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.
Leafhoppers transmit viruses in a different manner.
Leafhoppers require a longer feeding period when compared to aphids, but still may acquire the virus in as brief a period as one minute. Once acquired, leafhoppers may be able to transmit viruses throughout their lives. Some viruses multiply within leafhoppers. The indiscriminate probing of aphids and leafhoppers in search for a suitable feeding host can result in the rapid and wide-spread transmission of viruses. Leafhopper-spread virus problems can be reduced in small gardens if the the plants are shaded.