It is the time of the year when Department of Pesticide Regulation (DPR) licenses need to be renewed. I usually have enough continuing education hours to renew, but this year I fell short. A few days ago, I took the new "Pesticide Resistance" online course offered by UC IPM. It is a narrated presentation put together by people with lots of field experience. The course describes the mechanisms of resistance in pathogens, insects, and weeds and discusses ways to manage resistance. It is not specific to rice, but very applicable to the rice system.
The online course is divided into three narrated presentations followed by a final test for each section. This course has been approved for 2 continuing education units in the “Other” category from DPR.
This course is based on a series of workshops held in Davis, Fresno, and at the Kearney Agricultural Research and Extension Center during the spring of 2014 presented by Dr. Doug Gubler (Dept. of Plant Pathology, UC Davis.), Dr. Larry Godfrey (Dept. of Entomology and Nematology, UC Davis), Dr. Beth Grafton-Cardwell (Lindcove Research and Extension Center and UC Riverside), and Dr. Kassim All-Khatib (UC Statewide IPM Program).
Check out the new course at http://www.ipm.ucanr.edu/training/pesticide_resistance.html.
It has been demonstrated that baling rice straw immediately after harvest (called rice strawlage) greatly increases its nutritional value for livestock. Baling at 30 to 40 percent moisture can have the challenge of mold management. With the help of producers, the University of California has been researching rice strawlage during the last two years. Two tours will offer livestock and rice producers a chance to determine if rice strawlage would work in their operations.
Monday, December 15, 2014 12:00-3:30 PM: Tour and hosted lunch at the Parker Ranch in Williams and Sand Creek Ranch in Arbuckle.
Meet at the Shell gas station directly off of the Interstate 5 exit for Highway 20 (on the south west side of the off ramp) at 12:00 noon and we will head to the ranch from there. Discussion with Doug and Judy Parker will cover the multi big bale wrapper process which includes treatments of rice straw with molasses sprayed on at baling, anhydrous ammonia added after wrapping, Storage Mate (proprionic acid) and bacteria inoculants, both applied at baling. Forage quality data providing initial treatment differences will be presented. The tour will then go to Ron LaGrande's Sand Creek operation at Arbuckle to see rice strawlage that was professionally tarped and cattle currently consuming the fall harvest of strawlage. RSVP to Josh Davy at (530) 527-3101 to make sure that he cooks enough hamburgers.
Wednesday, December 17, 2014 9:00-11:00 AM: Tour of the research heifers on rice strawlage at the Sierra Foothill Research and Extension Center at 8279 Scott Forbes Road in Browns Valley.
Results from the first 5 week feeding phase showing animal performance and nutritional evaluation will be covered. The treatments include a control (Quadris only), Storage Mate (proprionic acid), bacteria inoculant and both proprionic acid and bacteria. The 600 pound heifers will be on their second feeding phase and producers can see the different kinds of rice strawlage being consumed. Some are currently consuming 20 pounds of strawlage per day. How to stack and tarp the strawlage will be covered.
Last week I got two calls regarding unusual symptoms starting to appear on ripening rice plants. In both cases, the symptoms were described as medium sized round patches turning reddish or orange. Close inspection of plants showed typical symptoms of K deficiency.
Leaf tips turned reddish and yellow and started to dry out. Stems looked thin and soft. At first, the symptoms were only in small patches, but as plants matured the symptoms extended to the whole field, with some areas showing more symptoms than others.
The critical flag-leaf K value in mature plants is 1.2% (optimal is between 1.5-2%). Leaf samples from asymptomatic parts of the field were at 1.22%, while samples from areas where symptoms were clear were around 1.18%.
I've been seeing K deficiency for several years now. The take-up of K by plants is similar to N, around 150 lbs/a. Most of the K (80%) goes to the straw, while a smaller fraction (20%) goes to the grain. This means that even in fields where straw is incorporated, 20-30 lbs/a of K are removed each year. Over time, K levels in fields thought to be high in K could be reduced substantially. Currently, Bruce Linquist is examining soil K levels and his research shows that K fertilizers may be needed when soil K is below 120 ppm.
The annual Rice Field Day will be Wednesday, August 27, 2014, at the Rice Experiment Station (RES), Biggs, California. You and your associates are cordially invited to join us to observe and discuss research in progress at RES. The Rice Field Day is sponsored by the California Cooperative Rice Research Foundation and University of California with support from many agricultural businesses.
7:30 - 8:30 A.M.: REGISTRATION
- Posters and Demonstrations
8:30 - 9:15 A.M.: GENERAL SESSION
- CCRRF Annual Membership Meeting
- D. Marlin Brandon Rice Research Fellowship
- California Rice Industry Award
9:30 – NOON: FIELD TOURS OF RICE RESEARCH
- Variety Improvement
- Disease Resistance
- Insects and Control
- Weeds and Control
The program will begin at 8:30 a.m. with a General Session that serves as the Annual CCRRF Membership Meeting. Posters and demonstrations will be in place during registration until after lunch. Field tours of research will emphasize progress in rice variety improvement, disease, insect, and weed control. The program will conclude at noon with a complimentary luncheon. The RES is located at 955 Butte City Highway (Hwy. 162), approximately two and one half miles west of Highway 99 north of Biggs, California.
- Author: Luis Espino
- Author: Whitney Brim-DeForest
The Weed program at the Rice Experiment Station (RES) in Biggs conducts herbicide resistance testing for the major rice herbicides used in California. This information helps growers improve their weed control programs if resistance is confirmed, and also helps the rice industry as a whole to keep track of resistance issues.
Sprangletop and smallflower umbrella sedge seeds are the first weed seeds to mature. If you suspect herbicide resistance, bring seeds of these weeds to the RES to be tested, together with the Resistant Weed Testing form available here. Follow the guidelines below to ensure that enough seed of the right species is collected. Later in the year we'll update these guidelines to include ricefield bulrush and watergrass.
General guidelines to collect suspected herbicide resistant weed seeds:
- Don't wait until harvest to collect seed. By then, most weeds have shattered their seeds. If you collect after harvest, you'll probably be collecting seeds from weeds growing around the field that may not be the correct species.
- Collect seed when they are mature and dislodge easily from the seedhead. In general, sprangletop matures the earliest, between rice PI and heading. Early watergrass, barnyardgrass, smallflower umbrella sedge, and ricefield bulrush follow, between rice heading and maturity. Late watergrass is the last weed to mature.
- Collect seed from areas of the field where you are certain the herbicide application in question was appropriate. Avoid field borders, tractor tire tracks, skips or areas where you suspect the herbicide was not sprayed correctly.
- Collect seed from several areas of the field. Usually, when herbicide resistance is the problem, weed growth will be distributed uniformly across the field and not just in one “hot spot”.
- Collect seeds, not seedheads. Take the seedhead and gently shake it inside a paper bag. Seeds that shatter are mature and will readily germinate. If seedheads are collected, seeds might not be mature or might have shattered already.
Collect seeds by shaking the seedheads gently into a paper bag
- Collect enough seed. In order to have conclusive results, several replications of the herbicide resistance testing are needed. When not enough seed is provided, replications may not be possible. For small sized seed weed species such as sprangletop, smallflower or sedge, collect seeds from at least 20 mature seedheads. For barnyardgrass, early and late watergrass, collect from at least 30 mature seedheads.
- Monitor seed development. If seeds are not dislodging during collection, they are probably still immature. Return in 2 or 3 days and try again.
Species specific guidelines:
- Sprangletop seeds shatter easily. Mature seedheads that have shattered their seeds will look dry, while seedheads with immature seeds will look green. Seedheads with mature seeds will have a thicker appearance than empty seedheads.
- There are two sedge species similar to smallflower. Whitemargined flatsedge (Cyperus flavicomus) and ricefield flatsedge (Cyperus iria) grow in field borders and shallow areas in the field. Be careful not to confuse them with smallflower.