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Tordon 101: picloram/2,4-D

Author: OMAFRA Staff
Creation Date: 25 November 2002
Last Reviewed: 21 January 2008
Pub 75: Guide to Weed Control > Notes on Herbicides > Tordon 101: picloram/2,4-D
Excerpt from Chapter 4, Publication 75, Guide to Weed Control, Order this publication
Trade Names
Tordon 101
Formulation Sn
Guaranteed active concentration (1:3.7) 305 g/L
Groups 4
Ontario Schedule 2
Winter Storage A
Chemical Family: Pyridine/phenoxy.
Crop and/or Non-Crop Registrations: Weed and brush (including conifer) control in non-crop locations, industrial sites and rights-of-way.
Sensitive Weeds: Most broadleaf herbaceous weeds including Canada thistle, sweet and red clover, wild carrot, common ragweed, dandelion, goldenrod, dock, plantain, prickly lettuce, burdock, fleabane and vetch; deciduous and coniferous woody plants except white ash.
Uptake and Translocation: Rapidly absorbed by the roots, stems and foliage. Translocation can be up or down but, like 2,4-D, accumulation is in young, rapidly growing meristematic tissue.
Basis of Selectivity Effects on nucleic acid metabolism and growth are not observed in grasses and other tolerant species.
Application Methods For deciduous and coniferous brush, apply either broadcast using a fixed nozzle (constant volume per hectare) or selectively using a spray gun (variable volume per hectare). As spray gun applications use a more dilute spray mix, this type of application must thoroughly wet the foliage, stem and root collar. Brush should be treated after foliage is well developed in spring or early summer. To ensure thorough coverage and minimize drift, brush to be treated should be less than 2.5 m tall. For cut-surface treatment, mix with water or ethylene glycol (to reduce the freezing point, if necessary) and apply to cover the cambium layer of freshly cut stumps. For broadleaf herbaceous weeds, apply broadcast in spring or early summer after growth begins.
Residual Activity Soil residue carryover into the year following application is minimal when applied at recommended rates. Degradation is most rapid under warm, humid conditions. Because small residues of picloram in soil can be phytotoxic to crops such as soybeans, tobacco, tomatoes, potatoes, grapes and many desirable ornamental plants, picloram may not be applied to land used, or land that may be used, for the production of agricultural and horticultural crops.
Unique Characteristics A permit from the Ministry of the Environment is required for the purchase and use of picloram/2,4-D in Ontario. Picloram/2,4-D must not be applied over, or near, areas where roots of desirable trees or other plants may extend. Because spray drift is phytotoxic to sensitive plants, an approved drift-control system or additive is recommended when making low-volume applications adjacent to desirable trees or crops.
Manufacturer / Registrant Dow Agrosciences Canada Inc.

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