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!
The UC Agriculture and Natural Resources Agricultural Issues Center (UC ANR) has released two new studies on the costs and returns of producing garbanzo beans (chickpeas), in the Sacramento and San Joaquin Valleys. Although acreage is relatively small (about 10,000 acres), garbanzos are an important crop because California growers produce the large, cream-colored seed for the canning industry. Canned garbanzos are often used for garnishes for salads.
The studies estimate the cost of producing garbanzo beans on 200 acres as part of a row crop rotation, using sub-surface drip irrigation. A 3-row bed tillage implement shallowly chisels, tills and re-shapes the beds, avoiding disturbance of the buried drip tape left in place. Planting of treated seed (for fungal and seedling diseases, Ascochyta rabiei, Rhizoctonia and Pythium), into residual soil moisture occurs in December. Seeding rates for the garbanzo beans are 85 pounds per acre.
Input and reviews were provided by UC ANR Cooperative Extension Farm Advisors and other agricultural associates. Current costs for the garbanzo bean crop were used, including material inputs, cash and non-cash overhead. A ranging analysis table shows profits over a range of prices and yields. Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs, and the whole farm annual equipment, investment and business overhead costs.
The importance of these studies right now is that they are currently being used to help secure USDA crop insurance for garbanzo production, expected in 2020.
The new studies are titled: “Sample Costs to Produce Garbanzo Beans (Chickpeas), in the Sacramento and Northern San Joaquin Valleys – 2018”
“Sample Costs to Produce Garbanzo Beans (Chickpeas), in the Southern San Joaquin Valley – 2018
These studies and other sample cost of production studies for many commodities are available through UC ANR They can be downloaded from the UC Davis Department of Agricultural and Resource Economics website at http://coststudies.ucdavis.edu.
For additional information or an explanation of the calculations used in the studies, contact the Agricultural Issues Center at (530) 752-4651 or the local UCCE Farm Advisors; Sarah Light, firstname.lastname@example.org, Rachael Long, email@example.com, Michelle Leinfelder-Miles, firstname.lastname@example.org, or Nicholas E. Clark, email@example.com.
- Author: Rachael Freeman Long
- Author: Sarah Light
Ascochyta blight (Ascochyta rabiei, Didymella rabiei) was recently found in volunteer garbanzos in the Sacramento Valley, so keep an eye out for this disease in your production fields and be sure to control all volunteer garbs on your farm (yes, these volunteers are now long gone).
Ascochyta is a serious fungal disease of garbanzos that can kill seedlings and significantly reduce yields and seed quality in older infected plants. There are no other known crop or weed hosts. This disease is favored by cool, rainy weather and only infects the above ground parts of the plants. Early symptoms include circular light brown lesions on the plants that cause stems to weaken and break. Over time small, black, raised spots (pycnidia-like spores) will form concentric rings in the lesions. Developing seeds can become infected and, if used for seed, can lead to early infections in the next crop. The fungus survives outside or inside the seed.
The fungus survives only on crop debris (and seed), not in soil. It does not produce resting spores to survive in soil. How long the debris can persist before decomposing depends on the climatic conditions. It lasts longer in drier conditions. During wet weather, spores are released and infect plants. Moderate temperatures (68º to 77ºF) and wet weather are optimal conditions for severe disease development.
- Plant Ascochyta tolerant varieties.
- Keep stands healthy, as disease resistance can break down in stressed fields.
- Always use certified, disease free seed.
- Thoroughly incorporate infested garbanzo residue to hasten decomposition and to minimize the possibility of spore production and dissemination.
- Rotate to other crops for two or three years. That will eliminate inoculum in the soil because the fungus will not survive in the absence of a garbanzo host.
- Avoid early plantings (November and early December) since they result in large plants and a thick canopy, which provides ideal conditions conducive to disease development.
- Consider wide row and plant spacing. This increases ventilation between plants, reducing favorable conditions for plant infection.
- Use treated seed to avoid introducing the fungus to the field, such as Mertect 340-F, thiabendazole.
- Foliar applications of fungicides limit the rate of disease spread. Apply fungicides at first sign of disease and reapply according to the label if rainy weather is forecasted. Thorough coverage of the plant canopy is important. Options include Quadris (azoxystrobin), Endura (boscalid), or Headline (pyraclostrobin).
Our cool, wet conditions are favoring white mold (sclerotinia) in garbanzo beans this year. This disease is characterized by a white fungal growth that attacks the above ground plant parts, often near the soil line for garbanzos. The affected tissue dries quickly and bleaches to a pale tan or almost white color. Black sclerotia formed on the stem of dying plants are often visible. These are masses of fungi compacted to form small, dark pellets that range in size from 1-8 mm (about the tip of a pencil to a pencil-size eraser) that allow the fungus to survive in adverse conditions (e.g. hot, dry weather). When the main stem is affected near the soil line, the entire plant wilts and dies; lesser infections will show dead branches, causing yellow flagging in the field.
The black sclerotia pellets formed in the mold can survive many years in the soil and re-infect crops. The development of white mold is greatly influenced by prevailing weather conditions and certain agronomic practices such as late extensive irrigation, plant density, and plant growth characteristics, which are all closely linked with the life cycle of the pathogen. A thick dense plant growth provides a micro climate of cooler temperatures and high moisture beneath the plant canopy where conditions are favorable for disease.
The best control focuses on cultural practices to prevent the disease from developing in the field. This includes higher beds that keep lower plant parts and tops of the bed drier, wider row spacing to increase air movement in the canopy to keep the foliage drier, and planting garbanzo beans later (December through early February) rather than early (November) since the extra growing time can result in heavy canopies that increase humidity and cause infestations late winter/early spring (favorable disease conditions, 68oF-77oF). Crop rotation generally does not prevent white mold infection due to the broad host range of the pathogen.
Fungicides are available for white mold control, but getting good coverage and control is difficult because the inoculum is in the soil and the disease is often deep in the plant canopy. Fungicides would have to be applied when plants are smaller to provide good coverage and protection from this disease. For a list of fungicides available for white mold control in in garbanzos, see http://ipm.ucanr.edu/PMG/r52100111.html.
- Author: Michelle Leinfelder-Miles
I later visited the field with the PCA in order to assess the situation for myself. The disease appeared to be most apparent in one corner of the field where the water tends to sit a little longer. (This is a furrow irrigated field that has had beans for several consecutive years.) Moist or humid conditions favor white mold, as do heavy canopies. The leaves were showing some unusual brown lesions, and some plants had white mycelium growing on the pods (Figure 2). The most detrimental symptom that we observed, however, was complete infection of the stem at the soil line, causing the tissue to dry up (Figure 3). In this case, the upper canopy looked ok, but I am uncertain, perhaps doubtful that the pods will fill on these plants.
What we can hope is that the disease won't appear on more plants in the next two weeks because there are really no management strategies at this stage in the game. The grower needs to think about how to manage this disease in the future, and rotating out of beans to a non-host crop (like small grains or corn) is probably a good strategy.
If wider row spacing is an option, this can also improve air movement in the canopy, which makes conditions less favorable for white mold. Monitoring for the disease should begin at flowering, which is also the best time to apply fungicides (like thiophanate methyl or boscalid) because the plants are small enough for the treatment to penetrate into the canopy.