Cotton Disease Management CSCRC Trey Price

Transcription

1 Cotton Disease Management CSCRC 2017 Trey Price

2 Cotton Seedling Diseases Fungicide seed treatments very effective Most beneficial under stressful conditions Poorly-drained soils Cool weather Poor seed quality Me trying to kill seedlings Proper planting date Appropriate soil temperature Long range forecast calling for warm temperatures

3 Stand (plants/ft) Seedcotton (lb/a) * * * * Stand (Inoculated - Rhizoctonia solani) b b ab a a a a a ab a Stand (Non-Inoculated) Yield (Inoculated - Rhizoctonia solani) Yield (Non-Inoculated) a a a a a a a ab a c Effect of seed treatment on cotton stand and yield MRCT1606

4 Cotton Diseases - Leaf Spot Complex Alternaria Stemphylium Cercospora Ascochyta Drought Potassium deficiency Crop injury May be resistant varieties Fungicides effective.not RECOMMENDED MOST OF THE TIME COSMETIC ISSUE

5 Fungicide Trial, MRRS, Winnsboro, LA, 2014 COTTON LEAF SPOTS Lint Yield (lbs/a) AUDPC (0-9) * * * * st wk bloom 3 rd wk bloom AUDPC (0-9) Yield D&PL 1137 MRCT1410

6 Target Spot

7

8 Target Spot Distribution

9 Target Spot Distribution

10 Target Spot Distribution

11 1-Jul 3-Jul 5-Jul 7-Jul 9-Jul 11-Jul 13-Jul 15-Jul 17-Jul 19-Jul 21-Jul 23-Jul 25-Jul 27-Jul 29-Jul 31-Jul 2-Aug 4-Aug 6-Aug 8-Aug 10-Aug 12-Aug 14-Aug Rainfall (in.) Rainfall, , Chase, LA (10 in. Total) 16 events 2015 (2.5 in. Total) 7 events 2016 (7.7 in Total) 12 events

12 Lint Yield (lbs/a) Regional Fungicide Trial Alexandria, LA, 2014 Defoliation (%) * * st wk bloom 3 rd wk bloom Defoliation (%) Yield PHY 499 DLCT1402

13 Lint Yield (lbs/a) Defoliation (%) a BASF Fungicide Trial Winnsboro, LA, 2014 ab abc a bcd cd d d st wk bloom only Defoliation (%) Yield 1 st and 3 rd wk bloom (2 applications) PHY 499 MRCT1406

14 Regional Fungicide Trial St. Joseph, LA 2016 Lint Yield (lbs/a) Defoliation (%) * * * st wk bloom 3 rd wk bloom 8/11 Defoliation (%) 8/23 Defoliation (%) Yield PHY 499 NECT1603

15 Regional Fungicide Trial Winnsboro, LA 2016 Lint Yield (lbs/a) Defoliation (%) * * st wk bloom 3 rd wk bloom 8/11 Defoliation (%) 8/22 Defoliation (%) Yield PHY 499 MRCT1607

16 Multi-year Regional Evaluation of One and Two Applications of Registered and Experimental Fungicides for the Management of Target Spot on Two Cotton Varieties H. L. Mehl, N. Dufault, M. Mulvaney, A. Hagan, H. Kelly, R. Kemerait, P. Price, T. Allen, and R. L. Nichols 1 st and or 3 rd wk bloom applications 16 site-years 1 of 12 locations in 14 and 15 showed significant yield increase 3 of 8 in 16 showed significant yield increase AVERAGE YIELD RESPONSE = 5%

17 Target Spot Management Scout! If disease starts during the 1 st 3 weeks of blooming, yield loss may occur. Watch the weather. Frequent rain favors target spot. Watch neighboring soybeans. Disease is usually spotted in early beans before cotton. Manage excessive canopy growth. Any rank cotton variety can get target spot. Timely application of PGRs. Timely application of fungicides. Fungicides are effective on target spot. The likelihood of a return on the investment are not high to begin with and decreases as the season progresses. Use maximum total water volume. High volume and pressure are needed to deliver product low in the canopy. Ideal timing is just prior to canopy closure. Don t panic! If target spot develops late, yield loss due to disease is less likely. Don t seek revenge! Rescue applications usually will not provide economic returns.

18 Regional Fungicide Trial St. Joseph, LA 2016 Boll Rot Ratings Seedcotton (lb/a) Boll Rot (%) /23 Boll Rot (%) 1 st wk bloom 3 rd wk bloom Yield PHY 499 NECT1603

19 Regional Fungicide Trial St. Joseph, LA 2016 Boll Rot Ratings Seedcotton (lb/a) Boll Rot (%) /23 Boll Rot (%) 1 st wk bloom 3 rd wk bloom Yield PHY 499 MRCT1607

20 Boll Rots

21 Boll Rots Caused by at least 170 different species of mostly fungi. Main culprits are Alternaria spp., Colletotrichum (anthracnose), Fusarium spp., Lasiodiplodia, Phomopsis, Phytophthora, Rhizoctonia solani, Xanthomonas (bacterial leaf blight) 3 kinds of disease cycles: Soilborne (Rhizoctonia solani) Seedborne (Xanthomonas campestris pv. malvacearum) Foliar pathogens/saprophytes (Alternaria spp.)

22 Boll Rots Management Pathogen-free seed. Anthracnose has mostly been eliminated by fungicide seed treatments. Rainy weather or long periods of high humidity favor disease outbreaks. Excessive vegetative growth favors boll rots. Proper N fertilization Timely PGR application Skip row/wide row spacings Fungicides?

23 Boll Rots Fungicide Efficacy 15 Plant Disease Management Reports ( ) 11/15 no significant yield increase relative to nontreated 8/15 lowered boll rot or hardlock severity with several different fungicides: Benlate, Folicur, Quadris, Tilt, Topsin Topsin (at least 2 shots, 41% (23,25, and 75 %) of treated plots showed yield increase) no cotton label? Quadris (one shot, one trial showed yield increase in 50% of the plots). Currently not recommending fungicides for boll rot. More work needs to be done

24 Bacterial Leaf Blight (Angular leaf spot)

25 Bacterial Leaf Blight (Angular leaf spot)

26 Bacterial Leaf Blight (Angular leaf spot)

27 Bacterial Leaf Blight ( black arm )

28 Bacterial Leaf Blight (Angular leaf spot)

29 Bacterial Leaf Blight (Angular leaf spot)

30 Bacterial Leaf Blight (Field Diagnosis)

31 Bacterial Blight Management Resistant varieties Overhead irrigation may exacerbate Manage plant height (PGRs) Otherwise, manage it like you re going to make 3 bales. Worst defoliation I ve seen in LA is around 10 to 15%. That farmer picked 3 bales

32 Thank YOU for Supporting Us! Boyd Padgett Brandi Woolam Brenda Tubana Charlie Overstreet Clayton Hollier Dan Fromme Daniel Stephenson Darrell Franks and Crew Donnie Miller Eduardo Chagas Hunter Pruitt Josh Copes Myra Purvis Raj Singh Ray Schneider Rick Mascagni Ronnie Levy Scott Washam and Crew Sebe Brown Steve Harrison Vinson Doyle Warren Ratcliff and Crew Agents Consultants Industry Trey Price