Evaluation of Fiesta and liquid corn gluten meal for pre-emergent control of turfgrass weeds greenhouse and bare soil trial. E. Lyons, K. Jordan, and K. Carey Department of Plant Agriculture and the Guelph Turfgrass Institute, University of Guelph, Ontario. Sponsor: Neudorff North America The objective of this research project was to determine the effect of Fiesta chelated iron alone and in combination with liquid corn gluten meal on germination and emergence, plant survival, shoot and root growth of turfgrass weeds (large crabgrass, white clover, dandelion, and plantain) as well as turfgrass species (perennial ryegrass). Data collected included observation of the rate (timing and percentage) of germination of weed seed, the total shoot growth of seedlings, and the survival rate relative to untreated controls. MATERIALS / METHODS The treatments were different rates and mixtures of Fiesta and liquid corn gluten meal (Table 1) as well as an untreated control. Four weed species (large crabgrass - Digitaria sanguinalis, white clover - Trifolium repens, dandelion Taraxacum officinale and narrow leaf plantain - Plantago lanceolata) and one turfgrass species (perennial ryegrass Lolium perenne) were treated with each herbicide treatment. Greenhouse trial. Each treatment was replicated five times in 8x8 cm plastic pots filled to the rim (45 ml) with soil. Experimental units were seeded August 5, 215 with 3 seeds of each species. Treatments were sprayed August 6, 215 with a compressed air sprayer (Teejet 81VS flat fan nozzles - 5 ml/sec/nozzle at 2 psi). Because of the suspended particles in the liquid corn gluten meal material, it was necessary to switch to a single higher volume nozzle (82VS) and increase the sprayer pressure and spray volumes. The rate of application of active ingredient for all treatments remained as in Table 1. Treatments were placed in a randomized split plot layout in the greenhouses at the Bovey Bldg., University of Guelph (Figure 2). Pots and soil plots were kept moist until seeding, at which point seed was applied and sprayed with treatments. Thereafter the seedbed was kept moist. Germination and establishment were assessed by counting seedling plants as long as possible, and thereafter by ranking pots according to a visually estimated scale. Seed germination observations were made regularly during the germination period. At an appropriate time in the greenhouse experiment (3 weeks after the end of the germination period), living plants from the pots were counted, and shoot systems were dried and biomass was measured. Bare soil plot trial. Each treatment were replicated four times in 2 cm x 2 cm small plots arranged in a randomized complete block design in tilled bare soil in the research ranges at the Guelph Turfgrass Institute (Figure 3). Experimental units were seeded with a weight of seeds which represented approximately 1 seeds. An additional positive control herbicide (Acclaim phenoxaprop-ethyl) treatment was included in the bare soil plot trial. Fiesta and Acclaim treatments were sprayed with a compressed air sprayer (Teejet 81VS flat fan nozzles - 5 ml/sec/ nozzle at 2 psi). Because of the suspended particles in the liquid corn gluten meal material, it was applied with a hand sprayer to the 2 x 2 cm seeded area of each plot. Plots were seeded and liquid corn gluten meal applied to 2 x 2 cm areas using a 1 x 2 m quadrat divided into 2 cm grids (Figure 4). An anecdotal photographic record of the experiment was kept. All measurements were analysed by appropriate statistical analyses (general linear models). Guelph Turfgrass Institute 215 Annual Research Report 1
Table 1. Treatment list. Herbicide treatments: Fiesta rate LCGM rate 1 Fiesta 4% 1 ml m -2 2 Fiesta 4% 2 ml m -2 3 Fiesta 4% 4 ml m -2 4 Fiesta 4%+ LCGM 2% 1 ml m -2 43 ml m -2 5 Fiesta 4%+ LCGM 2% 2 ml m -2 43 ml m -2 6 Fiesta 4%+ LCGM 2% 4 ml m -2 43 ml m -2 7 Corn gluten meal (liquid) 2% 43 ml m -2 8 Untreated control 9 Acclaim (positive control).125 ml m -2 Field trial only Target Species: 1 Large crabgrass 2 White clover 3 Narrowleaf plantain 4 Dandelion 5 Perennial ryegrass Application Timing: Sprayed directly on seeds at seeding. Figure 1. Pots seeded and ready to be sprayed (left). 25 pots (5 species x 5 replicates) were sprayed with each treatment (right). August 5, 215. Figure 3. Plot area for bare soil trial, seeded and sprayed, September 1, 215. Figure 2. Seeded and sprayed pots arranged in randomized complete block under misters in the greenhouse. August 12, 215 (6 DAT). Figure 4. Representative seeded/treated area: Block 1, Fiesta 2 ml m -2 treatment. Species were assigned randomly to the five 2x2cm areas in the centre of each 1 m 2 plot. 2 Guelph Turfgrass Institute 215 Annual Research Report
RESULTS Environmental data Daily air temperatures, evapotranspiration demand, and rainfall data for summer 215 are presented in Figures 2-4. Air temperature ( C) 3 2 1-1 May Maximum Minimum Jun Jul Aug Sep Oct Figure 2. Daily air temperatures at GTI, summer 215. Estimated ET (mm) 8 6 4 2 May Jun Jul Aug Sep Oct Figure 3. Daily estimated ET at GTI, summer 215. Daily rainfall (mm) 8 6 4 2 May Daily Cumulative Jun Jul Aug Sep Oct 6 4 2 Figure 4. Daily and cumulative rainfall at GTI, summer 215. Cumulative rainfall (mm) Greenhouse trial. There were no significant treatment effects of any of the herbicide combinations on germination and establishment of any of the species (Table 2). Germination rate was near 1% for the perennial ryegrass, more than 5% for all the weeds except narrowleaf plantain, which had an ultimate germination rate of about 2%. Again with the exception of the plantain, most of the germination of the seeds had completed by 11 days after seeding/ treatment. There were very slight differences in growth as measured by total shoot biomass at harvest (46 DAT) in the dandelion and crabgrass pots, but this was not reflected in per plant biomass differences, and so may reflect differences in plant number rather than growth rate. In any case, the differences were very small. Bare soil plot trial. There was no observable germination of the seeds of the five target species planted in the bare soil plots, in spite of the reasonably good germination rates of the same seed on soil in the greenhouse pots. It was not possible to maintain the same levels of constant moisture in the field, which may have been the chief cause of lack of germination. Nevertheless, the existing vegetation (seeds, seedlings and some scattered plants) showed a response to the herbicide treatments. Because these were not added plants, it is not possible to be confident that these are pre-emergent or early post-emergent effects. The existing weed community is a mixture of agricultural weeds, dominated at this stage in this trial by common purslane (Portulaca oleraceae). Assessment of weed cover at 14 DAT by digital image analysis (colour threshold methods using ImageJ software see Figures 5 and 6), showed a significant difference among the treatments, based mainly on presence of Fiesta in the treatment (Table 3). DISCUSSION AND CONCLUSIONS We did not observe any strong pre-emergent herbicide effect of any of the treatments on the five target species in the greenhouse trial. There were clear differences between the treatments with and without Fiesta in the field trial, and a suggestion of a rate effect within the different rates of Fiesta, but because these effects were observed in non-target plants (i.e. not the seeded species), it is not possible to be confident that Guelph Turfgrass Institute 215 Annual Research Report 3
Table 2. Germination and growth of treated pots. Herbicide Germinated seedlings Harvest dry weight 3 DAT 5 DAT 11 DAT 46 DAT Total Per plant Dandelion Control 13.2 1 19.6 17.6 17.8.17 2 ab.1 CGM 13. 18. 17.6 16.2.18 ab.12 F 1 14.2 17. 17.2 18.6.2 ab.11 F 1 + CGM 13.6 2.4 19.8 19.8.2 a.1 F 2 13.6 2.4 19.4 16.4.14 ab.9 F 2 + CGM 11.2 17.6 17.6 14.2.18 ab.13 F 4 9. 13. 13.8 13.4.13 b.1 F 4 + CGM 9. 15.6 15.2 15.2.16 ab.12 msd p=.5 NS NS NS NS.7 NS White clover Control 13.6 21.2 2. 16.6.13.8 CGM 11. 21.6 2.8 18.6.22.12 F 1 17.8 22.6 22. 16.2.18.1 F 1 + CGM 11. 18.6 2.6 19.4.17.9 F 2 14.4 2.6 18.2 15.4.18.12 F 2 + CGM 13. 21. 19.6 15.6.19.12 F 4 1.8 16.2 16.4 13.6.16.12 F 4 + CGM 17.6 21.4 2. 14..19.14 msd p=.5 NS NS NS NS NS NS Narrowleaf plantain Control.2.2 3.6 5.6.11.21 CGM.4.4 4. 5..12.24 F 1..4 3.2 4.2.13.34 F 1 + CGM.4. 3.4 5.8.12.21 F 2..2 3. 5.6.12.21 F 2 + CGM.2.6 5.2 7.6.18.24 F 4 1..2 5.2 7..13.2 F 4 + CGM.2.4 4. 7.2.13.2 msd p=.5 NS NS NS NS NS NS Crabgrass Control 6.6 12.6 16. 16.4.22 ab.13 CGM 7.2 14.8 16.8 17..27 a.16 F 1 5.2 11.2 15. 14.4.19 ab.14 F 1 + CGM 5.4 12.4 16.8 17..23 ab.14 F 2 5.4 12.6 15.4 15..22 ab.15 F 2 + CGM 4.8 12.4 15. 13.8.18 ab.14 F 4 3. 1. 14.2 11.2.14 b.12 F 4 + CGM 5.6 12.8 16.8 17.2.23 ab.13 msd p=.5 NS NS NS NS.11 NS Perennial ryegrass Control 19.4 27.8 27.4 28.8.21.7 CGM 19. 26.4 26. 28.2.25.9 F 1 21.6 27.8 27.2 28.8.25.9 F 1 + CGM 16.2 24.6 26.2 27..26.1 F 2 18.8 27. 26. 27..23.9 F 2 + CGM 12.6 24. 24.4 26..22.9 F 4 15. 21.4 22.8 23.6.17.8 F 4 + CGM 15.2 22.8 23.6 25.8.28.11 msd p=.5 NS NS NS NS NS NS 1 Count of germinated/established seedlings; mean of 5 replicates. 2 Dry weight (g); mean of 5 replicates. Means within columns followed by the same letter are not statistically significantly different (Tukeys HSD, p=.5) 4 Guelph Turfgrass Institute 215 Annual Research Report
Control CGM Acclaim Fiesta 1 + CGM Fiesta 2 + CGM Fiesta 4 + CGM Fiesta 1F Fiesta 2 Fiesta 4 Figure 5. Representative treated areas, September 15, 215 (14 DAT). Block 1 of four blocks; seeded areas are the four corners and the central 2 x 2 cm squares. Most of the visible vegetation is common purslane (Portulaca oleraceae). these are pre-emergent effects rather than early postemergent effects. The plot areas had been treated with non-selective herbicides and cultivated prior to seeding (Figure 3), but there were clearly still many viable seeds/seedlings present. There was no effect of liquid corn gluten meal or phenoxyprop-ethyl on the weed growth, when compared to the untreated control. Guelph Turfgrass Institute 215 Annual Research Report 5
Figure 6. Example of quantification of weed cover with digital image analysis (Image J colour threshold tool). Table 3. Percent cover of unidentified weeds in treated plots as estimated by digital image analysis, 14 DAT. Herbicide Crabgrass 1 Dandelion 1 Narrowleaf Perennial White All plots plantain 1 ryegrass 1 clover 1 Control 15.7 2 ab 27.3 ab 3.3 ab 39.1 a 36.4 a 29.8 a Acclaim 29.5 a 31. a 27.1 ab 28. ab 3.7 a 29.3 a CGM 27.1 a 29.6 a 34.4 ab 21. abc 23. ab 27. a F 1 1. b 13.3 ab 11.5 bc 8.9 bc 4.9 b 9.7 b F 1 + CGM 9.3 b 5.6 ab 14.8 abc 13.7 bc 7. b 1.1 b F 2 5.2 b 7. ab 3.9 c 7.1 bc 4.1 b 5.5 b F 2 + CGM 8.7 b 6.8 ab 5. c 7.8 bc 6.7 b 7. b F 4 2.9 b 5.6 ab 5.5 c 2.8 c 4.6 b 4.3 b F 4 + CGM 2.8 b 3. 4.5 c 2.9 c 4.7 b 3.6 b msd p=.5 16.5 25.7 2.7 24.6 2.3 8.8 1 Species seeded into 2 x 2 cm plot actual species measured is mostly common purslane. 2 Percentage of area covered by weed; mean of 5 replicates (except for All plots, which is the mean of 25 replicates). Means within a column followed by the same letter are not significantly different (Tukeys HSD, p=.5). 6 Guelph Turfgrass Institute 215 Annual Research Report