Black Shank and Granville Wilt Resistant Varieties

2014 Resistance Tables (PDF | 162KB)

Blue Mold Forecast - (link to North American Plant Disease Forecast Center)

Black Shank

Black shank is caused by a fungal pathogen that lives in the soil and attacks tobacco roots and stalks. Widespread continuous planting of flue-cured tobacco cultivars possessing single-gene (designated Ph) resistance to black shank enabled tobacco producers to dramatically reduce application of soil fungicides beginning in 1996. However, this has led to the breakdown in the efficacy of this resistance by shifting the distribution of the pathogen populations from host race 0 to race 1.

Tobacco Cyst Nematode

Tobacco cyst nematodes (TCN) are microscopic worms that live in the soil and feed on tobacco roots. TCN populations are thought to be decreasing in some fields due to the widespread planting of flue-cured cultivars with the Ph gene. Nematicide tests are conducted annually to evaluate their influence on nematode reproduction and tobacco yield and quality. TCN resistant cultivars are also evaluated for their potential.

Tobacco Mosaic Virus

Tobacco mosaic virus (TMV) is the most widely distributed virus that affects tobacco crops. TMV can be spread by contaminated clippings mowers in the greenhouse, from tobacco roots and stalks remaining in the soil from previous crops, from weed hosts such as horsenettle and ground cherry, and from contaminated objects and surfaces such as trays and sheets, and from manufactured tobacco products. Mosaic resistant cultivars can reduce damage and may help reduce residual virus in infested fields. If a TMV-resistant cultivar is planted, the entire field should be planted to the resistant cultivar.