- Author: Rachael Freeman Long
Recently, I received a call about a blackeye bean field in the San Joaquin Valley with a lot of bean pods that did not fill out at the tips (photo). I contacted the UC Riverside blackeye bean breeders Drs. Phil Roberts and Bao Lam Huynh and they shared that this problem is primarily caused by heat, which affects pollen viability and thus fertilization. Here's their response:
It [lack of pod fill] is the typical male-sterility symptom [lack of pollen viability] associated with extreme temperatures (heat or cold). Based on the planting date you gave, we just checked the temperature in Denair, CA [farm location] and noted that it was quite warm (~100) during the flowering time (40-50 days after planting) and recently during the pod filling stage, so heat must have been a main cause. The symptom could also be more severe if water is limiting.
Always be prepared with good irrigation management practices for all crops going into heatwaves, like the one we're having now. The minimum seasonal irrigation needed to produce a blackeye bean crop being managed for full yield from one pod set is 16 to 18 inches. This estimate includes a pre-irrigation of 4-inches, and irrigations of 4-inches when floral buds first appear, and 8 to 10 inches during 5 to 6 weeks of flowering and pod filling. If additional irrigations are needed during the vegetative stage, one could increase the total irrigation requirement to 20 or more inches. Irrigating for a second flush of pods could require an additional 8 to 12 inches of water. Irrigation requirements are further increased by any water required to leach salts or to compensate for an inefficient irrigation system.
Additional water may need to be applied during extreme heat events which drive plant transpiration rates to the limit. Make sure to check the soil moisture in the top 12 to 24 inches of the soil profile and apply additional water if the soil is dry. If in doubt about how much additional water is needed, check the reference evapotranspiration (ETo) and make sure to irrigate to replace at least 120% of your daily ETo in your area. The current (mid to late August) daily ETo in the San Joaquin Valley ranges from 0.25 to 0.30 in/day; make sure your applied irrigation replaces 120% of these values.
More information on growing blackeye beans can be found in the publication, UC ANR Blackeye bean production in California, http://beans.ucanr.edu/files/226601.pdf.
- Author: Rachael Freeman Long
- Author: Sarah LIght
Field trials in the Central Valley with two new varieties of blackeye beans, CB74 and CB77, show impressive resistance to cowpea aphids compared to standard CB46, CB5, and CB50 lines. Four varieties of blackeyes including CB46, CB77, CB74, and CB5 were seeded into a blackeye CB50 field, in single lines on 30-inch beds in the Sacramento Valley in May 2020 (Photo 1). By mid-summer, CB50, CB46, and CB5 were heavily infested with aphids (photo 2), whereas CB74 and CB77 were clean (photo 3).
Cowpea aphids are serious insect pests of blackeyes. These aphids can quickly colonize plants and cause injury by direct feeding and injecting toxic saliva into plants, leading to stunted growth or death of plants. Sticky honeydew released by the aphids can stimulate black mold growth on plants, reducing photosynthesis and plant health. Cowpea aphids also vector a number of viral mosaic diseases that can cause serious losses in many crops. Biological control cannot be relied on because natural enemies often appear when cowpea aphid infestations are already high and causing serious damage. Applying pesticides early in the season prevents cowpea aphid infestations but beneficial insects can be destroyed, leading to outbreaks of other insect pests. Thus, the development of cowpea aphid resistant blackeye lines is an important breakthrough in managing this pest.
Blackeye beans, also known as cowpeas, or blackeye peas in southern states, are an important food crop worldwide. In California, about 8,000 acres are grown annually for dry or canned blackeye bean markets. These new blackeye bean lines are being developed by the UC Riverside blackeye breeding program, led by Drs. Phil Roberts and Bao Lam Huynh, with support from the California Dry Bean Advisory Board and the US AID Feed the Future Innovation Lab for Legume Systems Research (formerly Innovation Lab for Collaborative Research on Grain Legumes). The aphid resistance and other traits have been introgressed into California Blackeye elite backgrounds using natural selection and new molecular markers to expedite the breeding process. Compared to standard varieties, CB74 and CB77 also have more stable yields resulting from heat tolerance, better tolerance to lygus bugs, and equivalent resistance to Fusarium wilt and root-knot nematodes.
Blackeye variety observation trials are being conducted in fields by UCCE Farm Advisors Rachael Long, Sarah Light, and Nick Clark in the Sacramento and San Joaquin Valleys, in collaboration with local farmers. More information on blackeye beans can be found in the Blackeye bean production manual for California, UC ANR 21518, http://beans.ucanr.edu/files/226601.pdf. The lead UC bean breeders hope to have these lines available to farmers within the next few years.
- Author: Rachael Freeman Long
In May, I looked at a lima bean field in the Sacramento Valley that showed poor seedling emergence scattered throughout the field (photo 1). I sent samples to the UC Davis Plant Pathology lab and the main pathogen consistently recovered from the roots was Fusarium root rot, a fungal disease caused by Fusarium solani f. sp. phaseoli. This pathogen is specific to beans and field peas and will not infect other field crops. A few bean seedlings also had Rhizoctonia and Pythium (also fungal pathogens).
Finding Fusarium root rot in a lima bean seedling field was a surprise because this disease is most commonly encountered in established fields during mid- to late season, where it is one of the causes of early maturity ("cut out"). Rhizoctonia and Pythium can cause seedling damping-off in dry beans. However, plants usually outgrow these pathogens, particularly if the seed is treated with a fungicide and conditions favor rapid emergence.
Fusarium solani attacks underground stems and roots of plants. In established plants, early infection is characterized by elongated reddish streaks on the roots. As the disease progresses, these eventually form reddish-brown lesions that will surround the entire root, causing decay. The above ground plant symptoms of affected plants included yellowing, wilting, stunting, and dieback. On seedling plants in the affected field, I observed dieback of the growing point, stems that were a bit swollen, and roots that were brownish and not well developed (Photo 2, diseased roots on left, healthy on right).
Fusarium root rot causes little damage to healthy plants, but under conditions of plant stress due to drought, poor nutrition, or oxygen-stressed, waterlogged soils, Fusarium root rot can cause plant dieback and yield losses, particularly in fields with a long history of bean production. In this particular lima bean field, soil moisture was lost, causing plants to be extremely water stressed. Crop rotation, use of seed treatments, and closely watching field conditions to ensure plants are not stressed will help manage Fusarium root rot. This disease tends to be a problem in fields with a long history of bean production. More information on diseases in dry beans can be found on the newly revised UC IPM guidelines for dry beans.
- 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 California Dry Bean Advisory Board (CDBAB) is requesting applied research proposals for 2020. This commodity-based research request is sponsored by the CA Dry Bean Marketing Order, under the guidance of the CA Department of Food and Agriculture (CDFA). The Board has supported applied research by University programs for many years.
Please review the list of applied research priorities that were developed by the Dry Bean Advisory Board for 2020, and use the attached grant application template. In particular, the board is looking for projects in food science, developing new products for consumers using California beans.
Please share this call for proposals with colleagues and others who might be interested in dry bean research. Proposals are due by Friday, February 7, 2020. Progress reports for projects funded by the dry bean industry in 2019 will also be due Friday, February 7, 2020.
Please submit proposals and final reports electronically to: Rachael Long, email@example.com. The final report will be uploaded to the UC Dry Bean publication database.
If you have any questions, please contact Rachael Long or Michelle Leinfelder-Miles (firstname.lastname@example.org), UC co-liaisons to the CDBAB.