A Review of Weed Control Practices in Container Nurseries

Abstract

<jats:p>Container production has increased rapidly in many parts of the U.S. over the past 15 years. Container production has been the fastest growing sector in the nursery industry and the growth is expected to continue. Weed growth in container-grown nursery stock is a particularly serious problem, because the nutrients, air, and water available are limited to the volume of the container. The extent of damage caused by weeds is often underestimated and effective control is essential. Various researchers have found that as little as one weed in a small (1 gal) pot affects the growth of a crop. However, even if weeds did not reduce growth, a container plant with weeds is a less marketable product than a weed-free product. Managing weeds in a container nursery involves eliminating weeds and preventing their spread in the nursery, and this usually requires chemical controls. However, chemical controls should never be the only management tools implemented. Maximizing cultural and mechanical controls through proper sanitation and hand weeding are two important means to prevent the spread and regeneration of troublesome weeds. Cultural controls include mulching, irrigation methods (subirrigation), and mix type. Nursery growers estimate that they spend $500 to $4000/acre of containers for manual removal of weeds, depending on weed species being removed. Economic losses due to weed infestations have been estimated at approximately $7000/acre. Reduction of this expense with improved weed control methodologies and understanding weed control would have a significant impact on the industry. Problems associated with herbicide use in container production include proper calibration, herbicide runoff concerns from plastic or gravel (especially when chemicals fall between containers) and the need for multiple applications. As with other crops, off-site movement of pesticides through herbicide leaching, runoff, spray drift, and non-uniformity of application are concerns facing nursery growers. This article reviews some current weed control methods, problems associated with these methods, and possible strategies that could be useful for container nursery growers.</jats:p>

Impact of Container Nursery Production Practices on Weed Growth and Herbicide Performance

“…As profit margins decline and the input costs continually increase, researchers and nursery growers have looked for ways to decrease production costs. From a weed control perspective, this would include many different preventative and sanitation measures, as well as chemical and nonchemical methods of weed control to improve crop growth, reduce economic burden, and increase product marketability (Case et al, 2005;Fausey, 2003).…”

“…This is no longer the case as labor costs continue to increase and labor availability decreases. Mathers (2003) reported that nurseries may spend as much as $9900 per ha on the manual removal of weeds, and economic losses due to weed infestations have been estimated at $17,300 per ha (Case et al, 2005). Similarly, Darden and Neal (1999) reported a cost of $1367 to hand weed 1000 3-L pots over a 4-month period.…”

“…Because of the high cost of hand weeding and most nonchemical methods of control, chemical control measures are typically required to reduce costs, with most these being preemergence herbicides. A comprehensive review of common nursery pre-and postemergence herbicides has been published recently (Case et al, 2005) and has remained current. One notable addition to Case et al (2005) was the introduction of indaziflam for nursery use in recent years.…”

“…A comprehensive review of common nursery pre-and postemergence herbicides has been published recently (Case et al, 2005) and has remained current. One notable addition to Case et al (2005) was the introduction of indaziflam for nursery use in recent years. Indaziflam is classified as an alkylazine herbicide and a cellulose biosynthesis inhibitor, inhibiting crystalline cellulose deposition in the cell wall affecting wall formation, cell elongation, and division and only affects growing meristematic regions of seeds as they emerge (Brabham et al, 2014).…”

Influence of Pine Bark Substrate Age on Performance and Leaching of Nursery Preemergence Herbicides

“…Research focusing on metolachlor has shown that it is tightly bound to organic substrates (Grey et al, 1996;Koncal et al, 1981;Mahnken et al, 1994). One of the most common preemergence herbicides in nursery production, oxyfluorfen, has been shown to be more mobile in pine bark than peat; however, it was largely immobile in both substrates (Case et al, 2005;Horowitz and Elmore, 1991). A study conducted by Simmons and Derr (2007) demonstrated that there was greater pendimethalin leaching in pine bark compared with a Tetotum fine loam field soil.…”