Efficacy of Azoxystrobin, Pyraclostrobin, Potassium Phosphite, and Mefenoxam for Control of Strawberry Leather Rot Caused by Phytophthora cactorum

Abstract

Efficacy of azoxystrobin, pyraclostrobin, mefenoxam, and potassium phosphite for control of strawberry leather rot, caused by Phytophthora cactorum, was evaluated on a commercial farm. Foliar sprays of azoxystrobin, pyraclostrobin, and potassium phosphite were applied weekly from bloom through harvest and mefenoxam was applied twice as a soil drench at early plant growth and at fruit set. All fungicide treatments had significantly less leather rot than the untreated control and there were no significant differences in leather rot incidence between any fungicide treatment during both years of testing. Mefenoxam (Ridomil Gold) and potassium phosphite (ProPhyt) are currently registered for control of strawberry leather rot in the U.S. Although they are registered for use on strawberry, leather rot is not on the azoxystrobin (Abound) or pyraclostrobin (Cabrio) labels. Results from these studies indicate that both of these strobilurin fungicides provide excellent control of strawberry leather rot. Accepted for publication 28 November 2004. Published 7 January 2005.

Pre- and Post-Infection Activity of Azoxystrobin, Pyraclostrobin, Mefenoxam, and Phosphite Against Leather Rot of Strawberry, Caused by Phytophthora cactorum

“…All of these fungicides provide effective control of leather rot (28). In addition, the QoI (strobilurin) fungicides azoxystrobin and pyraclostrobin provide excellent activity against leather rot under very high disease pressure in the field (28). The efficacy of these QoI fungicides in field trials was similar to mefenoxam and phosphite fungicides (28).…”

“…Currently, mefenoxam, fosetyl-Al, and several phosphite fungicides are registered for control of leather rot in the United States. All of these fungicides provide effective control of leather rot (28). In addition, the QoI (strobilurin) fungicides azoxystrobin and pyraclostrobin provide excellent activity against leather rot under very high disease pressure in the field (28).…”

Optimizing Fungicide Applications for Plant Disease Management: Case Studies on Strawberry and Grape

“…No significant differences were detected among the fungicides treatments. Disease incidences ranged from 0.3 to 0.5% with the QoI fungicides (azoxystrobin and pyraclostrobin), 0.8 to 5.4% with potassium phosphite, and 0.3 to 11% with mefenoxam (Rebollar-Alviter et al 2005). Interestingly, these experiments showed that both QoI fungicides tested were highly effective for control of leather rot of strawberry.…”

“…In order to select the proper fungicide, the efficacy of fungicides was defined in the field (Rebollar-Alviter et al 2005). During 2003 and 2004, the efficacy of pyraclostrobin, azoxystrobin, potassium phosphite and mefenoxam was evaluated in Wooster Ohio, USA against leather rot of strawberry grown in a matted row system.…”

Estudios de etiología, epidemiología y control de un nuevo síndrome de lesiones en tronco y ramas principales de cítricos asociado a Phytophthora.

“…El mefenoxam es un fungicida de reciente introducción al mercado español, y su eficacia viene precedida por diversos estudios sobre enfermedades radiculares (Tsor et al, 2005;Stiles, et al, 2005); y sobre las partes aéreas de la planta por oomicetos patógenos (Rebollar-Alviter, 2005 Bajo condiciones controladas en invernadero, todos los tratamientos mostraron porcentajes de control superiores al 50 %, con promedios de área de lesión bastante bajos. Esto podría deberse al menor tamaño de las plantas, lo cual suele maximizar la eficacia de determinados compuestos.…”