California Fruit and Vegetable

Tag: UCCE

  • Farming Tips for Enduring Historic Drought in Northern CA

    It has been heart breaking to seeing wheat and alfalfa fields dry up the last few weeks.  The recent hot temperatures caused many fields to wither, while placing greater irrigation needs on the few crops being irrigated with well water.   It’s the driest year I have experienced in my 10 years in the Klamath Basin!

    Several people asked me about strategies moving forward this summer and what yields they can expect from crops with limited irrigation.  I do not know all the answers, but I tried to highlight some of my past experiences from research and farming below.  Please keep in mind every field situation is unique and one strategy rarely works in all situations.  I want to commend the farming community for being resilient in a terrible situation.  I also want to thank all those that have spent countless hours trying to improve the water situation today and in the future.

    Irrigation tips

    Almost all fields started this year with very little residual soil moisture.  At IREC, not a drop of water flowed through our tile drains this winter and spring.  Darrin and I noticed the first irrigation on many fields did not even refill the soil profile especially when irrigating during strong winds.  This made 2021 even more difficult as winter precipitation did not refill the soil profile naturally.  As a result, many alfalfa and grain fields are starting to show unusual patterns from drought such as wind strips and tall growth under sprinkler drains.  If you can water fields with well water, it is very important to check the sprinkler heads to make sure they are the proper size, check water pressure on the ends of irrigation lines, and make sure your irrigation is providing good coverage.  Offset your wheel-lines one roll the next irrigation in fields with wind strips.    As many of us are irrigating out of drains, it is important to make sure you have adequate sprinkler pressure.  If you do not have adequate pressure, you need to reduce the size of your sprinkler heads and extend the duration of the irrigation set (16 hrs vs 12 hrs) or run less lines.

    Many alfalfa producers are in the position to harvest 1st cutting and cannot water for the next couple weeks until the hay is picked up.  In this situation, producers should consolidate limited water on their most productive fields.  Once an alfalfa field wilts from drought it will typically go dormant.  This is good as the alfalfa will likely survive until next year, but it also means the alfalfa is resistant to green-up and grow again in mid-summer.  As such, I’d recommend using limited water to irrigate healthy fields instead of trying to stretch it across all fields especially those fields that are already wilted with poor growth going into first cutting.

    Potato producers will need to apply long sets to refill the soil profile when the potatoes emerge.  Most field have very little residual soil moisture, and it is important to avoid drought stress during vegetation growth and tuber initiation to maximize tuber set and tuber quality.  I advise potato growers to check soil moisture frequently throughout the potato rooting zone to make sure water reached the bottom of the hill and is uniform throughout the field.

    Most farmers should be done irrigating winter grain, and I see a few producers irrigating spring grain.   If you decide to irrigate spring grain, I recommend irrigating the crop fully until you run out of your water allocation instead of trying to space irrigation throughout the summer.  Irrigating spring grain fully to meet the crop water demand during tillering and elongation will maximize forage yields, and once wheat and barley fields show signs of drought stress, they will start to head producing low forage and grain yields.

    Fertilization tips

    Producers that decide to irrigate grain and grass fields should make sure to apply adequate nitrogen.  The cost of the fertilizer will easily pay for itself with high forage prices and nitrogen can double grass forage yields compared to leaving fields unfertilized.  Granular nitrogen fertilizer applied as a topdress (over the top of the crop) should be watered into the soil with at least an inch of water within a few days of application to prevent volatility losses.  Don’t fertilize fields if you do not have adequate water to irrigate crop!

    Pest Management tips

    2021 is shaping up to be a very bad pest year.  We have already witnessed problems with blue aphid and weevils in alfalfa, and I am starting to see armyworms in grain and alfalfa.  We had a very high population of seedcorn maggot in onions as all the maggot flies seemed to congregate in the few irrigated fields throughout the basin.  Thrip populations are also very high.  Onion producers should start scouting for thrips earlier than normal and be ready to start insecticide applications if thrip numbers build on young plants.  Potato producers should expect higher than normal pest populations.  Aphid populations are high, and many insects will be moving into potato fields after alfalfa and grain harvest.  Mites may be more problematic than normal as fields are receiving less overhead irrigation and we have a lot of dust in the air.  I hope the dry weather will help reduce foliar crop diseases, but the hot temperatures and stagnant water sources may make my prediction incorrect.   Potato and onion farmers need to apply frequent irrigation to keep up with crop water use, so make sure to scout for foliar diseases and try to avoid keeping leaf surfaces wet for extended periods. — By Rob Wilson, UCCE Farm Advisor, ANR Intermountain Research & Extension Center

  • Conventional Melon Weed Management in the Sacramento Valley

    Sutter County grows between 300 and 800 acres of fresh-market honeydew, mixed melon and cantaloupe each year. The fields vary between furrow and drip irrigation, with many fields in the Sutter Basin only receiving a pre-irrigation.

    Because of the rapid growth of melons, they are competitive with weeds and one cultivation may be sufficient to control weed issues. The growing habits of melons reduce the need for herbicides, which is fortunate since the availability of registered and effective herbicides is limited.

    Generally, in Sutter County, the field is tilled, pre-irrigated, worked again, and melons are planted into moisture. When weed pressure is high, a hand-hoeing crew comes in and cultivates. Since many of the conventional fields in the northern region receive little water, herbicides may not be as effective since they do not work well without water. If water is available, herbicides like Prefar and Curbit may be used.

    Bensulide (Prefar) can be applied before planting and incorporated shallowly or as a preemergent herbicide under sprinkler irrigation. It is used to control small-seeded annual grasses, pigweed and purslane. Remember to always check the label and consider plantback restrictions, especially if following with corn or sorghum. A layby application of ethalfuralin (Curbit) may also be used after thinning when melon plants are young (4-5 leaf stage) to control late germinating weeds.

    In 2017, I received a farm call about a grassy weed in a honeydew field that the pest control adviser had never seen in a melon field during his long career. He applied sethoxydim (Poast) twice and the grass (johnsongrass) kept coming back. When grasses are moisture stressed, sethoxydim can be less effective, which makes sense in a melon field receiving little irrigation. — By Amber Vinchesi-Vahl, Area Vegetable Crops Advisor, UCCE Colusa County

    References

    UC IPM, Pest Management Guidelines-Cucurbits, Integrated Weed Management.  http://ipm.ucanr.edu/PMG/r116700111.html

  • New UCCE IPM advisor in Imperial County

    Apurba Barman joined UC Cooperative Extension as low desert integrated pest management advisor on Jan. 11, 2021. He will be headquartered at the UCCE Imperial County office, which adjoins the UC Desert Research and Extension Center in Holtville.

    “I am very excited for my new role as an IPM advisor based in Southern California and for the opportunity to serve one of the most important vegetable production regions in the state,” Barman said. “The diversity and intensity of crop production in this region demand targeted research to solve pest management issues and effective extension programs to reach diverse clientele. I feel prepared for this job with my experience and passion to serve the community.”

    Barman earned a bachelor’s degree at Assam Agricultural University in India, and master’s degrees in Indiana and at Texas Tech University, Lubbock. In 2011, he completed a doctorate degree at Texas A&M University in College Station, where he developed a research program to understand the extent of damage and management of thrips in the Texas High Plains region.

    Barman comes to UC Cooperative Extension from the University of Georgia, where he led a whitefly monitoring and management progress across cropping systems in the southern region the state.

    Barman can be reached at (209) 285-9810 and akbarman@ucanr.edu. His Twitter handle is @Ento_Barman.

  • New Avocado Study Outlines Costs & Returns of High-Density Plantings

    Growers considering producing avocados in San Diego County with high-density plantings now have help to determine the economic feasibility. A new study on the costs and returns of establishing and producing avocados in San Diego County has been released by UC Agriculture and Natural Resources’ Cooperative Extension, UC Agricultural Issues Center and the UC Davis Department of Agricultural and Resource Economics.

    A worker prunes weak tree branches to improve sunlight penetration in a high-density avocado orchard.

    Avocado has been one of the prominent crops produced in Southern California since the early 1950s. California avocado production peaked in 1987-88 with about 76,300 acres. San Diego had been the leading producer accounting for about 60% of the acreage.

    “Beginning in the early 1980s, there has been a continuous decline of acreage and production of avocados in San Diego County, said Etaferahu Takele, UC Cooperative Extension farm management advisor for Southern California and co-author of the study. “This is mainly because of the expansion of urban development that has increased the cost of producing the crop and especially the cost of water, reaching to up to $2,000 per acre feet in 2020.”

    The same amount of water was sufficient for the high-density avocados as it was for the traditional planting (Photo by Gary Bender).

    High-density planting increases profitability of avocado production given there is suitable land for high-density orchard development.

    Although the cost of water accounts for 44% of the total production cost in the high-density planting, the water cost is proportionally less than in the conventional planting of 145 trees per acre when distributed over a higher yield per acre, the authors write.

    Their cost analysis describes production operations for avocados planted at 430 trees per acre, with an expected life span of 40 years. The study includes a detailed summary of costs and returns and a profitability analysis of gross margin, economic profit and a break-even ranging analysis table, which shows profits over a range of prices and yields. Growers can identify their gross margin and returns to management based on their yield and prices received.

    UC Cooperative Extension advisor Gary Bender checks sunlight penetration in a high-density avocado orchard.

    Input and reviews were provided by a UC Cooperative Extension farm advisor and grower cooperators in San Diego County. The authors describe the assumptions used to identify current costs for avocado establishment and production, material inputs, cash and non-cash overhead.

    The new study, “Avocado Establishment and Production Costs and Profitability Analysis in High Density Planting, San Diego County-2020,” can be downloaded for free from the UC Davis Department of Agricultural and Resource Economics website at http://coststudies.ucdavis.edu and UCCE Riverside County Farm Management website at https://ucanr.edu/sites/Farm_Management/Costs_and_Returns. Sample cost of production studies for many other commodities are also available on the websites.

    For additional information or an explanation of the calculations used in the studies, refer to the “Assumptions” section of the report or contact Takele at (951) 683-6491 Ext. 243 or ettakele@ucanr.edu or Donald Stewart at the UC Agricultural Issues Center at destewart@ucdavis.edu. — By Pamela Kan-Rice, UCANR

  • UCCE Vegetable Crop Guru Burt Hoyle Passes

    Burton John Hoyle passed away in McKinleyville on Nov. 9, 2020, just weeks from reaching his 101st birthday.

    Burton (Burt) was born in Saranac Lake, NY, in 1919. He grew up in the Jamestown, New York, area. He graduated from high school in 1938 and spent several years pursuing odd jobs before starting college in 1941. He did not serve in WWII because of a childhood injury. In 1944, he graduated from the University of New Hampshire with a degree in horticulture.

    There was a war going on and jobs were scarce, so Burt applied to graduate schools. The University of California, Davis, wrote that classes were closed, but they did have a job opening in vegetable crops. After Burt got to Davis, classes soon resumed with the end of the war, and he graduated in 1946 with an M.S. in vegetable crops. That same year he also married True Dolson.

    As 1946 drew to a close, Burt took a job with the University of California Cooperative Extension system to pioneer the Agricultural Experimental Field Station in Tulelake, now known as the Intermountain Research and Extension Center (IREC). From 1947-1965 Burt’s research and work shaped many of the crops still grown in the Tulelake Basin today including potatoes, barley, peppermint and strawberries, according to a letter Rob Wilson, current Intermountain REC director, wrote to Burt for his 100th birthday.

    However, Burt’s big winner was the introduction of horseradish as a cash crop. In 1983, he was featured in an NBC nationally broadcast news show as the “Godfather of Horseradish.”

    Hoyle and wife True at Intermountain REC in 1947.

    In 1965, Burt relocated to Fresno where he worked as a vegetable crops specialist at the University of California’s West Side Station in Five Points. Two major publications from his many projects were A Guide to Commercial Vegetable Production (1970), Curley Top Identification Handbook (1977) [Curly top is a plant disease]. His work on “aggresizing” [a process for making the soil optimum for successful seed growth], for which he received a patent, led to widespread recognition in the agricultural research community.

    Burt and True were active in the First Presbyterian Church in Fresno. One of the ways they lived out their faith was by opening their home to many foreign students. Over a period of more than 10 years, they hosted a number of Chinese, African and Middle Eastern students. Their involvement with these students was a ministry as they helped them with practical matters, and also spent hours counseling them about their lives.

    Burt retired from UC ANR in 1983 and he and True relocated to Humboldt County. During the 1980s Burt enjoyed Rotary, his friends and taking pictures of beautiful Humboldt scenery. He traveled up and down the coast shooting pictures; then with his scanner and Adobe Photoshop, Burt explored the creative expressions of the visual, displaying some of his photos at local art shows. He and True were very involved with the Arcata Presbyterian Church and participated in many community activities. Burt and True also engaged in developing housing on land in Arcata, which True had inherited from her family.

    True Dolson Hoyle passed away in 2005, and Burt married MaryAlice Comstock in 2006. MaryAlice preceded Burt in death on Sept. 16, 2020. She was 91 years old.

    Burt was blessed by health, mental clarity and mobility throughout his life. He was known for his brilliant thinking and ever-present curiosity. During his final years, he was working on a book on statistical thinking and re-analyzing data from his field crop experiments he had collected more than 50 years ago. Even in his last days, his caretakers commented on his intellectual curiosity, his smile and sense of humor.

    He is survived by his three children, Joe and Glenn Hoyle and Pamela Lund, three grandchildren, Julie McGuffey, Karin Ballstadt and Dennis Hoyle, and 10 great-grandchildren.

    His three children remember the significant impact Burt had on their lives, but more importantly his love and concern for them, their families, and for the large number of people whom Burt influenced. — By Glenn C. Hoyle

    To read more about Hoyle’s work at IREC, see this 1964 California Agriculture article //ucanr.edu/sites/anrstaff/files/340045.pdf.

  • Farmer’s Inspiration Leads to Squash Donation to Central CA Food Bank

    West Side farmer John Diener had flash of inspiration. Why not plant butternut squash?

    Diener is a long-time research cooperator with UC Cooperative Extension specialist Jeff Mitchell, who has studied innovative, sustainable farming practices for 21 years at the UC West Side Research and Extension Center under four different treatments: no-till plus cover crops, no-till with no cover crops, conventionally tilled with cover crops and conventionally tilled without cover crops.

    Since it was established, the research plots have been managed in an annual rotation of cotton, processing tomatoes and, more recently, sorghum, garbanzo beans and melons. When trying to decide what crop to bring into the rotation for 2020, Diener thought of butternut squash, a relatively large, thick-skinned squash that has little pest and disease problems and a long-shelf life. He suggested the squash could be donated to the Central California Food Bank and made available to local families in time for Thanksgiving and Christmas.

    CCFB provides food to more than 220 agencies in Fresno, Madera, Kings, Kern and Tulare counties, serving more than 280,000 people each month. Last year, CCFB supplied over 40 million pounds of food in all.

    Diener arranged for butternut squash seed to be donated by David Bodine of AgSeeds. He generously paid for several days of labor to harvest the crop. Diener contacted family friend Joan Minasian, who serves on the Food Bank board, to make arrangements for delivering 101 bins of squash – more than 70,000 pounds – to the food bank’s Fresno distribution center.

    The front entrance to the Central California Food Bank in Fresno

    “The Central Valley Food Bank is working on diversifying the food we offer in meal boxes and distributions,” Minasian said. “I’m really proud of the food bank’s efforts to increase healthy foods. We’re always looking for farmers to partner with.”

    Butternut squash, a winter squash, has a 90-day shelf life without refrigeration. It is grown in the summer; the name is derived from the fact that the mature vegetable can be stored for winter eating.

    In addition to supporting farmers with research and advice, UC Cooperative Extension offers nutrition education programs to low-income Californians. Deepa Srivastava – UCCE nutrition, family and consumer sciences advisor for Kings and Tulare counties – manages two programs that extend information to families on healthy eating, food safety, food resource management, gardening, physical activity and youth engagement.

    Srivastava said butternut squash is a nutritious addition to family diets. The vegetable is a good source of vitamin A and vitamin C, and also supplies vitamin B-6, protein, fiber, magnesium, potassium and iron.

    The squash’s buff exterior protects golden flesh that is nutty and sweet. It can be baked, boiled or grilled whole or chopped. Cooked squash can be pureed for soup or baby food, added to casseroles, pies, salads and stuffing. The cooked flesh adds beautiful fall color to everyday meals or holiday spreads.

    Roasted butternut squash

    One easy way to prepare butternut squash is roasting in the oven. Preheat the oven at 350 degrees. Carefully cut the squash in half and scrape out seeds and strings with a spoon. Place cut side up in an oven-safe pan, then brush the flesh lightly with olive oil. Season to taste with salt, pepper, cayenne pepper, fresh or dried herbs and spices. Bake for one hour, or until it can be easily pierced with a fork. — By Jeannette Warnert, UCANR Communications Specialist

  • Pythium & INSV Infections in Salinas Lettuce Fields

    In 2020 the incidence of Pythium wilt (caused by Pythium uncinulatum) of lettuce has increased in severity and in the number of affected fields. Pythium infections in lettuce fields have been observed frequently, but not always, occurring with INSV infection. As a result, there has been confusion distinguishing between these two diseases and the role of each of them in causing the problems in fields. In this blog we will discuss these two diseases and explain from our current state of knowledge about the disease dynamics occurring in affected fields.

     INSV has been a production problem on lettuce in the Salinas and surrounding valleys for a number of years and in 2020 it continues to be a serious production issue. Pythium wilt of lettuce is a relatively new problem and was first discussed in a blog entry in October 2015 by Steve Koike (https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=19327 ). However, in 2019 and 2020 we have seen an increase in the number of acres affected by Pythium wilt as well as the severity within fields. Given that Pythium is a relatively new problem and the extent of the problem suddenly increased, some growers and PCAs are confronting this problem for the first time. To add to the confusion, at times INSV and Pythium infections are occurring together on the same plants which has caused confusion and has led to much speculation about the role of each disease in the observed damage.

    Symptoms of INSV

    Issues with INSV infections on head and leaf lettuce types are not a new occurrence in the Salinas Valley and many growers and PCAs are familiar with the symptoms and the patterns of infection in the field, especially on romaine. In general, INSV on lettuce causes characteristic patterns of chlorosis and necrosis on the inner leaves of the plant, as well as significant stunting (Photo 1). However, INSV can cause significant necrosis and lesions on and at the base of the ribs of lettuce plants (Photo 2). It should be mentioned that Tomato Bushy stunt virus (TBSV) can cause symptoms that can be confused with INSV and Pythium wilt; however, lettuce dieback symptoms are always seen on the outer, older leaves and the TBSV pathogen is commonly restricted to low-lying areas along the river. In addition, head lettuce varieties and some romaine varieties are resistant to this virus. When in doubt, it is important to have a sample tested. That said, INSV is the overwhelming virus issue facing growers and PCAs in 2020.

    Moderate to severe symptoms of INSV on ribs of romaine.

    Viral vs. Fungal Symptoms

    One important detail about lettuce plants infected with only INSV is that they do not exhibit wilting of the outer leaves of the plant or show root rot or root discoloration. This is important to note because in 2019 and 2020 we have visited many fields where the plants exhibit symptoms of INSV and have wilting older leaves. In these situations,  the roots and crowns of the plants should be examined for symptoms caused by soilborne pathogens such as the wilt pathogens (Fusarium and Verticillium), Sclerotinia, and Pythium. Fusarium and Verticillium do not cause rot on the fine roots or crown. However, they always cause characteristic vascular discoloration in the taproot and crown of the plant. Distinguishing these two pathogens without a laboratory evaluation is not advised, but in general, Fusarium occurs earlier in the crop cycle and often causes a red-to-brown discoloration internally along the taproot and at the base of the crown. Symptoms of Verticillium on the above ground parts of head lettuce become obvious close to harvest; the taproot and crown tissue of infected plants have dark brown-to-black discolorations. Plants with INSV can also be infected with Sclerotinia (S. minor) which is recognized by the characteristic rotting of the crown tissue of the plant and the presence of white, cottony growth and small blacksclerotia (Photo 3). Plants infected with Sclerotinia easily break off at the soil line when you gently tug on them. However, if the plants do not break off at the soil line and do not show any rot on the crown tissue but do exhibit rot on the fine feeder roots or lower down on the taproot, then Pythium wilt is suspected and can be verified by laboratory evaluation.

    Sclerotinia infection on lettuce. Note that it infects and rots crown tissue of the plant.

    Biology and Symptoms of Pythium

    Pythium wilt is caused by the water mold, Pythium uncinulatum. It infects lettuce roots with swimming spores (zoospores) that move to the roots within the water film in the soil. Additionally, it produces a second type of spore (oospore) that allows the pathogen to survive in the soil in the absence of a host plant. Previous studies have reported P. uncinulatum is almost exclusively a pathogen of lettuce and does not cause disease on other vegetable crops. However, it remains unknown whether other crops may contribute to a build-up of the pathogen in the soil. Affected plants will exhibit rotting of the fine and tap roots (Photo 4) and frequently dark discoloration of the inner core of the main root (Photo 5). Symptoms of the above ground parts of the plant include stunting, yellowing, and wilting of the outer leaves and eventual death (Photo 6). Sometimes the plants have a characteristic look where the younger leaves remain upright, but the older leaves are totally wilted down to the soil (Photo 7). This year, we frequently observed fields where plants are infected with Pythium wilt but are also infected with INSV. These mixed infections are confusing and make it more difficult to distinguish what is the cause of the damage. In our experience to date, plants that show foliar symptoms of INSV and that have wilting older leaves are typically infected with both INSV and, in many cases, Pythium wilt. It should be mentioned that we have also observed plants infected with INSV as well as Fusarium.

    Pythium wilt infection of fine lettuce roots.
    Pythium wilt infection on lettuce taproot.
    Mini romaine infected with Pythium wilt.
    Romaine infected with INSV and Pythium wilt. Note that the older leaves are wilted and lay on the ground.

    The distribution of Pythium wilt in a lettuce field can be variable. Earlier in the summer, fields with this disease typically were infected along the upper or lower ends of the field indicating that the disease may be responding to irrigation or drainage issues. It is possible that there may be a difference in the level of infection between sprinkler and drip irrigated fields, but we cannot say anything definitive at this time. The disease has been found from King City to Castroville. There is a significant difference in the susceptibility of varieties. In fields with multiple leaf type lettuce, we have observed significant differences in susceptibility among varieties with red types being less susceptible (Photo 8). Recently, there have been severe losses in some fields. It is not clear as of this writing, but it is possible that the incidences occurred in response to the heat spells. It is likely that diseased plants were not able to withstand the weather stress due to damaged roots or that extra water applied to address the heat may have stimulated the development of Pythium wilt. Another observation we have made is that at times Pythium mostly infects the fine roots higher up on the root system and in other situations it is more severe at the bottom of the taproot (Photo 9) which may indicate disease initiated farther down on the root system. Given that the disease needs a period of soil saturation for the swimming spores to travel to the roots, issues with soil preparation, drainage and irrigation management may affect the severity of the disease.

    Difference in susceptibility of two green leaf lettuces and a green leaf and red leaf lettuce to Pythium.
    Plant with Pythium wilt infection lower down on the tap root (note the plant on the top with healthy fine roots higher up and infected tip of the tap root).

    Research Efforts

    Daniel Hasegawa is conducting research on the epidemiology and spread of thrips and INSV. JP Dundore Arias is working on a project with the California Leafy Greens Research Board monitoring the occurrence of Pythium wilt in the Salinas Valley. He is also characterizing isolates of this disease to better understand the organism and will be conducting preliminary evaluations of the sensitivity of the organism to fungicides. Given the rapid onset of severe damage of Pythium and the continued severity of INSV, we are trying to better understand these diseases and how they may interact. We are interested in receiving samples of Pythium wilt. Please contact Richard (rifsmith@ucdavis.edu) or JP (jdundorearias@csumb.edu) to submit samples.

    Authors: Richard Smith, JP Dundore Arias, Daniel Hasegawa and Steve Koike

    Farm Advisor, UCCE Monterey; Plant Pathology Professor, Cal State Monterey Bay; Research Entomologist, USDA ARS; Director, TriCal Diagnostics, respectively

  • Managing Root-Knot Nematodes in Crop Rotations

    A question came up about managing root-knot nematodes in processing tomato and lima bean rotations.  Root-knot nematodes are tiny worm-like soil dwelling pests that cause root galling on plant roots, resulting in significant yield and quality losses. Symptoms of severe root-knot infestations include patches of chlorotic, stunted, necrotic, or wilted plants. These nematodes also predispose plants to other soilborne pathogens that cause root rot and wilt diseases. For example, a bean variety resistant to infection by the Fusarium wilt pathogen will become susceptible to this disease if infected with root-knot nematodes.

    What is the link between nematodes in tomatoes and limas? Dr. Phil Roberts, Nematologist at UC Riverside shared the following response:

    There are several root-knot nematode species and they differ in their response to resistance in tomato and various bean crops. Most common in our Sacramento Valley area are Meloidogyne incognita and M. javanica. These nematodes are normally controlled by Mi-1 gene based resistant tomatoes, but there are resistance-breaking populations so that could be the reason for the infection on tomato (unless the tomatoes grown were not actually resistant). A further possibility is that the species is M. hapla, which is not controlled by the tomato resistance. M. hapla tends to induce smaller pearl-like galls on tomato roots and is not common in the Sacramento and northern San Joaquin Valleys.

    Root-knot Nematodes Causing Galling on Tomato Roots

    As to rotating with lima beans, limas are susceptible to these root-knot species but there are resistant varieties available. Beja Flor baby lima has strong root-knot resistance. It was bred to contain three resistance genes that do a good job of blocking M. incognita and M. javanica. It yields well with the caveat that Steve Temple (former UCCE legume specialist) used to remark that it is more Lygus bug susceptible than some varieties, so if a grower went with UC Beja Flor they would need to keep up on the Lygus management. UC Luna baby lima has no root knot resistance. Other lines carrying M. incognita (but not M. javanica) resistance are the large limas White Ventura N and UC92.

    If root-knot nematodes are present in a field with a history of Fusarium wilt, choose varieties that are resistant to root-knot nematodes as well as to the particular Fusarium wilt race present when possible. Another option is to rotate with root-knot nematode resistant cowpeas (blackeyes) instead of limas.  Based on host-range tests, some varieties of cowpea have more root-knot nematode resistance than tomato. For example, some root-knot nematode races are virulent and highly pathogenic to Mi-1 gene based resistant tomatoes but not to nematode resistant cowpeas. — By Rachael Freeman Long & Amber Vinchensi-Vahl, UC Cooperative Extension

  • UCCE Tulare County Dried Plum Program Assists Efforts for Detection of Invasive Beetle

    Following a tip generated by citizen scientists in the Porterville/Tulare area, UC ANR researchers have installed traps to determine the potential for Velvet longhorned beetle, Trichoferus campestris (Coleoptera: Cerambycidae), introduction to the southern San Joaquin Valley. The beetle, also called Mulberry longhorn beetle, is native to Asia and Russia, but now has an extended geographic range across Europe and North America.  The pest is currently established in 4 counties in Utah, with cherries and peaches serving as hosts.

    The Velvet longhorned beetle is not a serious pest in Asia and has only had a low impact on European timber and orchard production.  The insect pest is of concern due to its potential to impact fruit yield and decrease tree longevity. It has been repeatedly intercepted at ports of entry in California; however, it is not known to be established in the state.  Because the pest has a wide host range, affecting over 40 genera of broadleaf and coniferous plants, and is tolerant of dry conditions, researchers and regulators have initiated monitoring efforts for the pest.  Locally, traps have been installed in dried plum and fresh prune orchards in Tulare County.

    The Velvet longhorned beetle may serve as a pest of forests and orchards, and it has been moved internationally on wood packing material and in furniture and home décor. The adult beetle is large (around 1-2 cm), brown, has long antennae, and is nocturnal. Its peak mating activity is in June/July in Utah.  Black Intercept Panel Traps were established in Tulare County in June and will be removed prior to prune harvest in September. — By Elizabeth Fichtner & Houston Wilson, UC Cooperative Extension

  • Six Ways to Improve Pesticide Sprayer Calibration/Coverage

    Are you not seeing the results you expected in your latest fungicide/insecticide application? Watch this brief interview with Peter Ako Larbi from the UC Cooperative Extension who shares several considerations on how growers can improve their pesticide spray coverage in their orchard or vineyard.