sacrificed for stand maintenance. Let alfalfa in the uninjured area reach about 25% bloom so that injured areas can regain some plant vigor prior to harvest.
There have been a lot of reports of evergreen problems this year. Once again it comes down to the usual culprits. They are; winter injury, Rhizosphaera needle cast and Cytospora canker.
Winter injury: Winter injury can be labeled as sunscald, bark scorch, winter dying and winter burn, but they all occur due to environmental conditions. Sunscald is caused by the combination of high and low temperatures in the late winter or early spring. Temperatures get high enough to cause the cells in the needles to become active and as a result give off water. Since the soils ar still frozen, the tree cannot replace the depleted water causing the cells to die. The following link will provide more information on sunscald and ways of prevention. Sunscald.
Rhizosphaera Needlecast: This disease is causing
problems throughout eastern North Dakota. Rhizosphaera needle cast is
caused by a fungus, Rhizosphaera kalhkoffii. Colorado blue and
white (Black Hills) spruce are susceptible to this pathogen, however white
spruce is far less susceptible except when adjacent to severely infected
Colorado blue spruce.
Symptoms: Severely infested trees often exhibit reduced needle
retention. The trees will have very few if any needles on branches except
for last year's growth and the new buds on the tips of the branch. Needles
become infected in late spring during we weather but do not begin to turn brown
until fall of the following year, at which time fruiting bodies of the fungus
are abundant as row of small black spots on the needles. Damage by
rhizosphaera needle cast may resemble environmental damage but can be identified
by using a hand lens and looking for the presence of the fruiting bodies.
Controls: Two registered fungicides that can be found at local
nurseries or garden supply stores are Bordeaux mixture 8-8-100 (8 lb. hydrated
lime, 8 lb. copper sulfate, 100 gal. water) and chlorothalonil (Bravo).
Fungicides should be applied in early June (or when new needles have reached
half their normal length) and again three weeks later (or when new needles have
reached their full length). Two consecutive years of fungicide application
may sufficiently disrupt the disease cycle. The following link will
provide additional information. Rhizosphaera
needlecast.
Cytospora Canker: Cytospora canker is a fungal
pathogen (Cytospora kunzii) that is most severe on Colorado blue spruce,
but also infects Black Hills spruce. The fungus can attack spruce of all
ages, however it is more common on older, larger trees. The fungus
enters branches through wounds, and eventually kills the branch. It can
spread to nearby branches or other trees by rain splash, small animals or
pruning tools.
Symtoms: Branch dieback from Cytospora canker generally beins on
the lower branches of the tree and eventually spreads upward through the
tree. Needles on the ends of infected branches turn brown and eventually
fall. Cankers covered with white/blue-gray sap can be found on the
infected branches. To distinguish between rhizosphaera needle cast and
cytospora canker, look at the needles. Rhizosphaera needle cast needles
will have fruiting bodies present where as cytospora canker will have
none. Cytospora canker can be similar to sunscald damage but upon closer
examination, the presence of the white/blue-gray sap will confirm cytospora
canker.
Controls: Management is the only effective control of this
disease. Diligent removal of infected branches for at least two years can
greatly reduce the progress of the disease. Prune branches to the branch
collar at the trunk. Make sure to properly clean pruning equipment between
cuts with rubbing alcohol to prevent infecting other branches or trees. If
the disease has progressed so much that the trees no longer provide the intended
function, removal should be considered. The following link will provide
more information. Cytospora
canker.
This article is taken from the 1937 Griggs County Extension Annual Report prepared by County Extension Agent Gilbert Moum.
11 Farmers Work to Eradicate Leafy Spurge
Leafy spurge has been found on 66 farms in
Griggs County and those farmers have been encouraged to eradicate it.
11 farmers have taken measures to control and eradicate this
weed. 12,455 spare rods were sprayed with chemical (atlacide) the past
year and an attempt to eradicate the weed by proper tillage was practiced on
62.8 acres.
To date the county commissioners have not approved of setting
up a county organization to cope with this serious weed.
Educational work is continuously being carried on with the
farmers and they are realizing the seriousness of the weed and will in future,
undoubtedly, take some step towards eradicating the weed on a cooperative basis.
In 1936, the county purchased a small barrel sprayer which
was used to spray a few patches. However, this sprayer is too slow and is
not practical where weed spraying is carried on extensively.
Farmer Purchases Sprayer For Weed Control
Arnold Arndt of Tyrol township purchased a
power sprayer which he used on his farm. Mr. Arndt has several scattered
patches of leafy spurge on his farm and he stated that he would either have to
eradicate the leafy spurge or eventually abandon his farm. He has now
sprayed 920 square rods on his farm and is well satisfied with the spraying.
Several patches were sprayed on his farm in 1936 at the rate
of 3 lbs. of atlacide to the square rod. In 1937 there were only a few
plants which came back on the area sprayed. These were sprayed in 1937 and
no re-growth has appeared there.
In 1936, the spraying did not seem to be effective as most of
the roots seemed to survive and the entire area sprayed was covered with small
plants. However in the spring of 1937, only a few plants reappeared.
The spraying was done in 1936, when the ground was very dry and it is possible
that the chemical did not penetrate very deeply. Possibly the moisture
resulting from the thawing snow and the spring rains wshed the chemical down
deeper and killed the remaining roots.
In June 1937, and acre of spurge was sprayed on J. H.
Langford's farm in Sverdrup township. This spraying was done at the rate
of 3 gallons of solution per square rod and the solution was made by mixing 1
pound of atlacide to 1 gallon of water.
On this patch the plants withered within a week and remained
black until late this fall. On my last inspection made October 26th, I
found that there were a large number of plants just coming through the
ground. However, I expect that the roots sustaining these plants will
winterkill and only a few plants will reappear next spring.End
Note: Atlacide is a total weedkiller in soluble
powder form containing 58% w/w sodium chlorate (with a fire depressant).
It is used for killing all plant growth in areas such as drives, paths,
asphalt etc. It is particularly effective in killing and preventing re-growth of
perennial weeds, and generally effective on many species of perennial grasses.
Atlacide persists in the soil for three to six months.
Please Contact Our Office For Additional Information
E-mail: john.swenson@ndsu.edu
Go to the 2007 AgAlert Index Page