Investigations on the problem of black-leg and tuber rots have revealed an interaction between two pathogenic organisms, a bacterial species and Pythium aphanidermatum.

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In potato variety trials in Central Arizona, Kennebec and Merrimack performed the best as potatoes for chipping. Red varieties Viking, LaRouge, and Red LaSoda yielded about the same as Red Pontiac, the standard for the area; however, Viking had much better appearance and uniformity than the other three reds.

In a fertilizer study in the Queen Creek area, a strong response to nitrogen and phosphorus fertilizers was obtained. Potatoes did not respond to potassium when applied with nitrogen and phosphorus.

Results from experiments with varying levels of nitrogen, phosphorus and potassium have shown that the ratios of 1 - 2.5 - 0 to 1 - 3 - 0 produce the highest yields. While the ratio between nitrogen and phosphorus appears important, the water solubility of the phosphorus seems to be the most important factor in proper fertilization. Proper placement of the fertilizer as well as irrigation and other cultural practices are musts in potato production.

No description available.