The design was a split plot with turf species as the main plot factor and herbicide and/or fertilizer treatment as the subplot factor. Two turfgrass species, 'Brightstar' perennial ryegrass (tested Jan 98) and 'Limousine' Kentucky bluegrass (Williams Seed - tested Jan 99) were seeded into a newly tilled and prepared bare soil plot. Seeding rates were 1.5 lb/1000 ft² for bluegrass and 5.0 lb/1000 ft² for ryegrass. There were two rows per replication with one turf species per row and three replications. Three-foot barrier areas were placed between rows within replications and between replications.

Three materials were screened: L-0384 Drive 0.43% + Novex starter fairway fertilizer (16-24-11), Drive 75DF, and Novex starter fairway fertilizer (16-24-11) as the standard. An untreated control was included. Treatment applications were made at specific intervals throughout the study based on seedling emergence. Seeding was performed May 25 and immediately following seeding and raking, the at seeding (0 DAS) materials were applied. Granular materials were applied with containers used as 'shaker dispensers' to ensure uniform distribution. Sprayables were applied using a carbon dioxide powered backpack sprayer equipped with TeeJet #8006 nozzles at a spray pressure of 30-40 psi. Ryegrass emergence was on May 30 and the 7 days after emergence (7 DAE) treatments were applied on June 7, the 14 DAE on June 19, and the 28 DAE on June 30, 2000. Bluegrass emergence was on June 12 and the 7 DAE materials were applied on June 19, the 14 DAE on June 27, and the 28 DAE on July 11, 2000.

Seedling tolerance was monitored throughout the season. Turf quality was visually assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable, and 1 = worst quality (Tables 1 and 2). Turf tolerance was further measured by estimating percentage turf cover per individual plot for ryegrass (Tables 3 and 4) and bluegrass (Tables 5 and 6). Weed populations were assessed by estimating the percentage cover for all weed species (Tables 7 and 8). Quality, turf cover, and weed cover data were taken from June 8 through September 12. In addition, on September 12, weed populations per individual plot were assessed by species (Tables 9 and 10). The predominate species were witchgrass (Panicum capillare) and crabgrass.

Data were analyzed using the Statistical Analysis System (SAS Institute Inc., 1989-1996) and the Analysis of Variance (ANOVA) procedure. Additional analyses using the General Linear Model (GLM) procedure were conducted for ryegrass and bluegrass percentage turf cover omitting data for those plots not as yet treated. Treatment effects on seedling growth, weed populations, and turf quality were tested using Fisher's Least Significant Difference (LSD) test.

There were no phytotoxic symptoms found on ryegrass throughout the study. The only quality differences were observed on June 30 and July 7 (Table 1). On June 30, the worst quality was for ryegrass that was to receive 28 DAE applications. These treatments were applied on June 30 following data collection. By July 7, the quality of this turf had improved and was similar to other treated turf and to the fertilized control.

From June 8 through June 30 there were differences in percentage ryegrass cover between rye treated with Drive and rye treated with only the Novex fertilizer (Table 3). The significantly lower percentages were for ryegrass that was not as yet treated. By July 30, the 14 and 28 DAE treatments had been made and the data from July 7 show no differences in percentage cover between ryegrass treated with Drive + fertilizer formulations and ryegrass treated with fertilizer alone. The data suggest that from July 14 through the remainder of the season, differences in percentage cover between Drive treated and untreated ryegrass are related to the percentage weed cover.

The GLM analysis showed no differences in percentage cover among treatments for June 8 and June 15 (Table 4). On June 23, the percentage ryegrass cover treated at 14 DAE on June 20 was lower than the other treated ryegrass.

By July 7, all of the treatments had been applied and there were statistical differences in weed cover (Table 7). Drive 75DF and L-0384 Drive reduced weed cover as compared with the Novex fertilizer throughout the test. The mean data suggest that the best weed control was provided by the Drive products applied 7 DAE but these levels were not statistically different from control provided by 0 DAS, 14 DAE, and 28 DAE.

The predominant weed species throughout the plot were witchgrass and crabgrass (Table 9). There were statistical differences in witchgrass and crabgrass percentage cover among the treatments. The best witchgrass control was provided by Drive 75DF applied 0 DAS and 7 DAE. Crabgrass control was best in ryegrass treated with Drive 75DF at 0 DAS and 14 DAE or with L-0384 Drive at 7 DAE, 14 DAE and 28 DAE.

The data for bluegrass show that none of the treatments affected turf quality as compared with the fertilized control (Table 2). Bluegrass quality remained constant throughout the growing season.

There were some statistical differences in percentage bluegrass cover (Table 5). Percentage cover for June 23, July 7, and August 8 was statistically higher than the fertilized control for bluegrass treated with Drive 75DF + fertilizer at seeding. For the balance of the duration, percentage cover was statistically similar for all bluegrass but cover remained numerically higher for grass treated with Drive 75DF + fertilizer at seeding than the fertilized controls. Mean data show that treatment with Drive 75DF + fertilizer produced a larger bluegrass cover than treatment with Novex fertilizer alone.

The GLM analysis of these data removed the statistical differences in cover for July 7 (Table 6). There were no other changes in significant effects of the treatments.

In general, percentage weed cover was much higher in the bluegrass plots than in the ryegrass (Table 8). Because bluegrass germination is much slower than ryegrass, weed populations were able to become established in bare plots not treated at seeding. There also was a significant replication effect on weed cover throughout the duration of the test. Percentage weed cover was higher in replication 3 than in the other replications.

Through June 30, percentage weed cover was low in bluegrass treated with either Drive 75DF or L-0384 Drive formulations at seeding. From July 7 through August 8 and August 29 through September 12 there were statistical differences in percentage weed cover. Weed cover was greater than 50% in all bluegrass plots for much of the duration of the test. Mean data show that all applications of Drive 75DF reduced weed cover as compared with the Novex control. The L-0384 Drive formulation provided similar weed control when applied 7 DAE. Witchgrass and crabgrass infestation levels were similar in all bluegrass plots (Table 10). Treatment with either Drive 75DF or L-0384 Drive did not significantly reduce the populations of these weed species. Numerically, the least crabgrass was in bluegrass treated at 28 DAE with Drive 75DF.

Table 1. Visual quality of perennial ryegrass¹ seeded for the 2000 Lesco Drive Seeding Tolerance Study.