- Author: Michelle Leinfelder-Miles
We can use trap counts and Growing Degree Day modelling (i.e. a temperature measure of time) to determine whether and when to treat fields. UC IPM provides treatment guidelines that include damage assessment and signs of the worms in the field. Earlier this year, Methoxyfenozide (Intrepid 2F) received full registration, so we now have a new tool in the toolbox when treatment is necessary.
The monitoring that I do in the Delta is part of a larger effort that is spearheaded by my colleague, Luis Espino, rice advisor in Butte and Glenn counties. Luis writes a weekly blog to provide real-time information on trap counts to help growers and consultants with scouting and decision making. In his blog announcements, he will link to an interactive mapping tool called Ag Pest Monitoring, where you can view counts across trapping locations. Please consider subscribing to Luis Espino's blog, but don't hesitate to reach out to me if you'd like to discuss what is happening in the Delta.
Good luck this season, and I hope to see you in the field!
- Author: Michelle Leinfelder-Miles
University of California Cooperative Extension and the UC Davis Department of Agricultural and Resource Economics collaborate on cost of production studies for commodities grown in California. The purpose of the studies is to provide sample costs for producing commodities and expected returns, based on current production practices and economic conditions.
We have recently published a study for Sacramento-San Joaquin Delta rice production, available here. The study is based on a hypothetical 1,100 acre farm, where 1,000 acres are annually planted to rice, and it details the unique production conditions and practices of the Delta. The study assumes the farm's soil has high organic matter and employs drill-seeding (Figure 1). This soil type and planting practice differs from Sacramento Valley conditions, where rice is water-seeded onto mineral soils with high clay content. Nutrient and pest management practices also differ between the regions; hence, the study will more accurately reflect the costs associated with Delta rice cultivation. The study details the operating costs associated with Delta practices and the total costs for farm operation and management. A ranging analysis presents potential returns based on typical yields and recent crop pricing.
The study also details the costs associated with converting land from other annual crops to rice, including levee construction and land leveling. Conversion costs are significant and can inhibit adoption of rice cultivation because they may take years to recuperate.
We thank the growers who contributed their time and expertise to informing this study. Please don't hesitate to reach out to me if you have any comments or questions.
- Author: Michelle Leinfelder-Miles
The annual UC Davis Alfalfa and Small Grains Field Day will take place on Thursday, May 11, 2023 at the Department of Plant Sciences Field Facility (2400 Hutchison Drive, Davis, CA 95616). Registration opens at 7:30am, and the wagons leave for the field at 8am. The event is free and open to the public, but registration is requested. Lunch is sponsored by the CA Crop Improvement Association, and continuing education credits will be available. Directions are as follows:
The field day is located on Hutchison Drive, just west of Davis. Take the Hwy. 113 exit north from I-80, or Hwy. 113 south from Woodland. Exit west on Hutchison Drive. Take a right at the first roundabout, a left at the second roundabout, and the field headquarters is about ¼ mile down in a clump of trees and buildings on the left.
The agenda is as follows:
8:10 Alfalfa Breeding Efforts at UC Davis - Charlie Brummer
8:20 Choosing Varieties for Pest Resistance - Dan Putnam
8:30 IPM and Importance of Management of Insect Resistance in Alfalfa - Ian Grettenberger
8:40 Test your Weed IQ - Identification of Weeds - Brad Hanson
8:55 Use of Compost to Improve Soils in Alfalfa - Michelle Leinfelder-Miles
9:05 Sorghum Projects for Forage and Biofuels - Jackie Atim
9:15 Improving Agronomic and Grain Quality Traits in Sorghum under Well-watered and Drought Conditions - Christine Diepenbrock
9:35 Flood or Drought? Alfalfa Strategies for Coping with California's Future - Dan Putnam
9:45 Teff as an Alternative Summer Forage Crop - Dan Putnam
9:50 Overhead Irrigation Technologies for Improved Efficiency - Isaya Kisekka
10:05 Updates from UC Davis Small Grains Breeding Program - Jorge Dubcovsky
10:20 Effects of Genotype and Environment on Productivity and Quality in California Malting Barley - Maany Ramanan
10:30 California Grain Foundation and Research on Food Use of Triticale - George Fohner
10:40 Small Grain Research Update from Tulelake - Rob Wilson
10:55 Evaluating Digestate and Hydrolysate as Alternative N Sources in Small Grains - Valentina Roel
11:05 Biosolids as a N Fertilizer Source in California Small Grains - Konrad Mathesius
11:15 Helping Farms in the Central Coast get N Scavenging Credits for Cereal Cover Crops - Eric Brennan
11:25 DIY In-field Plant Tissue Tests to Determine N Sufficiency in Wheat - Karla Estrada
11:30 Updates on Small Grain Research and Production in the Central Valley - Mark Lundy
11:45 Tour Small Grain Variety Trials
12:10 Lunch
1:20 Small Grain Breeding Field Day
- Author: Michelle Leinfelder-Miles
UC Cooperative Extension collaborates with the California Rice Experiment Station to evaluate commercial varieties and advanced breeding lines. The San Joaquin County Delta location was one of seven locations in the 2022 statewide trial. The Delta is a test site for very-early maturing varieties because it has cooler growing conditions than other rice growing regions of the state. The trial was drill-seeded on April 19th at a rate of 150 lb/acre and harvested on October 2nd. Plot size was 150 ft2, and varieties were replicated four times. Table 1 (below) shows variety results at the Delta location (advanced breeding lines omitted). Among the entries, M-206 is the most commonly planted variety in the Delta and across the state. It has good agronomic characteristics and consistent quality across different harvest moistures. Some Delta growers also plant M-105, which is a very-early variety that has yielded well in Delta trials but may be slightly more susceptible to rice blast disease than M-206. Among the newer varieties, M-210 is early maturing, blast resistant, and may be a good option for the Delta. Variety M-211 is not as well adapted to cooler environments, like the Delta, and quality appears to decrease below 18 percent harvest moisture. One of the advanced breeding lines, which is not shown in the table below, but which yielded better the M-206 in the Delta trial, will become CH-203. For a comparison of yield across all seven trial locations, please see the recent edition of the UCCE Sutter-Yuba newsletter. Special thanks go to our grower cooperators for hosting the variety trials. If you have questions about the Delta trial or about Delta rice production, please don't hesitate to reach out to me.
UCCE will host two upcoming meetings for the rice industry:
1. The 2023 Rice Production Workshop will be held March 15-16 at the Lundberg Family Farms facility in Richvale (5311 Midway, Richvale, 95974). This is an in-depth workshop that covers the principles and practices of rice production in California. The workshop is directed toward folks who are new to growing rice or serving the rice industry. The program is available here. Registration is limited, so please sign up early. The registration fee covers the workshop manual and lunches both days. We have applied for DPR, CCA, and CDFA nitrogen management continuing education credits.
2. The Cover Crops in Rice Field Demonstration Day will be held March 27 from 10:00am to 12:00pm. The field day will be held at the corner of Hwy 45 and White Road, Colusa, 95932 (38.969148, -121.866552). At the field day, we will discuss the CDFA Healthy Soils Program, and attendees can walk through the cover crop trial. No registration is required. We have applied for CCA and CDFA nitrogen management continuing education credits. The agenda is attached below.
Table 1. 2022 San Joaquin County rice variety trial results.
2023 Rice Cover Crop Meeting Agenda
- Author: Luis Espino
- Author: Michelle Leinfelder-Miles
Thankfully, 2022 was not a bad year for rice diseases, but it is worth mentioning a couple of observations. Overall, there was very little blast this year. In the Sacramento Valley, UCCE did not diagnose any blast in the field but did receive a couple reports of it after harvest.
Blast was identified in the San Joaquin Delta in a field of M-206. Blast in the Delta is a rare occurrence because of the cooler temperatures in the area. In fact, UCCE has only identified blast there once before. Back in 2010, one Delta field of variety M-104 was confirmed as infected with blast. Year 2010 was a bad blast year, with many fields affected across the Sacramento Valley.
Blast can infect seed, it can survive in crop residue, and its spores can move long distances. Additionally, weeds are suspected to be alternate hosts. All these factors can be sources of inoculum that can result in a blast epidemic. In seed, the mycelium of the blast fungus has been found colonizing the internal surfaces of the lemma and palea (the seed coat), the pericarp and endosperm. Unfortunately, treating the seed with bleach for bakanae does not help with the blast fungus. In general, seed is not considered a major source of blast inoculum in California. Until a few years ago, certified seed used to be tested for blast. The requirement for this test was stopped in 2018 because results were always negative. However, if during the certification inspection a seed field or a portion of a seed field is identified as infected with blast, that field or portion can be rejected. Research has shown that under water seeding, there is no seed to seedling blast transmission. Seedling transmission has been documented from infected seeds planted in soil or infected seeds that remain on the soil surface. Given that most of the acreage in California is water seeded, the risk of infected seed producing blast inoculum is low. However, in the Delta, where rice is drill seeded, the risk is higher.
While disease was low overall, we did come across another fungus that is relatively new to us. A report of possible blast in M-211 was received in late summer form a PCA in Butte County. Inspection of the field revealed only a few plants affected with symptoms that looked like collar blast (Fig. 1). Samples were submitted to the UC Davis Plant Pathology Lab, and the identification came back as Nigrospora oryzae, which causes “panicle branch rot”. Interestingly, this fungus was also identified in three Delta fields (Fig. 2), one of which also had blast. Prior to 2022, we identified this fungus from samples with symptoms similar to stem rot in 2017 and 2021, and in a field with heavy discoloration of rice panicles in 2021 (Fig. 3).
The Compendium of Rice Diseases and Pests (2018, APS Press) indicates that Nigrospora species are common and occur in senescing plant tissue, and may cause lesions in plants weakened by diseases, insects, or poor nutrition. This fungus is reported to cause an ear blight and blackening of rice kernels. These descriptions fit the symptoms mentioned above. Additionally, Nigrospora oryzae has recently been identified as the causal agent of panicle branch rot disease in China (Liu et al., 2021, Plant Disease 105 (9): 2724), a disease very similar to blast, with reported yield and quality losses.
It is not clear if this fungus is developing in tissues that are already affected by stem rot or blast, or if it is causing disease symptoms. In any case, given the information in the literature and the low frequency of observation, at this point the identification of Nigrospora oryzae from California rice samples is not cause for concern, but it does warrant vigilance from the industry. Please reach out to us in the future if you see symptoms similar to these so that we can gather more information about this fungus.