Oxathiapiprolin-based fungicides provide enhanced control of tomato late blight induced by mefenoxam-insensitive Phytophthora infestans

Abstract

Oxathiapiprolin is a new fungicide with extremely high efficacy against oomycete plant pathogens. Solo components oxathiapiprolin (OXPT), chlorothalonil (CHT), azoxystrobin (AZ), mandipropamid (MPD), and mefenoxam (MFX) were compared with each other and with four oxathiapiprolin pre-packed fungicidal mixtures, OXPT+CHT 1+66.7, OXPT+AZ 1+10.3, OXPT+MPD 1+8.3, and OXPT+MFX 1+3 (weight active ingredient ratio), for control efficacy of late blight induced by MFX-insensitive Phytophthora infestans strains in tomato in growth chambers and the field. Mixtures performed better than all partner fungicides alone, except OXPT. Of the four mixtures, OXPT+MFX outperformed, with the highest preventive, curative, translaminar, and systemic efficacies. In the field, OXPT+MFX was superior to other fungicides in controlling late blight epidemics induced by MFX-insensitive isolates. Its deployment in the field will combat the dominating MFX-insensitive isolates, reduce the selection pressure imposed on P. infestans and delay the buildup of subpopulations resistant to oxathiapiprolin.

Novel synergistic fungicidal mixtures of oxathiapiprolin protect sunflower seeds from downy mildew caused by Plasmopara halstedii

“…Oxathiapiprolin mixtures (with azoxystrobin, mandipropamid or mefenoxam) were reported to be highly effective against Phytophthora infestans in tomato [27] and Pseudoperonospora cubensis in cucumber [28]. Interestingly, the mixture of OXPT+mefenoxam was also effective against a mefenoxam-resistant isolates of these pathogens.…”

A new strategy for durable control of late blight in potato by a single soil application of an oxathiapiprolin mixture in early season

“…Our data showed that ZE is a synergistic mixture, namely it provides a significant better disease control than the combined control efficacies of its two components [ 5 , 6 ]. OXPT was proved to act synergistically with mefenoxam in controlling P .…”

“…OXPT was proved to act synergistically with mefenoxam in controlling P . infestans in tomato [ 5 ]. It also acts synergistically with mefenoxam and/or Bion in controlling downy mildew in sunflower [ 4 ].…”

“…These findings provided the conceptual basis for the developing of a new strategy to control late blight in potato by fungicidal soil application. The new fungicidal mixture Zorvec Endavia© by Corteva looked ideal for this purpose as it was proven highly effective when applied as a root treatment to tomato against late blight [ 5 ]. It is composed of two systemic fungicides, oxathiapiprolin and benthiavalicarb (3+7, w/w) that can protect each other from resistance development due to their different modes of action.…”

Downy Mildew of Basil: A New Destructive Disease Worldwide

“…Oxathiapiprolin acts at multiple stages of the pathogen's asexual life cycle at extremely low concentrations and due to translaminar and acropetally systemic movement, it protects treated leaves and new leaves as they emerge and grow. In P. belbahrii, it inhibits sporangia germination and curatively, it stops mycelial growth within the host plant before visible lesions occur and inhibits further lesion expansion, offering protection at 1 and 2 days post-infection [50]. It was found to be effective against mefenoxam-resistant biotypes as well [30].…”