Development of lawns in response to applications of imazapic alone or combined with imazapyr

Ricardo F Marques,Sidnei R De Marchi,Dagoberto Martins

doi:10.1590/1807-1929/agriambi.v25n11p727-732

Abstract

ABSTRACT Successive mowings are the major maintenance cost of lawns. These costs have led to the search for alternatives to mechanical management. This study aimed to determine the effects of imazapic herbicide doses applied alone or combined with imazapyr as a growth regulator of Tifton 419 and Zoysia grasses. The experimental design was randomized blocks with four replicates, and the treatments consisted of four doses of herbicide imazapic applied alone (35; 70; 105 and 140 g a.i. ha-1) and three doses of imazapic + imazapyr mixture (7.875 + 2.625; 15.57 + 5.25 and 23.625 + 7.875 g a.i. ha-1) in two sequential applications on both grass lawns. Visible injury symptoms, canopy height, height and number of inflorescences, and total dry matter of clippings were determined. Applications of imazapic alone or combined with imazapyr effectively reduced all morphological variables of Tifton 419 grass. Imazapic applied alone or mixed with imazapyr provided adequate control of growth and quantity of dry matter of Zoysia grass clippings. Still, with some application doses of this herbicide, the number of inflorescences present in the lawns increased.

Highlights

Tifton 419 (Cynodon dactylon (L.) Pears. × C. transvaalensis Burtt-Davy) and Zoysia grass, known as Japanese or Korean lawn grass (Zoysia japonica Steud.), are adapted to the climate of Brazil; which are used in residential, industrial, and public lawns, as well as airports, parks, square gardens, roadsides, and sports fields (Santos & Castilho, 2018; Amaral et al, 2019; Gazola et al, 2019).Successive mowings are the main source of lawn maintenance costs, which, together with the large number of clippings produced and the repetitive operations of piling up the residues and transporting them, have become the main factors of rejection to the use of this technique
The imazapic with imazapyr mixture caused low levels of injury on Tifton 419 lawn grass, and the values found at 7 days after the second application (DASA) were lower than 7%, irrespective of the herbicide dose applied (Table 3)
Visible injury caused by the application of imazapic alone and combined with imazapyr on lawns with Tifton 419 (Cynodon dactylon) and Zoysia (Zoysia japonica) ns, **, * - Not significant and significant at p ≤ 0.01 and p ≤ 0.05 by the F test, respectively; Means followed by the same letter in column belong to the same group by the Scott-Knott test at p ≤ 0.05; \1 DASA - Days after the second application evaluation (28 DASA), it was observed total recovery of the C

Summary

Introduction

Tifton 419 (Cynodon dactylon (L.) Pears. × C. transvaalensis Burtt-Davy) and Zoysia grass, known as Japanese or Korean lawn grass (Zoysia japonica Steud.), are adapted to the climate of Brazil; which are used in residential, industrial, and public lawns, as well as airports, parks, square gardens, roadsides, and sports fields (Santos & Castilho, 2018; Amaral et al, 2019; Gazola et al, 2019).Successive mowings are the main source of lawn maintenance costs, which, together with the large number of clippings produced and the repetitive operations of piling up the residues and transporting them, have become the main factors of rejection to the use of this technique. The use of selective herbicides that provide a regulating effect of plant growth without detriment to the visual quality of lawns can be a very interesting management tool due to the dual purpose to be attained (Maciel et al, 2011; Queiroz et al, 2017). In this context, the present study aims to study the effects of imazapic herbicide applied alone or combined with imazapyr on the vegetative growth and inflorescence of Tifton 419 and Zoysia grasses

Objectives

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Results

Conclusion