Not available – first paragraph follows: Tehama County is California's northernmost area of sugarbeet production. Sugar-beets previously were planted in the early spring and harvested in the fall of the same year. In 1978, however, it was decided to overwinter the crop in this area for harvest the following spring. This decision was based on improving the efficiency of the nearby processing plant by increasing the length of its run and on the 10-mile isolation of the Tehama County beet-growing area from other beet-growing areas. This isolation was considered sufficient to prevent the transfer of aphid-borne viruses from the overwintered beets to the early-spring-planted beets to the south.