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CDFA Plant Health

Curly Top Virus: Introduction

Beet Curly Top Virus (BCTV) is a viral disease of sugar beets, tomatoes, melons, peppers, beans, cucumbers, squash, pumpkins, spinach, vine seed and other commercially important crops, but at times devastates backyard vegetable and flower gardens. The only known vector of BCTV is Circulifer tenellus (Baker), commonly known as the sugar beet leafhopper (BLH).

Control of BLH may take place at various locations throughout the San Joaquin Valley, Salinas Valley, Cuyama Valley, Antelope Valley of northern Los Angeles County, Riverside County and the Imperial Valley including portions of Stanislaus, San Joaquin, Merced, Fresno, Kings, Kern, San Luis Obispo, Monterey, San Benito, Santa Barbara, Los Angeles, Riverside and Imperial Counties.

The size of the control program is dependent on the location, size and distribution of the BLH population. In years with above normal rainfall, BLH populations can be large and widespread but reduced in numbers. In periods of drought (successive years of below normal rainfall), the Beet Curly Top Virus Control Program (BCTVCP) has observed a reduction in rangeland vegetation and a corresponding increase in the BLH populations which increases the need for treatments.

In years with low BLH populations, 40,000 acres or less in western Fresno, Kings, and Kern Counties may require treatment. In years with high BLH populations, 40-60,000 acres may be treated in western Fresno, Kings, and Kern Counties. The BCTVCP has not conducted treatment in Cuyama, Salinas, Riverside or Imperial Valley's in several years due to low BLH populations, host free roadsides, and increasing environmental restrictions. Not all areas require treatment on an annual basis. The mode and probability of treatment varies within the potential treatment area. The BCTVCP has been instrumental in supporting research, which utilizes a Polymerase chain reaction (PCR) testing method to determine the presence of BCTV. This information is reported to growers, PCA's, and industry.

Curly Top Virus in Tomato
Curly Top Virus in Tomato