Tom F. Cummings

Potato Late Blight in the Columbia Basin: An Economic Analysis of the 1995 Epidemic

The cost of managing late blight in potatoes during a severe epidemic caused by new, aggressive strains of Phytophthora infestans in the Columbia Basin of Washington and Oregon in 1995 was documented. The mean number of fungicide applications per field varied from 5.1 to 6.3 for early- and midseason potatoes, and from 8.2 to 12.3 for late-season potatoes in the northern and southern Columbia Basin, respectively. In 1994, a year when late blight was not severe, the mean number of fungicide applications per field made to early- and midseason potatoes was 2.0; whereas late-season potatoes received a mean of 2.5 applications. The mean per acre cost of individual fungicides applied varied from

Effect of Seed-Tuber Generation, Soilborne Inoculum, and Azoxystrobin Application on Development of Potato Black Dot Caused by Colletotrichum coccodes

4.90 for copper hydroxide to

Resistance to Root Galling Caused by the Powdery Scab Pathogen Spongospora subterranea in Potato

36.00 for propamocarb + chlorothalonil. Total per acre expenses (application costs plus fungicide material) for protecting the crop from late blight during 1995 ranged from

Postinfection Activity of Selected Late Blight Fungicides

106.77 to

Disease Potential of Soil- and Tuberborne Inocula of Colletotrichum coccodes and Black Dot Severity on Potato

110.08 for early and midseason potatoes in different regions of the Columbia Basin and from

Field Resistance to Potato Stem Colonization by the Black Dot Pathogen Colletotrichum coccodes

149.30 to

Evaluation of mint mutants, hybrids, and fertile clones for resistance to Verticillium dahliae.

226.75 for lateseason potatoes in the northern and southern Columbia Basin, respectively. Approximately 28% of the crop was chemically desiccated before harvest as a disease management practice for the first time in 1995, resulting in an additional mean cost of

Influence of Timing of Harvest in Relation to Haulm Killing and Planting Date on Potato Tuber Rot Caused by Phytophthora infestans

34.48/acre or

Genetic Stability in Potato Germplasm for Resistance to Root Galling Caused by the Pathogen Spongospora subterranea

1.3 million for the region. Harvested yields were 4 to 6% less than in 1994. The total cost of managing late blight in the Columbia Basin in 1995 is estimated to have approached

Comparison of deposition patterns in two programs for applying protectant fungicides to potato stems and leaves for the control of late blight (Phytophthora infestans)

30 million.