Empirical research is largely supportive of the assertion of instrumental stakeholder theory that a positive relationship exists between “managing for stakeholders” and firm performance. However, despite considerable debate on the subject, the amount of variation across firm investments in stakeholders (stakeholder management performance) has not been adequately investigated. We address this gap using a sample of more than eighteen thousand firm-level observations over ten years. We find evidence to support an inverted U–shaped relationship between variation in stakeholder management performance and Tobin’s q, suggesting that firms that have some imbalance in their stakeholder management, but not too much, perform best. We discuss the implications of our study for instrumental stakeholder theory and managerial practice.

Growth chamber experiments were conducted to determine the effects of UV light and riboflavin on photolysis of 2,4-D applied to Zea mays leaves. Droplets of 100 mg L−114C-2,4-D were applied to Z. mays leaves with and without 10 mg L−13H-riboflavin and exposed to either UV-enhanced or UV-attenuated polychromatic light in a time-course assay. Photolysis of nonabsorbed 14C-2,4-D residues on Z. mays leaves was sensitized by riboflavin regardless of UV light regime, but a larger percentage of nonabsorbed herbicide was degraded under UV-enhanced light compared to UV-attenuated light. Riboflavin was almost completely photolyzed during the first 10 h of exposure; yet, photolysis of 14C-2,4-D surface residues in treatments containing riboflavin increased from 59% at 10 h of exposure to 87% at 42 h of exposure. In corresponding treatments without riboflavin, photolysis of 14C-2,4-D surface residues was 37% at 10 h of exposure and 84% at 42 h of exposure. In contrast, only 7% of the 14C-2,4-D deposited on glass microscope slides was degraded after 42 h of exposure in the absence of riboflavin, whereas 59% was degraded in the presence of riboflavin. Photolysis of 2,4-D on Z. mays leaves in treatments without riboflavin suggests that certain epicuticular component(s) of Z. mays acted as photosensitizers or catalytic agents that promoted photolysis of nonabsorbed 2,4-D residues.

A mixture of 2,4-D with either thiameturon, DPX-L5300, or DPX-R9674 controlled common chickweed in winter wheat better than 2,4-D alone. None of these herbicides affected wheat height, lodging, or yield. Similarly, no significant differences in wheat height or lodging occurred among seeding rates. Wheat sown near South Charleston, OH, at a seeding rate of 67 kg/ha yielded significantly less than that sown at 100 or 134 kg/ha; however, there was no difference in wheat yield among seedling rates at a second location near Columbus, OH.

A 2-yr field study was conducted to determine effects of posttreatment irrigation timing on pendimethalin efficacy and dissipation in turfgrass. Factors investigated included herbicide rate, formulation, and the interval between pendimethalin application and the initial posttreatment irrigation. Plots received an initial posttreatment irrigation of 1.25 cm 0, 7, 14, 21, and 28 d after treatment. Pendimethalin efficacy on smooth crabgrass was evaluated, and turfgrass foliage and the upper 2.5-cm layer of soil were periodically assayed for pendimethalin residues. Pendimethalin 1.71% granular provided better weed control than pendimethalin 60% wettable powder at all rates, irrigation events, and years. Efficacy of granular pendimethalin was not affected by a delay in posttreatment irrigation, whereas efficacy of pendimethalin in the wettable powder formulation was reduced when irrigation was applied later than the day of treatment. Chromatographic analyses indicated that an average of 54% of the applied pendimethalin (wettable powder formulation) was retained on turfgrass foliage immediately after treatment, compared to 9% for the granular formulation. Soil residue analyses confirmed that a greater proportion of applied pendimethalin reached the soil surface immediately after treatment in the granular formulation than in the wettable power formulation.

Field experiments were established at Columbus and near South Charleston, OH to determine the effects of giant ragweed population density on soybean yield and to characterize the development of giant ragweed grown in 76-cm soybean rows. An economic threshold was calculated for Ohio using a common treatment for giant ragweed control in soybean. A cost of $41/ha was estimated for a farmer to apply 0.56 kg/ha bentazon plus 0.28 kg/ha fomesafen plus COC (1.25% v/v). Assuming a soybean value of $0.22/kg, the cost of control was equivalent to 5.4 and 7.1% of the soybean yield in 1991 and 1992, respectively, which corresponded to the yield loss caused by 0.08 and 0.03 giant ragweed plants/m2. The competitiveness of giant ragweed can be at least partly attributed to its ability to initiate and maintain axillary leaves and branches within the shaded confines of the soybean canopy.

Greenhouse experiments were conducted to determine the statistical precision of estimating herbicide dose-response treatment effects by covariance analysis (ANOCOVA) relative to standard analysis of variance (ANOVA). Analyses of corn seedling response to the translocated herbicides fluazifop-P, sethoxydim, and quizalofop at 10 to 60 g ai ha-1 indicated that treatment effects were estimated with 26 to 116% greater precision by ANOCOVA than ANOVA. Covariance analyses of treatment effects for corn response to the contact herbicides paraquat, acifluorfen, and lactofen at 50 to 300 g ai ha-1 gave 8 to 13% greater precision than ANOVA. Gains in precision by ANOCOVA for all experiments were generally greatest when shoot dry weight was analyzed as the response variable and pretreatment fifth leaf length served as the covariate.

Laboratory experiments were conducted to determine the effect of three phenolic acids, acetone, and riboflavin on aqueous photolysis of chlorimuron and imazaquin. The phenolic acids investigated were caffeic acid (CA), ferulic acid (FA), and p-coumaric acid (PCA). Treatment solutions were contained in quartz vessels and irradiated with 300 to 400 nm UV light in a photoreactor. The extrapolated photolysis half-life of chlorimuron in pure solution was 107 h, compared to a half-life of 0.42 h for pure aqueous imazaquin. Chlorimuron in solutions containing 10 ppmw riboflavin, acetone, CA, FA, or PCA exhibited half-lives of 9, 57, 58, 67, and 146 h, respectively. Imazaquin in solutions containing 10 ppmw riboflavin, acetone, CA, FA, or PCA had half-lives of 0.70, 0.55, 0.55, 0.48, and 0.55 h, respectively. The presence of PCA in aqueous media delayed chlorimuron photolysis, whereas all other compounds, especially riboflavin, sensitized chlorimuron photolysis. In contrast, imazaquin photolysis was delayed in the presence of the test compounds, with riboflavin having the greatest effect and causing in a 68% increase in imazaquin half-life over that of imazaquin alone. Quantum yields for sensitized photolysis of chlorimuron by riboflavin and for riboflavin by imazaquin were 0.1134 and 0.0477, respectively. These results suggest that some soluble and naturally occurring organic compounds may enhance chlorimuron photolysis yet delay imazaquin photolysis in surface waters.

Multiple regression and response surface plots were used to analyze the effects of common lambsquarters population density and interference duration on weed growth and soybean seed yield. Under favorable growing conditions in 1986, weed biomass production at all population densities and interference durations was four to five times that produced in 1987, under less favorable conditions. However, there was no significant treatment by year interaction for soybean seed yield reduction by common lambsquarters, and production of each kg/ha weed biomass resulted in an average soybean yield reduction of 0.26 kg/ha. Utilizing 5% yield loss as an arbitrary threshold level, the regression equation predicted a common lambsquarters density threshold of 2 plants/m of row for 5 weeks of interference after crop emergence and 1 plant/m of row for 7 weeks. Seed production by individual common lambsquarters plants was highly correlated (r=0.92) with weed dry weight, and seed production ranged from 30 000 to 176 000 seeds/plant.

Experiments were conducted at Urbana, IL, in 1983 and 1984 to determine the effect of adjuvants, adjuvant rate, and carrier volume on postemergence weed control with bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] and sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} in soybeans [Glycine max (L.) Merr. ‘Williams’]. Little difference was observed between a petroleum oil:emulsifier blend (83:17, v/v) (POC) and a soybean oil: emulsifier blend (85:15, v/v) (SBOC) in enhancing control of velvetleaf (Abutilon theophrasti Medik. # ABUTH) with 0.6 or 1.1 kg ai/ha bentazon. Application of bentazon in a carrier volume of 94 L/ha provided velvetleaf control equivalent to that applied in 187 L/ha. Increasing the adjuvant rate from 2.3 to 11.7 L/ha increased visible soybean injury but had no effect on velvetleaf control with bentazon. Control of giant foxtail (Setaria faberi Herrm. # SETFA) with 0.1 kg ai/ha sethoxydim was enhanced more by POC than by SBOC. Phytotoxicity of sethoxydim was not altered by changes in carrier volume or adjuvant rate under conditions of adequate soil moisture in 1983. Under limiting soil moisture in 1984, giant foxtail control with sethoxydim increased slightly when the adjuvant rate was increased from 4.6 to 11.7 L/ha, and carrier volume was increased from 47 to 187 L/ha.

Laboratory photolysis rates of 2,4-D [(2,4-dichlorophenoxy)acetic acid], bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide], and haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} in dilute aqueous solution were enhanced by the presence of adjuvants. Addition of 1.0% (v/v) petroleum oil concentrate (POC), 1.0% (v/v) soybean oil concentrate (SBOC), and 0.15% (v/v) emulsifier package (EP) enhanced herbicide photolysis rates more than addition of 0.15% (v/v) oxysorbic (20 POE) (polyoxyethylene sorbitan monolaurate). Bioassays showed that phytotoxicity of photolyzed herbicide solutions was negatively correlated with time of exposure to ultraviolet light. Addition of 0.85% (v/v) acetophenone to aqueous herbicide solutions containing 0.15% (v/v) oxysorbic strongly sensitized photodegradation of 2,4-D, and to a lesser extent, haloxyfop. Acetophenone had no effect on bentazon photolysis in the presence of oxysorbic. In another study, herbicides were dissolved in white mineral oil or once-refined soybean oil and exposed to ultraviolet light. After a 6-h exposure, there was 92% loss of haloxyfop in mineral oil and 36% loss in soybean oil. There was no difference between oils in affecting the photolysis rate of 2,4-D or bentazon.

Two nonionic surfactants altered photolysis rates of chlorimuron and metsulfuron in aqueous solutions and on glass slides exposed to sunlight. Photolysis of both herbicides followed first-order kinetics over an 8-day exposure period. Chlorimuron half-lives in solution were 5.8, 3.7, and 2.7 days in the presence of no surfactant, oxysorbic, and octoxynol, respectively. The extrapolated half-life of metsulfuron in solution with no surfactant was 15.7 days, compared to half-lives of 2.9 and 1.5 days in solutions containing oxysorbic or octoxynol, respectively. With the exception of metsulfuron in the absence of a surfactant, rates of chlorimuron and metsulfuron photolysis on glass slides were approximately two- to fourfold slower, and surfactants had little or no effect on herbicide photolysis rates compared to those in aqueous solution. Extrapolated half-lives on glass ranged from 9.9 to 12.5 days for chlorimuron and from 7.6 to 11.7 days for metsulfuron. Presence of oxysorbic or octoxynol did not greatly alter rates of riboflavin-sensitized herbicide photolysis on glass but did increase photolysis rates of metsulfuron in aqueous solution containing riboflavin.

Lower leaves of greenhouse-grown common cocklebur and velvetleaf were shaded to 5% of full light over a 12-d period while upper leaves remained exposed to full light to determine weed foliar and branching responses to partial shading similar to that encountered in soybean crops. Shading increased lower leaf senescence and specific leaf area, and decreased branch length and number of second-order leaves in both species compared to unshaded controls. Common cocklebur branched more extensively along the lower portion of its stem than velvetleaf under both shaded and unshaded conditions. Upper leaves of partially shaded velvetleaf were held in a more perpendicular position to the light source beginning 3 days after treatment (DAT) compared to upper leaves of unshaded plants. Shading of lower leaves caused an increase in upper (unshaded) leaf area beginning 3 and 6 DAT in velvetleaf and common cocklebur, respectively. Petiole length of upper leaves also increased in response to shading in both species. Total plant dry weight at 12 DAT was unaffected by shading in velvetleaf but was reduced 10% by shading in common cocklebur. While common cocklebur maintained greater lower shoot growth in the presence of shade than velvetleaf, there was a greater change in upper leaf angle by velvetleaf in response to shading than by common cocklebur. These results support previous field observations of apparent greater shade tolerance of common cocklebur compared to velvetleaf and indicate that both species have the ability to compensate for shading of lower leaves by altering upper shoot growth.

Laboratory experiments were conducted to determine the effects of nonionic surfactants and reaction media (water, glass, and corn leaf residue) on photolysis and subsequent phytotoxicity of chlorimuron and metsulfuron residues. Oxysorbic and octoxynol enhanced rates of chlorimuron and metsulfuron photolysis in aqueous solution and on glass slides compared to controls with no surfactant. Enhanced photolysis of chlorimuron by surfactants was greatest on glass, where 93 and 89% loss occurred after 48 h exposure to ultraviolet light in the presence of oxysorbic and octoxynol, respectively, compared to 38% loss with no surfactant. Similarly, surfactant-enhanced metsulfuron photolysis was greatest on glass with 37 and 67% loss after 48 h exposure in the presence of oxysorbic and octoxynol, respectively, compared to 9% loss with no surfactant. Photolysis of herbicides deposited on corn leaf residue was significantly slower than that on glass or in aqueous media at all exposure times and metsulfuron photolysis on corn residue was enhanced by surfactants only after 144 h exposure. Bioassays confirmed that phytotoxicity of photolyzed herbicide residues was negatively correlated (r=-0.94 for chlorimuron and r=-0.92 for metsulfuron) with loss of parent herbicide as measured by liquid chromatography.

The effects of adjuvants and relative humidity (RH) on absorption, translocation, and metabolism of the methyl ester of 14C-haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid} in corn (Zea mays L. ‘B73 X Mo17’ hybrid) were evaluated. Addition of 1.0% (v/v) petroleum oil concentrate (POC) to the treatment solution resulted in greater foliar absorption and translocation of 14C than addition of 1.0% (v/v) soybean oil concentrate (SBOC), 0.1% (v/v) oxysorbic (20 POE) (polyoxyethylene sorbitan monolaurate) (OXY), or no adjuvant (NONE). The least amount of 14C absorption occurred in the treatment containing OXY. Absorption and translocation of radioactivity were significantly greater at 70% RH than at 30% RH. Thin-layer chromatography revealed that most of the 14C recovered from treated plants was in haloxyfop-methyl 5 h after treatment (HAT). The remaining 14C recovered was haloxyfop and an unidentified polar metabolite. The average percentage of 14C-haloxyfop in the nonabsorbed fraction was 5, 39, 7, and 7% for treatments containing NONE, OXY, POC, and SBOC, respectively. The ratio of haloxyfop-methyl to haloxyfop and the percentage of polar metabolite in the absorbed 14C fraction was not different among adjuvant treatments or between levels of RH.

Interference studies utilizing manipulated and natural infestations of giant foxtail (Setaria faberi Herrm. ♯ SETFA) in soybeans [Glycine max (L.) Merr. ‘Williams’] were conducted at Urbana, IL, in 1982 and 1983. Giant foxtail clumps, each consisting of 3 to 6 plants per dm2, were used to determine the effect of clump density on giant foxtail dry weight and soybean seed yield. In both years, regression equations predicted a soybean seed yield loss of 0.8% for each giant foxtail clump per 9 m of row. The highest density of 30 clumps per 9 m of row reduced soybean yield 26%. In a second study, fluazifop {(±)-2-[4-[(5-(trifluoromethyl)-2-pyridinyl)oxy]phenoxy]propanoic acid} at 0.28 kg ai/ha or fluazifop + alachlor [2-chloro-2’,6’-diethyl-N-(methoxymethyl)acetanilide] at 0.28 + 2.24 kg/ha applied 10 or 15 days after emergence gave maximum giant foxtail control with little or no reduction in soybean seed yield. Interference from uncontrolled giant foxtail began to reduce soybean dry-matter accumulation 15 days after emergence under favorable growing conditions in 1982. Under less favorable conditions in 1983, similar effects were not observed until 25 days after emergence.

Purple deadnettle is an obligate winter annual weed and an alternate host of soybean cyst nematode (SCN). Field experiments were conducted using microplots to determine (1) the effect of purple deadnettle planting date and (2) the effect of purple deadnettle removal time on SCN egg population density in continuous no-tillage soybean. A population change factor (PCF) to assess treatment effects on SCN population densities was calculated by dividing the SCN population density at each sampling time (Pf) by the initial population density before treatments were applied (Pi). In the planting date experiment, purple deadnettle seeded on October 3, 11, and 18 resulted in PCF values ranging from 7.28 to 11.41, which were three- to fivefold higher than the PCF values for the weed-free control or purple deadnettle seeded on September 6, 20, and 27. Self-thinning of purple deadnettle seeded in September may have resulted in higher levels of SCN mortality compared to later seeding dates. In the removal time experiment, purple deadnettle removal at 2 and 4 wk after emergence (WAE) resulted in PCF values of 1.19 and 1.54, respectively, which were similar to the PCF for the weed-free control. In contrast, PCF values for purple deadnettle removal times of 6 WAE or later ranged from 2.46 to 5.44. Field and greenhouse experiments provided evidence that completion of the SCN life cycle on purple deadnettle was prevented if the weed was removed before the accumulation of 380 soil degree days within the 5 to 30 C range. Results from the removal study also suggested that completion of the first SCN generation on purple deadnettle in the fall was the primary factor causing increases in egg population density, since PCF values did not continue to increase significantly beyond the 6 WAE removal time.

Giant ragweed germination is delayed by both a physiological dormancy of the embryo (embryo dormancy) and an inhibitory influence of embryo-covering structures (covering structure-enforced [CSE] dormancy). To clarify the roles of embryo and CSE dormancy in giant ragweed seedling emergence timing, we conducted two experiments to address the following objectives: (1) determine changes in germinability for giant ragweed dispersal units (hereafter “involucres”) and their components under natural burial conditions, and (2) compare embryo and CSE dormancy alleviation and emergence periodicity between successional and agricultural populations. In Experiment 1, involucres were buried in crop fields at Columbus, OH, periodically excavated, and brought to the laboratory for dissection. Involucres, achenes, and embryos were then subjected to germination assays at 20 C. In Experiment 2, temporal patterns of seedling emergence were determined at a common burial site. Reductions in embryo and CSE dormancy were compared with controlled-environment stratification followed by germination assays at 12 and 20 C, temperatures representative of soil conditions in spring and summer. Results indicated that overwinter dormancy loss involved sequential reductions in embryo and CSE dormancy. CSE dormancy, which may limit potential for fatal germination during fall, was caused by the pericarp and/or embryo-covering structures within the pericarp. In Experiment 2, successional populations emerged synchronously in early spring, whereas agricultural populations emerged throughout the growing season. Levels of embryo dormancy were greater in the agricultural populations than the successional populations, but CSE dormancy levels were similar among populations. In 12 C germination assays, embryo dormancy levels were positively correlated with time required to reach 95% cumulative emergence (run 1: r = 0.81, P = 0.03; run 2: r = 0.76, P = 0.05). These results suggest that late-season emergence in giant ragweed involves high levels of embryo dormancy that prevent germination at low temperatures in spring.

A greenhouse study was conducted to determine the effects of sublethal dicamba concentrations in the nutrient media on hydroponically grown tomato plants. Tomato leaf area was the most sensitive vegetative growth parameter measured in response to dicamba concentrations, ranging from 0 to 22 µg/L. Leaf area was reduced 31 and 76%, and specific leaf weights, a relative measure of leaf thickness (g/cm2), increased 26 and 121% after 30-d exposure to dicamba concentrations of 2.2 and 22 µg/L, respectively. In long-term experiments conducted until plants produced first ripe fruit, regression analysis indicated leaf area reductions of 8 and 66% from initial dicamba concentrations of 1 and 10 µg/L, respectively. Reductions in total fruit fresh weight were highly correlated (r = 0.93) with leaf area reductions caused by dicamba. A hyperbolic regression model gave predicted losses in fruit fresh weight per plant of 6% at 1 µg/L dicamba and 73% at 10 µg/L dicamba (r2 = 0.87). Results generally indicated that the level of dicamba in the nutrient media of hydroponically grown tomatoes that produced no observable effect was ≤ 1 µg/L.

Giant ragweed exhibits a high degree of polymorphism among individual plants in seed size, shape, spininess, and color. These features may play an important role in giant ragweed seed survival and predation avoidance; however, they are difficult to evaluate because of lack of quantification methods. A computer imaging technique was developed for describing and classifying giant ragweed seeds using digital images of the seed top and side views. Seed samples collected from 20 different giant ragweed plants (classes) were mounted and digitally scanned. Quantitative features were extracted from the seed images, including color, width, height, area, and seed perimeter. A polygon (convex hull) of the seed image based on the seed outline was constructed, from which spininess indices were developed. Fisher's linear discriminant with normalized nearest neighbor classification was used to classify randomly selected images of individual seeds according to class (maternal origin), using the extracted features as a database. The best classification rate achieved was 99%, with 138 out of 140 seeds correctly matched using data from both the top and side views. Seed features were easily extracted and varied from 1.2- to 4.5-fold among classes. Area and perimeter measurements varied least within classes but varied most among classes, suggesting that these features discriminate effectively among seeds from different plants in giant ragweed. Convex hull area : seed area ratio, using the seed top view images, was the best index of seed spininess, aligning well with visual assessment and providing greatest discrimination among classes. This experiment shows that in the case of giant ragweed, seeds from different plants are distinguishable in an objective and quantitative manner. This imaging technique can be applied to identification of seeds from different species and to studies on variable seed morphology within a species.

Studies were conducted in 1998 and 1999 in Ohio to determine the effect of postemergence (POST) application timing of glyphosate on weed control and grain yield in glyphosate-tolerant corn, and how this was influenced by corn planting date and the use of soil-applied herbicides. Glyphosate was applied based on giant foxtail height. Two applications of glyphosate provided better weed control than a single application, especially when applied to weeds 10 cm or less in early-planted corn. Yield was reduced occasionally with a single application on 5- or 10-cm weeds, because of weed re-infestation. Failure to control weeds before they reached a height of 15 to 30 cm also resulted in occasional yield loss. Application of atrazine or acetochlor plus atrazine prior to glyphosate did not consistently increase weed control or yield. Results suggested that glyphosate should be applied before weeds reach 15 cm in height to avoid corn grain yield loss.