Evaluations of Herbicides in Slow-release Formulations for Container-grown Landscape Crops

Abstract

Alachlor (2-chloro-2',6'-diethyl-N-(methoxyinethyl) acetanilide), chloramben (3-amino-2,5-dichlorobenzoic acid), naptalam (N-1-napthylphthalamic acid (2-N-1-naphthy) aminocarbaryl benzoic acid), and propachlor (2-chlor-N-isopropylacetanilide) incorporated into dicalcium phosphate and plaster of paris slow-release tablet formulations successfully controlled weeds for 16 weeks with no significant injury to cotoneaster (Cotoneaster dammeri C.K. Schneid. ‘Royal Beauty’), euonymus [Euonymus fortunei (Tarcz.) Hand Mazz. ‘Emerald ’N Gold’], forsythia (Forsythia X intermedia Zab. ‘Spring Glory’), ind privet (Ligustrum X vicaryi, a hybrid between L. ovalifolium Hasst. ‘Aureum’ and L. vulgare L.). One tablet per container was applied, delivering 20 or 40 kg/ha active ingredient. Metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide) was incorporated in the tablet formulations to deliver a rate of 40 kg/ha active ingredient per tablet to evaluate area of weed control. Weed density was significantly reduced in containers treated with metolachlor tablets. An essentially weed-free area (7- to 8-cm radius) encompassing a single herbicide tablet was observed. Tablet formulations did not significantly differ in reduction of weed density in nursery containers.