Herbicide Screening Trials on Earthquake Damaged Leptinella Maniototo Bowling Greens

Lawn bowls in New Zealand is played on a native herb in the Asteraceae family, Leptinella maniototo (Petrie). Only three herbicides are currently recommended for postemergence broadleaf weed control in Leptinella maniototo greens by New Zealand Sports Turf Institute. Following the Christchurch earthquakes of 2010 and 2011, a number of abandoned bowling greens were available for trials. Nine trials were carried out on five greens screening 51 active ingredients or mixtures. The first eight non replicated screening trials used a single nozzle sprayer fitted with a TeeJet even flat nozzle adjusted to 0.5m width spraying strips 5-6 m long. The eighth trial was replicated twice, using a 4 nozzle boom sprayer. The trials were scored at two weekly intervals on a 1-9 scale, where 9=no visible effect. Thirteen active ingredients caused no visible discoloration or growth check. Four active ingredients caused discoloration for a single scoring, which may be acceptable. The active ingredients with most potential for broadleaf weed control are nicosulfuron, chlorsulfuron, carfentrazone-ethyl, oxyfluorfen, thifensulfuron-methyl. Preemergence herbicides with acceptable safety are trifluralin, dimethenamid, oryzalin, oxadiazon, chlorpropham, propachlor, chloridazon. Grass control herbicides are clethodim, fluazifop-P butyl, haloxyfop.