Salinas Valley Agriculture
Diamondback moth (DBM) is a persistent pest in the Salinas-Castroville area. We were able to find late instar caterpillars in several spots along Blackie road on Tuesday January 22nd. Basically, these caterpillars were feeding on brassica weeds, located along the side of the road (Fig. 1). This is an example of how insects exploit weeds as alternative hosts when there is a lack of a preferred and abundant host plant in the landscape. DBM will continue feeding on these weeds, while increasing their numbers. These DBM adults, originated from weeds, have the potential to infest any commercial cole crop during the upcoming weeks and months. Based on our observations, most of these caterpillars were close to pupate. Within the next two weeks, we might see an influx of DBM adults flying around fields and weed patches. A new generation of caterpillars may be present around mid-February in our system, depending on temperature fluctuations.
It seems like not all of these caterpillars will become adults. Approximately, 10% of the caterpillars collected from Blackie road were parasitized by Diadegma wasp. We took these caterpillars to the UCCE Entomology lab to refresh and re-introduce DBM into our colony; and we were able to spot the parasitic wasp pupae inside our rearing containers (Fig. 2).
Ideally, controlling weeds outside our fields and along the roads could be part of our strategies to manage resident pest populations. Control of these weeds will allow to reduce population of these pests cycling through the winter here in the Salinas-Castroville area. Managing these weeds could be challenging too, due to accessibility and other issues. Please, keep in mind that cole crop fields surrounded by weedy patches will have a higher chance to be infested with DBM. You could prioritize the scouting of those fields to timely detect any economically damaging DBM population in your crop.
If you would like to learn more about DBM and the research conducted by the UCCE Entomology team, please contact Alejandro Del-Pozo at email@example.com or 831-759-7359.
The UC Cooperative Extension is holding a Vineyard IPM Conference on Thursday, Feb. 21 in San Luis Obispo.
DPR CE and Certified Crop Adviser CEUs have been requested.
Date: Thursday, Feb. 21, 2019
Location: San Luis Obispo Veteran's Hall, 801 Grand Avenue
Cost: $100, includes morning coffee and lunch
Advanced registration is required, please register at this website: http://ucanr.edu/seminar
8:00 - Check in and refreshments
8:30 - CaCO3 foliar spray affecting sunburn and fruit chemistry
George Zhuang , UCCE Fresno County
9:00 - Nematode resistant rootstocks
Karl Lund, UCCE Madera/Merced/Mariposa Counties
9:30 - Pierce's Disease Update
Rhonda Smith, UCCE Sonoma County
10:00 - Maximizing effectiveness of spraying
Lynn Wunderlich, UCCE Sierra Foothills
10:30 - Planting for root health
Larry Bettiga, UCCE Monterey County
11:00 - Controlling ice-nucleating bacteria with copper sprays
Glenn McGourty, UCCE Mendocino & Lake Counties
11:30 - Avoiding winter freeze damage
Mark Battany, UCCE San Luis Obispo & Santa Barbara
12:00 - Lunch
1:00 - Management of Vine Mealybug
David Haviland, UCCE Kern County
1:30 - Epidemiology of Leafroll
Kari Arnold, UCCE Stanislaus County
2:00 - Effects of GRBV on grapevine physiology
Johann Martinez, UC Davis Viticulture & Enology
2:30 - Grapevine virus and vector management
Kent Daane, UC Berkeley
3:00 - Adjourn
Monterey County Agricultural Center
1432 Abbott Street, Salinas, CA
Tuesday, February 26
7:45 a.m. to 12:30 p.m.
7:45 Registration (free)
8:00 Production of organic baby spinach using buried drip irrigation
Ali Montazar, Irrigation Advisor UCCE, Imperial and Riverside Counties
8:30 Mitigating pesticides and sediments in tail water using polyacrylamide (PAM): a new approach
Michael Cahn, Irrigation and Water Resources Advisor, Monterey County
9:00 Full season nitrogen management of vegetables
Richard Smith, Vegetable Crops and Weed Science Adivsor, Monterey County
9:30 Optimizing water management in celery using ET weather-based scheduling
Michael Cahn, Irrigation and Water Resources Advisor, Monterey County
10:30 Region 5 water quality coalitions – demonstrating achievements in water quality
Parry Klassen, Executive Director, Coalition for Urban Rural Environmental Stewardship (CURES)
11:00 Evaluation of salinity effects on strawberry production
Andre Biscaro, Irrigation Water Resources Advisor, Ventura County
11:30 Water and nitrogen management of Asian vegetables/SWEEP and Healthy soils programs
Aparna Gazula, Small Farms Advisor, Santa Clara County
12:00 Grower Panel: Nitrogen Management in Practice
Saul Lopez, D'Arrigo Brothers; Mark Mason, Huntington Farms; and Sal Montes, Christiansen Giannini
12:30 Pizza Lunch
CCA & DPR continuing education credits have been requested
Summary: Following the crop production season in the fall, residual soil nitrate-nitrogen (N) levels increase when N-rich residues from crops such as broccoli are incorporated into the soil. Soil temperatures in the fall and early winter are adequate to allow decomposition of crop residues, as well as mineralization of soil organic matter. The resulting pool of residual soil nitrate-N is vulnerable to leaching by winter rains. Winter-grown cover crops trap a significant portion of this nitrate in their crop biomass thereby providing a useful practice to reduce nitrate leaching during the winter fallow period; however, although growers may want to include cover crops in their rotations, conflicts with spring planting schedules and high land rents often preclude their use. Over the past two years we have conducted trials to evaluate the potential of using high carbon/nitrogen (C:N) organic amendments during the winter fallow period to immobilize (tie up) soil nitrate-N and reduce leaching. Soil microbes utilize the supplemental carbon and available soil nitrate for their growth, thereby reducing the pool of nitrate in the soil that is susceptible to leaching. On the Central Coast, fall compost applications is a common practice used by many growers. We were interested in determining whether a high C:N amendment could be substituted for compost to immobilize soil nitrate-N during the winter fallow and serve as a best management practice (BMP) to reduce nitrate leaching.
During the winter of 2016-17 we evaluated the impact of a high C:N green waste mulch (GWM) (C:N 31.4) on nitrate-N leaching following a fall broccoli crop. No reduction in soil nitrate-N was observed with 5 or 10 tons/A of GWM. The lack of efficacy was probably due to the coarseness of the GWM particles, which were too big to provide soil microbes with sufficient carbon quick enough to utilize and effectively immobile soil nitrate-N. During the winter of 2017-18 we evaluated almond shells (C:N 70.3), ground to 0.5 millimeters in size, and applied at 5 and 10 tons/acre, as well as 2.50 tons/acre of glycerol, and 1.25 tons/acre of glycerol + 5 tons/acre of ground almond shells. At the end of the winter fallow period, all these materials reduced the load of nitrate-N in the top three feet of soil by nearly half compared to the untreated control. Almond shells applied at 10 tons/acre significantly reduced the subsequent lettuce crop yield, presumably because it continued to immobilize nitrate during the cropping season. The other treatments did not significantly reduce crop yield. These data show promise for winter fallow immobilization of nitrate as a viable BMP that growers could utilize to help reduce nitrate leaching during the winter fallow without substantially changing other production practices. However, there are aspects of this practice that we still need to understand to effectively reduce nitrate leaching, safeguard yields and minimize cost differences between standard compost applications and the high carbon amendments. The costs of the high-carbon materials used in these studies ranged from $270 and $720 more per acre than the standard grower treatment; subsequent experiments will need to focus on test materials that have costs that are closer to standard compost application to be a realistic option for growers to consider and routinely utilize. In future testing of GWM, particle size will need to be small enough to allow soil microbes to obtain sufficient C to drive the immobilization process during the winter.
Methods: The trial was established in a commercial vegetable production field west of Gonzales, CA on a site with Mocho silty clay loam soil. In the 2017 production season romaine lettuce was produced in the spring through early summer and broccoli was grown from mid-summer through fall. The N content of the broccoli residues at harvest was measured on October 4. After harvest, crop residue was mowed and disced, and the land was prepared for winter beds according to standard practices in the Salinas Valley (discing, ripping to three feet deep, chiseling and land planing). Tillage was complete on October 23 and 350 lbs/acre of 6-20-20 (21 lbs N/acre) was applied on October 24, 2017. On October 28, ground almond shells (C:N 70.3, Table 1), were applied with a commercial spreading truck at three rates: 0 (untreated control), 5 and 10 tons/acre. Each plot was 20 feet wide (the width of throw of the applicator) by 100 feet long. The plots were arranged in a randomized complete block design with four replications. Following the ground almond shell application, the field was chiseled and then listed into peaked 40-inch wide winter beds. Glycerol treatments were applied to the listed beds at 1.25 and 2.50 tons/acre (240 and 479 gallons/acre, respectively) on October 30 with a commercial spray rig. Before application, glycerol was diluted with water at a ratio of 1:1. All treatments were then lillistoned into the beds. Drain Gauge G3 lysimeters from Decagon were installed in the untreated control and the 10 ton/acre almond shell treatment on October 30 after the fields were lillistoned They were capable of measuring nitrate leaching down to a depth of six feet. Sample of drainage water would have been collected after each rainfall event. However, the rainfall was insufficient to generate drainage and sprinkler pipe was installed in early February and 1.5 inches of irrigation water was applied to simulate rainfall. The lysimeters were removed on February 22, 2018 prior to planting the lettuce. Rainfall totals for winter of 2017-18 were retrieved from the Soledad CIMIS weather station (Figure 1). Soil temperature at the CIMIS station was in a range of 50 to 60 °F during the evaluation period. Soil samples were collected from the top three feet of soil each month during the fallow period from November 2017 to February 2018 and during the subsequent lettuce crop cycle (March to May 2018). Soil samples were extracted with 2M KCl and analyzed for nitrate and ammonium.
Following the winter-fallow period, iceberg lettuce was planted on March 7, 2018. The anti-crustant 6-16-0 supplied 24 lbs N/acre. Crop biomass and biomass N uptake were measured on May 9. Yield of the iceberg lettuce was evaluated on May 25 by harvesting 36 heads per plot for crop biomass and biomass N accumulation.
Results: Broccoli residue contained 188 lbs N/acre at broccoli harvest. Soil nitrate levels in the first foot was 25 ppm nitrate-N at the beginning of the trial on October 28 (Figure 2). Minimum soil temperatures at 6 inches deep ranged from 53 to 66 °F from October 1 to December 1, 2017 (Soledad CIMIS station) which was warm enough to allow mineralization of crop residues and soil organic matter; as a result, soil nitrate-N levels increased to over 40 ppm by the end of November and to over 60 ppm by early February (Figure 2) in the untreated control. Levels of nitrate-N declined in the first foot of soil after the application of 1.5 inches of water with sprinklers used to simulate rainfall and to obtain nitrate samples in the lysimeters. However, soil moisture content was not sufficient from rainfall or supplemental irrigation to obtain drainage samples. The levels of nitrate were also elevated in the untreated control in the second foot of soil until after the irrigation event (Figure 3); no difference among treatments were observed in the third foot of soil (Figure 4). The combined total of nitrate-N was higher in the top three feet of soil in the untreated control than all other treatments on February 2 (Figure 5). These results indicate that all treatments reduced the amount of nitrate-N in the soil that would be at risk for leaching. The 10 ton/acre rate of almond shells significantly reduced lettuce yield (Table 2). The plants were stunted and yellow and presumably this rate of almond shells reduce nitrogen availability to the crop. The other rates of almond shells and of glycerol did not significantly reduce lettuce yield. The high carbon amendments increased costs from between $270 and $720 per acre over the standard compost application. For this practice to be considered a realistic and recommended BMP for growers to reduce nitrate leaching during the winter fallow, additional research on more affordable materials and/or application rates will be needed
Introduction. To gain insight into the agricultural industry and help develop research programs,the University of California and University of Arizona surveyed growers about their use of automated (mechanized) technologies in vegetable crops. The survey's goal was to determine the current use and potential for adoption, as well as to understand the reasons why industry may—or may not—adopt existing or new vegetable technologies. For the purposes of the survey, automated (mechanized) technologies were defined as automated devices that plant, thin, weed or harvest vegetable crops with limited use of hand labor.
The research team developed a 10-question survey to discern current use and level of satisfaction for automated technologies in planting, thinning, weeding and harvesting vegetable crops. By design, the questionnaire was kept short to encourage greater industry participation. Questions related to general farm characteristics were included to determine each respondent's primary role in the vegetable industry, farm size, crops grown and gross sales. The survey was administered in-person at UC Cooperative Extension's Salinas Valley Weed School on October 31, 2017 and at UCCE's Central Valley Fresh Market Tomato Meeting on February 28, 2018. Arizona vegetable growers were surveyed online between March 14 and April 1, 2018.
The number of potential respondents was estimated at 203; 98 surveys were returned for a 48 percent response rate. Fifty-eight questionnaires were deemed complete (59 percent); 40 were partially completed (41 percent). All responses are reported here.
The technology most often used by responding participants was automated thinning, at 52 percent (Figure 1). It is also the technology that industry was most satisfied with, with 89 percent of respondents reporting they were either very satisfied for somewhat satisfied with the technology (Figure 2). Transplanting systems followed, with 49 percent of those that responded currently using the technology, and 83 percent satisfied with its use. This result is not surprising given the level of development and commercial availability of these technologies. Weeding technology is being used by only 30 percent of those responding, with 65 percent satisfied with its use; another 35 percent were not at all satisfied. Although the level of dissatisfaction for weeding technology is higher than for thinning or transplanting systems, 39 percent of those responding also report that they plan to increase its use in the future. From a marketing perspective, the data suggest that the automated thinning market is nearly saturated with only 13 percent of respondents indicating that they plan on becoming new users of the technology within the next 1 to 3 years. Conversely, the business opportunities for weeding and harvesting technologies appear to be larger with roughly 40 percent of respondents reporting they plan on adopting these technologies in the next 1 to 3 years. The supplemental comment “auto weeding is getting very important” supports this idea.
Harvest technology responses followed a pattern similar to weeding technology responses. This is very likely due to the labor intensive nature of the two practices, the labor constraints that growers
currently face, and the difficulty in developing technologies that could be used effectively as a substitute for, or at least a supplement to, field or manual labor. Indeed, several supplemental comments discuss the importance of developing harvest technology for industry. One comment: “the sooner these machines can be introduced in the harvesting area the better… it is the most labor intensive area of our business”. Another comment: “automation has to replace workers rather than just make the total number more productive… the reason is due to labor scarcity”.
In deciding to use automated technologies, 93 percent of those responding viewed labor constraints, costs and regulations as a “very important” factor (Table 1). This response may help explain, at least in part, respondents' plans to increase use of weeding and harvest technology in the future while at the same time reporting some level of dissatisfaction with its use (Figures 1 and 2). That is, industry may be inclined to adopt weed management (and other) technology as a supplement to, or as a substitute for, a shrinking labor pool and costly labor intensive practices, but may also feel that the technology is not yet advanced or precise enough to fully embrace. Supplemental comments, for example “good stuff but needs improvements”, “some of the technology is bonafied, and some is iffy at times”, and “I don't feel the industry is moving fast enough” offer support for this idea. Adding further support, the reliability of mechanized technology and its speed and timeliness in field operations were also reported as important by the majority of those industry participants that responded. Lower production costs and higher net returns were reported as additional important aspects for adoption of new technologies. This is not surprising given the known rising costs of labor and the thin profit margins that vegetable growers often face. About one-quarter to one-third of all participants indicated that they have no future plans to use one or more of the different technologies highlighted in this questionnaire. Although it is not clear why participants answered in this way, one comment “there are mechanical solutions that are less expensive…we do not always need computers and software if there are simple solutions” sheds some light on one potential reason. The least important indicators for automated technology adoption, with less than 45 percent of respondents ranking the factor as “very important”, were reduced environmental impacts and vulnerability to hacking.
Participants were also asked what factors may limit adoption of automated technologies. An unexpected result was that the majority of respondents indicated that investment cost and proven economic value were viewed as only “somewhat of an obstacle” (Table 2). Historically, these have been seen as significant barriers to adoption of new practices. When evaluated in the context of rising labor costs and limitations, advancements in technology and improved commercial availability in the future, these costs may no longer be seen as optional but rather necessary given current production conditions. The supplemental comments “labor shortage will drive this technology”, “speed of development is important, especially with labor challenges now” and “you are already behind if you do not have current focused engineering, software and fabrication programs in operation” support this idea. The need for technology support and specialized training were also seen as impediments to adoption rather than outright barriers. Interestingly, though, a smaller number of respondents also report that specialized training is not an obstacle. It may be that some operations already have staff with advanced technological know-how and are more at ease with new practices and production approaches. This may also help explain why precision land preparation and ease of repairs and maintenance were not seen as an obstacle by some. In contrast, lack of reliability or accuracy for mechanized equipment were reported as definite obstacles to adoption of new production methods by roughly half of all respondents. Adequate attention to both could improve acceptability and satisfaction with the use of any new technology in the future. Respondents also show some uneasiness with the pace of technological development and the possibility of relatively rapid obsolescence, a notable investment risk.
Thirty-five percent of questionnaire respondents described themselves as pest control advisers (PCA)/certified crop advisers (CCA), 28 percent as managers of operations, and another 23 percent were owners/principals. When asked to describe their attitude to adoption of new technologies or production methods, 69 percent fell into the category “I normally wait to see if new technology or production methods are successful before trying them”, with another 29 percent reporting that they are early adopters. A substantial portion of respondents declined to answer questions related to farm size, crops farmed and gross sales, however, partial indicators are reported here. Of those responding to the “acreage and crops farmed” questions, almost two-thirds indicated that they farm using both conventional and organic production approaches. Conventionally farmed operations are generally larger in size than organic operations, with the greatest number of large operations farming leafy greens and brassicas. This makes sense because the majority of all respondents were from regions in California and Arizona that have large production areas for both of these crop groups. Median farm size for the three different grower groups combined was 3,000 and 291 acres for conventional and organic, respectively. Sixty-five percent of those responding reported gross sales of more than $5 million, with another 17 percent reporting sales between $1 million and $5 million, further indicators of larger sized operations. The high value of the fresh market vegetable crops that are characteristic of the areas targeted here may also help to explain this result. It is important to note, however, that gross sales are not a measure of profitability and do not take into account production and harvest expenses.
Study Limitations. The survey results are from a relatively small group sample size and therefore may not represent the larger vegetable industry. Also, not all respondents chose to answer every question. The research team plans to survey additional growers during 2019, which will add to an understanding of use, satisfaction and obstacles limiting adoption of automated technologies.