Blue Mold Found Growing in Tobacco Field in Lancaster County

Tobacco Blue Mold (Peronospora tabacina) has been found growing on burley tobacco in the Terri Hill area of Lancaster County. Growers need to be aware of the disease and take appropriate action.  Under moist growing conditions, this disease can spread quickly and has the potential to significantly damage both the quality and yield of our local crop. All tobacco fields should be watched closely. Blue mold likes moisture; scouting shady and low lying areas within a field where the disease often starts is especially important. 

The recent hot, dry weather will slow the spread; however, fields should continue to be closely monitored and, in many cases, a protective spray applied. Also, be aware that younger tobacco is more sensitive and susceptible once plants are topped, the leaves thicken, and plants become less susceptible.

Several products are available to choose from including the active ingredients Dimethomorph (brand name: Forum), and Mancozeb (brand names: Dithane, Penncozeb DF, & Manzate Pro-stick). Additional products labeled for use in tobacco include Quadris (azoxystrobin), Actiguard (acibenzolar-S-methyl), and some newer products including Presidio (Fluopicolide), Revus (mandipropamid, and Orondis (oxathiapiprolin).

It is important to keep in mind that most of these products work best as a preventative and protectant; therefore, for best results, they should be applied before the disease is found in your fields. 

Do not apply Forum (Dimethomorph) fungicide alone, the label requires that you combine it with another product such as Mancozeb to prevent the development of resistant strains of blue mold. Also, consider rotating these two with another labeled product for the most effective control. Always read and follow the label of any pesticide. It is recommended that growers who have questions regarding control and prevention check with their local buying representative.