- Author: Sarah L Marsh
- Posted by: Sam Romano
Globally, approximately 570 million small and medium-sized farms need training in various agricultural fields. However, the delivery of agriculture training faces significant challenges. In some areas, the difficulty in obtaining this training has led to people turning to generative artificial intelligence (AI) models such as ChatGPT to ask questions relating to their agricultural production.
The way that ChatGPT and other models work is that the models are trained on vast amounts of data to learn patterns and relationships between words. This enables the models both to understand language in nuanced ways and to generate answers to a wide range of prompts, which means that ChatGPT can become adapted to specific uses and theoretically provide a comprehensive answer to any question. Researchers supported by the CGIAR's Excellence in Agronomy Initiative and the Digital Innovation Initiative studied the accuracy of Chat GPT-provided information and professional advice in response to queries from African farmers. Tzachor et al (2023) found significant inaccuracies that could potentially lead to poor management and crop losses. The problems with the answers ranged from vagueness to inaccuracy.
I became curious as to how accurate ChatGPT was with regards to questions relating to California rice and so conducted an informal test of my own. I asked ChatGPT questions relating to California water-seeded rice management to see how accurate the model was.
When queried about the insecticides that are registered for use in California water-seeded rice to control armyworms, ChatGPT responded with 6 insecticides – only one of which (lambda-cy) is used in CA rice systems. The remaining insecticides “recommended” were not used in California, not used for armyworms, or no longer commercially available.
I also asked ChatGPT “How to manage weedy rice in California water-seeded rice fields.” The model returned several paragraphs, with one problematic paragraph reproduced below:
"Apply herbicides labeled for controlling weedy rice in water-seeded rice fields. Herbicide options may include products containing penoxsulam, propanil, or other active ingredients specifically targeting weedy rice. It's crucial to follow label instructions carefully and use herbicides at the appropriate timing and application rates to maximize effectiveness and minimize off-target effects."
As evidenced by these examples, ChatGPT is responding with answers that are not accurate and should not be taken as recommendations.
- Author: Michelle Leinfelder-Miles
Figure 2 shows monitoring data since 2016 when I began trapping in the Delta. Data are expressed as moths caught per day, averaged across all nine Delta traps. Notice the large arrow indicating the 2024 trend line and how it compares to previous years. While this year appears to be a high-population year, I have noticed variability among the sites where we trap. At one of the three locations, the population peaked at only 9 moths per day, but at the other two locations, the populations peaked at over 40 moths per day. Therefore, it's important to get into the field and look for feeding damage before making a treatment decision.
We reached the peak moth flight last week. Our years of monitoring experience indicates that, if treatment thresholds are met, the optimum time to spray is between one to two weeks after the peak population. So, this would be the week to check your fields for feeding damage and treat as necessary. Please don't hesitate to reach out to me if you have any questions about the IPM guidelines or would like to further discuss this work.
- Author: Deniz Inci
- Author: Kassim Al-Khatib
- Posted by: Samson Romano
Loyant® CA Section 2(ee) Recommendation Bulletin for Control of Cattail in Rice
A recommendation bulletin has been released for florpyrauxifen-benzyl (Loyant® CA, Corteva Agriscience LLC, Indianapolis, IN, USA) to control cattail plants in California rice fields and permitted under FIFRA Section 2(ee). Cattail (Typha latifolia L.) also known as common cattail or broadleaf cattail is a perennial wetland weed that naturally occurs widely in nearly all North America and are often considered undesirable, weedy, or invasive. Common cattail is cosmopolitan weed that can grow up to 10-ft tall under favorable conditions. Common cattail has recently been more problematic in the drill-seeded rice systems of the River Delta in California, where common cattail patches infested rice fields in short time intervals. Therefore, we studied the potential use of newly registered rice herbicide, Loyant® CA, on the control of common cattails when applied at different timing.
Cattail control with Loyant® CA at 1.33 pint/A treated plot at 14 days after herbicide application in 2023.
Two field studies were carried out in 2022–2023 at McDonald Island of Sacramento-San Joaquin River Delta. The 2,400-ha island is bounded on the north by San Joaquin River, on the west by Middle River and Latham Slough, and on the south by Empire Cut. The rice fields were at Stockton, CA. Experiments were conducted as a randomized complete block design, with four replicates, where a 3-m by 3-m rice plot was an experimental unit. Herbicide treatments included Loyant® CA at 1.33 and 2.66 pint/A rates at different cattail growth stages.
All Loyant® CA treatments regardless of application rate or timing resulted in 100% cattail control at 28 days after treatments. None of the treatments caused a significant rice injury. Loyant® CA at 1.33 pint/A controls 100% of up to 3-ft tall. For taller cattails from 3-ft to 6-ft, a sequential application of Loyant® CA within 14-days intervals at 1.33 pint/A may be required. The Section 2(ee) Recommendation Bulletin states the following use directions. For control of cattail in rice fields, apply Loyant® CA at 1.33 pint/A plus 0.5 pint/A MSO as a broadcast spray to cattail plants up to 3-ft tall. Apply in sufficient water to provide good coverage of the cattail without washing spray solution from leaves. A second application may be made if needed with a minimum retreatment interval of 14 days.
/h3>- Author: Michelle Leinfelder-Miles
With funding from the CDFA Healthy Soils Program and CA Rice Research Board, we are evaluating how well different cover crop species establish, provide soil coverage, affect soil carbon and nitrogen dynamics, and/or impact rice yield in subsequent growing seasons. Since rice may be grown over multiple seasons without rotation, cover crops may provide an opportunity to introduce plant diversity, including nitrogen-fixing legumes. Other potential benefits include increasing soil organic matter, reducing nitrogen loss in the winter, reducing nitrogen inputs during the rice season, and improving rice straw decomposition. While evaluating winter cover crops in the rice system is the primary purpose of the trial, the project has relevance for other annual systems where winter cover cropping may be employed.
The trial took place on Staten Island. We planted the cover crops on November 13th by hand-broadcasting seed over 200-ft2 plots and then gently raking it in. We planted 10 single species and two mixes (Tables 1-2). Each treatment was replicated four times, and the graphs below illustrate cover crop stands over the season (Figs. 1-4).
Table 1. Cover crop species and seeding rates. Table 2. Cover crop mixes and seeding rates.
The 2023-24 winter season started off dry, which worked well for cover crop sowing and establishment. The site received approximately 0.2” of rain within a week of planting and about 0.4” by mid-December. The brassicas emerged quickly and started covering the soil after just one month. More frequent storms started in late December, and the project field was adjacent to fields that were winter-flooded. The combination of rain plus seepage from flooded fields meant the project field stayed quite wet after the new year. The data show that the brassicas did not tolerate the wet conditions, and their stands diminished over time. The two vetches and balansa clover started off slowly but had vigorous stands by early spring, despite the wet conditions. While the bell bean did not provide extensive coverage, it survived the wet conditions and was prominent in the plots. We observed that the grass cover crops (i.e. rye, oats) suffered from bird feeding. Based on our experiences and preliminary data, we share the following ‘lessons learned':
- Timing of operations is critical. Growers should strive to plant winter cover crops as early as conditions allow (e.g. early to mid-November). Drill seeding is more effective (i.e. better stand establishment) than flying on and harrowing in seed.
- Stand establishment is impacted by conditions outside the control of the manager (i.e. weather, herbivory). If neighboring fields will be winter-flooded, having drainage ditches between fields will help cover crop growth.
The project will continue through 2025, and in addition to the Delta site, we are also trialing cover crops in Colusa and Butte counties. Please don't hesitate to reach out if you would like to learn more information about this project.
- Author: Whitney B Brim-Deforest
- Posted by: Gale Perez
This year brings several new chemical tools to California rice. With many herbicide-resistant species as well as emerging problematic weed species, the new chemistries are a welcome tool for managing resistance and preventing the selection of resistant biotypes.
Cliffhanger™ (benzobicyclon) was just registered in 2024, and is a new formulation of a previously-registered granular product already widely in use in California rice. Since it can be applied as a foliar product, it expands the timing that benzobicyclon can be applied in the flooded system. It can also be applied as a direct-stream application into the water. It is an HPPD-inhibitor, providing a good option for rotation. It controls sprangletop, ricefield bulrush and smallflower umbrella sedge. Additional tank-mix testing will be occurring this season to determine if it might be a good partner in combination with other herbicides for added late-season watergrass control.
The last product recently registered is Zembu™ (pyraclonil). Zembu™ is a granular formulation of pyraclonil, applied pre-emergence or at day-of-seeding into a flooded field. It provides control of smallflower umbrella sedge and broadleaf weeds, and provides suppression of watergrass. As a PPO-inhibitor, it is a new mode of action for watergrass, as the only other PPO-inhibitor registered in California rice only has activity on sedges. It will provide a great rotational option for growers at the beginning of the season, as well as a great partner product (for added control) with other granular into-the-water products.
As always, the label is the law, so make sure to read and follow the current labels for each of these herbicides (found on the manufacturers website or at the Department of Pesticide Regulation's website). Also check in locally with your Agricultural Commissioner's office for training information and any other county-specific requirements.
With these three new options, as well as the currently-registered products, rice growers in California should have a great suite of tools available this year, both for resistance management as well as to prevent the selection of future resistance. For help planning a weed management program, please reach out to your local Rice Farm Advisor.
Original source: UC Rice Notes newsletter • April 2024