Integration of bio-fungicides in Botrytis disease management programs on field-grown ornamental geophytes

Management of Botrytis diseases on ornamental geophytes relies on a combination of cultural practices and the use of fungicide treatments. On crops like tulips and lilies, multiple applications of fungicides are often applied by growers to limit the development of Botrytis. The high number of applications used in these systems is costly for growers, increases the risk of fungicide resistance problems, and raises concerns about potential environmental impacts associated with grower disease management programs. Recently there has been increasing interest, particularly among small growers who sell cut flowers to local markets, to increase the use of bio-fungicides to control Botrytis on field-grown geophytes. Previous trials to evaluate the effectiveness of new reduced-risk fungicides and bio-fungicides in controlling Botrytis elliptica on lilies showed that F91101 (extract of Lupinus), Proud 3 (thyme oil), MBI110 (Bacillus amyloliquifaciens strain F727), Prestop WP (Gliocladium catenulatum strain J1446), and Regalia (extract of Reynoutria sachalinensis) were either ineffective or provided variable levels of controls. From 2013-2015, a number of trials were conducted relating to the management of Botrytis tulipae on field-grown tulips in the US Pacific Northwest (PNW). Several reduced-risk fungicides consistently provided excellent disease control. The bio-fungicides Proud 3 and MBI110 were ineffective, while applications of F91101 provided intermediate levels of disease control. Trials are currently underway on tulips and lilies to determine if F91101 can be integrated into a traditional fungicide disease management program on tulips and lilies.