Results from Surveys Conducted on the Status of Glyphosate- resistant Weeds in Missouri and Current Weed Management Programs Utilized in Soybean

Transcription

1 Results from Surveys Conducted on the Status of Glyphosate- resistant Weeds in Missouri and Current Weed Management Programs Utilized in Soybean

2 2007 Missouri Retailer Survey 15-question phone survey of agricultural retailers / custom applicators conducted in cooperation with Syngenta Crop Protection Survey of soybean weed management practices and perceptions about glyphosate resistance 86 surveys completed out of 250 (34% response rate) Responses cover 1,409,700 soybean acres out of 4,600,000 acres planted in 2007 (31% of total)

3 2007 Missouri Retailer Survey: Soybean Acreage Serviced by Respondents in Each Region / % of Total Acreage Planted Northwest (342,500 / 32%) West Central (143,500 / 29%) Northeast (203,500 / 22%) Central (499,500 / 65%) East Central (116,000 / 38%) Southwest (91,940 / 66%) South Central (5,250 / 13%) Southeast (7,500 / 1%)

4 What % of the soybean acres you service received a preemergence residual herbicide this year? % of Acres None 1-10% 11-30% >30%

5 What % of the soybean acres you service received a preemergence residual herbicide this year? % of Acres Breakdown of Responses Across 3 Regions: NW Region Central Region NE Region None 1-10% 11-30% >30%

6 What were the three most common preemergence residual herbicides you used in soybeans this year? Other 19% Domain 2% IntRRo 9% Canopy EX 2% AuthFirst/Sonic 17% Prowl 16% Valor XLT 8% Valor 14% Treflan 1% Boundary 3% Prefix 9%

7 What % of the soybean acres you service were sprayed with glyphosate this year? % of Acres All 95-99% 90-94% <89% 7 3

8 What was the typical glyphosate product used and use rate at the time of the first application in RR soybeans? 27 ozs 37 ozs Generic 49% Roundup OriginalMax 37% Touchdown Total 14% 30 ozs

9 What is the average size of weeds at the time of the first postemergence glyphosate application? 60 % of Respondents to 6" 7 to 9" 10 to 12" 13 to 15" >15"

10

11 On the soybean acres you service, what is the typical number of postemergence glyphosate applications (includes tank-mixes)? % of Respondents or more 1 1

12 On what % of the soybean acres you service is glyphosate used alone without a tank-mix partner? 60 % of Acres All 90-99% 80-89% 70-79% <70%

13 On what % of the soybean acres you service is glyphosate used alone without a tank-mix partner? Breakdown of Responses Across 3 Regions: 60 NW Region Central Region NE Region 43 % of Acres All 90-99% 80-89% 70-79% <70%

14 What are the three most common postemergence herbicides that you tank-mix with glyphosate in Roundup Ready soybeans? Ultra Blazer 3% 2,4-DB/Butyrac 8% Other 15% Harmony GT 1% Classic 13% Flexstar/Reflex 6% Firstrate 15% Phoenix/Cobra 5% Resource 34%

15 What is the average size of weeds at the time of the first postemergence glyphosate application? % of Respondents Breakdown of Responses Across 3 Regions: NW Region Central Region NE Region to 6" 7 to 9" 10 to 12" 13 to 15" >15"

16 On what % of the soybean acres you service did glyphosate fail to control waterhemp this year? % of Acres Never 5% 10% 20% 7

17 If glyphosate failed to control waterhemp in your soybean fields this year, do you think the waterhemp was glyphosate-resistant? 80 % of Respndents Yes No

18 If yes, on how many soybean acres you service do you believe you have glyphosate-resistant waterhemp? # Acres with Glyphosate-resistant Waterhemp Per Region: Northwest (14,050 acres) Northeast (4,400 acres) Central (24,650 acres) West Central (0 acres) Total: 51,400 acres East Central (3,800 acres) Southwest (3,500 acres) South Central (250 acres) Southeast (750 acres)

19 2006 Waterhemp Screening Opportunity for agricultural retailers, farmers, etc. to have waterhemp accessions screened for resistance to glyphosate and PPO-inhibitors 10 samples sent in (compared to 2 glyphosateresistant waterhemp biotypes & 1 susceptible)

20 2006 Waterhemp Screening: Materials and Methods Applications -Treatments applied to waterhemp 6 inches in height -Applications made with a compressed air, laboratory spray chamber equipped with a TeeJet 8001EVS nozzle delivering 15 gal/a Data Collection and Analysis -Visual ratings and counts of surviving plants taken at 1,2, and 3 weeks after treatment -Fresh and dry weight biomass recorded 3 weeks after trtmnt -Waterhemp biotype classified as glyphosate- or PPO-resistant when survival 50%

21 2006 Waterhemp Screening: How big of a problem do we have? = waterhemp sample confirmed as resistant to glyphosate = waterhemp sample confirmed as resistant to glyphosate and PPOinhibitors = waterhemp sample confirmed as susceptible to glyphosate and PPOinhibitors Results indicate glyphosate-resistant waterhemp in at least 6 MO counties.

22 Other than waterhemp, what were the weeds that were most frequently not controlled or poorly controlled by glyphosate? Lambsquarters 10% Other 4% Velvetleaf 1% Teaweed 4% Common Ragweed 1% Horseweed 15% Morningglory Species 31% Shattercane 1% Giant Ragweed 32% Foxtail Species 1%

23 Winter Meeting Survey Results Audience response systems utilized during winter meeting season to understand problems/perceptions with glyphosateresistant weeds in Missouri Identical questions posed at each meeting, results summarized across ~400 responses

24 What do all the current cases of glyphosateresistant weeds have in common? A. All of these weeds developed glyphosate resistance in a continuous RR soybean system. B. All of these weeds developed glyphosate resistance in a continuous RR cropping system. C. All of these weeds developed glyphosate resistance in Missouri and then spread outward to other states. D. All of these weeds developed glyphosate resistance after repeated applications of glyphosate year after year. E. Both B and D are correct. 83% 8% 4% 3% 2% A. B. C. D. E.

25 What is the best thing to do to prevent the development of glyphosate-resistant weeds? 79% A. Rotate Crops B. Break out the plow C. Rotate herbicide mode of actions D. Spray a generic glyphosate 17% 2% 2% Rotate Crops Break out the plow Rotate herbicide mod... Spray a generic glyp...

26 How concerned are YOU as a crop consultant, retailer, etc. about the development of glyphosate-resistant weeds? 36% 48% 14% 2% A. Very concerned. I think it has the potential to be devastating to our current cropping systems. B. Moderately concerned. It s an issue we can t ignore. C. Somewhat concerned. I think we ll deal with it if it does occur. D. Not concerned. All we re seeing is a few isolated cases. These will not become wide-spread issues.

27 How concerned do you think farmers are about the development of glyphosate-resistant weeds? 16% 29% 45% 10% A. Very concerned. I think it has the potential to be devastating to our current cropping systems. B. Moderately concerned. It s an issue we can t ignore. C. Somewhat concerned. I think we ll deal with it if it does occur. D. Not concerned. All we re seeing is a few isolated cases. These will not become wide-spread issues.

28 Which of the two statements below best describes the predominant reason that some are NOT concerned with glyphosate-resistant weeds? A. There are more active ingredients on the way that will take care of any resistance problem that we might have. B. Resistant weeds are not a problem for me until they occur on my land. 29% 71% A. B.

29 Which scenario creates the highest risk of developing glyphosate-resistant waterhemp in your fields? 1% 5% 7% 3% 85% A. Conventional Corn/RR Soybean Rotation (conventional PRE & POST herbicides in corn, glyphosate-only in RR soybean) B. RR Corn/RR Soybean Rotation (Glyphosate-only in RR Soybean, Atrazine PRE followed by glyphosate in RR Corn) C. Continuous RR Soybean Rotation (Glyphosate as only herbicide used 1 or 2 times per year) D. Continuous RR Corn Rotation (Glyphosate as only herbicide used 1 or 2 times per year) E. Both C and D are equally at risk

30 What is the best stewardship practice that will prevent the development of glyphosate-resistant weeds? A. Use right glyphosate rate for weed size/stage B. Tank-mix with a herbicide with a different mode of action C. Use preemergence herbicides followed by glyphosate D. Rotate glyphosate with other herbicides in alternate years Use right glyphosate... 11% Tank-mix with a herbi... 16% Use preemergence he... 31% Rotate glyphosate wi.. 42%

31 Conclusions: Glyphosate-resistance in Missouri Results from all surveys reveal a heavy reliance on glyphosate for weed control in soybeans Glyphosate-resistant waterhemp is present in at least 6 counties and is perceived to occur on approximately 4% of the soybean acreage in Missouri Key weeds poorly controlled or not controlled include giant ragweed, morningglory species, horseweed, and lambsquarters Growers and retailers seem to understand what leads to glyphosate resistance, but are not concerned until these problems occur on their land