ROUNDUP AVAILABLE AS A FLAX HARVEST AID
A section 18 label
has been approved for the use of Roundup Ultra or Roundup Ultra RT for
pre-harvest application in flax. The label was granted to control weeds
including Canada thistle, perennial sowthistle, and kochia. A single ground or
aerial application of Roundup may be used at one quart/acre. Application must
be made at least seven days before harvest and when the crop is physiologically
mature. A rule-of-thumb to determine when flax is physiologically mature is
when at least 75% of the bolls have turned brown. Applicators must read and
follow label directions, and have the crisis label in their possession during
Roundup application.
WHEAT
DISEASE UPDATE
Jerry Schneider, surveying in Wells, Sheridan, Foster, Eddy, Benson, Griggs,
Barnes, LaMoure, Dickey and Stutsman counties, found 100% of the 34 monitor
spring and winter wheat fields to have some level of leaf rust.
Severity of leaf rust on the flag leaf ranged from 1-25% but was difficult to
see because of the ripeness of the crop. Septoria leaf blotch was
observed on flag leaves in 96% of the spring and winter wheat fields and 100%
of the durum fields surveyed, with severity ranging from 4-60% on the flag
leaf. Glume blotch, the head infection phase, was observed in 93% of the
fields surveyed. Head scab was detected in only 63% of the wheat fields
surveyed but was again difficult to see due to the advanced stage of the
crop. Field severity for head scab
ranged from 8% to 32%. Black chaff
was found in 37% of the spring fields at 4-28% incidence in the field. Other head diseases found in spring, winter,
& durum wheat fields include: Ergot
(19% of the fields, low severity), loose smut (15% of the fields), and Alternaria
sooty mold (11% of the fields).
SUNFLOWER DEVELOPMENT
Most of the
region’s sunflower fields are nearing or are in the flowering stage. The
flowering stage (R5) can be divided into substages dependent upon the % of the
head area (containing disk flowers) that are open or have completed pollen
shed. As examples, R5.1 indicates 10% of the disk flowers have opened and R5.5
indicates 50% of the disk flowers have opened.
As sunflower are
monitored for insects including banded sunflower moth and seed weevil, you may
be interested in time required for sunflower development during the recommended
insect scouting and treatment periods. The following table is a compilation of
data from selected sunflower hybrids during 1994-96 at the Carrington Research
Extension Center that provides an estimate of time required for sunflower to
reach various development stages.
Sunflower
stage and description |
Average
days accumulated from planting |
VE - plant
emergence |
13 |
R4 -
inflorescence begins to open (immature ray flowers visible when viewed from
above) |
71 |
R5.1 - beginning
of flowering |
73 |
R5.5 - 50% of
disk flowers open |
77 |
R6 - Flowering
complete and ray flowers wilting |
85 |
R9 -
Physiological maturity (bracts yellow and brown) |
117 |