Page 25 - 2019 Ag Mag

KMAland 2019 Integrated Pest Management 25
there is a lot of discus- growers always use a in 2011 in the Bootheel protecting against yield
sion by growers to re- pre-emergence herbicide of Missouri. As far as reductions.
duce soybean popula- at full rate and apply as integrated pest manage- These are two in-
tions. Research at the close to planting time as ment practices, we en- stances of resistance to
University of Missouri possible. Growers should courage growers to use pesticides in Missouri.
indicate that there was carefully read labels and tolerant or resistant va- Integrated pest manage-
a significant difference determine the full rate. rieties. The resistance or ment, using all the strate-
in waterhemp competi- Some labels reduce pre- tolerant seed trait may gies available and under-
tion when increasing the emergence herbicide provide enough control standing the biology of
final soybean stand from rates when using with that a fungicide may not the pest, will reduce the
130K plants to 160K. In- glyphosate post emer- be required. However, opportunity for pesticide
creased soybean popula- gence program. Better fields should be scouted resistance. If pesticides
tion reduced tall water- control will result when routinely. are used, use and follow
hemp weed competition. using maximum labeled The source of this dis- the label and use mul-
Also, another way to rate. ease is in the residues, so tiple modes of actions in
reduce waterhemp is the Also, when using pre- any way we can reduce weeds, insects and dis-
use of cover crops. Small emergence herbicides, the disease inoculum is eases.
grains such as cereal rye they can be used as over- important. Crop rotation
may provide a reduction lapping residuals. This is an important method For more information,
in summer annuals with happens when a soil re- to reduce inoculum. contact Wayne Flanary,
residues. In studies at sidual is applied with a Warm, humid weather Field Specialist in Agron-
University of Missouri, burn-down herbicide. with frequent moisture omy, University of Mis-
cereal rye reduced tall Then another soil re- and heavy dews favor souri Extension at 660-
waterhemp density by sidual is applied during disease development. 446-3724.
40 to 50 percent. the second weed control There are no econom-
Rotation can affect re- pass during the glypho- ic thresholds for foliar
sistant tall waterhemp. sate application. fungicide application.
In one Missouri survey, Good weed control One should consider the
the likelihood of finding practices are always growth stage, disease
resistant waterhemp was control weeds with cor- level and variety sus-
44% higher in fields with rect timing, height and ceptibility. Susceptible
soybeans grown contin- size, using the full label varieties would provide
uously for 5 years com- rate and correct rate of greater yield response
pared to fields that had at carrier along with any from the fungicide appli-
least one other crop add- recommended adjuvants cation than those whom
ed to the rotation during according to the label. are resistant. If you need Wayne Flanary,
CPAg, CCA
the 5-year time period. Always read and study to apply a fungicide, ap- University of Missouri
Rosenbaum and Bradley the label. ply with multiple modes Extension
published this in 2013 in Another resistance is- of action. Also, research 101 E. Missouri,
Weed Technology. sue in Missouri has in- indicates foliar fungi- PO Box 407
When we use herbi- volved fungicides. Frog- cides applied during the Oregon, Mo 64473
cides to control water- eye leaf spot has been pod development stages Office: 660-446-3724
Cell: 913-220-3670
hemp, Dr. Kevin Bradley, found to be resistant to (R3-R4) are the most
State Extension Weed strobilurlin fungicides. effective for managing
Scientist, recommends The first case was found frogeye leaf spot and