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Richard L. Harkess and Robert E. Lyons

Combinations of seed rate, spacing and weed control treatments were evaluated for their effect on the performance of The Virginia Tech Transplanted Meadow technique. The treatments consisted of seed rates of 112 g or 56 g per 90 m-2; within-row transplant spacing of 30, 45, or 60 cm; and mulch, oryzalin, or nothing applied for weed control. Plant competition alone was insufficient for effective weed control whereas oryzalin was the best but also reduced the plant stand and floral display. Mulch provided effective weed control with maximum floral display. Close transplant spacing within rows resulted in quick site coverage but this advantage disappeared after 8 weeks when no difference in floral display was observed. Seeding rate did not affect site coverage until the meadow reached maturity at 12 weeks. The lower seed rate allow ed more lodging, resulting in a more open appearance and greater light transmission through the canopy. Chemical name used: 4-(dipropylamino)-3,5dlnitrohenzenesulfonamide (oryzalin).

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Joseph DeFrank, Tadashi Higaki, and Joanne Imamura

Yield components of 4 anthurium cultivars over a 2 year harvest period were determined. The varieties are `Ozaki' (red color-OZ), `Nitta' (orange-NT), `Kozohara' (dark red-KZ) and `Marian Seefurth' (pink-MS). The herbicide treatments are: diuron (1.1 kg ai/ha) every 3 months (DN); granular formulation of oxyfluorfen (2%) and oryzalin (1%) (3.4 kg ai/ha) in an alternating 3 month cycle with diuron (1.1 kg ai/ha) (OO). Black polypropylene mulch (PM) is the non-chemical control treatment. Yield components include: total cut flower yield, mean stem length and mean flower size (spathe width × length). Total flower yield was not significantly affected by weed control treatments. Yield ranking was: MS>KZ=NT>OZ. A significant interaction was recorded for stem length and flower size. OZ stem length was unaffected by weed control treatments while the others showed variations dependent on treatments. KZ and OZ flower size was not affected by weed control treatments, however, herbicide treatments did reduce flower size of MS and NT. Weed control ranking was: PM=00.>DI.

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Darren E. Robinson, Nader Soltani, Allan S. Hamill, and Peter H. Sikkema

Combining herbicides and fungicides can improve production efficiency; however, there is little information on the effect of these mixtures on weed control and processing tomato crop response. Six field trials were conducted from 2002 to 2004 in Ontario to study the effect of rimsulfuron and thifensulfuron applied alone or in combination with metribuzin and with or without chlorothalonil or copper fungicides on processing tomato. There was no visual injury or reduction in marketable yield of processing tomato with rimsulfuron or thifensulfuron alone or when tank-mixed with chlorothalonil or copper hydroxide. Rimsulfuron, thifensulfuron, rimsulfuron plus metribuzin, and thifensulfuron plus metribuzin could be tank-mixed with chlorothalonil without a reduction in weed control. However, efficacy of rimsulfuron and thifensulfuron were reduced when tank-mixed with copper hydroxide. The reduction in weed control incited by adding copper hydroxide was overcome with a low rate (150 g·ha–1 a.i.) of metribuzin for thifensulfuron but not rimsulfuron. Application of rimsulfuron and thifensulfuron alone or with low rates of metribuzin and chlorothalonil could provide tomato growers with a single-pass treatment for the control of troublesome weeds and diseases.

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Sujatha Sankula, Mark J. VanGessel, Walter E. Kee, and J.L. Glancey

Field studies were conducted in 1997 and 1998 to evaluate labeled (1×) or reduced (0.5×) rates of metolachlor plus imazethapyr preemergence either broadcast or band applications to lima bean (Phaseolus lunatus L.) planted in 30-inch (76-cm) or 15-inch (38-cm) rows for weed control, yield, harvestability, and harvest recovery. Lima bean was planted in large plots simulating a commercial production system. All 30-inch rows were cultivated once 40 days after planting in 1997 and 21 days after planting in 1998. No differences were noted in weed densities between treatments both years. Marketable lima bean yield was greater from plots thatwere spaced 15 inches apart in 1997 only. However, total hand-harvested yield in both years, machine-harvested yield in 1998, and marketable yield in 1998 were not different between treatments. Measurements on harvest recovery revealed that a greater number of unstripped pods were left on plants after harvest in 15-inch row plots that were sprayed broadcast with 1× herbicide rate in 1997 only. Weight of beans lost per unit area and trash weight from 7-oz (200-g) bean sample was similar among treatments both years. Overall, weed control, yield, and harvest efficacy of lima bean was not impacted by row spacing, herbicide rate, or method of herbicide application in a commercial production system.

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Jialin Yu, Nathan S. Boyd, and Zhengfei Guan

adequately control the weeds, and as a result, some seed production occurred which resulted in increased weeds present in the following strawberry crop. Despite the different weed spectrum between sites, the results consistently show that leaving the mulch in

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John Caldwell and Maurice Ogutu

Greater plant diversity is associated with reduced insect pest pressure, but field-scale vegetable production systems incorporating plant diversity have been lacking. Cucumber was grown in 1998 and 1999 at the Virginia Tech Kentland experimental farm, by direct seeding or transplanting into rye/vetch mixture rolled to make a no-till mulch alternating with strips of vetch left to flower as a habitat for beneficial insects between cucumber rows, or direct-seeded into black plastic mulch between habitat strips or with bare soil between rows. Rye and hairy vetch were seeded at 56 kg·ha–1 each the preceding fall; only rye was planted in plots without habitats. A rippled coulter, cutting shank, and daisy wheels mounted on a tractor-drawn toolbar enabled a belt-driven seeder to seed cucumbers without pulling the no-till mulch. One hand weeding in cucumber rows at 3 weeks after planting (WAP) provided weed control equivalent to pre-emergence herbicide. At 3 WAP, no-till transplanted cucumbers had higher above-ground plant dry weights than no-till direct seeded cucumbers in both years, but, at 6 WAP, cucumber above-ground plant dry weights were equal (1999) or higher (1998) in direct seeded no-till than in transplanted no-till or black plastic mulch on bare soil. In 1999, Pennsylvania leatherwings, Chauliognathus pennsylvanicus DeG. (Coleoptera: Cantharidae), a cucumber beetle predator, had higher densities and cucumber beetles lower densities in no-till plots than in black plastic mulch plots, and bacterial wilt incidence was reduced in plots with habitat strips and no insecticide application compared to plots without habitat strips and four insecticide applications. Cumulative marketable yields in no-till were 59% higher in 1998 and 23% higher in 1999 compared to yields on black plastic mulch.

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Joseph G. Masabni

Experiments were conducted in the last 3 years to evaluate the safety and efficacy of halosulfuron (Sandea 75WG) application under the plastic mulch within 7 days of transplanting tomato. In 2003, tomato plants were transplanted daily from day 0 through 7 after halosulfuron 0.051 kg a.i./ha application. Plant survival and height were collected. Tomato plants survived all dates of transplanting treatments. Plant height indicated that plants transplanted early were taller than those transplanted late, only because they had more time to establish and grow in the field. In 2004, tomatoes were set on a 2-day interval from day 0 through 10 after halosulfuron application. Halosulfuron 0.025 or 0.052 kg a.i./ha had no effect on plant height or yield. In 2005, an experiment was initiated to determine whether addition of trifluralin to halosulfuron under the plastic mulch will improve grass control and remain safe to tomatoes. Halosulfuron at 0.025, 0.052, and 0.1 kg a.i./ha, was applied alone and combined with trifluralin 0.63 kg a.i./ha. All treatments were applied under the plastic mulch. Tomato plants were transplanted at 6 days after application (DBT) and 0 DBT. Halosulfuron 0.1 kg ai/ha resulted in slight stunting and yield reduction of tomato, whether applied at 6 or 0DBT. However, this stunting was not statistically significant. Trifluralin didn't affect tomato yield at 6DBT and significantly increased yields at 0DBT for 0.052 and 0.1 ka a.i./ha halosulfuron rates. Trifluralin reduced grass biomass but resulted in an increase of nightshade biomass. Halosulfuron was determined to be very safe on tomato growth and yield, even if tomato was transplanted on the same day of application. Trifluralin also was found to have little or no effect on tomato growth or yield, and appears to have a potential use as an herbicide for under plastic application in tomato production.

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Monica Ozores-Hampton

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Joseph G. Masabni

Halosulfuron (Sandea 75WG) is labeled for pre- or posttransplant use in tomato, cucumber, cantaloupe, among other vegetable crops. For pretransplant usage, the label specifies a 7-day waiting period after halosulfuron application under the plastic mulch before transplanting tomatoes. This period may be too long for growers who are busy in the spring with planting and pesticide sprays while on a race with the constantly changing climate of early spring. Experiments were conducted in the last 2 years to determine whether transplanting tomato within 7 days of halosulfuron application had any deleterious effects on tomato. In 2003, tomatoes were transplanted daily from day 0 through 7. Plant survival and height were collected. Tomato plants survived all dates of transplanting treatments. Plant height indicated that plants transplanted early were taller than those transplanted late, only because they had more time to establish and grow in the field. There was no adverse effect to tomato growth. In 2004, tomatoes were set on a 2-day interval from day 0 through 10 after halosulfuron application under the plastic mulch. Plant height, visual rating, % early blight infection, and yields were collected. A severe early blight infection confounded the results of herbicide applications. Still, it was clear that halosulfuron 0.026 or 0.051 kg a.i./ha had no effect on plant height or visual rating. Yields were not statistically different from those of the control, when the effect of early blight was factored out.