- Author: Rachael Freeman Long
- Contributor: Brad Hanson
- Contributor: Kurt Hembree
With generous donations from seed companies and support from the California Dry Bean Advisory Board, we're working on two research projects in garbanzo beans this year. One is focusing on the herbicide Tough 5EC (pyridate) for broadleaf weed control in established garbanzo stands. Currently there are no herbicides registered for use in garbanzos after crop emergence except hooded sprays or directed sprays (not on the crop). Tough by Belchim Crop Protection, is currently being registered for use in garbanzos in other states. We're conducting two trials with Tough in garbanzos; one at the UC West Side Research and Extension Center and the other at UC Davis. Hopefully this will lead to Tough being registered for use on garbanzos in our state because it's needed by the industry. Broadleaf weed control in garbanzos is particularly challenging because of the long growing season and need to control weeds from winter to summer (planting to harvest) especially if there are late rains bringing up weeds, like last spring.
The second trial is with USDA Risk Management. The purpose of this project is to conduct field trials on garbanzo beans under common production systems across the United States, in garbanzo producing regions (including California, Arizona, Washington, and Idaho). The resulting data will be used to determine whether the loss adjustment procedures by the USDA Risk Management Agency (Crop Insurance) for garbanzos should be continued or modified. Two trials are needed for California, one in the Sacramento Valley (UC Davis) and the other in the San Joaquin Valley (West Side) for looking at production in different growing areas. Annual field tests for garbanzo yield and quality are needed for up to three growing seasons over a three-year period. Six garbanzo varieties are being evaluated, with support by USDA Risk Management.
The Insect and Mite sections of the UC IPM Pest Management Guidelines for Dry Beans have been recently revised and updated and are now available online at: UC IPM Dry Beans Pest Management Guidelines.
Authors include UCCE Farm Advisor Rachael Long and UC IPM Advisor Pete Goodell (emeritus). The guidelines include an updated photo page to help identify pests and the damage they cause to dry beans at: Photo Identification.
These guidelines can help with managing pests in your fields. Interested in Lygus bugs and how to control them? Take a look at the guidelines on lygus and see that the thresholds vary by bean class and type. For example, blackeye beans (cowpeas) have different tolerance levels to lygus than lima beans. Some lima bean varieties are more tolerant to lygus than others. Interested in biocontrol of aphids? See photos of natural enemies that prey on aphids at: Photos to identify natural enemies of aphids.
There is also a newly revised table on the relative toxicities of insecticides and miticides to natural enemies and honey bees in dry bean production, found at: Insecticide Toxicities.
This information and much more is available through the newly revised 2018 UC IPM Dry Bean guidelines! This follows the recent revision of diseases and abiotic disorders in dry beans. The weed management section is currently in review and will be available later this year.
- Author: Rachael Freeman Long
- Author: Sarah Light
UC Davis Agronomy Farm
Directions: In the field across from the UC Davis Bee Biology Lab (same place as previous years). From Hwy 113 in Davis, exit on Hutchison Dr. Go west, turn north at the first roundabout, then west at the second roundabout. Continue west on Hutchison Dr for about 1 mile. Turn south on Hopkins Lane (look for a row of olive trees), make your first left, and park under the trees. For questions, contact Rachael Long at 530-666-8143. No RSVP needed.
10:00 Sign in, introductions, updates, Antonia Palkovic, UCD Assistant Specialist
10:05 UC Dry Bean Blog and IPM update, Sarah Light, Farm Advisor, Sutter-Yuba Co.
10:15 Dry bean breeding program, pest and disease resistance, Dr. Paul Gepts, UCD
10:30 Cooperative dry bean nursery, MAGIC Beans, and interspecific crosses for drought tolerance, Dr. Jorge Berny, UCD Post-doc (with Santos Barrera Lemus)
10:55 Cowpea herbicide trial, Dr. Mariano Galla, Farm Advisor Glenn Co.
11:10 Bean seed moisture and quality at harvest, Rachael Long, Farm Advisor Yolo Co.
11:20 Diallel Crossing project, Kimberly Gibson, UCD PhD student
11:35 Lima RIL trial, Stephanie Smolenski Zullo, UCD PhD student
11:50 Caravan to field location 1, near sheep barn
12:05 Heirloom breeding and Mesoamerican Diversity Panel; Drones for high throughput phenotyping, Travis Parker, UCD PhD student
A baby lima bean field in the Sacramento Valley was recently found to be infected with southern blight (Sclerotium rolfsii), a fungal pathogen that's found in many crops. The field was double-cropped with barley and planted late June.
Symptoms and signs: Initial symptoms of southern blight include a yellowing of the foliage with a slight darkening of the stem, just above the soil line. Lesions rapidly develop, girdling the stem, causing sudden and permanent wilt of the plant. The fungus grows downward in the stem, causing rot. White mats of mycelium develop on the stem and nearby soil. In a few days, tan to brown spherical sclerotia (tiny compact masses of hardened fungal mycelium) may appear on the fungal mat. If present, these are a good diagnostic feature of this disease.
Comments on the disease: Southern blight is usually a minor disease of beans and other crops in California. However, high temperatures above 85°F together with high moisture favor the disease. High summertime temperatures combined with a later planting date likely stressed the young lima plants in this field, making them more susceptible to this disease. The best time to plant baby limas in the Sacramento Valley is around the third week in May; for large limas it's early May. Last year was a big year for southern blight in many crops, likely due to late plantings and high heat stressing the plants. This year the disease seems to be a little less common, but is still widely detected on many crops, from Kern to Sutter counties. Detections in the northern counties of the central valley have become more frequent in the last three weeks.
Disease Management: The fungus attacks a wide range of plants and survives for a long time in the soil as sclerotia. Rotations are not considered effective since this pathogen has over 500 hosts. However, it is thought that rotations to corn or small grains for at least 2 years may reduce inoculum; studies are underway to determine whether these rotations are effective. For most crops, southern blight resistant cultivars are not available. However, for vegetable crops such as tomatoes, there are some rootstocks reported to be resistant to southern blight, which are currently under study in field trials in California. Discing and burying plant refuse helps destroy sclerotia.
The Diseases and Abiotic Disorders section of the UC IPM Pest Management Guidelines for Dry Beans have been recently revised and updated and are now available online at UC IPM Dry Beans Pest Management Guidelines.
Authors include Farm Advisors Carol Frate (emeritus) and Rachael Long and UC Davis Professor Paul Gepts. Two new diseases were added, including pythium in established plants and chocolate blotch on limas. The Fusarium wilt sections were also consolidated and new photos were added throughout the guidelines. This includes an updated photo page to compare common diseases and abiotic symptoms to help identify them (Photo Identification).
With the upcoming planting season for dry beans, these guidelines can help with managing diseases in your fields. Worried about southern blight? Yes, beans are susceptible and you'll need to rotate to a non-host crop, including corn or grains for at least 2-years to reduce the inoculum. How about alfalfa mosaic virus? This disease is transmitted by aphids from alfalfa fields, so avoid planting beans adjacent to alfalfa. This information and much more are available through the revised UC IPM Dry Bean guidelines!
The remaining pest management sections, including insect pest and weed management, are in the process of being revised and will be published soon!