CONTROL BROADLEAF WEEDS THAT COMPETE WITH SPINACH (PROCESSING) AND RED BEETS
A POST ALTERNATIVE FOR BROADLEAF WEED CONTROL IN SPINACH AND RED BEETS.
Over the last few decades, the popularity of spinach and red beets has increased as consumers become more health conscious, becoming aware of the nutritional benefits of these two vegetables. What many consumers are not aware of with these “minor crops” are the meticulous standards, especially concerning weed control, required of growers. In processed spinach, there is low to no tolerance for weeds at harvesttime as it is very difficult to separate the weeds from the spinach. Just one weed per square yard can be responsible for reduced spinach yield and quality, contaminating crops, increasing labor costs and can even cause fields to be abandoned. The USDA has rigorous grading standards for processed spinach, in addition to specifications employed by processors. Similarly, garden beets do not fare well when coexisting with weeds. Weeds can impact the development and growth of the beet, ultimately impacting yield and processors require specific varieties are grown with certain size roots required throughout the season.
In the USA, The majority of spinach is grown in California, New York, New Jersey and Texas with varying crop cycles corresponding to varying climates. On the East Coast, there are two main plantings with seeds sown over a protracted growing season of 8-10 months. While the western states, with more temperate climates, allow fields to be turned over numerous times throughout the year. With a wide variety of growing strategies employed in different climates and the photosensitivity of the spinach plant, growers are challenged by the lack of herbicides on the market, especially those applicable after planting.
California, New York and Texas also are top growers of garden beets (in addition to Wisconsin and Michigan). As with spinach, post emergent solutions are scarce. While mechanical weeding is sometimes done, hand weeding for “escape weeds” is also often necessary which is becoming more costly every year.
A Valuable Tool for Spinach Growers
Dr. Steve Fennimore, Extension Specialist at University of California, Davis’ Department of Plant Sciences confirmed the lack of post-emergence control products, and the challenges spinach growers face, especially in shorter crop cycle markets, such as California and Arizona. But there is some good news. Dr. Fennimore relayed the success he’s personally seen through his research in spinach fields, specifically detailing observations of SpinAid® (Phenmedipham) when applied to early stage spinach, in California. In a UCANR Blog published in April 11, 2017, by Richard Smith and Dr. Fennimore they revealed; Over the past three years we have evaluated Spin-Aid for use in clipped spinach. Spin-Aid is registered for use on processing spinach and has a 21 day preharvest interval (PHI); this use pattern fits the production practices for freezer spinach. However, washing and bagging spinach is also considered processing and would allow its use for clipped spinach. During the summer months, clipped spinach matures in 25-30 days which makes complying with the 21 day preharvest interval difficult.1
Dr. Fennimore explains a few underlying factors for SpinAid’s effectiveness, as well as some best practices growers can use to cut back on the costs associated with manual weed management. “We are seeing real positive results with SpinAid® when used earlier in the shorter crop cycle markets at a modified rate, growers can still comfortably meet the required PHI. For the east coast, it remains even more effective at clearing the fields with higher rates of application when applied to more mature plantings.”
Dr. Fennimore’s studies illustrate that if you apply SpinAid® post-planting, you can reduce weed density by up to 87%, with optimal results achieved when the product is applied at night. He explains, “It is because the spinach itself can process the post-emergent herbicide at night without burning the plant.” (See Fig. 1)1
East Coast growers have been seeing similar success using SpinAid® for post-emergence control. Since they have longer growing seasons – typically 55 to 70 days from seeding to harvest depending on the season, they also may experience increased weed pressure, as the weeds have more time to grow or even re-emerge. Byron DuBois of Springbrook Farms in Pittsgrove, New Jersey, uses SpinAid® herbicide on all of his 500 acres of processed spinach. He commented, “If weeds get out of control, we need to hire a hand weed crew, which is costly and difficult to find. As soon as I see weeds emerging, I do my first application of SpinAid.” Byron then follows up in 7-10 days with a second application, also applied in the evening, to make sure he gets any additional weeds that emerge. “After that,” he says, “the plant canopy is wide enough to fight off any other [weeds] that might appear.” (See Fig 2).
Don’t be fooled by the name. SpinAid® is also one of a few herbicides registered and used by growers for post emergent broadleaf weed control in red garden beets. According to Cornell Cooperative Extension, SpinAid provides good control over problem weeds such as Common Lambsquarters, chickweed, ragweed as well as Purslane and Shepherdspurse2.
1 https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=23774