CDFA: BCTV Report for April 1-18, 2014, Fresno County
- At the end of March, a beet leafhopper (BLH) hatch had taken place in the Tumey Hills area, on the south side of Mannning Avenue. Counts were on average 7-9 2nd and 3rd instar nymphs and 1-3 adult BLH per 10 sweeps.
- There was also a BLH population north of Panoche Creek. Counts were on average 5-7 nymphs and 1-2 adult BLH per 10 sweeps.
- These areas were mapped and aerial treatment began on April 16, 2014.
- During the first week of April, sweep surveys revealed a population of BLH in the Coalinga area. Sweeps were conducted on the Zwangs, Big C, Gujarrals, Zapatos Canyon, and the Coalinga Nose properties. Counts were average, with 1-4 adult BLH and 3-15 2nd and 3rd instar nymphs, per 10 sweeps. Those areas were mapped and waivers were sent. Treatment for those areas is expected to begin on April 21, 2014.
- There was an increase in the number of beet leafhoppers identified on the yellow panel traps about the second week of April. Counts went from 1-4 adult BLH to 40+ adult BLH a few of the traps. Majority of the traps have zero BLH to 1-5.
- The Narbaitz Brothers property was surveyed for BLH populations and host plants. Counts were 4 adult BLH and 12 nymphs per 10 sweeps. The area will be mapped for treatment; however, the vegetation is still fairly green and viable.
- While out conducting surveys, BCTV staff noticed a few fallow fields that had recently been disked or in the process of being disked. Those fallow fields had BLH and were adjacent to tomato fields. Sweeps to confirm the presence of BLH and treating the field if BLH are present, prior to disking, is a good idea. Disking causes the beet leafhoppers to move into nearby tomato fields, potentially causing infection. Majority of the BLH sent for testing have been positive for Beet Curly Top Virus.
- On April 14, 2014 Beet Curly Top Virus Control Program (BCTVCP) staff met with a representative from Brandt Consolidated Inc. They set up a few trial plots to test the efficacy of organic pesticides on the beet leafhopper. Results of this trial will be included in the next report.
- Western Kern County remains very dry and void of substantial winter vegetation.
- Trace amounts of precipitation fell in the hills around Taft and Maricopa. That rain event occurred March 30th -April 1st and allowed scattered filaree to develop. However, with the lack of rain since then, the filaree was stunted and drying out a week later.
- BLH counts were still less than 1 per 10 sweeps.
- Survey in Cuyama Valley produced less than 1 BLH per 10 sweeps. There was sparse filaree on the hillside slopes.
- Survey of the high desert of south eastern Kern County (Antelope Valley and Rosamond) produced average BLH counts. Counts were 1-5 adult BLH and 4-6 nymphs per 10 sweeps. Host vegetation consisted of filaree, London rocket, and young Russian thistle.
- This area is not covered in the Program’s environmental permits and therefore, the BCTV program cannot treat.
- BLH population and host plant vegetation survey was conducted along the Kern County line within the hills west of Interstate 5, to Highway 33 northwards through Devil’s Den Road and into the Kettleman Hills.
- A total of 1,500 sweeps conducted produced zero beet leafhoppers.