Experiments were conducted in pots and in the field to determine the influence of seed depth on seedling emergence pattern and control of Mexican sunflower with or without imazethapyr plus pendimethalin. Mexican sunflower seeds were placed at 0-, 2.5-, 5-, 7.5-, and 10-cm soil depths, and imazethapyr–pendimethalin mixture was applied PRE at 0, 0.05 + 0.65, 0.09 + 1.31, and 0.18 + 2.62 kg ae (+ ai)/ha. Mexican sunflower emergence was 57, 30, 14, 3, and 2% from 0-, 2.5-, 5-, 7.5-, and 10-cm seed depths, respectively. Seedling emergence started 2 to 3 d after planting and continued for 4 to 5 d. At 0- to 5-cm seed depths, 84 to 100% of total seedling emergence occurred within 3 d after the first seedling emerged, but emergence rate was less from 7.5- and 10-cm seed depths. Imazethapyr plus pendimethalin at 0.05 + 0.65 and 0.09 + 1.31 kg/ha had no effect on seedling emergence in Mexican sunflower, but subsequent growth was severely inhibited regardless of seed depth. The herbicide treatments were more injurious to Mexican sunflower seedlings that emerged from 5- to 10-cm depths than to those that emerged from 0 and 2.5 cm. Burying seeds 7.5 cm deep or more is a potential control measure for Mexican sunflower, and the deeper the emergence depth, the more susceptible the seedling is to imazethapyr plus pendimethalin.

A field experiment was conducted for 2 yr near Scottsbluff, NE, to evaluate the growth and yield response of nine commercial sugarbeet cultivars to five postemergence herbicide mixtures applied two times. Sugarbeet cultivars varied in their response to herbicides. Three of the five postemergence herbicide mixtures reduced sugarbeet leaf area at 9 wk after planting (WAP), while two treatments had no significant effect. Root yield reductions from herbicide treatments ranged from 3 to 11% averaged over the nine cultivars. Two applications of desmedipham plus phenmedipham at 180 plus 180 g/ha reduced root yield 3% compared to untreated plots. Two applications of clopyralid at 100 g/ha, triflusulfuron at 18 g/ha, or ethofumesate at 160 g/ha plus desmedipham plus phenmedipham resulted in a 17, 29, and 22% reduction in leaf area at 9 WAR respectively, and a 6, 8, and 6% reduction in root yield, respectively, compared to untreated plots. Sethoxydim at 280 g/ha plus desmedipham plus phenmedipham did not cause additional sugarbeet injury.

A time course of Egyptian broomrape development on tomato roots grown in pots in the greenhouse revealed an increase in the number of parasitic attachments from 2.6 at 4 weeks after planting (WAP) to 139 when rated 2 wk later. Rimsulfuron sprayed on tomato foliage as single and split applications (12.5 g ai/ha) 3, 4, 5, 6, and 7 WAP did not decrease Egyptian broomrape damage to tomato plants, as expressed by reduced tomato plant height and fresh weight, and the total number of parasitic attachments on the roots was not significantly different compared to the nontreated control. A single foliar application of rimsulfuron (25 g ai/ha) to tomato at 10 days after planting (DAP) and split applications at 10 and 20 and 10, 20, and 30 DAP significantly reduced the number of Egyptian broomrape inflorescences to 2.2, 0.2, and 0, respectively, 9 WAP compared with 19.6 inflorescences in the nontreated control. Application of the herbicide under the same conditions to tomato plants in pots covered with activated charcoal did not significantly influence the number of Egyptian broomrape inflorescences. Chlorsulfuron and triasulfuron applied directly to the soil at rates ≥ 3: 3.75 g ai/ha completely controlled Egyptian broomrape. Primisulfuron and chlorimuron, each at 22.5 g ai/ha, reduced the number of inflorescences to 0.6 and 0.4, respectively. Chlorimuron did not significantly reduce the total number of parasitic attachments on the roots, but primisulfuron at the same concentration significantly increased the total number of parasitic attachments on the root system to 50 as compared to 23 in the nontreated control. Tribenuron had no effect on the parasitism process, as reflected in the number of inflorescences and parasitic attachments on the roots.

The efficacy of reduced rates of metolachlor plus cyanazine for weed control in sweet corn was evaluated over a 2-yr period. Early postemergence (POST) and POST herbicide applications at reduced rates gave control of broadleaf weeds comparable to control at the 1 × rate, except for the early POST application at the ¼ × rate in 1993. Preplant incorporated (PPI) and preemergence (PRE) herbicide applications at reduced rates gave poor broadleaf weed control, except for the PRE application at the ½ × rate in 1993. Early POST applications at the ¼ × rate resulted in significantly reduced grass control in 1994, while POST applications at the ¼ × rate gave significantly reduced grass control both years. Generally, POST applications controlled broadleaf weeds better than early POST applications, while grass control with early POST applications was superior to POST applications at reduced rates. Preemergence and PPI applications at reduced rates gave poor broadleaf weed control but satisfactory grass control. Preplant incorporated applications at reduced rates resulted in reduced yield both years, while PRE applications at reduced rates reduced yield only in 1994. Early POST and POST applications at reduced rates did not affect sweet corn yield. The addition of adjuvants to the ¼ × application rate had no effect on weed control or yield.

Field studies were conducted in 1994 and 1995 to determine the contribution of PRE applications of alachlor, metolachlor, acetochlor, SAN 582H, or pendimethalin on woolly cupgrass and wild-proso millet control when followed by POST nicosulfuron at 0, 0.018, 0.027, or 0.036 kg ai/ha. Sequential treatments controlled woolly cupgrass and wild-proso millet greater than single applications of PRE herbicides, which when applied alone resulted in the least wild-proso millet control and lowest corn grain yield. Lack of complete woolly cupgrass control with POST nicosulfuron alone resulted in corn grain yield that was less than with sequential treatments but was equal to PRE treatments. Wild-proso millet control with nicosulfuron at 0.027 kg/ha resulted in corn grain yield that was less than with sequential treatments, but greater than with all PRE treatments except for SAN 582H. All PRE herbicides, regardless of early season performance, when followed by nicosulfuron resulted in woolly cupgrass and wild-proso millet control that was similar. Woolly cupgrass seed production compared to the nontreated check was reduced 98% with acetochlor followed by nicosulfuron. Sequential treatments provided the most consistent woolly cupgrass and wild-proso millet control, the highest corn grain yield, and the greatest reduction in woolly cupgrass and wild-proso millet seed production.

An experiment was conducted at four locations in North Carolina during 1994 and 1995 to evaluate weed control, cotton yield, fiber quality, and net returns in no-tillage bromoxynil-tolerant cotton. The experiment focused on using bromoxynil or pyrithiobac sodium applied early POST over-the-top as alternatives to fluometuron plus MSMA applied early POST directed. Fluometuron plus MSMA was more effective than bromoxynil or pyrithiobac sodium on tall morningglory, large crabgrass, goosegrass, and broadleaf signalgrass. Bromoxynil and fluometuron plus MSMA were similarly effective on common lambsquarters, common ragweed, and eclipta and more effective than pyrithiobac sodium. Pyrithiobac sodium and fluometuron plus MSMA were similarly effective on smooth pigweed and Palmer amaranth and more effective than bromoxynil. Prickly sida control by bromoxynil and pyrithiobac sodium was equal to or greater than control by fluometuron plus MSMA. All early POST herbicides controlled pitted morningglory similarly. Regardless of the early POST herbicides used, fluometuron applied PRE and cyanazine plus MSMA applied late POST directed increased control of most weeds and increased cotton yield and net returns. Bromoxynil and pyrithiobac sodium effectively substituted for fluometuron plus MSMA only in systems that included fluometuron applied PRE and cyanazine plus MSMA applied late POST directed. Effects of herbicide systems on cotton fiber quality were minor.

Field studies were conducted in 1991 to 1993 to determine the effects of PRE and POST herbicides alone and in factorial combinations on sicklepod control, weed biomass, and soybean seed yields. Herbicides evaluated were metribuzin PRE, metribuzin + chlorimuron PRE, imazaquin PRE and POST, chlorimuron POST, and AC 263,222 POST POST herbicides alone provided better sicklepod control than PRE herbicides alone. However, sequential (SEQ) treatments [PRE followed by (fb) POST] provided better sicklepod control than single herbicide treatments. Metribuzin and metribuzin + chlorimuron alone or used in a SEQ program provided similar PRE control of sicklepod, and both controlled sicklepod better than imazaquin in 1991 and 1992. Chlorimuron alone or in a SEQ program provided better POST control than AC 263,222 or imazaquin alone when soil moisture levels at planting favored weed seed germination. When soil moisture levels at planting were unfavorable for weed seed germination, the residual activity of imazaquin provided the best season-long control. SEQ herbicide applications allowed soybean to attain higher seed yields than single (PRE or POST) herbicide treatments all 3 yr. However, only metribuzin fb chlorimuron in 1991 and 1992 and imazaquin fb imazaquin and imazaquin fb chlorimuron in 1993 allowed soybean to achieve seed yields similar to weed-free soybean. Soybean seed yields were greater with POST than with PRE herbicides 2 of 3 yr, but no single herbicide treatment provided soybean seed yields similar to weed-free soybean.

Field experiments were conducted in 1992 to 1993 and in 1995 to 1996 in Ibadan, Nigeria, to assess the effect of velvetbean and herbicides on maize (corn) and cogongrass growth and to assess regrowth of the weed 1 yr after treatment. In 1992 and 1995 cover cropping with velvetbean and imazapyr and glyphosate application reduced cogongrass density as much as the handweeded control. The smothering effect of velvetbean was equivalent to that of glyphosate at 1.8 kg/ha but was less than imazapyr even at the lowest rate of 0.5 kg/ha. Addition of adjuvant did not improve the efficacy of either herbicide. Maize grain yield was higher in velvetbean plots than in fallow plots dominated by cogongrass. Velvetbean and herbicide effects on cogongrass 1 yr later (1993 and 1996) followed a similar trend as observed in the year of application. Annual weed density was highest in glyphosate plots, followed by imazapyr, and least in plots previously seeded to velvetbean. Maize grain yield was higher in herbicide plots (average yield of 3,170 and 1,920 kg/ha in 1993 and 1996, respectively) than in velvetbean plots (2,800 to 1,180 kg/ha in 1993 and 1996, respectively) and handweeded plots (2,890 and 723 kg/ha in 1993 and 1996, respectively). In 1996 the lowest maize yield was in handweeded plots without velvetbean, suggesting that weeding four times suppressed cogongrass density and biomass, but was not sufficient to minimize the subsequent competition from annual weeds. Uncontrolled cogongrass reduced maize yield to zero. These studies suggest that planting velvetbean for cogongrass control may be a better alternative for farmers without the resources to purchase herbicides.

A postemergence (POST) timing study was conducted on established populations of burcucumber (Sicyos angulatus) in corn (Zea mays), and a second study examined the residual activity of several herbicides for burcucumber control under greenhouse conditions. In the field study, flumiclorac, halosulfuron, primisulfuron, CGA 152005, and CGA 152005 + primisulfuron (45, 71, 40, 40, and 20 + 20 g ai/ha, respectively) were applied at two POST timings. CGA 152005, primisulfuron, and the combination provided greater than 85% control of burcucumber 14 wk after planting (WAP). Flumiclorac and halosulfuron provided 60% control or less by 8 WAP. Timing of the POST applications did not influence burcucumber control by 11 WAP with any herbicide. In the greenhouse, germinated burcucumber seeds were placed in soil treated with atrazine, chlorimuron, primisulfuron, or CGA 152005 at normal field use rates. All treatments provided similar residual control early; however by 4 wk after treatment (WAT), control from atrazine was less than 10% compared to 69% for chlorimuron and about 50% for primisulfuron and CGA 152005. This research suggests that CGA 152005 and primisulfuron can both be effective for managing burcucumber in corn, whereas flumiclorac and halosulfuron proved ineffective.

Field trials were conducted in no-till field corn in northern Missouri to compare weed control and crop response of metolachlor plus atrazine applied under five preplant herbicide management practices. The practices consisted of (1) applying the entire dose of metolachlor plus atrazine 15, 30, or 45 d early preplant (EPP), (2) applying a split application of an EPP (67%) followed by (fb) a PRE (33%), (3) applying the entire dose PRE, (4) applying metolachlor PRE fb dicamba early post (EPOST), or (5) applying atrazine alone EPOST. Weed control at 7 wk after planting was more variable with EPP treatments than with EPP fb PRE or PRE treatments. Giant foxtail and fall panicum control was greatest with treatments that included metolachlor PRE. Velvetleaf and common cocklebur control was greatest with atrazine or dicamba EPOST and was generally unacceptable (< 80%) with any soil-applied herbicide treatment. Common lambsquarters control was greater than 90% with all treatments that included metolachlor, atrazine, or dicamba, regardless of timing. Corn yields were slightly higher with EPP fb PRE and PRE fb EPOST dicamba than with EPP alone. The results suggest that herbicide applications made nearer to the date of planting provide less variable weed control and corn yield than treatments made more than 15 d EPP.

An experiment was conducted at five locations in North Carolina to compare management systems utilizing glufosinate applied postemergence (POST) in glufosinate-resistant corn with standard systems of metolachlor plus atrazine preemergence (PRE) or nicosulfuron plus atrazine POST Glufosinate alone and both standard systems controlled common ragweed and prickly sida at least 98%, whereas sicklepod control was < 20% late in the season. Late-season control of common lambsquarters, smooth pigweed, pitted morningglory, and tall morningglory was generally less with glufosinate alone than with the standard systems. However, late-season control of common lambsquarters, smooth pigweed, pitted morningglory, tall morningglory, and sicklepod by mixtures of glufosinate plus atrazine was at least 99, 100, 89, 93, and 81%, respectively, and was equal to or greater than control by either standard. Broadleaf signalgrass, large crabgrass, and fall panicum were controlled similarly by glufosinate and the standards. Goosegrass control by glufosinate was similar to control by nicosulfuron plus atrazine, but it was less than control by metolachlor plus atrazine. Metolachlor applied PRE or atrazine mixed with glufosinate increased goosegrass control to that achieved with metolachlor plus atrazine. Mixing atrazine with glufosinate did not affect fall panicum control, but metolachlor PRE followed by glufosinate controlled fall panicum as well as the standards. Cultivation or ametryn applied at layby increased control when PRE or POST herbicides alone controlled weeds less than about 90%. Ametryn was generally more effective than cultivation. Glufosinate POST followed by ametryn at layby controlled sicklepod > 90% and other species > 95% late in the season. Corn yield and net returns were similar in the glufosinate and standard systems.

Field studies were conducted at five locations in North Carolina and Virginia during 1996 and 1997 to evaluate weed control, peanut (Arachis hypogaea) response, and peanut yield following diclosulam applied preplant incorporated (PPI) and in systems with commercial herbicide standards. All plots received a PPI treatment of ethalfluralin at 840 g ai/ha. Ethalfluralin plus diclosulam controlled entireleaf morningglory (Ipomoea hederacea var. integriuscula), ivyleaf morningglory (I. hederacea), pitted morningglory (I. lacunosa), common lambsquarters (Chenopodium album), eclipta (Eclipta prostrata), and prickly sida (Sida spinosa) as well as and frequently better than ethalfluralin PPI followed by (fb) acifluorfen plus bentazon postemergence (POST), paraquat plus bentazon early postemergence (EPOST) fb imazapic POST, or imazapic POST. Systems with ethalfluralin plus diclosulam PPI at 26 g ai/ha fb acifluorfen plus bentazon POST controlled a broader spectrum of weeds and yielded greater than systems of ethalfluralin PPI fb imazapic POST or ethalfluralin PPI fb acifluorfen plus bentazon POST. Peanut exhibited excellent tolerance to diclosulam PPI at 17, 26, or 35 g/ha.

Soil-applied herbicides alone or followed by postemergence (POST) applications of CGA-277476 were evaluated for season-long weed control in soybean. Common cocklebur, hemp sesbania, and pitted morningglory control was not consistently improved with a soil-applied herbicide followed by a POST application of 79 g ai/ha CGA-277476. However, in locations with heavy weed pressure, a tank-mix of chlorimuron + metribuzin + trifluralin or imazaquin + pendimethalin followed by CGA-277476 improved common cocklebur, hemp sesbania, and pitted morningglory over CGA-277476 alone. Sequential application of CGA-277476 following SAN 582 improved weed control over SAN 582 alone. When weed pressure was not severe, there were no differences in control from CGA-277476 alone or following soil-applied herbicides. A POST application of CGA-277476 following soil-applied herbicides did not consistently improve soybean yield over CGA-277476 alone. Yield from soybean treated with SAN 582 was improved when CGA-277476 was applied. In contrast, when chlorimuron + metribuzin + trifluralin or imazaquin + pendimethalin were applied at planting, yield was similar with or without POST application of CGA-277476.

Field studies were conducted from 1992 to 1994 to evaluate herbicides applied preplant incorporated (PPI), preemergence (PRE), and postemergence (POST) for red rice and Echinochloa spp. control in soybean. Metolachlor PPI at 3.4 kg ai/ha controlled red rice late season 90 to 92%. Alachlor at 4.5 kg ai/ha and SAN 582H at 2.2 or 3.4 kg ai/ha, PPI or PRE, metolachlor plus imazaquin at 2.8 + 0.14 kg ai/ha PRE, and quizalofop-P POST at 0.07 kg ai/ha provided 83 to 95% red rice control in at least 2 of 3 yr. The addition of imazaquin to metolachlor or pendimethalin did not improve red rice control. Early-season Echinochloa spp. control with trifluralin, pendimethalin, and pendimethalin + imazaquin applied PPI; metolachlor, SAN 582H at 2.2 or 3.4 kg/ha, and metolachlor + imazaquin applied PPI or PRE; alachlor, AC 263,222 + imazaquin, and AC 263,222 + imazethapyr applied PRE; and sethoxydim and quizalofop-P applied POST was 90 to 100% in at least 2 of 3 yr. However, Echinochloa spp. control decreased for all treatments later in the season. Pendimethalin applied PPI at 2.2 kg ai/ha or in mixture with imazaquin at 1.7 + 0.14 kg ai/ha injured soybean 14 to 34% in 2 yr. Trifluralin PPI, SAN 582H at 2.2 or 3.4 kg/ha PPI or PRE, imazaquin PPI, metolachlor + imazaquin PPI or PRE, and AC 263,222 + imazethapyr injured soybean 12 to 41% in at least 1 of 3 yr.

Various chemical and mechanical weed control treatments for kidney bean production were evaluated on irrigated, sandy loam sites from 1993 to 1995 near Staples, MN. Weed biomass can be controlled either mechanically or chemically, but a combination of the two gave the most effective and dependable weed control over years. Good weed control by either mechanical or chemical means reduced white mold infection of dry bean because of better aeration of dry bean plants and thus less favorable conditions for infection. Dry bean seed yields were inversely related to weed yields, and weed competition was similar from indigenous stands of either grass or broadleaf weeds. Row cultivation was more effective than rotary hoeing for controlling weeds, reducing white mold infection of dry bean, and increasing dry bean seed yields.

Field trials were conducted at two sites in 1996 and 1997 to evaluate weed control and crop response to herbicide programs in no-till soybean that include flumioxazin or sulfentrazone alone and each herbicide tank-mixed with either chlorimuron or imazaquin. A prepackaged mixture of metribuzin plus chlorimuron also was included for comparison. Cool, wet conditions after herbicide application in both years were conducive to soybean injury up to 21% at 3 wk after planting (WAP). Flumioxazin and sulfentrazone alone provided ≥ 89% control of velvetleaf, Pennsylvania smartweed, and common cocklebur. Sulfentrazone alone provided greater control of common waterhemp, common cocklebur, and ivyleaf and pitted morningglories than flumioxazin. Flumioxazin provided greater control of common ragweed than sulfentrazone. The addition of chlorimuron to flumioxazin or sulfentrazone provided greater control of velvetleaf than flumioxazin or sulfentrazone alone. The addition of imazaquin or chlorimuron to flumioxazin provided greater control of common cocklebur than flumioxazin alone. The addition of imazaquin or chlorimuron to sulfentrazone provided greater control of common ragweed than sulfentrazone alone. The addition of chlorimuron or imazaquin to sulfentrazone or flumioxazin provided little or no additional control of pitted morningglory, common waterhemp, or Pennsylvania smartweed. Metribuzin plus chlorimuron provided control of velvetleaf, Pennsylvania smartweed, common ragweed, and common cocklebur that was equal to or better than the control provided by sulfentrazone or flumioxazin plus chlorimuron or imazaquin.

Weed management systems were compared in bromoxynil-resistant, glyphosate-resistant, and nontransgenic cotton. A standard system of pendimethalin preplant incorporated (PPI), fluometuron preemergence (PRE), fluometuron plus MSMA early postemergence-directed (POST-DIR), and cyanazine plus MSMA late POST-DIR in combination with cultivation controlled broadleaf signalgrass, large crabgrass, common lambsquarters, jimsonweed, pitted morningglory, prickly sida, sicklepod, and smooth pigweed 98 to 100% late season. Weed control, cotton yield, and net returns were similar when pyrithiobac or bromoxynil plus MSMA postemergence (POST) replaced fluometuron plus MSMA POST-DIR. Fluometuron PRE had little to no effect in bromoxynil systems. Glyphosate POST to three- to four-leaf-stage cotton followed by cyanazine plus MSMA late POST-DIR and cultivation controlled weeds 96 to 100%. Glyphosate POST followed by glyphosate POST-DIR and cultivation controlled pitted morningglory and large crabgrass 89 to 90% and other species at least 94%. Yields and net returns at one location were similar for glyphosate applied twice or glyphosate POST followed by cyanazine plus MSMA POST-DIR and the standard system. Pendimethalin plus fluometuron in glyphosate systems did not increase yield or net returns. At a location severely infested with large crabgrass, pendimethalin plus fluometuron in glyphosate systems increased yield 37 to 44% and net returns 85 to 108%, respectively, when glyphosate was applied to cotton at the three-to four-leaf stage, but not if glyphosate was applied to cotton at the one-leaf stage. Yield and net returns were similar when bromoxynil-resistant, glyphosate-resistant, and nontransgenic cotton were treated using the standard system.

Greenhouse and field experiments were initiated to evaluate rapeseed and mustard species as green manure crops for weed suppression. Under greenhouse conditions incorporating 20 g fresh wt leaf and stem tissue of rapeseed, two white mustards, and brown mustard into 450 g Sharpsburg, silty clay loam soil resulted in significant reductions in weed emergence, biomass, and height. Kochia, shepherd's-purse, and green foxtail emergences were reduced by all green manure crops. Redroot pigweed emergence was reduced by all green manure crops except brown mustard, and velvetleaf emergence was reduced by white mustards only. Kochia and shepherd's-purse fresh weights were reduced by all green manure crops, while redroot pigweed and velvetleaf fresh weights were reduced by brown mustard and white mustard var. Salvo. Green foxtail fresh weight was reduced by all green manure crops except rapeseed. With the exception of shepherd's-purse, no relationship between glucosinolate content of the incorporated green manure and suppression of weed growth was found. Under field conditions, early spring-planted green manure crops reduced early season weed biomass in soybean at one of the two locations. Mustard species as green manure crops reduced total weed biomass in soybean by 40% 4 weeks after emergence (WAE) and 49% 6 WAE. Soybean biomass and yield were sometimes reduced by the incorporation of green manure crops in treatments containing weeds; however, hand-weeded plots with green manure treatments yielded similar to hand-weeded plots without green manure.

Field experiments were conducted at one location in Georgia (1994) and at two locations in Alabama (1994 and 1995) to evaluate the effects of MSMA or DSMA plus pyrithiobac applied postemergence (POST) in cotton. Pyrithiobac at 0.07 kg ai/ha was applied POST alone or in combination with MSMA at 1.1 kg ai/ha or DSMA at 1.7 kg ai/ha at the pinhead square stage of cotton growth. Cotton was tolerant to the POST applications of pyrithiobac. Adding MSMA or DSMA to pyrithiobac injured cotton similar to MSMA or DSMA applied alone. Plant mapping data indicated that all treatments had no effect on height : node ratio, reproductive or vegetative node production, or square retention at the first or second fruiting position. Cotton maturity response to MSMA and DSMA ranged from no effect to delayed maturity. Adding DSMA to pyrithiobac increased Florida beggarweed and common cocklebur control over pyrithiobac applied alone in 1995 but did not increase control in 1994. Adding DSMA to pyrithiobac increased sicklepod control over pyrithiobac applied alone in the three site years it was rated in the Alabama tests. Where sicklepod is present, the addition of an arsenical herbicide to pyrithiobac will generally increase control but has the potential to delay maturity and decrease cotton yield equal to the arsenical herbicide applied alone.

A 3-yr field study was conducted in peanut in which weed control systems with varying levels of herbicides, cultivation inputs, or both were supplemented with mowing to remove weeds extending above the crop canopy. Highest yield and net returns were consistently obtained with the highest level of herbicide/cultivation inputs, and mowing was of no value. However, mowing was consistently beneficial to yield and net return when the only other weed control inputs were paraquat and 2,4-DB applied at 4 wk after planting (WAP) and cultivation at 10 WAP. In the absence of any other weed control inputs, mowing was detrimental in a drought stress year, but beneficial in years with near-normal growing conditions. Although disease incidence was aggravated by the lack of weed control inputs, it was generally independent of mowing.