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- Author or Editor: Thomas E. Hines x
Reports concerning the success of no-till (NT) production of vegetable crops are mixed, with results influenced by soil type, precipitation, mulching, and weed control. Similar yields have been obtained with no-tillage (NT) and conventional tillage (CT) of sweet corn (4), tomatoes (3), potatoes (2), and cabbage (1). Conversely, yield suppression in NT has been reported for cucumbers (3), cabbage (5), and tomatoes and bell peppers (4). Beste (3) reported that lima bean yields were similar in both tillage systems. Snap beans have been grown successfully in NT systems, and yields have been equivalent to or greater than CT snap beans (6-8).
Mugwort (Artemisia vulgaris) is a perennial invasive weed species that has infiltrated row crops, turfgrass, ornamentals, and various noncrop areas. Currently, multiple mimics of indole-3-acetic acid can provide control of this species; however, these herbicides can damage certain sensitive ornamental plants. When applied at reduced rates, the p-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides mesotrione and topramezone have demonstrated some selectivity among certain ornamental plants. Field and greenhouse studies were initiated to evaluate whether these herbicides could control mugwort when applied alone, or in mixtures with photosystem II (PSII)-inhibiting herbicides that often provide synergistic weed control. In the field, mesotrione controlled mugwort between 30% and 60% by 21 days after treatment when applied at 0.093 to 0.187 lb/acre. When the PSII-inhibiting herbicide atrazine was added, control increased to 78% and 79%. In the greenhouse, similar rates produced greater control in mugwort, and all mesotrione treatments limited mugwort regrowth by at least 95% when compared with untreated control. When HPPD inhibitor rates were reduced further, the addition of the PSII inhibitors atrazine or bentazon was not sufficient at providing acceptable control of mugwort.
Bush-type snap beans (Phaseolus vulgaris L.) were seeded by a no-tillage method into standing wheat (Triticum aestivum L.) stubble of 8, 15, 23, 30, and 38 cm in height to evaluate the effects of stubble height on pod mechanical harvest efficiency, plant morphology, and shoot component yield. Basal internode elongation, stem plus leaf yields, pod yields, efficiency of mechanical pod harvest (MH), and height of basal pod set were related in a positive linear or curvilinear fashion to wheat stubble height. Quantity of pods missed during MH was related negatively to height of basal pod set. Harvest efficiency was maximized with 15-30-cm stubble heights, and these notillage systems yielded MH pod levels that equaled or exceeded those of a conventional tillage (plow, disk 2 times) system. Superior MH efficiency was attributed to increased basal internode length and mechanical support of the shoots by the wheat stubble.
Field and greenhouse studies were conducted in 2001 and 2002 near Painter, VA, to determine the level of weed control and pepper (Capsicum annuum) tolerance to postemergence applications of the acetolactate synthase (ALS) inhibitors trifloxysulfuron, halosulfuron, sulfosulfuron, cloransulam, and tribenuron. Based on measurements of visual injury, heights, dry weights, and chlorophyll content of pepper, the safest ALS inhibitor to pepper was trifloxysulfuron followed by halosulfuron, cloransulam, sulfosulfuron, and tribenuron. In addition, trifloxysulfuron was the only herbicide that provided greater than 86% control of pigweed species (Amaranthus spp.) and carpetweed (Mollugo verticillata) in both years of the field study. Trifloxysulfuron was also the only herbicide evaluated that did not reduce pepper yield compared with the control in both years of the field study.
Chemical desiccants are commonly used to regulate tuber size, strengthen skin, and facilitate harvest for potato (Solanum tuberosum) production. Glufosinate is labeled for potato vine desiccation; however, limited data are available. Saflufenacil, a protoporphyrinogen oxidase–inhibiting herbicide, is an effective desiccant in other crops. Field research was conducted to evaluate glufosinate and saflufenacil as desiccants applied to ‘Dark Red Norland’ potato. Desiccants consisted of diquat, glufosinate, saflufenacil, glufosinate plus carfentrazone, and glufosinate plus saflufenacil applied at three timings, DESIC-1, DESIC-2, and DESIC-3, when size B potatoes averaged 43%, 31%, and 17% of total potato weight. Potato vine desiccation was more difficult at DESIC-1 and DESIC-2 because of immature vines. Diquat was the most effective desiccant 7 days after treatment (DAT), desiccating potato vines 88% at DESIC-1 7 DAT. Glufosinate alone desiccated potato vines 65% at the same timing; however, carfentrazone and saflufenacil added to glufosinate increased vine desiccation 8% and 16% compared with glufosinate alone, respectively. Vine desiccation by all treatments ranged 99% to 100% at 14 DAT. Desiccant and timing effects on skin set were determined using a torque meter before harvest. Skin set resulting from all desiccants and timings ranged between 1.88 and 2 lb-inch, and no significant differences were observed. No significant differences in yield were noted among desiccants. This research indicates that glufosinate and saflufenacil are suitable alternatives to diquat for potato vine desiccation; however, safety of saflufenacil applied to potatoes before harvest has not been determined.