IPC Programs
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Curly Top Virus: Background
A brief review of the Program's history and development will aid in understanding the purpose and objectives of the CTVCP.
In the early part of the 20th century, large areas in California and the western United States, were cleared of natural vegetation to plant grain. In succeeding years, price fluctuation led to alternate use and abandonment of much of this land. At the same time, unrestricted grazing of cattle and sheep denuded what was once lush grazing land. The long-range result has been an enormous increase in areas ideal for BLH reproduction where natural vegetation was replaced by mustards, Bassica sp., Russian thistle, Salsola sp. and other annual BLH host plants. A study by Piemeisel and Chamberlain (1936) found well managed grazing land does not produce economically important numbers of BLH.
BLH is a desert insect introduced from the Middle East probably in the late 1800's. Years with below normal precipitation provide favorable environmental conditions for the insect causing BCTV to be devastating to the agricultural economy. The year 1919 was such a year and nearly ended the young sugar beet industry in California. Out of the disaster of 1919 emerged a concerted effort by private, state and federal researchers to design control methods that would minimize BCTV incidences.
After extensive research over a period of several years, it was found that in California, BLH migrated between the valleys and the foothills and at times concentrated on particular host plants (Severin 1933). It was apparent that once breeding grounds and migration patterns were determined, control efforts could be economically carried out with a minimum of expense.
The sugar companies originally carried out control until the realization that a number of other important crops were susceptible to infection. As the other susceptible crops such as tomatoes, melons, and beans increased in acreage, growers found control work becoming futile because of the migratory nature of BLH and the fact that the main breeding grounds were in uncultivated foothill areas under control of disinterested parties. Private growers and industry could not pursue the insect into the breeding grounds where control was most effective.
In 1943, the State of California, Department of Food and Agriculture (CDFA), assumed full responsibility for the control of BLH. In the first years, the annual control budget was only $15,000; however, as the effectiveness and cost of the Program increased, the State Legislature enacted a law requiring grower assessments totaling 65% of the budget. The Program is now 100% funded by individual grower assessments.
Were it not for the Program's effective control of BLH and the support of the affected industries, the state and nation would lose a substantial portion of its tomato, sugar beet, melon, bean, squash, pumpkin, cucumber, pepper and spinach crops valued in excess of $1.2 billion annually.
Contact Information
Program Supervisor: Jim RudigE-mail: jrudig@cdfa.ca.gov
Phone: (916) 654-0768