Beet Curly Top Virus Report

Report for March/April, 2016

Program-wide notice

Beet leafhopper (BLH) counts were minimal at the beginning of March in most areas. There were some locations with populations beginning to increase, with average counts of 5-7 adults and some nymphs per 10 sweeps. The majority of the peppergrass dried up in February, which encouraged the spring BLH generation to hatch. Filaree and Plantago also became stressed by the end of February and more BLH began to hatch. The heavy rainfall in March didn’t seem to impact the BLH as much as anticipated. The rain then allowed additional host plants to germinate and kept most of the mature host plants viable longer for the BLH to feed and reproduce on. BLH populations significantly increased toward the end of March, with average counts of 10-15 adults and 10-20 nymphs per sweep. In some locations the nymphs averaged 40-50+ per 10
The Beet Curly Top Virus Control Program (BCTVCP) began making arrangements for treatment the week of March 21st. The spring treatment campaign started on March 25th in Kern County, working north to Fresno County. Upon surveying the Kettleman Hills March 26th and 27th, the Program made arrangements to utilize two planes for more effective coverage since the vegetation was drying quickly. The Program split field crew personnel to allow for treatment in Kern County to take place concurrently with treatment conducted in Kings and Fresno Counties. Treatment concluded on April 7, 2016. There were a few days that treatment was impeded by high winds. Portions of some treatment fields were avoided due to bee boxes within a mile of the treatment boundaries. Every effort was taken to contact bee keepers to have the boxes moved, however, most did not

· A total of 64,450 acres were treated during the spray campaign. A treatment

map is included at the end of the report.

The Program will continue to monitor fallow fields and roadside host plants for BLH populations. It is important to have fallow fields surveyed for BLH and, when possible, treat infested fields with an insecticide prior to any disking or
The overall incidence of virus in BLH samples submitted for analysis have been approximately 50% positive. The overall incidence of virus in host plant samples submitted have been approximately 30%

Fresno County

Beet leafhopper surveys were ongoing during March in all the historical “hot spots”. Peppergrass was the first host plant to dry up due to a warm, dry February and produced a BLH hatch. Filaree and Plantago remained viable and allowed for a second hatch to occur in March. In most of the locations surveyed, the majority of the hillsides were very overgrown with winter
On March 30th, the Program began treatment in Fresno County, starting in the

southern most fields, from Zapatos Canyon working north to Panoche Creek.

Panoche and Tumey Hills had an abundance of peppergrass, filaree, and Plantago.

The peppergrass began to stress early. BLH counts were 8-10 per 10 sweeps in early March and increased to an average of 35-40 adults and nymphs per 10 sweeps during the spray campaign.

The Chevron and North Chevron properties had low BLH counts at the beginning of

March. Counts were 0-1 nymphs per 10 sweeps. The properties were overgrown with winter grasses. Host plants were filaree, peppergrass and Plantago. The peppergrass dried quickly. BLH counts the week of treatment had increased slightly with 6-7 adults and nymphs per 10 sweeps, and were inconsistent throughout the property. This area was not treated during the treatment campaign due to low BLH counts.

A portion of the non-treatable property was granted permission for treatment. It is known as the “Gyp-Pitts” and is south of Manning Avenue, north of Kamm Avenue, west of Interstate 5. BLH counts were on average 45 adult and nymphs per 10 sweeps during the spray
The non-treatable property from Kamm Avenue south to Cantua Creek, west of Interstate 5 was granted permission for treatment. BLH counts were moderate at the beginning of March but increased to an average of 40 adult and nymphs per 10 sweeps during the spray
The Big “C” and Zapatos Canyon had BLH counts on average of 3-5 adults per 10 sweeps and increased to 10-17 adult and nymphs per 10 sweeps. Some locations within each field had high counts of 20-40 BLH per 10
Warthan Canyon had good host plant coverage and 3-5 adult BLH per 10 sweeps in early March. There were some locations within Warthan Canyon that had 50+ BLH counts prior to treatment. The Program was not able to treat the south eastern portion of Warthan Canyon due to bee

· A total of 25,920 acres were treated in Fresno County.

Post treatment BLH averages were low with an average of a 92%
Program personnel will continue to monitor roadside host vegetation and fallow fields for BLH
Thirty-nine (39) host plant samples were collected and sent to the lab for virus analysis. Eight (8) were positive for curly top
Forty-seven (47) BLH samples were collected and sent to the lab for virus

Twenty-four (24) were positive for curly top virus. There were ten (10) samples not tested and results will be reported next month.

Kern County

Beet leafhopper surveys were ongoing during March with the south western region of Kern County in the hills, slopes, and valleys of Taft, Maricopa, Dustin Acres, Derby Acres, Valley Acres, Fellows, McKittrick, Buttonwillow, and Lokern monitored closely due to an abundance of host plants and their history of having high counts of
BLH counts in Lake Webb Flats, Elk Hills, Buena Vista Hills, Western Minerals, Gardner Field Road, the flats along Lokern Road west of Buttonwillow, the Water Bank, 36 Hills, Kitty Care, and Elkhorn averaged 0-2 adults and 0-1 nymphs per 10 sweeps at the beginning of the month. The first BLH nymphs were observed on March 1st. Host plants such as filaree, peppergrass, and Plantago were beginning to stress after a warm, dry
By the third week of March, BLH nymph counts began to increase in all areas surveyed. Average counts for nymphs were 18-20+ per 10 sweeps in some locations such as 36 Hills, Elk Hills, Kitty Care, and the Buena
The Program began making arrangements for treatment to begin the week of March 21st. Treatment for Kern County began March 25th and was completed April 3rd.
The area west of Buttonwillow off Lokern Road was treated in areas that the

Program had access to and that did not indicate conservation or endangered species. After those areas had been treated, the Program was notified that permission for treatment should not have been granted and in the future, the area will not be allowed to be treated. That property had been designated as conservation land by Chevron and USFWS. There were very high BLH counts in the area at time of treatment, with counts as high as 35 adult BLH and 20+ nymphs per 10 sweeps.

· A total of 28,380 acres were treated in Kern County.

Post treatment BLH averages were low with an average of a 90%
Due to recent rainfall on some of the hills that were dried in early April, some host plants have
Program personnel will continue to monitor roadside host vegetation and fallow

fields for BLH populations. Some ground rig treatment was conducted in fallow fields after the spray campaign ended. There was a fallow field that should be treated, however, the Program was notified it is conservation land and is not treatable. This property is off South Lake Road, township 32, range 25, section 19.

Fifty-seven (57) host plant samples were collected and sent for virus testing. Twenty-six (26) were positive for curly top
Twenty-one (21) BLH samples were obtained and sent for virus Eleven

(11) were positive for curly top virus.

Kings County

Treatment began in the Kettleman Hills north of Highway 41 on March 28th, 2016. The hills north of Highway 41 had an abundance of filaree and peppergrass with patches of Plantago. BLH counts in early March were 7-10 adults and 5-7 nymphs per 10 sweeps. BLH increased to an average of 50 BLH adults and nymphs per 10 sweeps during the spray campaign. There was an area on the north east side of the field that was avoided due to bees within an almond
The Kettleman Hills south of Highway 41 was treated on March 29th. BLH counts

were 5-7 adults and nymphs in early March and increased to an average of 35 adults and nymphs per 10 sweeps. Host plants were the same as the north Kettleman Hills.

Surveys took place along Utica Avenue from Interstate 5 east to 10th

Fallow fields along Utica Avenue were inspected for BLH and host plants. Primarily there was London rocket and Russian thistle. BLH counts were minimal and inconsistent with 1-3 adult BLH and 3-4 nymphs per 10 sweeps.

· A total of 10,150 acres were treated in Kings County.

Post treatment BLH averages were low with an average of a 90%
Program personnel will continue to monitor roadside host vegetation and fallow fields for BLH
Five (5) host plant samples were collected and sent for virus analysis. Five (5) were

negative for curly top virus.

Six (6) BLH sample was collected and sent for virus analysis. Two (2) samples were positive for curly top virus. One sample has not been tested and will be reported next

Merced County

Surveys were conducted near the San Luis Reservoir. Vegetation was predominantly winter grasses mixed with some filaree. There were no BLH adults or nymphs observed on the hillsides in March. There were a lot of sharpshooters and non-target leafhoppers. There were no bees observed in sweep
Surveys in late April were conducted along roadsides. BLH counts were
One (1) BLH sample was collected and sent for virus analysis. It has not been tested and results will be reported next
Personnel will continue to monitor BLH populations and collect both host plant and

BLH samples for virus analysis.

San Joaquin County

BLH and host plant surveys were conducted west of Highway 580 and south of Corral Hollow Road. Vegetation was thick and was predominately winter grasses with a mix of filaree and peppergrass. Only trace amounts of Plantago was observed. Only two BLH nymphs per 10 sweeps were observed in sweep
One (1) host plant sample was collected and sent for virus analysis. It was negative for curly top
One (1) BLH sample was obtained and sent for virus It was positive for

curly top virus.

Personnel will continue to monitor BLH populations and collect both host plant and BLH samples for virus

Stanislaus County

Surveys took place on the Simon Newman Conservation property. BLH host and non-host vegetation was thick and widespread. There was some peppergrass already showing signs of stress. There were no BLH adults or nymphs observed in early March. There were a lot of sharpshooters and non-target
Two (2) BLH samples were collected in late April and sent for virus Results are pending and will be reported next month.
Personnel will continue to monitor BLH populations and collect both host plant and BLH samples for virus analysis