Beet Curly Top Virus Monthly Report

Taylor HillmanGeneral

Beet leafhopper (BLH) counts remained very low throughout the month of September. Disking and grazing were actively underway as growers received the Program’s treatment waivers. Typically, disking and grazing reduces the available BLH host vegetation and increases the beet leafhopper populations on remaining viable host vegetation.

For Fresno county by the end of September, the Program usually observes a significant increase in BLH populations and begins making arrangements for aerial treatment in October. This year, however, BLH counts were still very low at the end of September with only occasional nymphs observed.


Personnel continued to identify and monitor fallow fields for BLH populations as the Program prepares for the fall spray campaign. • BLH population surveys and host plant surveys were conducted in Mendota. Disking and grazing considerably reduced potential treatment acreage. BLH counts did not increase significantly with the reduction of viable host vegetation. Average BLH counts in this area were 0-1 adult BLH per sweep.

BLH population surveys and host plant surveys were conducted in the Three Rocks and Cantua Creek areas. BLH counts in the Three Rocks area were low with an average of 1-2 adult BLH per sweep. Counts were inconsistent as many of the sweeps produced zero counts. Personnel observed high counts of thrips and aphids. In the Cantua Creek area, BLH counts remained low with an average of 0-1 adult BLH per sweep. There were three areas that were mapped for treatment, but due to disking, these fields were eliminated from treatment maps. 4

BLH population surveys and host plant surveys were conducted in the Firebaugh area. All of the mapped fields were disked and will not be treated. Personnel will continue to monitor any roadsides that develop in this area. Mapped areas such as the staircase, Chevron, North Chevron, and properties south of Mount Whitney were eliminated from treatment maps due to undeveloped BLH host plants.

BLH population surveys and host plant surveys took place in the Five Points area. Disking has eliminated all of the mapped fields from treatment maps. The Coalinga oilfields were surveyed for BLH populations and host plants. Russian thistle was observed along the oil field roads. BLH counts were on average less than 1 adult per sweep. Overall, acreage has been reduced for fall treatment and BLH counts remained very low. No BLH nymphs were observed during surveys in Fresno County in September.