These disease symptoms were caused by insect spread viruses. There is no cure once a virus invades a plant. Viruses are systemic and spread throughout the plant.
Native vegetation dries out forcing insects into irrigated fields.
Winds also carry these insects into our area from neighboring counties and states. Differences from year to year and region to region in aphid migration have been shown to have a great influence on the spread of several aphid-borne plant viruses. Virus can be picked up from infected weeds or vegetables by aphids after only 5 to 10 seconds of probing. Once the virus is acquired, the aphid can immediately transmit the virus to the next plant probed. Most of the aphid borne viruses are carried on or near the mouthparts of the insect and do not multiply in the insect.