I recently visited a couple of fields in Glenn County with severe armyworm injury. It seems somewhat early to be seeing this type of injury. Application of pyrethroids are not controlling these really high infestations. Fortunately, the really heavy injury is confined to corners and borders of fields.
The challenge with armyworms is to detect them early. Usually, the presence of worms is not noted until severe defoliation is observed. By this time, the worms are large and hard to kill with any insecticide. The fields I visited were about 45 days, and had large worms in them, which means that the infestation probably started at least 2 or 3 weeks ago.
Keep in mind that at this stage, rice can take quite a bit of defoliation before a yield reduction or delay in maturity is observed. If defoliation is higher than 25%, a treatment is warranted. Also, most of the armyworms you observe in the field now will drop off the plants to try to pupate in the soil, but will drown. So they won't be a source of moths for the infestation we see around heading. But the earliness and high pressure of armyworms now is an indication that growers need to be on the alert near the boot and heading stages to try to detect early armyworm infestations at that point. During booting and heading, armyworm injury can cause more damage because they can feed on the flag leaf or directly on the developing panicle.
For more information, visit the Rice IPM Guidelines here.
The 2015 Rice Production Workshop will be held on July 24th, at The Refuge Restaurant, 1501 Butte House Road, Yuba City, CA. The Workshop, organized by University of California Cooperative Extension (UCCE), aims to present current and potential growers, pest control advisers, industry representatives, regulatory agencies and other interested parties with a broad view of the California rice production system and the most up to date research findings.
Information will be presented by UC Davis and UCCE scientists and extension personnel with many years experience working in California rice. Topics include land preparation, varieties, rice growth and development, water management, crop fertility, and pest management.
Prepaid enrollment ($100) is required, and enrollment is limited to 75 people. Please enroll by July 21st to ensure your participation. Seats will be filled on a first-come basis. The registration fee covers lunch and workshop educational materials.
Register online at http://ucanr.edu/2015riceworkshop
For more information, contact Cass Mutters (530-538-7201), Luis Espino (530-458-0578), or Michelle Leinfelder-Miles (209-953-6120), Farm Advisors, UCCE. Remember that space is limited, so register early!
The University of California Cooperative Extension Rice site (UC Rice On-line) has been updated with a new look and a lot of new information which we think you will find useful.
Thanks to support from UC ANR and UC Davis (Department of Plant Science), we have been able to hire a webmaster to develop this site and keep it maintained. On this site you will find rice management guidelines (variety selection, nutrient and pest management, water use, straw management), presentations from recent meetings, production costs, links to the UC Rice Blogs and newsletters, dates and venues for upcoming meetings, contacts, and links to other important rice sites.
We invite you to visit the site and take a look. We want to make sure this site is relevant and meets your needs, so your comments are more than welcome. Just click on the "Click to tell us!" button and leave your thoughts. The address for the site is http://rice.ucanr.edu/; however, if you use the old address you will still be directed to this site.
Planting is starting to pick up now that water allocations are known. One of the first pest problems one is going to find in recently flooded rice fields is tadpole shrimp (TPS). Most of the time, when muddy water or uprooted plants are observed, it means the TPS are large and probably already done quite a bit of damage. Young TPS are hard to detect; because of their size they might not cause mudding of the water. However, look carefully to see if you can spot them. Small TPS, when their shell is about half the size of a rice seed, can injure rice roots as they emerge from the seed; they have a hard time chewing on the coleoptile that emerges first from the seed. Larger TPS, when their shell is about the size of a rice seed, are capable of feeding on the coleoptile and roots, and can dislodge seedlings easily.
Look carefully, there are other bugs that can be confused with small TPS, such as small beetles and clam shrimp. Small TPS look just like fully grown TPS. The very first TPS instars do not look quite like TPS, but those are really hard to spot, and do not feed on rice seedlings anyway. Here's a few images.
TPS first instars next to eggs
Second or third TPS instar
By California Rice Commission
We are in regular contact with the Northern California Water Association and area water managers to assess likely impacts from year four of the drought.
The latest information continues to point towards reductions in available surface water supplies throughout the Sacramento Valley. When the official announcements are made in the coming weeks, the Sacramento River settlement contracts currently point to a 75 percent supply, although there could be a sticking point in this dry year with the timing and amount of water needed for salmon runs in the Sacramento River. Regarding Feather River settlement contracts, signs currently point to a 50 percent water delivery. The Yuba River situation is close to last year, although dry conditions in recent weeks provide a significant challenge for water supplies in Yuba County. A nearly full reservoir is helpful for South Sutter, although the lack of a snowpack will likely keep surface water deliveries at about one acre-foot per acre. The Bureau of Reclamation has announced a zero allocation for surface supplies along the Tehama-Colusa Canal. In many areas, groundwater pumping will increase due to lack of surface supplies.
Hope remains that a few late season storms will improve water storage and the inflow into reservoirs, which in turn could help with water supplies.
We will continue to closely monitor the water outlook and provide frequent updates as more information becomes available. We also continue to impress the need of additional water storage through construction of Sites Reservoir to help in future dry years.