Weed Control J 2026; 25: e202600804

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Selectivity of herbicides applied in pre-emergence for eucalyptus and pinus

DOI: 10.7824/wcj.2026;25:00804

Abstract:

Background:

Factors such as herbicide formulation, dose, application technology, soil characteristics, species and temperature, influence the selectivity of herbicides. Crops such as eucalyptus and pinus lack registered products in Brazil.

Objective:

This study aimed to evaluate the selectivity of pre-emergent herbicides applied before or after planting eucalyptus and pinus.

Methods:

Two experiments were conducted in pots, in a randomized block design with five replications. The application modalities ‘spray and plant’ (SP) and ‘plant and spray’ (PS) were tested for Eucalyptus urograndis – Clone 1407 and Pinus caribaea var. hondurensis to five active ingredients: flumioxazin (90 g a.i. ha⁻¹), indaziflam (75 g a.i. ha⁻¹), isoxaflutole (150 g a.i. ha⁻¹), oxifluorfem (960 g a.i. ha⁻¹) and sulfentrazone (800 g a.i. ha⁻¹), plus a control without herbicide. The treatments consisted of a 2×6 factorial, with two application modalities and six chemical treatments (including the control). Evaluations of injury, plant’s height, stem diameter and dry matter (DM) were carried out, in addition to the calculation of the absolute growth rate.

Results:

For eucalyptus DM, leaf area and height, there was no difference between the application modalities and the tested herbicides. For pine’s stem diameter, there was no difference between the treatments in the SP modality, and between the herbicides tested in the PS modality.

Conclusion:

Indaziflam and isoxaflutole were harmful to pine in the SP modality, causing reductions of 38% and 25% in DM, respectively, compared to control.