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.
Joseph G. Masabni
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.
Joseph G. Masabni and Dwight E. Wolfe
Flumioxazin (Chateau 51WG) is an herbicide for the preemergence and early postemergence control of broadleaves and grasses. Chateau was recently labeled for use in non-bearing fruit trees and bearing grapes. Long-term weed control in apple, peach, and blueberry was investigated following fall application of herbicides. Treatments consisted of simazine 2.8 kg a.i., norflurazon 2.24 kg a.i., napropamide 2.24 kg a.i., and oryzalin 2.24 kg a.i. were applied on 11 Nov. 2003. Flumioxazin was also applied at 0.1 and 0.43 kg ai on apple and peach. All treatments included glyphosate 1 lb a.i. for burndown control of preexisting weeds. Weed control evaluation in mid-April or 4 months after application showed that flumioxazin-treated plots had no weeds present and no weed regrowth. Plots treated with napropamide, norflurazon, and oryzalin showed significant regrowth of dandelion, common ragweed, and chickweed. Simazine plots had fewer weeds germinating than the other herbicides. By early June or 6 months after application, no differences in residual weed control were observed for all treated plots when compared to the control. All plots were equally weedy and required immediate floor management measures. It appears that flumioxazin weed control benefit was exhausted by 6 months after application, compared to 4 months for all other herbicides. Fall application of flumioxazin can eliminate the need for early spring weed control. This time saved can be spent on other important activities such as pruning and disease and insect control.
Joseph G. Masabni and S. Alan Walters
A field study was conducted in 2010 and 2011 to determine the suitability of Earth-Kind® production principles for home vegetable gardening. Earth-Kind® production encourages water and energy conservation, and reduction of fertilizer and pesticide use. Seven vegetable cultivars [Sweet Banana and bell pepper (Capsicum annuum); Celebrity and Juliet tomato (Solanum lycopersicum); Spacemaster cucumber (Cucumis sativus); Ichiban eggplant (Solanum melongena); Spineless Beauty zucchini (Cucurbita pepo)] were grown in mushroom compost (MC) or city compost (CC). Both composts were incorporated preplant into the soil with shredded wood mulch placed over them. In each year, nitrogen (N) fertilizer (15.5N–0P–0K from calcium nitrate) was applied preplant to CC plots to bring initial soil fertility levels similar to MC plots. No additional fertilizer was applied during the growing season. Drip irrigation was supplemented weekly. One application each of neem oil and pyrethrin (organic insecticides) and chlorothalonil (synthetic fungicide) was applied before harvest in 2010, but none was applied in 2011. Results indicated that Earth-Kind® technique could be effectively implemented in a home vegetable garden. MC is better suited for Earth-Kind® vegetable production than CC for some vegetables. Banana pepper, bell pepper, and zucchini had twice the yield in MC plots when compared with CC plots. No yield differences (P > 0.05) were observed between composts for tomato, eggplant, or cucumber. With proper irrigation and soil preparation practices such as addition of compost and mulch, Earth-Kind® vegetable gardening techniques can be used for selected vegetable crops without additional N fertilizer or pesticides. Furthermore, Earth-Kind® vegetable gardening can be successful as long as the home gardener understands that low yields may result from using this production method. However, often the home gardener is more concerned about producing vegetables using sustainable, environmentally friendly methods than maximizing yields.
Youping Sun, Joseph Masabni, and Genhua Niu
Excessive salinity in soil and irrigation water in combination with waterlogging in coastal regions can significantly reduce the productivity of many agricultural crops. To evaluate the plant growth responses to simulated seawater (SSW) flooding, seedlings of 10 vegetables (broccoli, chinese cabbage, chinese greens, cucumber, eggplant, kale, radish, ‘Red Crunchy’ radish, spinach, and tomato) were flooded with SSW at electrical conductivity (EC) of 44.0 ± 1.3 dS·m−1 or tap water at EC of 0.8 ± 0.1 dS·m−1 for 24 hours and grown subsequently for 2 weeks in a greenhouse. Chinese greens and cucumber plants died shortly after flooding with SSW, whereas other vegetables exhibited various degrees of visible salt damage. Chinese cabbage suffered the strongest reduction, whereas spinach, tomato, and eggplant exhibited the least decrease in dry weight (DW) due to SSW flooding in comparison with their perspective control. Two weeks after flooding treatment with SSW, net photosynthetic rate of broccoli, kale, spinach, and tomato was reduced by 43% to 67%, transpiration rate by 35% to 66%, and stomatal conductance (g S) by 51% to 82%. In summary, spinach, eggplant, and tomato were the most tolerant, whereas chinese cabbage, chinese greens, and cucumber were the least tolerant to SSW flooding.
Joseph Masabni, S. Kaan Kurtural, Dwight Wolfe, and Chris Smigell
The effect of cropload (kg yield/kg pruning weight) on yield components and fruit composition of 17 eastern European grapevine cultivars was evaluated from 2000 to 2004 in a vineyard, at the research station in western Kentucky, characterized by a long and warm season. There was a cubic relationship between number of clusters retained per vine and the cropload (R 2 = 0.6374, P < 0.0001). Similar relationship was evident between yield per vine and cropload (R 2 = 0.5908, P < 0.0001). Of the observed variation in cluster weight, 28% was attributed to variation among predictions, based on the value of cropload in a quadratic relationship (P < 0.0001). As cropload increased, pruning weight per meter of row decreased (R 2 = 0.4513, P < 0.0001). However, there was very little effect of cropload on the percentage of total soluble solids and juice pH measured at harvest. Optimum cropload values fell in between 13–18 (kg yield/kg pruning weight) depending upon cultivar evaluated, based on optimum ranges for pruning weight per meter of row for optimum vine balance in the lower Midwest.
Youping Sun, Genhua Niu, Joseph G. Masabni, and Girisha Ganjegunte
A greenhouse experiment was conducted to determine the relative salt tolerance of pomegranate (Punica granatum) cultivars. Twenty-two pomegranate cultivars were irrigated weekly with a saline solution at an electrical conductivity (EC) of 10.0 dS·m–1 for 4 weeks and subsequently with a saline solution at an EC of 15.0 dS·m–1 for another 3 weeks (salt treatment). Another group of uniform plants was watered with a nutrient solution without additional salts at an EC of 1.2 dS·m–1 (control). No visual foliar salt damage (leaf burn, necrosis, or discoloration) was observed during the entire experimental period; however, salt treatment impacted pomegranate growth negatively, with a large variation among cultivars. Salt treatment reduced shoot length by 25% and dry weight (DW) by 32% on average for all cultivars. Cluster analysis classified the 22 tested pomegranate cultivars in two groups. The group consisting of ‘Arturo Ivey’, ‘DeAnda’, ‘Kazake’, ‘Russian 8’, ‘Apseronski’, ‘Purple Heart’, ‘Carolina Vernum’, ‘Chiva’, ‘Kunduzski’, ‘Larry Ceballos 1’, ‘ML’, ‘Salavatski’, ‘Spanish Sweet’, and ‘Wonderful’ was more salt tolerant than the group including ‘Al-Sirin-Nar’, ‘Kandahar’, ‘Surh-Anor’, ‘Early Wonderful’, ‘Angel Red’, ‘Ben Ivey’, ‘Utah Sweet’, and ‘Mollar’. The sodium (Na) concentration in the leaf tissue of all 22 pomegranate cultivars was less than 1 mg·g–1 on a DW basis. All pomegranate cultivars in the salt treatment had an average leaf chloride (Cl) content of 10.03 mg·g–1 DW—an increase of 17% from the control. These results indicate that pomegranate plants have a strong capability to exclude Na and Cl accumulation in leaf tissue. In conclusion, the pomegranate plant is very tolerant to saline water irrigation up to an EC of 15 dS·m–1 with little foliar salt damage and a slight growth reduction. Investigation is needed to determine the effects of saline water on the fruit yield and nutritional quality of pomegranate.
Kevin M. Crosby, Daniel Leskovar, John L. Jifon, and Joseph Masabni
Catur Herison, Joseph G. Masabni, and Bernard H. Zandstra
Three onion (Allium cepa L.) cultivar transplants were grown in the greenhouse in 200-cell plastic trays with one, two, or three plants per cell; at 75, 150, or 225 ppm N; and for 8, 10, or 12 weeks. Increasing the number of plants per cell resulted in smaller seedlings at transplanting and reduced time to maturity in the field by 1 week. Two and three plants per cell yielded more bulbs ≥76 mm in diameter, but one plant per cell had the highest percentage of bulbs ≥102 mm in diameter. Older seedlings and higher N applications produced larger plants at transplant and larger bulbs at harvest. Increasing N applications reduced maturation time slightly. Bulb fresh weight at harvest and yield of bulbs ≥76 mm in diameter were highest with 10- and 12-week-old transplants, and at 150 and 225 ppm N.
Joseph Masabni, Youping Sun, Genhua Niu, and Priscilla Del Valle
Southern U.S. states such as Texas experience high temperatures and intense solar radiation during the summer production season. Use of shadecloth is common in Spain and other Mediterranean countries and is becoming popular with homeowners or small-acreage farmers in Texas. Little information is available on the applicability of using shadecloth on tomato (Solanum lycopersicum) and chili pepper (Capsicum annuum) in the warm climate of Texas. The effects of two shade nets differing in shading intensity on growth, chlorophyll fluorescence, and photosynthesis of ‘Celebrity’ tomato and ‘Sweet Banana’ chili pepper was investigated from May to Aug. 2014. Plants were grown in 50% shade, 70% shade, or full sun. Compared with the unshaded control, tomato grown in 50% shade had similar yield and shoot fresh and dry weight and less photochemical stress. The 50% shade reduced number and weight of unmarketable tomato fruit. Similar results were obtained with chili pepper except for lower numbers of marketable fruit. The 70% shade significantly reduced yield parameters of both tomato and chili pepper. Both 50% and 70% shadecloth reduced leaf temperatures of tomato and chili pepper with variable results in June and July. Growth index [(height + width 1 + width 2) ÷ 3] of tomato and chili pepper was the highest with 50% shade, the lowest with full sun, and intermediate with 70% shade. The maximum net photosynthetic rates (Pn) of tomato determined from a Pn to light response curve supported the results on growth and yield. However, the maximum Pn of chili pepper was higher in full sun treatment compared with 50% or 70% shade. The latter two were almost identical. This one growing season study indicated that shading at 50% benefits tomato and chili pepper production in west Texas by reducing heat stress; however, a shading percentage below 50% may be better.