The IR-4 Project offers three new crop safety reports on the efficacy of Dimethenamid-p, Dithiopyr and Isoxaben, summaries of which appear below. The full analyses can be found at http://ir4.rutgers.edu/Ornamental/ornamentalSummaryReports.cfm.
Dimethenamid-p Crop Safety
From 2007 to 2015, IR-4 completed 460 trials on Tower EC (dimethenamid- p). The data contained in this report was generated to register uses of dimethenamid- p on and around ornamental horticulture plants with over-the-top applications. The dimethenamid-p rates in the testing program were 0.97, 1.94 and 3.88 pounds active ingredient per acre (lb ai per A) as the 1X, 2X and 4X rates. Tower EC had been applied to 139 plant genera or species. Of these, 60 plant species exhibited no or minimal transient injury after application at all three rates. Nine crops exhibited no phytotoxicity at 0.97 and 1.94 lb ai per acre but did have some injury at 3.88 lb ai per acre. Seven crops—Catharanthus roseus, Cladrastis, Echinacea, Epilobium canum, Muhlenbergia dubia, Teucrium chamaedrys and Viburnum opulus—exhibited significant phytotoxicity at even the lowest rate…
Dithiopyr Crop Safety
Dimension was initially registered in 1992 for ornamental horticulture uses. This initial label contained an extensive list of ornamental horticulture plants in landscapes where Dimension could be used without causing phytotoxicity. In 2006, the new Dimension 2EW label contained registered uses for field container and in ground nursery production, the first dithiopyr product to have these use sites. Starting in 1992, IR-4 examined 83 crops to expand this label to other crops, including several different fern species grown in field containers. Of the researched crops and Dimension formulations, only one crop (Rosa sp.) can be added at this time based on the data provided here. It is recommended the trials conducted using emulsifiable concentrate formulations be repeated with Dimension 2EW.
Isoxaben Crop Safety
Gallery 75DF (isoxaben) was initially registered in 1992 for ornamental horticulture uses. This initial label contained an extensive list of ornamental horticulture crops where Gallery could be used without causing phytotoxicity. It also included a short list of crops where Gallery applications were not recommended. Between 1992 and 2013, IR-4 examined 93 crops to expand this label to other crops, including several different fern species grown in field containers. Of these, 24 crop species exhibited no or minimal transient injury with 20 already placed on the Gallery label. Eight crops exhibited injury in this research: Astilbe sp., Athyrium filix-femina, Buddleia davidii, Dendranthema × morifolium, Digitalis purpurea, Echinacea purpurea, Stachys byzantine, and Thymus sp. A new formulation, Gallery SC, was tested in 2014 and 2015 to determine crop safety on 21 crops in 25 trials. Of these, one species, Chasmanthium latifolium, exhibited no or minimal transient injury; this species is already in the Gallery label.