Broccoli, cabbage, squash and watermelon response to halosulfuron preplant over plastic mulch

Abstract

Nutsedge species are problematic in plastic-mulched vegetable production because of the weed’s rapid reproduction and ability to penetrate the mulch. Vegetable growers rely heavily on halosulfuron to manage nutsedge species; however, the herbicide cannot be applied over mulch before vegetable transplanting due to potential crop injury. This can be problematic when multiple crops are produced on a single mulch installation. Field experiments were conducted to determine the response of broccoli, cabbage, squash, and watermelon to halosulfuron applied on top of mulch prior to transplanting. Halosulfuron at 80 g ai ha−1 was applied 21, 14, 7, and 1 d before planting (DBP), and 160 g ai ha−1 was applied 21 DBP. In all experiments, extending the interval between halosulfuron application and planting reduced crop injury. For squash and watermelon, visual injury, plant diameters/vine runner lengths, marketable fruit weights, and postharvest plant biomass resulted in similar values when applying 80 g ha−1 21 DBP and with the nontreated weed-free control. Reducing this interval increased injury for both crops. Visual crop injury and yield reductions up to 40% occurred, with halosulfuron applied 14, 7, or 1 DBP in squash and 1 DBP in watermelon. Broccoli and cabbage showed greater sensitivity, with injury and plant diameter reductions greater than 15%, even with halosulfuron applied at 80 g ha−1 21 DBP. Experimental results confirm that halosulfuron binds to plastic mulch, remains active, and is slowly released from the mulch over a substantial period, during rainfall or overhead irrigation events. Extending the plant-back interval to at least 21 d before transplanting did overcome squash and watermelon injury concerns with halosulfuron at 80 g ha−1, but not broccoli and cabbage. Applying halosulfuron over mulch to control emerged nutsedge before planting squash and watermelon would be beneficial if adequate rainfall or irrigation and appropriate intervals between application and planting are implemented.

Triploid watermelon response to flumioxazin

“…The data from the present study suggest that the observed reduction in watermelon yield from the broadcast flumioxazin application was due to reduced fruit number and not average fruit weight. Randell et al (2020) applied halosulfuron-methyl over the top of plastic mulch-covered raised beds at different time intervals prior to transplanting 'Sangria' watermelon and reported the greatest injury and marketable yield loss occurred when halosulfuron was applied 1 d before transplanting. Injury and yield loss were significantly reduced by extending the interval between herbicide application and transplanting.…”

2,4-D and dicamba removal from the surface of plastic mulch using overhead irrigation: analytical analysis and cucurbit bioassay crop response

“…In contrast to fomesafen, neither flumioxazin nor halosulfuron are easily or effectively removed from plastic mulch with rainfall or irrigation (Culpepper et al 2009;Grey et al 2009). In fact, broccoli, cabbage, and squash were damaged by halosulfuron applications to plastic mulch after 30 d and 19 cm of rainfall had fallen between applications and planting (Randell et al 2020). Halosulfuron can be removed from mulch eventually, but often not in a realistic time frame for planting sensitive crops such as squash, broccoli, or cabbage (Grey et al 2018;Randell et al 2020).…”

“…In fact, broccoli, cabbage, and squash were damaged by halosulfuron applications to plastic mulch after 30 d and 19 cm of rainfall had fallen between applications and planting (Randell et al 2020). Halosulfuron can be removed from mulch eventually, but often not in a realistic time frame for planting sensitive crops such as squash, broccoli, or cabbage (Grey et al 2018;Randell et al 2020). Therefore, herbicides that can be used in multicrop plasticulture must effectively control troublesome weeds, mix well with glyphosate or paraquat, and be easily removed from plastic mulch with rainfall or irrigation.…”

Quantifying glyphosate plus 2,4-D or dicamba removal from the surface of totally impermeable film using analytical and bioassay techniques

“…Although numerous herbicides are available to control these weeds, broadcast applications over plastic mulch increase complications. Herbicides applied over plastic mulch wash off of the mulch with an initial irrigation or rainfall event, partially wash off of mulch over time, or bind to the mulch without release (Culpepper et al 2009;Grey et al 2009;Grey et al 2018;Randell et al 2020). For example, flumioxazin applied over plastic mulch persists, resulting in significant injury and yield reductions for squash and tomato (Solanum lycopersicum L.) (Culpepper et al 2009;Grey et al 2009).…”

“…botrytis L.), and cabbage (B. oleracea L. var. capitata L.) at varying levels (Culpepper et al 2009;Randell et al 2020). Thus, identifying potential herbicide tools to improve weed control in vegetables grown on plasticulture must begin with understanding the relationship of the herbicide and the mulch.…”