FROM AROUND THE STATE
ISSUE 9 June 29, 2000
Canola Insect Pests Update
Grasshopper nymphs are being detected more readily in the Small
Grains IPM Survey
this past week. Numbers are still below economic threshold levels, usually 1-2 per square
yard in the margin. The threatening level is 30-45 nymphs per square yard in the field
and 50-75 nymphs per square yard at the margin.
Orange Wheat Blossom Midge Emergence Underway for Some Areas of
the North Central and Northwest Regions.
The male wheat midge begins to emerge at 1100 degree days (DD) and the female at
1300 DD, using 40"F Base. The following insect DD have been accumulated as of June
24, 2000: Rollette Co., Rolla = 1039, Burke Co., Columbus = 1043, Bottineau Co.,
Bottineau = 1117, McHenry Co., Towner = 1146; Renville Co., Mohall = 1140,
McLean Co., Turtle Lake = 1232, Ward Co., Minot = 1247, and Williams Co.,
Williston = 1316 (Source: NDAWN). After female emergence, any wheat fields in the
heading stage should be scouted at night to confirm that fields are below the economic
threshold level 1 wheat midge per 4-5 wheat heads.
Who Is Chewing on the Spruces in Shelterbelts?
Yellowheaded spruce sawflies are out in large numbers and causing damage to all
species of spruces. Larvae have yellowish to reddish_brown heads and olive_green bodies
with six gray_green stripes running the length of the body. They will rear up in a characteristic
"S" when disturbed. Larvae will reach a length of about 3/4 inch before they drop to the
ground in July and spin a cocoon where they will overwinter. Yellowheaded spruce sawflies
tend attack the same trees repeatedly; therefore, chemical control often becomes necessary
as sawfly populations increase. Acephate (Orthene® and Isotox®), carbaryl (Sevin®),
chlorpyrifos (Dursban®), and cyfluthrin (Tempo®) are labeled for use against sawfly larvae.
Read and follow pesticide labels.
Janet J. Knodel
Area Extension Specialist Crop Protection
Many area barley and spring wheat fields that were planted in April are beginning to head
Spike counts with the early spring wheat crop range from 12 to 17 per head. There are a few fields
with 16 to 17spikes per head with four heads per plant;excellent yield potential fornorth central
NoDak!! Most of the durum crop was planted later and themajority of the crop is in the four to
six leaf stage. The main issue now is disease and what will the rain amounts be in July. There
are growers beginning to spray fungicides with the early crop. Ascochyta blight has been found
in chickpeas and lentils in western NoDak. This disease is serious, especially in chickpea. Growers
should be on the alert and should check their fields for the presence of the disease on a regular basis.
Bravo Ultrex and Bravo Weatherstick ZN are labelled for ascochyta blight control in chickpea.Most
early planted canola fields are blooming. There is some interest in Ronilan for white mold control.
Dormant canola fields are in their third to fourth week of bloom with no end of flowering in site. Row
crops are in need of warm weather. Sunflower, dry bean, and corn are already about ten days behind
in development compared to this same time last year.
Area Extension Agronomist
North Central Research/Extension Center
Minot, North Dakota 58701
Total rainfall as recorded at NDAWN sites in south-central ND during
June 21 to 27 ranged
from 0.16 at Linton to 0.65 inches at McHenry. Struggles with excessive soil moisture or standing
water continue in the region including Eddy, Foster, and Wells Counties. However, in the southwest
section of this region, additional moisture would be welcome. On June 27, estimated daily water
use of wheat emerged May 1 was 0.22-0.24 inches, and for corn emerged May 15 and soybean
emerged May 27 the estimated water use was about 0.15 inches.
Cool-season crops generally are in good- to excellent-condition. The
majority of the regions small
grain crop is near or beyond the heading stage. Spring-seeded canola has been flowering for 1 to 3
weeks. Warm-season crop development has been hampered by cool weather. Growers are
continuing efforts to apply herbicides in soybean, dry bean, and sunflower and to cultivate row crops.
Haying also continues. Scattered fields of canola have been treated with fungicides for sclerotinia
suppression. Fungicide application for leaf disease and scab control in small grain is being considered.
Wheat growers also are contemplating foliar N application for protein enhancement.
Leaf spot disease (tan spot and leaf rust in wheat, spot and net
blotch in barley) is rapidly
increasing in small grain. The NDSU foliar disease forecasting model for the Carrington site indicated
potential for tan spot nearly every day during June 16-27. Conditions for scab in small grain and
sclerotinia in canola appear very favorable. Barley yellow dwarf virus is becoming more common
and loose smut is appearing in headed small grain.
The NDSU Extension Service scout for this region, Jerry Schneider,
has started scouting sunflower
fields for downy mildew and currently has found low incidence.
Area Extension Specialist/Cropping Systems
NDSU Carrington Research Extension Center
Rainfall has been frequent but amounts are small, mostly wetting
foliage and adding to worries
about leaf and head diseases. Temperatures cooler than normal are delaying growth of warm season
crops. Cool season crops in non-flooded areas continue to have excellent yield potential.
April plantings of wheat and barley are heading, canola is in full
bloom. Early may plantings are in
the boot stage. Excessive wind has interfered with timely herbicide applications but most fields
are getting treated . Foliar disease in small grain is at low levels but growers are preparing to deal with
head and leaf disease in small grains as the initial acres of crop move into the heading stage. Many
acres of winter wheat on wheat stubble have been sprayed. Canola is being treated for sclerotinia as
much of the crop is in the the 10 to 30% bloom stage.
Pests found in crop this week includes powdery mildew in winter
wheat and barley, small
amounts of leaf rust in spring wheat, a few corn leaf and cherry oat bird aphid in small grain, septoria
in wheat and barley, sunflower beetle larvae. Some parts of the area should see the first orange
wheat blossom midge towards the end of the week. Alfalfa weevil damage is common.
Area Extension Specialist/Cropping