Elusive chemical control of hazelnut kernel mold

Hazelnut kernel mold, caused by many fungal species, is a chronic problem in Pacific Northwest hazelnut production.
Although the incidence of kernel mold increases the longer nuts remain in contact with wet soil, most of the fungi are already in the nut before dropping to the ground.
Covering mold susceptible breeding selections with plastic tents from leaf budbreak through early shoot growth resulted in 74% less kernel mold compared to non-covered trees.
Multiple applications of the broad-spectrum fungicides chlorothalonil (FRAC group M5) or ziram (FRAC group M3) during early shoot growth did not result in less kernel mold.
Multiple applications of propiconazole (FRAC group 3), iprodione (group 2), fenhexamid (group 17), or picoxystrobin (group 11) also did not result in less kernel mold.
Multiple applications of combination products occasionally resulted in significantly less kernel mold.
Using cyprodinil + fludioxonil (groups 9 and 12) resulted in two trials out of three with significantly less kernel mold for an average of 22% control.
The use of fluopyram + pyrimethanil (groups 7 and 9) resulted in two trials out of four with significantly less kernel mold for an average of 25% control.
This level of control is not economically viable.
Research investigating when kernel mold fungi enter nuts would help time applications for better management with fungicides.

X International Congress on Hazelnut

J.W. Pscheidt, S. Cluskey, S. Heckert, J.P. Bassinette

plastic tents, fungicide, postharvest

https://doi.org/10.17660/ActaHortic.2023.1379.51