North Foliar Fungicide Study Block 5S Beaumont, TX 2009 Young-Ki Jo, X. Mao, M.O. Way, Don Groth and Piper Roberts PLOT PLAN I II III IV 1 14 19 11 37 10 55 13 2 10 20 9 38 7 56 11 3 16 21 2 39 12 57 5 4 13 22 4 40 13 58 8 5 3 23 17 41 11 59 2 6 17 24 13 42 17 60 9 7 8 25 5 43 2 61 15 8 2 26 3 44 18 62 12 9 15 27 6 45 15 63 10 10 4 28 14 46 16 64 3 11 9 29 7 47 8 65 16 12 5 30 18 48 6 66 14 13 18 31 8 49 3 67 17 14 11 32 1 50 9 68 1 15 6 33 16 51 5 69 18 16 1 34 10 52 14 70 7 17 7 35 12 53 4 71 4 18 12 36 15 54 1 72 6 Plot size: 7 rows, 7 inch row spacing, 18 ft long Variety: Cocodrie (seed provided by LSU Foundation Seed) Note: smaller numbers in italics are plot numbers 46
TREATMENT DESCRIPTION, RATE AND TIMING Main Crop Ratoon Crop Trt. no. Treatment (fl oz prod/a) Treatment (fl oz prod/a) 1 Evito 480 SC + COC 3 Quadris 12 2 Evito 480 SC + COC 4 Quilt 20 3 Evito 480 SC + COC 5.7 Stratego 19 4 A15909 (AZO + PPZ) 17.5 Stratego 19 5 A15909 (AZO + PPZ) + Quadris SC + Tilt EC 21 + 10 + 5 Evito + COC 5.7 6 A13705 (Quilt) + Quadris SC 20 + 6.3 Convoy 23.4 7 Quilt SE 20 Stratego 19 8 Quadris SC 12 Quilt 20 9 Stratego EC 19 Quadris 12 10 Stratego + Gem 500 SC 19 + 1.5 Evito + COC 5.7 11 Stratego + Gem 500 SC 16 + 3 Convoy 23.4 12 Stratego + Quadris F 16 + 5 Quilt 20 13 Convoy 40 SC 11.7 Artisan 22.5 14 Convoy 40 SC 16.8 Artisan 15 15 Convoy 40 SC 23.4 Quadris 12 16 Artisan SE 15 Convoy 23.4 17 Artisan SE 22.5 Convoy 16.8 18 Untreated --- Untreated --- All treatments applied at 4 panicle 47
Agronomic and Cultural Information Experimental design: Randomized complete block with 18 treatments and 4 replications Planting: Drill-planted Cocodrie @ 80 lb/a into League soil (ph 5.5, sand 3.2%, silt 32.4%, clay 64.4%, and organic matter 3.8-4.8%) on Apr 6 Plot size = 7 rows, 7 inch row spacing, 18 ft long (no metal barriers) Emergence on Apr 15 Irrigation: Flushed blocks (temporary flood for 48 hours, then drain) on Apr 6 Note: Plots were flushed as needed from emergence to permanent flood Permanent flood (PF) on May 7 Ratoon flood on Aug 6 Fertilization: All fertilizer (urea) was distributed by hand. 56.7 lb N/A (1/3 of 170) on Apr 6 at planting 56.7 lb N/A (1/3 of 170) on May 7 at PF 56/7 lb N/A (1/3 of 170) on May 27 at 2 weeks after PF 40 lb N/A on Jun 22 Total main nitrogen = 210 lb N/A 100 lb N/A for ratoon on Aug 6 Total ratoon nitrogen = 100 lb N/A Herbicide: Stam 80EDF @ 2.0 lb, Basagran @ 0.75 lb, Facet 75DF @ 0.25 lb and Ordram @ 2.0 lb (AI)/A and Agri-Dex @ 1.0 pt/acre with a 2-person hand-held spray boom (13-80015 nozzles, 50 mesh screens, 16 gpa final spray volume) on May 6 for early season weed control Treatments: Inoculated with sheath blight (SB) inoculum (Rhizoctonia solani) on May 28. The inoculum was prepared using 5 parts rice hulls and 1 part whole rice substrate colonized with R.solani. Fungicide treatments for main crop applied with a 3-nozzle CO 2 pressurized spray boom (800067 nozzles and 50 mesh screens) on Jun 19 (12 days after panicle differentiation) by Dr. Jo Fungicide treatments for ratoon crop applied on Aug 27 by Dr. Jo Sampling: Stand counts on plots 3, 27, 42 and 66 as well as bird damaged plots 18, 36, 54, and 72 (3-3 ft counts on rows 2, 4 and 6) on May 2 Water was unintentionally added to block after inoculation which probably reduced SB severity; rice @ 1 panicle on Jun 12 Disease ratings by Dr. Jo on Jul 9, Jul 31 and Oct 5 Harvest: Harvested main crop plots on Aug 3 Size harvested plot = 7 rows, 7 inch row spacing, 18 ft long Harvested ratoon crop plots on Oct 21 Size harvested plot = 7 rows, 7 inch row spacing, 18 ft long 48
Data analysis: Yields converted to 12% moisture; all data analyzed by ANOVA and means separated by Fisher s Protected LSD (alpha 0.05). Discussion Sheath blight severity was not as high as desired, but mean severity in the non-treated control plots reached 7 in which lesions affected the lower ¾ of the sheaths and extended to leaf blades of the lower ⅔ of the plants. Most treatments significantly reduced disease severity compared to the non-treated control. A tank-mixture of azoxystrobin and propiconazole provided the best control; however, yields were not significantly different among treatments. The fungicide treatments on the main crop significantly increased the number of healthy tillers of the ratoon crop. Mixture of trizole and strobilurin fungicides applied for the main crop provided more than 90% tiller stands of the ratoon crop, compared with the non-treated control plot having only 76.3% viable tillers (Table 1). The fungicide treatments on the ratoon crop applied at 24 days after main crop harvest did not affect the disease severity of brown leaf spot and narrow brown leaf spot, and did not increase the yield of the ratoon crop. The main crop disease management seems to have a direct impact on the ratoon crop management. Table 1. Mean disease ratings for main crop. Beaumont, TX. 2009. Treatment (fl oz/a) Sheath blight disease rating a % stand of ratoon crop Evito 480 SC + COC 3 3.5 ed 83.8 c-g Evito 480 SC + COC 4 6.0 a-d 81.3 e-g Evito 480 SC + COC 5.7 4.4 b-d 87.5 a-f A15909 (AZO + PPZ) 17.5 2.4 ef 91.3 a-d A15909 (AZO + PPZ) + Quadris SC + Tilt EC 21 + 10 + 5 2.3 ef 96.3 a A13705 (Quilt) + Quadris SC 20 + 6.3 1.6 f 90.0 a-e Quilt SE 20 3.3 d-f 93.8 ab Quadris SC 12 2.4 ef 93.8 ab Stratego EC 19 4.6 b-d 91.3 a-d Stratego + Gem 500 SC 19 + 1.5 3.5 de 92.5 a-c Stratego + Gem 500 SC 16 + 3 3.1 d-f 93.8 ab Stratego + Quadris F 16 + 5 3.3 d-f 93.8 ab Convoy 40 SC 11.7 4.8 b-d 91.3 a-d Convoy 40 SC 16.8 4.3 cd 78.8 fg Convoy 40 SC 23.4 3.6 de 83.8 c-g Artisan SE 15 6.1 ab 82.5 d-g Artisan SE 22.5 4.6 b-d 86.3 b-f Untreated --- 6.9 a 76.3 g a Sheath blight rating 0 (no disease) to 9 (plant collapsed) Means in a column followed by the same letter are not significantly different (P = 0.05). 49
Table 2. Mean disease ratings for ratoon crop. Beaumont, TX. 2009. % stand of Brown leaf spot Narrow brown leaf spot Treatment (fl oz/a) ratoon crop Incidence Severity Incidence Severity Quadris 12 83.8 c-g 72.5 2.0 11.3 1 Quilt 20 81.3 e-g 72.5 2.0 15.8 1 Stratego 19 87.5 a-f 72.5 1.8 6.5 1 Stratego 19 91.3 a-d 82.5 1.8 8.0 1 Evito + COC 5.7 96.3 a 67.5 1.8 18.0 1 Convoy 23.4 90.0 a-e 85.0 1.8 12.5 1 Stratego 19 93.8 ab 80.0 1.8 8.3 1 Quilt 20 93.8 ab 80.0 1.5 15.5 1 Quadris 12 91.3 a-d 65.0 1.5 19.3 1 Evito + COC 5.7 92.5 a-c 72.5 1.5 11.8 1 Convoy 23.4 93.8 ab 65.0 1.5 25.0 1 Quilt 20 93.8 ab 72.5 1.5 4.3 1 Artisan 22.5 91.3 a-d 76.3 1.5 14.3 1 Artisan 15 78.8 fg 70.0 1.5 14.0 1 Quadris 12 83.8 c-g 67.5 1.5 10.5 1 Convoy 23.4 82.5 d-g 70.0 1.3 9.0 1 Convoy 16.8 86.3 b-f 77.5 1.3 6.8 1 Untreated --- 76.3 g 67.5 1.0 20.5 1 NS NS NS NS Means in a column followed by the same or no letter are not significantly (NS) different (P = 0.05, ANOVA and LSD). 50
Table 3. Mean yield data for main and ratoon crop. Beaumont, TX. 2009. Main Crop Ratoon Crop Yield (lb/a) Treatment (fl oz prod/a) Treatment (fl oz prod/a) M R T Evito + COC 3 Quadris 12 7389 3560 10949 Evito + COC 4 Quilt 20 7446 3542 10988 Evito + COC 5.7 Stratego 19 7445 3684 11129 A15909 (AZO + PPZ) 17.5 Stratego 19 7252 3507 10759 A15909 (AZO + PPZ) + Quadris 2.08 SC + Tilt 3.6 EC 21 + 10 + 5 Evito + COC 5.7 7801 3711 11512 A13705 (Quilt) + Quadris 2.08 SC 20 + 6.3 Convoy 23.4 7339 3256 10595 Quilt 20 Stratego 19 7461 3623 11084 Quadris 12 Quilt 20 7624 3675 11299 Stratego 19 Quadris 12 7725 3623 11348 Stratego + Gem 500 SC 19 + 1.5 Evito + COC 5.7 7213 3560 10773 Stratego + Gem 500 SC 16 + 3 Convoy 23.4 7379 3359 10738 Stratego + Quadris 2F 16 + 5 Quilt 20 6902 3702 10604 Convoy 11.7 Artisan 22.5 7123 3414 10537 Convoy 16.8 Artisan 15 7235 3481 10716 Convoy 23.4 Quadris 12 6845 3412 10257 Artisan 15 Convoy 23.4 7561 3411 10972 Artisan 22.5 Convoy 16.8 7443 3473 10916 Untreated --- Untreated --- 7460 3339 10799 NS NS NS Means in a column are not significantly (NS) different (P = 0.05, ANOVA) 51