Phytotoxicity of Post-Emergence Grass Herbicides to Ornamental Trees, Shrubs, Vines, and Groundcovers

Robert P. Rice

doi:10.48044/joa.1984.10.1.7

Purpose: To determine whether Fusilade, Poast, and CGA 24275, can be safely used as over-the-top treatments in ornamentals to control weedy grasses

Procedure: Plants were grown in containers and sprayed with herbicides at approximately 1 month intervals with a hand held small plot sprayer at 30 psi in a volume of 36 gallons/acre. Plants were assessed visually 1 month after each application using a scale of 0-10 where 1 equals no injury and 10 equals death.

Experimental Design: Completely randomized with 3 replications

Applications: 11 May 1983 — sunny, 70 F, soil dry, wind less than 5 mph 18 June 1983 — foggy, 65 F, soil dry, wind 5 mph

Treatments:

Control (Con)
Fusilade .5 #ai/A + .25% X77 (Fus. 5)
Fusilade 2.0 #ai/A + .25% X77 (Fus. 2)
Poast 1.0 #ai/A + oil* (Po 1)
Poast 2.0 #ai/A + oil* (Po 2)
CGA 24275 1 #ai/A + oil* (CGA 1)
CGA 24275 2 #ai/A + oil* (CGA 2)

	June 13, 1983							July 15, 1983
Species	Con	Fus		Po		CGA		Con	Fus		Po		CGA
Species	Con	0.5	2.0	1	2	1	2	Con	0.5	2.0	1	2	1	2
Ajuga reptans	1.7	1.0	0.0	0.3	0.3	0.3	0.3	0.7	0.3	0.3	0.7	0.3	0.0	0.7
Arbutus unedo	1.0	0.7	0.3	0.0	0.3	1.0	0.7	1.3	0.7	0.3	0.7	1.0	1.0	0.7
Arenaria verna	2.3	5.0	2.0	2.3	0.0	2.0	0.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0
Asparagus densiflorus ‘sprengeri’	0.0	0.3	0.7	0.7	0.7	0.7	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Campanula carpatica	0.0	1.0	0.0	0.0	0.0	0.0	0.0	0.3	0.0	0.3	—	0.0	0.0	0.0
Cerastium tomentosum	5.3	3.7	5.0	6.0	6.3	5.7	5.0	6.3	5.7	5.7	7.0	6.7	6.7	6.3
Eucalyptus citriodora	0.7	0.0	0.0	0.3	0.7	0.7	0.3	0.0	0.0	0.7	1.0	1.0	2.0	0.0
Eucalyptus nicholii	—	—	—	—	—	—	—	0.3	2.3	—	1.0	2.7	1.0	0.0
Euryops pectinatus	0.3	—	0.0	0.0	0.7	0.7	0.0	0.0	0.0	0.3	0.0	2.7	0.0	0.0
Gazania ringens ‘Ieucoleana’	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.3	1.0	0.3	0.3	0.5	0.3	0.0
Geijera parviflora	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.3	0.0	1.3	0.0
Hedera helix	0.3	0.0	0.0	0.3	0.7	0.7	0.3	0.3	0.0	0.0	0.0	0.0	0.3	0.3
Herniaria glabra	0.0	0.7	1.0	1.0	0.7	1.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Juniperus chinensis ‘Hetzi’	0.0	1.0	1.7	0.3	0.3	0.7	0.5	0.0	0.0	1.0	0.0	0.0	0.0	1.7
Juniperus horizontalis ‘Bar Harbor’	0.7	1.3	3.0	0.3	0.7	2.0	5.0	0.7	5.3	7.7	1.7	0.0	5.7	7.7
Juniperus scopulorum ‘Witchita Blue’	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0	0.0	0.0	0.0	1.0
Juniperus wiltonii	0.0	0.0	1.0	0.3	0.0	0.0	0.3	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Leptospermum laevigatum	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.7	0.0	0.0	0.7	0.0	0.0	0.0
Ligustrum japonicum	1.3	0.7	1.3	2.3	0.7	1.0	1.0	7.5	1.3	5.3	8.0	3.7	4.7	5.0
Liquidambar styraciflua	0.3	0.3	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Lonicera japonica	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.7	1.0	0.7	0.0	0.3	0.7	0.3
Lysimachia nummularia	0.0	0.0	0.0	0.7	0.0	0.0	0.3	0.0	0.0	0.3	0.3	0.0	0.0	0.0
Metrosideros excelsus	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Nandina domestica	0.3	0.7	1.3	1.0	0.7	1.0	1.7	0.0	0.7	0.3	0.7	0.3	0.0	0.7
Nerium oleander	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.7	0.0	1.0
Ophiopogon japonicus	0.0	0.0	1.0	0.0	0.3	—	1.7	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Pelargonium domesticum	0.3	0.3	0.7	0.0	0.7	0.7	0.3	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Photinia fraseri	0.3	0.0	0.3	0.0	0.3	0.3	0.3	0.7	0.0	0.3	0.0	0.0	0.7	0.0
Polygonum capitatum	3.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	2.0	1.5	1.5	2.0	2.0	1.5
Potentilla verna	0.7	3.0	2.0	2.7	1.7	3.0	1.0	0.7	1.0	1.0	1.3	0.7	1.0	1.0
Salix matsudana ‘tortuosa’	1.0	1.3	1.0	1.3	1.5	0.3	0.7	0.0	0.0	0.7	0.0	0.0	0.0	0.3
Sedum × rubrotinctum ‘Christmas cheer’	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0	0.0	0.0	0.0	0.0	0.7	0.5
Spirea Vanhouteii	0.0	0.0	0.5	0.0	0.0	0.0	0.0	0.5	1.0	0.0	0.7	0.5	2.0	0.0
Syzgium paniculatum	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.7	0.0	0.0	0.7	0.0
Vinca minor	0.3	1.3	1.0	0.7	1.0	1.0	0.7	0.7	0.7	0.3	0.7	0.3	0.7	1.0