Translator Disclaimer
1 May 2016 Evaluation of Cycloate Followed by Evening Two-Leaf–Stage Phenmedipham Application in Fresh Market Spinach
Ran N. Lati, Beiquan Mou, John S. Rachuy, Steven A. Fennimore
Author Affiliations +
Abstract

Fresh market spinach has one primary herbicide, cycloate, which does not control all weeds. Previous studies demonstrated that cycloate PRE followed by (fb) phenmedipham at the four-leaf spinach stage is a safe and effective treatment. However, this treatment is not useful for the main growing season of fresh spinach due to its short crop cycle and the 21-d preharvest interval requirement of phenmedipham. This study evaluates the potential to use the combination of cycloate PRE fb phenmedipham on two-leaf spinach. Greenhouse and field studies were conducted in 2014 using three spinach varieties with low (‘Nordic' and ‘Sardinia') and high (‘Regal') tolerance to phenmedipham. Greenhouse studies revealed that phenmedipham at 90 g ai ha−1 was safe to Regal when applied at the two-leaf stage. Sardinia was more susceptible to phenmedipham injury under high (310 W m−2) light conditions than low (258 W m−2) light conditions. Impact of time of day on phenmedipham safety was evaluated in the field: day-long exposure to high light intensity following morning applications vs. evening applications fb exposure to low light intensity. Injury estimations taken 3 d after treatment (DAT) were lower for evening than for morning applications. Nonetheless, injury 11 DAT and spinach yield evaluations found no differences between morning and evening applications. Subsequently, cycloate (1,700 g ha−1) PRE fb phenmedipham (90 and 180 g ha−1) applied in the evening at the two-leaf stage was evaluated. A reference treatment was cycloate PRE fb phenmedipham (270 g ha−1) at the four-leaf stage. Treatments with cycloate fb two-leaf phenmedipham at 90 and 180 g ha−1 were safe to spinach and improved weed control compared to cycloate alone. Cycloate fb 180 g ha−1 phenmedipham at the two-leaf stage reduced weed biomass by 88% compared to cycloate alone. This level of weed control was similar to the reference treatment. Results here show that phenmedipham applied at the two-leaf stage is safe to fresh market spinach and it has the potential to be used during most of the fresh spinach growing season.

Nomenclature: Cycloate; phenmedipham; spinach, Spinacia oleracea L. ‘Nordic', ‘Regal', ‘Sardinia'.

El mercado de espinaca fresca tiene un sólo herbicida primario, cycloate, el cual no controla a todas las malezas. Estudios previos demostraron que cycloate PRE seguido por (fb) phenmedipham en el estadio de cuatro hojas de la espinaca es un tratamiento seguro y efectivo. Sin embargo, este tratamiento no es útil para la principal temporada de crecimiento de la espinaca fresca, debido a su corto ciclo de producción, y al requisito para phenmedipham de un intervalo de aplicación de 21 d antes de la cosecha. Este estudio evalúa el potencial para el uso de la combinación de cycloate PRE fb phenmedipham en espinaca con dos hojas. Estudios de invernadero y estudios de campo fueron realizados en 2014 usando tres variedades de espinacas con baja (‘Nordic' y ‘Sardinia') y alta (‘Regal') tolerancia a phenmedipham. Los estudios de invernadero revelaron que phenmedipham a 90 g ai ha−1 fue seguro en Regal cuando se aplicó en el estadio de dos hojas. Sardinia fue más susceptible al daño del phenmedipham en condiciones de luz alta (310 W m−2) que en condiciones de luz baja (258 W m−2). El impacto del momento durante el día de la aplicación en la seguridad de phenmedipham fue evaluado en el campo: exposición durante todo el día a alta intensidad de luz seguida de aplicaciones en la mañana vs. aplicaciones al atardecer fb de exposición a baja intensidad de luz. Las estimaciones de daño tomadas 3 d después del tratamiento (DAT) fueron menores para aplicaciones al atardecer que en la mañana. Sin embargo, las evaluaciones del daño 11 DAT y el rendimiento de

Ran N. Lati, Beiquan Mou, John S. Rachuy, and Steven A. Fennimore "Evaluation of Cycloate Followed by Evening Two-Leaf–Stage Phenmedipham Application in Fresh Market Spinach," Weed Technology 30(2), 464-471, (1 May 2016). https://doi.org/10.1614/WT-D-15-00102.1
Received: 8 July 2015; Accepted: 1 November 2015; Published: 1 May 2016
JOURNAL ARTICLE
8 PAGES


Share
SHARE
KEYWORDS
Evening application
morning application
sequential phenmedipham application
time of day
two-leaf application
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top