Tomato is a major horticulture crop grown across the globe. Unfortunately, its yield is reduced by 25% because of auxin herbicides and glyphosate drift. In this present study, wild germplasm of tomato was screened for herbicide tolerance. From the greenhouse study nine accessions for glyphosate and 2,4-D, eleven accessions for dicamba, five accessions for quinclorac, eight accessions for aminocyclopyrachlor, and two accessions for picloram and aminopyralid were identified to be tolerant. A few accessions were selected from each herbicide tolerant group for field trials at two locations in Mississippi in 2016 and 2017. Results indicated that TOM18 was most tolerant to dicamba herbicide, while TOM87 and TOM129 to glyphosate and quinclorac herbicide, respectively, on the basis of yield and injury. Molecular experiments were conducted to measure the genetic diversity among diverse germplasm. Genetic diversity analysis showed wild accessions to be highly diverse as compared to cultivated tomato.

Sprayer hygiene and concerns of off-target injury from auxin herbicides have increased in recent years. New auxin tolerant crops have broadened the use patterns of these herbicides. Therefore, experiments were conducted across two locations in Mississippi in 2016, 2017, and 2018 to evaluate sprayer cleanout procedures to aid in dicamba removal. Standard sprayer cleanout consisted of a triple rinse of 10% tank volume, with either a tank cleaner or ammonia added in the second rinse. Samples collected in each rinse step for all treatments were applied to actively growing soybean and dicamba concentration quantified with HPLC. Experiments were conducted to determine if various tank cleaners and ammonia produce visual injury when applied to actively growing soybean and cotton alone and in conjunction with glyphosate. No tank cleaner caused visual injury nor affected plant heights or yield. Furthermore, experiments were conducted to evaluate tank cleaner effectiveness to remove dicamba utilizing the standard cleanout procedure, with increased rinse volumes, sequence of water and tank cleaner rinses, and cleanout effectiveness following durations of idle time from application to cleanout. No tank cleaner provided greater dicamba removal, with all cleaners performing the same as cleanouts utilizing water alone. Increasing rinse volumes did not positively affect dicamba removal compared to 10% rinse volumes. Multiple rinse steps utilizing a tank cleaner or altering the standard cleanout procedure utilizing a water-tank cleaner-water rinse sequence did not result in greater dicamba removal from contaminated sprayer systems. Finally, increases in time between contamination with dicamba and cleanout did not negatively influence dicamba removal using the standard cleanout procedure.