The British Society for Plant Pathology’s journal Plant Pathology will soon publish an article showcasing the highly effective pecan, apple and almond scab control achieved by combining tea tree oil with difenoconazole. It is this innovative combination that drives the preventive, curative and anti-sporulant disease control activity of REGEV hybrid fungicide.

The article is titled “A new highly effective hybrid fungicide containing difenoconazole and tea tree oil for managing scab of apple, pecan and almond trees and as a tool in resistance management.” Co-authored by Dr. Eric Tedford, R&D Manager at Summit Agro USA, it is the culmination of several years of research comparing the active ingredients of REGEV to standard fungicides. The article can be downloaded here.

Beginning with an in vitro study of apple scab, the authors found additive or synergistic interactions between tea tree oil and difenoconazole against the scab pathogen, with the tea tree oil used in REGEV effectively inhibiting mycelial growth of fungal isolates less sensitive to difenoconazole.

The researchers followed up with field trials of apple scab in Israel, pecan scab in Georgia and almond scab in California. Remarkably, they discovered that the added effect of tea tree oil was even greater in the field. The authors suggest this may be due to tea tree oil indirectly activating plants’ natural defense systems.

A truly noteworthy result came from the pecan field trials, where the researchers found that the application of tea tree oil and difenoconzaole completely inhibited the development of pecan scab, showing that it can be a highly effective fungicide for control of that disease.

Additionally, the apple and almond trials demonstrated that the combination of tea tree oil and difenoconazole can effectively control apple scab and almond scab with similar efficacy as standard fungicides.

NOTE: REGEV is not currently labeled for use on apples; an expanded label is expected in the near future.

NOTE: California registration is pending for REGEV.

Always read and follow label directions.