- Author: Whitney Brim-DeForest
Date: August 3, 2021
Location: UCCE Sutter-Yuba Office
142A Garden Highway, Yuba City
Free (lunch provided)
9:00–9:30 am Research Updates 2020-2021 (Whitney Brim-DeForest, CE Rice Advisor)
9:30–10:00 am Weedy Rice Survey 2020 (Luis Espino, CE Rice Advisor)
10:00-10:15 am Weedy Rice Identification (Luis Espino, Whitney Brim-DeForest, CE Rice Advisors)
10:15–10:30 am —BREAK— (plants to view)
10:30–10:45 am Non-conventional Path to Pesticide Registration (Roberta Firoved, California Rice Commission)
10:45-11:00 am Preventing Spread of Weedy Rice with Certified Seed (Timothy Blank, California Crop Improvement Association)
11:00-11:15 am Weedy rice emergence under various environmental conditions (Liberty Galvin, PhD Candidate, UC Davis)
11:15 am —LUNCH—
This project is sponsored with funding from the California Rice Commission.
**CE credits (CCA, DPR) pending**
The armyworm monitoring network started a few weeks ago. We have traps on 15 sites across the Sacramento Valley and three sites in the northern San Joaquin Valley. Moth numbers are starting to increase mostly in the northern part of the Sacramento Valley, and small worms have been found at very low densities (see pic below).
The armyworm moth numbers are updated weekly on our armyworm website. This year, we are using AgPestMonitor to show the trap catches per location. On the map, click on a location of interest and a graph showing the number of moths trapped will show up below the map. No registration is required.
To receive a weekly email with a brief description of the armyworm situation and a link to the moth numbers once they are updated, you can subscribe here.
Armyworm larva size found on 18 June 2021, Glenn County.
I got a question from a grower recently about Bakanae. The grower is seeing bakanae affected plants in the same field where the disease was observed last year. The question was if Bakanae can survive in the field. Studies from Asia have shown that resting structures of the Bakanae fungus can survive in the soil for up to four months. However, infested soil is not considered a major source of Bakanae inoculum. There could be some survival of the fungus in the soil, resulting in infections the following season; infection rate would be low. In cases of high infection rates, the disease was most likely transmitted by seed.
Over the years, I have heard from several growers and PCAs that after a dry winter like we just had, the soil profile can be really dry, and it may take longer to flood fields. Additionally, with the increase of area under fallow, water losses to seepage may be larger than usual, also resulting in longer time to flood fields. Longer flood times give TPS a head start over rice seedlings, increasing the risk of TPS injury.
TPS eggs hatch soon after the soil is saturated, and the young TPS are very small and hard to see. TPS grow very fast; sometimes it seems they appear out of nowhere from one day to the next. Monitor for TPS closely, especially if flooding is taking longer than usual.
When to treat: TPS will feed on the young coleoptile and radicle as they emerge from the seed. If you can see TPS while these structures are developing, a treatment is needed. Once seedlings have a well established root and well developed spike, the risk of injury is low. Even large TPS will not injure well established seedlings.
- Pyrethroid insecticides (Warrior, Mustang) work well, but resistance is a concern in some areas.
- Carbaryl (Sevin) is also effective. This insecticide is not used because of concerns of phytotoxicity when propanil is used. Phytotoxicity can occur when propanil is applied 14 days before or after carbaryl. Given the timing of TPS treatment, it is very unlikely that phytotoxicity will occur when propanil is used 30 days later.
- Copper sulfate works well. Because of poor winter rainfall, there is a lot of straw residue in some fields. Straw can bind copper, so do not lower the rate.
- Diflubenzuron (Dimilin) works well when applied to small shrimp. Large shrimp will be affected but may take longer to die.
- Clothianidin (Belay) has worked well in trials.
- Author: Bruce Linquist
With planting season coming up, thinking about appropriate variety selection is key, and one of the first steps towards ensuring a good 2021 crop. Each year the California Rice Research Board funds a statewide variety trial testing program. Here I summarize some of that data.
These trails are on grower managed fields in eight locations around the Sacramento Valley as seen in the map. One major difference in the locations selected is nighttime temperatures in mid to late July when most of the rice is booting. Cold temperatures during this period can cause blanking and lower yields. On the map, locations in red are where cold nighttime temperatures are usually not a problem. These locations are generally north of highway 20. In yellow are locations where growers need to be concerned about low nighttime temperatures; while they may not occur every year, they are common. In blue (South Yolo) is a location where cold temperatures occur almost every year. Importantly, in each of these regions may be micro-climates where temperatures vary from the “average”.
Map showing variety trial locations in the Sacramento Valley. Dot color refers to nighttime temperatures in the last half of July (during booting). Red dots refer show locations where cold nighttime temperatures are not normally a concern for blanking. Yellow dots are those locations where cold temperatures more common, and the blue dot location is where cold temperatures occur almost every year. Temperatures are a concern when they drop below 58oF.
Some varieties are more tolerant of cold than others. Therefore, it is important to select varieties that are suitable for the location you are farming. In the tables below, are yield data from the past five years for each location in the variety trial. Only the main medium grains varieties are shown (M-105, M-206, M-209, M-210 and M-211). This data will allow for a more informed decision when it comes to variety selection.
The warmer locations are north of Hwy 20,in Glenn, Butte and Colusa counties. At these locations, M-211 consistently outperforms the other medium grains by 4 cwt/ac, on average, over the five years and four locations. Among the other varieties shown, there were no consistent differences among them.
In the cooler locations, M-209 performed the worst in general. In the moderately cool locations (yellow dots on the map), M-105 and M-211 both did consistently well. In the coldest location (South Yolo), M 105 performed the best; while M-209 and M-211 performed poorly. Both M-209 and M-211 have similar days to maturity (about 5-7 days later than M-206). This data suggest that M-211 may have a broader adaptability range than M-209 because it appears to be slightly more cold tolerant. However, in the coolest location even M-211 did not perform well.
M-206 versus M-210: M-206 has been the most broadly adaptable variety available. While it may not always be the highest yielder, it generally does well across all locations. M-210 is a new variety which has blast resistance. It is basically M-206 with genes for blast resistance and has similar time to heading. Based on these data M-206 and M-210 have almost identical yields in both the warm and cooler regions.
Thoughts on M-211: As seen in the data provided, M-211 is a tremendously promising variety in terms of yield potential. Furthermore, its sensory qualities are similar to premium grain varieties such as M-401. However, one draw back is that for good milling quality, M-211 needs to be harvested at 20-22% moisture. Harvesting below this moisture can result in low milling quality. Given this, it may not be a variety that is suitable for large acreage planting and this should be tested by growers.