FROM AROUND THE STATE
ISSUE 10 July 6, 2000
Pest Update - July 5, 2000
Canola Insect Pests Update
Canola insect trapping network is on the internet at:
- Trap catches for Bertha armyworm are increasing in the North Central area,
but cumulative trap catches are still in the low risk category (0-300 moths
total). The high trap catch this past week was 188 moth per trap week in
the Mohall area, Trapper M. Hutter, Northern Ag Management.
- Diamondback moth flights are slowly increasing with the second flight. This
wet weather will NOT favor high populations.
- The new generation of the crucifer flea beetles is emerging now, as indicated
by increasing trap counts.
Orange Wheat Blossom Midge Emergence Underway for the North Central
Regions. Fields Should Be Scouted in the Heading Stage to Confirm Low Populations below
Threshold 1 wheat midge per 4-5 wheat heads. Wheat midge flight has been confirmed in the
Minot-Kenmare area. The male wheat midge begins to emerge at 1100 degree days (DD) and the
female at 1300 DD with peak activity at 1450 DD, using a 40"F Base. The following insect DD have
been accumulated as of July 4, 2000: Rollette Co., Rolla = 1221, Burke Co., Columbus = 1232,
Bottineau Co., Bottineau = 1307, McHenry Co., Towner = 1361; Renville Co., Mohall = 1328, McLean
Co., Turtle Lake = 1447, Ward Co., Minot = 1450, and Williams Co., Williston = 1544(Source: NDAWN).
Where Is the Sunflower Beetle? Populations of sunflower beetle
are low this year with limited or
no spraying activity in the North Central Region. There is no obvious reasons, except for a possibility
of biological control agent(s) catching up to higher populations of late 1990s and naturally reducing
sunflower beetle populations.
Sunflower Spotted Stem Weevil detected on sticky traps near Minot.
Janet J. Knodel
Area Extension Specialist Crop Protection
North Central Research and Extension Center
Total rainfall as recorded at NDAWN sites in south-central ND
during June 28 to July 4 ranged
from 0.03 inches at Linton and Streeter to 1.61 inches at Carrington. On July 4, areas of Wells, Eddy,
Foster, Stutsman, Ransom, and Sargent counties received at least 2 inches of rain and hail was
reported in Wells, Eddy, Dickey and Ransom counties. In Emmons and portions of neighboring
counties, additional moisture would be welcome. On July 4, estimated daily water use of wheat emerged
May 1 was 0.20-0.31 inches, and for corn emerged May 15 and soybean emerged May 29 the
estimated daily water use ranged from 0.17 inches in the north to 0.28 inches in the south.
Cool-season crops continue to be in generally good- to
excellent-condition. The majority of the
regions small grain crop is heading or beyond and some winter cereals and barley are starting to
ripen. Flowering is nearly complete with fall- and early spring-seeded canola. Warm-season crop
development has rapidly increased with recent warm weather. Growers are continuing efforts to apply
herbicides in soybean, dry bean, and sunflower and to cultivate row crops in northern areas.
Fungicide application for leaf disease and scab control in small grain continues north of I-94. Haying
has been a challenge but continues. Pastures and rangeland generally are in good condition.
Leaf spot disease (tan spot and Septoria in wheat; spot and net
blotch in barley) severity is
increasing. The NDSU foliar disease forecasting model for the Carrington site indicated potential for
tan spot nearly every day during June 23 to July 4. Conditions for scab in small grain and sclerotinia
in canola continue to appear very favorable. Up to 10% incidence of loose smut has been observed
in small grain. The NDSU Extension Service sunflower disease survey has indicated low incidence
of downy mildew based on over 25 fields surveyed in south-central ND.
Aphid numbers have increased in wheat but insecticide treatment is
not recommended in the
crop that is headed. Accumulated degree days (DD) for orange wheat blossom midge range from
1386 units at Harvey to 1715 units at Oakes. Continue scouting wheat fields that are at risk until
1800 DD have been reached.
Area Extension Specialist/Cropping Systems
NDSU Carrington Research Extension Center
Rainfall has been highly variable this past week. Rainfall at the
NDAWN station near Beach indicated
that they received 1.27 inches of rain while Mandan recorded the area s low of 0.19 inches. In the
New England area some reports indicated that as much as 2.00 inches of rain fell. Hail has been reported
in scattered areas. High winds in the Golva area flattened some grain fields.
Winter wheat on Monday, July 3 was reported as being in the soft
dough stage. Frost seeded spring
wheat was in the watery ripe stage while the earliest hard red spring wheat was flowering. The majority
of the hard red spring wheat crop has headed. With the soil moisture deficit developing in the crop
we symptoms of wheat streak mosaic virus and root rot are becoming more apparent in continuous wheat
fields. Septoria and tan spot can be found in most fields and rust is present in many. This is a good time for
producers to look for loose smut in the head.
Hay yields have been low for many producers. Limited moisture early
in the growing season reduced
yields significantly but in some fields high levels of alfalfa weevil and lygus bugs have been found. Producers
should scout alfalfa fields for these pests to determine if insect feeding is delaying or reducing regrowth.
If insect feeding activity is significant then treatment should be considered. Recent rains have raised hopes
of getting a good second cutting from alfalfa but second cuttings are not expected from grass and grass-alfalfa
hay fields. Some dryland alfalfa hay fields that were harvested in late May and early June will be harvested
again in two weeks.
Some crusting problems have been reported in late seeded sunflower
fields due to some of the intense
rains received after planting but prior to emergence. Sunflowers that was seeded in early and mid May
are doing well. Some producers have sprayed for stem weevils in fields with high weevil populations
but many fields have relatively low stem weevil populations. We are finding many assassin bugs and
lace wings in fields. These insects appear to be preying on sunflower beetle larva and aphids. Downy
mildew has been found in some fields. The bloom on early seeded canola is in decline. Ninety-degree
plus temperatures towards the end of last week caused some blasting of flowers in latter seeded canola.
We are expecting some 90 + temperatures this weekend. Crambe along with flax is in full bloom. Safflower
is budding and we expect those early-seeded fields of this crop to begin blooming towards the end of this
week or the beginning of next. The safflower crop appears to be in excellent condition.
The Hettinger Research Extension Center Field Day is scheduled for
Tuesday, July 11 to begin at 2:30
PM with a canola tour followed by the grain tour at 5:00 PM. The Dickinson Research Extension
Center Field Day is scheduled for Wednesday, July 12. Tours for the DREC Ranch and grain varieties
will begin at 8:30 AM with an agronomy tour at 1:00 PM and a horticulture tour at 3:30 PM. Call the
Research Extension Centers or your local county extension agent for further details.
Area Extension Specialist/Cropping Systems
NDSU Dickinson Research Extension Center
Rainfall continues throughout the region. Amounts this last week
varied from .5 inch to over
two inches. Crops in non flooded areas continue to look promising. Most questions this week
involve the topic of plant disease and fungicide options. May 5 plantings of wheat and barley are
heading or beyond, some early canola fields are in the last week of bloom, and flax is beginning to
bloom. Most small grain, canola and flax fields have been treated for weed problems. Dry beans,
sunflower, corn and soybeans benefited from the warmer weather this past week. Aphids incidence
is 5-10 % and leaf rust is present in the variety trial at Devils Lake. Net blotch of barley and septoria
in wheat and barley has increased in incidence and severity from the previous week.
Area Extension Specialist/Cropping