Pryor Laboratory - Focusing on Lettuce Diseases, Mycology, and Alternaria at The University of Arizona School of Plant Sciences, Tucson, Arizona USA Disease management is a principle activity for growers of all types of lettuce. Viral, bacterial, and most importantly, fungal diseases can seriously impact quality and yield.

Lettuce Diseases

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Lettuce is perhaps the most widely consumed vegetable in the US yet its commercial production is extremely restricted. Although limited commercial acreage can be found in states like Colorado, Texas, and Florida, Arizona and California account for more than 95% of the US lettuce production.

Most production is focused on three principle lettuce types:

  1. Crisphead (iceberg)
  2. Romaine
  3. Leaf lettuce

In California, lettuce is ranked as the 5th most important agricultural commodity with a gross value of $1.19 billion (California Agricultural Resources Directory 2008-09). In Arizona, the importance of lettuce as agricultural commodities is even more striking: The lettuce crop is ranked as the highest valued crop commodity with a gross value of $800 million or roughly 30% of the state's agricultural economy (Arizona Agricultural Statistics Service 2008).

Between these states, lettuce production occurs year-round and is primarily grown in three regions depending on the season. In summer, production occurs in the Salinas Valley and other coastal valleys in California, and in fall and spring production occurs in the San Joaquin Valley, CA. In winter, virtually all US production of the 3 lettuce types occurs in the deserts of Arizona and California, and is a critical industry for this region's economic health (California Agricultural Statistics Service. 2006; National Agricultural Statistics Service).