here is a recommendation from New Mexico. It sounds like you should avoid growing any alternate hosts for the beet leafhopper beetle which spreads the disease, but many of us are faced with soil-borne virii which means strict as possible rotations, and possibly even years not growing plants in the nightshade family.
Good luck.
Jay

Here is a link that might be useful: tomato Curly-top virus

This was first year for growing tomatoes in that field in a good many years. I did pull, bag, and haul it off. Never had beets in in that field. I must of pulled about 150. I had good crop okay but hated loosing that many. We use to never have it here. Few that died later needed to be cut off an I put in burn pile. I wonder if freezing will kill it?? This winter has not been down to zero as yet, Last winter was l0 below here. I do want to plant things in different locations. In half acre garden not far to move stuff. Thankyou.

sounds like these buggers can travel far but might have specific overwintering plants you could try and eliminate:

"This leafhopper overwinters on Russian thistle and other plants in weedy or waste areas and rangeland. In late spring the leafhopper migrates long distances to summer host plants, transmitting curly top virus to all susceptible crops. Host plants: sugarbeets, Russian thistle, tomatoes, povertyweed, lambsquarters, beans, filaree, melons, mustard, nightshade, squash."
http://info.ag.uidaho.edu/keys/plates/plate10.htm
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sounds like they move in early in spring. If you are forced to use pesticide, this might be the time:

"Life Cycle: Adults move into fields in early spring and lay eggs on suitable hosts. Eggs hatch, and nymphs develop to adults in 2 to 3 months. There may be multiple generations in Oklahoma.
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Description: The adult is a small wedge-shaped insect, is pale green to yellow in color with darker blotches and approximately 1/8 inch long. The adults have long slender rear legs and will jump or fly away when disturbed. Adults move into fields in early spring and feed on plants, often moving when suitable hosts are not located"
http://www.entoplp.okstate.edu/ddd/insects/beetleafhopper.htm

They came in spring, I set tomatoes May l5th to about end of May. They had gotten started and when this hit, I guess June. Really tiny little fleas. No sugarbeets here in the valley for years as the factory went out. They raised fields of tomatoes here for cannery till cannery went out. Fields behind and side is pasture. My field the rest is nasty grass. I do have some lambsquarters around not a lot. They are good to eat. No Russian thistle . It was said came in from Ariz because of the drought. They hit south of here 2003 about 60/70 miles and was in paper that market grower had put out l0,000 tomatoes and lost 9000 of them. First I had ever heard of it and I have been here 40 years on same place. I have read they don't like shade. I will keep mowing and hoping I guess. When I decided to market garden I did not know about this virus that had came in. I suppose then I could have it worse this year??? I am not really organic but use no sprays and do buy farm store fertlizers. Tomatoes are main thing I sold. Agent stated some type tomatoes were resistent to it but did not list any. I did not find any listed for that. Thanks.