1. Cost-Effective Weed Management in Peanuts
Eric P. Prostko
Extension Weed Specialist
University of Georgia
Tifton

2. How much do you spend on weed control?
USDA surveys indicate that peanut farmers in GA and AL spend $116/A on agri-chemicals
34% of total operating costs
Source: USDA/ERS

3. Weed Control in Peanuts A Typical program
PPI: Sonalan (2 pts/A) = $5.66/A
CRACK: Gramoxone Max (5.5 ozs) + Storm (1.5 pts) + NIS (0.25%) = $15.01/A
POST: Cadre (1.44 ozs) + COC (1%) = $14.62/A
Total Cost = $35.29/A

4. Has the recent price reduction of Cadre made weed control in peanuts a no-brainer???
cost no longer an obstacle
What about cotton rotations?
Should we still be applying reduced rates?

5. What can we do better? read label calibration and measuring
incorporation
timeliness
expert systems
reduced rates???

6. Why must you read the label?
good source of info
weeds
rates
timings
potential problems

7. Why must you read the label? Avoid potential problems!

8. Before anything else, calibrate your sprayer!!!
The only way to make sure the correct rate is applied.
to low = poor control
too high = waste money
accurate measuring also important

9. Sprayer Calibration Some Surveys said………
only 33% of operators were within 5% of target output (NE)
60% of the applicators were over or under applying pesticides by more than 10% (ND)

10. The foundation of weed management in peanuts is the yellow/DNA herbicides!
Sonalan, Prowl, Pendimax, Repose
inexpensive
Texas panicum
Florida pusley
must be incorporated by tillage or irrigation

11. Herbicide Incorporation
Equally as effective
Center-pivot irrigation is $2-7/A cheaper!
Less variable?

12. What about other soil-applied herbicides??
use as needed
can be expensive
need moisture
broad spectrum
may reduce/limit need for POST’S

13. Postemergence Herbicides
Timing,Timing, Timing!!!!
Smaller weeds easier to control
If removed early, weeds cause less or no effect on yield
lower rates can be used
don’t need 100% control

14. Optimum Timing of POST Applications
definitely
No way!!!
probably

15. Palmer Amaranth Control with Blazer Applied at Different Timings99 57 48 25 50 75
100
3-5"
7-9"
11-13"
Timing
Control (%)
Mayo et al (KS)

16. “Expert” Systems postemergence HERB (DOS) HADSS (Windows) weed density
weed size
yield goals
economics

17. HADSS Herbicide Application Decision Support System
Web-based version is free
Can be purchased for $95
Database needs to be updated for SE
time input for scouting and data entry

18. What about reduced rates?
not labeled but not illegal
companies will not support failures
not a guarantee to minimize crop rotation issues
part of a total program
future R&D and new products

19. What kind of grower might consider using reduced rates?
A grower who ……...
regularly calibrates his sprayer
has irrigation or can predict when it will rain
gets consistent weed control at full rates
understands the difference between 2” and 4”
can cover his acreage in a short time period
is willing to scout his field regularly
is willing to accept less than 100% weed control
is not a lawyer or close friends with one

20. Reduced Rates Do they work???

21. The Response of Weeds to Various Cadre Rates in Georgia20 40 60 80
100
P. nutsedge
Y. nutsedge
sicklepod
0.36 oz/A
0.72 oz/A
1.1 oz/A
1.44 oz/A
Applied EPOST (C-2LF)
Webster et al. 1997

22. The Response of Weeds to Various Cadre Rates in Georgia20 40 60 80
100
smallflower
morningglory
annual
cocklebur
bristly starbur
0.36 oz/A
0.72 oz/A
1.1 oz/A
1.44 oz/A
Applied EPOST
Webster et al. 1997

23. The Response of Weeds to Various Cadre Rates in Georgia20 40 60 80
100
coffee senna
Florida beggarweed
0.36 oz/A
0.72 oz/A
1.1 oz/A
1.44 oz/A
Webster et al. 1997
Applied EPOST

24. Hophornbeam Copperleaf Control Randolph County, GA - 2001
Strongarm
(0.45 ozs/A)
Valor
(3 ozs/A)
Strongarm ozs
+ Valor 0.75 ozs/A
Untreated
6 WAT

25. Weed control in peanuts with reduced rates of Strongarm and Valor, 2002.
Untreated
Strongarm
0.45 oz/A
Valor
3 oz/A
Strongarm
0.113 oz/A +
Valor
0.75 oz/A
Attapulgus, GA
7 WAP

26. Reduced rates can work if……..
The weed is susceptible
good growing/application conditions exist
the application is timely (small weeds)
Full rates help to overcome variability of application due to
weed size, improper sprayer calibration, environmental
conditions, etc.

27. Cost-Effective Weed Management Summary
read label
calibrate sprayer
use yellow herbicides
use other soil applied herbicides as weeds and rotations dictate
make earlier applications with POSTS
utilize “expert” systems?
Reduced rates? Not for everyone or every situation but can work

28. University of
Georgia
Extension Weed
Science
(gaweed.com)