- Author: Pamela Kan-Rice
A new study that outlines costs and returns of establishing and producing organic alfalfa hay has been released by UC Cooperative Extension, the UC Agricultural Issues Center and the UC Davis Department of Agricultural and Resource Economics.
High-quality organic alfalfa hay is an important ingredient in milk-cow feed rations for organic dairies. Organic dairy farms are required to use organic feed and allow cows to graze for part of their forage. Organic alfalfa hay comprises a major source of forage for the industry.
In 2019, organic dairy farms in California produced about 900 million pounds of milk — just over 2% of California milk output production, according to co-author Daniel Sumner, director of the UC Agricultural Issues Center and professor in the UC Davis Department of Agricultural and Resource Economics.
“Demand for organic alfalfa production has grown, including demand from dairy, horse, sheep, goat, and beef producers, but is still a small share of total alfalfa production,” said Daniel Putnam, UC Cooperative Extension forage specialist in the Department of Plant Sciences at UC Davis and co-author of the study. “However, understanding organic production methods and costs is very important for California's organic hay farmers.”
The new study estimates the costs and returns of establishing and producing organic alfalfa using flood irrigation in the Sacramento Valley, north and south San Joaquin Valley, and the Intermountain Region. The 100 acres of organic alfalfa is rented for $345 per acre annually and the alfalfa stand life is four years after the establishment year.
Input and reviews were provided by UCCE farm advisors and specialists and growers. The authors describe the assumptions used to identify current costs for organic alfalfa establishment and production, material inputs, cash and non-cash overhead and a ranging analysis table, which shows profits over a range of prices and yields.
“This cost study provides information on how to grow alfalfa hay organically,” said Rachael Long, study co-author and UC Cooperative Extension farm advisor in Yolo County. “The research that went into developing these practices represents a significant investment by UCCE farm advisors and specialists and California alfalfa farmer collaborators. We are pleased to team up with economics and cost study experts to provide this study, which indicates potential profits in growing this crop for the organic dairy market.”
The new study, “Sample Costs to Establish and Produce Organic Alfalfa Hay, California - 2020” can be downloaded for free from the UC Davis Department of Agricultural and Resource Economics website: http://coststudies.ucdavis.edu. Sample cost of production studies for many other commodities are also available on the websites.
For an explanation of calculations used in the study, refer to the section titled Assumptions. For more information, contact Jeremy Murdock, UC Agriculture and Natural Resources, Agricultural Issues Center, Department of Agricultural and Resource Economics, at (530) 752-4651 or jmmurdock@ucdavis.edu. To discuss this study with a local extension advisor, contact the UC Cooperative Extension office in your county: https://ucanr.edu/About/Locations.
- Author: Jeannette E. Warnert
Opportunities and challenges for industrial hemp production in California are being revealed in a series of UC Cooperative Extension research projects.
As a crop relatively new to California growers and researchers, there is still much to learn about variety choices, how varieties and crop responses differ across regions with different soils and climates, best practices for nutrient management, and pest and disease issues.
UCCE industrial hemp field research efforts began in 2019 after the previous year's Farm Bill declared the crop should no longer be considered a controlled substance, but rather an agricultural commodity. Hemp is valued for its fiber and edible seeds, however, in California, producing hemp for essential oils including medicinal cannabidiol (CBD) is thought to offer the best economic outlook.
UCCE is working with Lafayette, Colo.-based Front Range Biosciences to test 10 of the company's hemp varieties in Ventura County and the west side of Fresno County. In Fresno County, the trial is underway at the UC West Side Research and Extension Center (West Side REC) under the direction of UCCE specialist Bob Hutmacher. UC Cooperative Extension advisor Annemiek Schilder, the study leader in Ventura County, intended to conduct the trial at the UC Hansen Research and Extension Center in Santa Paula, but the Ventura County Board of Supervisors enacted an emergency ordinance in January prohibiting hemp fields within a half mile of residential areas and schools because of the odor.
“The odor can be quite strong,” Schilder said. “Once plants start flowering, some varieties smell skunky. But the crop is related to hops, and other varieties have a more pleasant hoppy smell. Weather conditions also play a role in odor complaints.”
The Ventura County industrial hemp trial was planted at an Oxnard farm where a hemp crop was already being grown.
The trial includes mostly photoperiod-sensitive cultivars, where the flowering response is triggered by shortening day lengths in mid- to late summer in this latitude. Varieties that do not require the shortening day length to flower are called auto-flower varieties.
“Industrial hemp cultivars grown for essential oils, such as CBD, can be photoperiod-sensitive or not sensitive,” Hutmacher said. “The auto-flower varieties have potential to be more versatile in some production systems, in that they could be planted at a broader range of times of year since they don't respond to day length.”
The studies include growth and yield evaluations, monitoring for pest or disease threats in the San Joaquin Valley and coastal California, and periodic plant sampling to monitor the changes in plant THC and CBD levels over time. THC (tetrahydrocannabinol) is the psychoactive compound found in greater concentrations in cannabis varieties grown for marijuana. Legal requirements for industrial hemp production for essential oils, fiber or seed mandate monitoring concentrations of THC. The crop may not exceed 0.3% at harvest or it must be destroyed.
2020 cooperative irrigation study with Oregon State University
In a new 2020 study led by Oregon State University, drip irrigation trials were set up in California at the UC West Side REC and the UC Davis campus in addition to three sites in Oregon. These studies were set up to determine water use of industrial hemp under irrigation regimes ranging from about 40% to 100% of estimated crop water requirements, with comparisons of responses observed across the five sites with different soils, climate and other environmental conditions.
The same four varieties (two auto-flower and two photoperiod-sensitive) are being grown in irrigation studies at each of the five sites. The California locations in these trials were both planted in mid-June. The two auto-flowering varieties were harvested in late August and early September. The researchers expect to harvest photoperiod-sensitive types in late September or October.
The total water use of the different hemp cultivars under the different irrigation regimes will be determined using applied water measurements and assessments of soil water use between planting and harvest for each cultivar.
Some of the irrigation treatments impose moderate to more severe deficit irrigation to help assess the crop responses to water stress. Deficit irrigation is a method of conserving water by applying less than what might be considered optimum for maintaining rapid growth.
“This plant appears to be quite tough under deficit irrigation,” Hutmacher said. “We need to learn more about benefits and drawbacks to stressing the plants.”
The auto-flower cultivars tested have used less water than the photoperiod-sensitive cultivars because they can be grown in a shorter season. In the San Joaquin Valley, auto-flower cultivars in these studies were ready for harvest in 75 to 90 days after seeding.
“Auto-flower varieties may have potential to be grown in the spring and harvested by early summer, or planted in late summer and harvested before winter. With a short-season crop, and with a decent water supply, farmers could consider double-cropping with such varieties, increasing profits,” Hutmacher said.
2019 and 2020 planting density studies
In cooperation with Kayagene Company in Salinas, Dan Putnam, UCCE alfalfa specialist at UC Davis, and Hutmacher have conducted studies in 2019 and 2020 with two auto-flower varieties to determine crop growth, yield and THC and CBD concentrations of planting densities ranging from about 7,500 plants per acre to 30,000 plants per acre. Since some of the auto-flower varieties are smaller and earlier maturing than many photoperiod-sensitive cultivars, data in these studies will help determine the tradeoff between higher densities needed to increase yields versus increases in the cost of growing more plants.
The studies also provided opportunities for the scientists to assess plant-to-plant variation and impacts of flower bud position on THC and CBD concentrations.
“We feel that when this type of basic sampling method data is collected across a range of cultivars differing in plant growth habit, it may help better inform both researchers and regulatory groups in decisions regarding how to monitor plant chemical composition,” Hutmacher said.
Hutmacher and Putnam are also working with scientists at Davis-based Arcadia Biosciences to refine sampling methods.
“There are a lot of challenges when it comes to estimating maturity with these varieties,” Putnam said. “Each variety will mature at different times and deciding when is the best time is a key decision.”
- Author: Ian Grettenberger
- Author: Rachael Freeman Long
- Author: Daniel H Putnam
- Author: Rob Wilson
"The enemy of my enemy is my friend" holds true in entomology as well!
The activity of natural enemies of pests (beneficial insects) is a key component of Integrated Pest Management in alfalfa to prevent pest resurgence and secondary pest outbreaks.
This is especially true for blue alfalfa aphid (BAA), a challenging pest in alfalfa (see companion article on managing BAA). Although BAA is frequently the most damaging and troublesome aphid to control, spotted alfalfa aphid, pea aphid, and cowpea aphid can also be problematic.
In alfalfa, aphids have many natural enemies. Some, like lady beetles, syrphid flies, and parasitoid wasps target aphids. Others, like damsel bugs and minute pirate bugs, are generalist predators and feed on a variety of prey. Aphids often are very susceptible to predators, with few defenses, and serve as a buffet for natural enemies. So, how are aphids so successful? They reproduce asexually and bear live young, leading to very short generation times and rapid exponential growth.
Accounting for natural enemies can help take advantage of their services and avoid potential pest resurgence and secondary pest outbreaks. Choosing a selective insecticide that targets aphids with minimal effect on natural enemies helps extend control and reduce the need for additional insecticide sprays. After the insecticide loses efficacy, preserved natural enemies are there to suppress any aphids that remain, a bio-residual effect. Killing most of the aphids, but not all, AND killing all of the natural enemies lead to aphid resurgence or secondary pest outbreaks.
The value of beneficials: Experimental evidence
We present data from a trial at the Intermountain Research and Extension from Tulelake, CA conducted by the late Steve Orloff and Rob Wilson in 2015 as an example to illustrate the importance of natural enemies for pest control in alfalfa.
Study overview
- Broad-spectrum materials/mixtures and more selective insecticides were tested.
- Treatments were applied April 17, with one application. Plants were already up and growing, so it is not directly comparable to some of the current scenarios growers are facing with heavily infested plants as they break dormancy.
- Aphids were assessed, 3, 7, and 14 days after treatment, along with natural enemies (lady beetle larvae and braconid parasitoid wasps).
Aphids
Key point: Selective materials provided extended control in this trial, while some of the broad spectrum materials suppressed aphids through 7 days, but then flared them by 14 days.
There were differences in short (7 day) vs extended (14 day) control. The three-day assessment is useful, but also not as relevant for newer materials that take longer to act, which may be especially true under cooler conditions. While some of the treatments gave good control through 7 days, control had disappeared at 14 days, with higher populations than even in the untreated (see Dimethoate + Warrior II and Lannate in Figs. 3 and 42). Sivanto, Transform, and Endigo ZCX all kept aphid populations very low through 14 days (extended control) and Beleaf also performed well in this trial, but has a 62-day PHI that limits its use.
Figure 3. Aphid populations across the three treatment dates for all of the tested treatments, assessed with a sweep net.
Figure 4. Aphid populations across the three treatment dates for a subset of the tested treatments to illustrate flaring of aphid populations at 14 days after treatment vs. extended control with other treatments (same data as Fig. 3).
Natural Enemies
Key point: Some treatments were very harsh on natural enemies, while others preserved their populations. Those that killed aphids AND preserved natural enemies (high ratio of natural enemies to aphids) provided excellent extended control through 14 days and likely afterwards as well.
So, what happened? Natural enemies clearly played a role here in terms of short- vs. long-term control. The broad-spectrum materials generally provided good control through 7 DAT. However, between 7 and 14 DAT, aphid populations surged in some treatments, left largely unchecked by natural enemies. We show both absolute counts (Fig. 5) and natural enemy: aphid ratios (Figs. 6 and 7). A high natural enemy to aphid ratio indicates that natural enemies are helping keep aphids in check. A low ratio of natural enemies to aphids indicates that the insecticide is doing all of the work and natural enemy numbers are low.
In terms of overall abundance of lady beetle larvae, the untreated check had numerous larvae. Meanwhile, mixtures containing Dimethoate and other broad-spectrum materials obliterated them through 7 days (Fig. 5). In the Lorsban and Lannate treatments, they recolonized the plots by 14 days, responding to the high aphid populations. They were never able to do this in the Dimethoate combination treatments. They also recolonized the Endigo treatment. Sivanto, Transform, and Beleaf all maintained lady beetle populations throughout the study.
By examining the natural enemy:aphid ratio, we can see how these treatments affect natural enemies and how this plays out for aphid management. Here, high values are best and typically indicate low aphid populations coupled with conserved natural enemy populations. For lady beetles (Fig. 6), the treatments of Sivanto and Transform alone, as well as Beleaf, have good ratios 3 and 7 DAT and even better values 14 DAT, illustrating how these materials can control aphids and conserve natural enemies. The Endigo treatment illustrates how natural enemies were wiped out initially (likely by the pyrethroid lambda-cyhalothrin), but then recovered while aphid populations were still low, helping provide control. A high ratio at 14 DAT indicates that natural enemies were able to help suppress aphids and provide a bio-residual effect. Ratios were so low in some broad-spectrum treatments because the aphid populations were too high for whatever natural enemies were there to control them.
The pattern was very similar for the wasp:aphid ratios (Fig. 75). A number of the materials clearly had high wasp to aphid ratios at 7 and 14 DAT, indicating wasps able to help supress the aphids. As with lady beetles, high ratios at 14 DAT indicate the potential for extended control and bio-residual past 14 days.
Figure 5. Lady beetle larvae abundance assessed with a sweep net.
Figure 6. Ratio of lady beetle larvae to aphids (measured per sweep). High values are best and typically indicate low aphid populations coupled with conserved lady beetle populations. A value of 0.04 corresponds to 1 larva per 25 aphids.
Figure 7. Ratio of parasitoid braconid wasps to aphids (measured per sweep). High values are best and typically indicate low aphid populations coupled with conserved parasitoid populations. A value of 0.1 corresponds to 1 wasp per 10 aphids.
Yields
Key point: Extended control of aphids produced the best yields and treatments that had flared aphids, resulting in lower yields than the untreated.
Yields and aphid injury reflected high aphid populations. All of the materials with good aphid control through 14 DAT had first-cutting yields between 1.97 and 2.10 tons/A. The untreated and Grandevo treatment (which behaved much like the untreated) had 1.81 and 1.75 tons/A, respectively. Meanwhile, the Stallion + Dimethoate, and Warrior + Dimethoate only yielded 1.19 and 1.50 tons/A. Lorsban and Cobalt only yielded 1.58 tons/A each. In this case study, some of the materials actually aggravated aphid populations and damage, leading to yield loss. A second application (or more) may have prevented yield losses, but was outside the scope of this trial and would obviously come with additional costs and possible consequences later with other secondary pests such as summer worms.
Conclusions
Watch for natural enemies, and treat when thresholds are reached, or when you consistently see aphids in alfalfa crowns and the plant is growing slower than expected. Take natural enemies into account when deciding if/when to treat and when choosing a material. Continue monitoring post-treatment, especially if using broad-spectrum materials such as an organophosphate or pyrethroid (or some combination).
Treatment options in California are currently limited, but we hopefully will see more selective materials enter the market in the future, such as Sefina (afidopyropen) and Transform (sulfoxaflor). There is a strong need for aphid-specific alternatives which are much softer on natural enemies to prevent aphid pest resurgence and secondary pest outbreaks.
This article was first published in the Alfalfa and Forage News Blog.
- Author: Jeannette E. Warnert
For the first time ever, UC Agriculture and Natural Resources (UC ANR) researchers harvested an industrial hemp crop at one of its nine research and extension centers this fall.
“It's an interesting crop,” said UC Cooperative Extension specialist Bob Hutmacher. “There is a tremendous amount of research that can be done to understand its growth and best cultural practices, optimal planting dates either by seed or transplants, irrigation and fertilization management, and, particularly, to address pest and disease management.”
The research project is part of a two-location study, one at the UC West Side Research and Extension Center (WSREC) in Five Points, in western Fresno County, and an identical companion study at the UC Davis farm headed by UC Cooperative Extension specialist Dan Putnam and UC Davis professor and plant breeder Charles Brummer. These initial studies included a planting density by variety trial and a breeding observation block representing a wide range of genetics. The research was launched mid-summer this year after the 2018 Farm Bill declared that hemp should no longer be considered a controlled substance, but rather an agricultural commodity.
Industrial hemp can be produced for grain and fiber, however, many growers currently consider the most profitable component of the crop to be cannabidiol, or CBD, and related compounds. CBD is valued for its purported health benefits. It is said to reduce inflammation, pain, nausea, depression and anxiety, among other conditions.
Hutmacher said he and colleagues around the state are interested in learning about industrial hemp production opportunities, and feel there is a place for UC ANR research to support the fledgling industry. Already, there are some observations coming out of these small trials.
“Some people believe that hemp is a pest- and disease-free plant. That's not what we found,” Hutmacher said. “In the absence of suitable measures for control, corn ear worms seemed to thrive in hemp, and did an astounding amount of damage to cultivars in our small plots.”
The scientists were forced to use a pesticide to control the pest and reduce damage to developing buds. The hemp produced in the trial will be destroyed after harvest data has been collected. The experience with corn ear worm and other pest issues demonstrate that pest control will require significant study, particularly if a goal is to produce the crop organically.
“Markets for some industrial hemp products may require low pesticide residues. If hemp is produced organically, some preliminary observations this year suggest farmers will have to put a big effort into pest and disease control,” he said.
Plant breeding can be another area of UC research. Hemp's natural genetic variations produce plants that vary widely in growth habit, size, response to day length, and time to maturity. There are hemp cultivars that mature when the plant is 18 inches tall and others that shoot up 12 feet high at maturity. Hemp grown for CBD production from seed or as transplants can vary greatly in size and other characteristics, such as amount of branching and the number of flower structures per plant. Multiple plant and production system factors also will influence options for mechanical versus hand harvesting.
Another breeding concern for growers is producing a crop with economic levels of CBD or other compounds of commercial interest, while staying within regulatory limits for THC (tetrahydrocannabinol), the psychoactive compound found in marijuana, a related plant. According to the California Department of Food and Agriculture, an industrial hemp crop grown in the state may have no more than 0.3% THC when plant samples are analyzed.
“This will be a challenge for growers. You don't want to risk too high a THC level,” Hutmacher said. “Farmers must test to make sure THC is at a level to meet regulations. If it's too high, CDFA regulations would require the crop be destroyed.”
Working with UC breeders, integrated pest management scientists, agronomists, irrigation specialists and agricultural engineers, there should be good opportunities to finesse hemp production at UC ANR's network of research and extension center system across California.
Research center locations stretch from Holtville, in the low desert at the California-Mexico border, to Tulelake, just south of the Oregon border. Other centers ideal to answer hemp research questions include the UC Davis campus, the Hopland REC in Mendocino County, the Hansen REC in Ventura County, and the South Coast REC in Orange County.
UC ANR plans to expand its hemp research in 2020. For more information, contact Bob Hutmacher at (559) 260-8957 or rbhutmacher@ucdavis.edu.
- Author: Rachael Freeman Long
- Author: Daniel H Putnam
- Author: Ian Grettenberger
The end is near for chlorpyrifos (Lorsban) applications in many California crops, now on a faster timetable than previously anticipated. This results from a recent agreement between CA Department of Pesticide Regulation (CA-DPR) and pesticide manufacturers to withdraw their products beginning in a few months (February 2020).
This is a major issue for alfalfa, since it is one of the most popular wide-spectrum insecticides for management of key alfalfa pests. These include the alfalfa weevil, Hypera postica, which chews on the foliage (Figure 1, Figure 2) and the aphid complex (several species) which suck juices from the plant – see UC IPM website http://ipm.ucanr.edu/PMG/selectnewpest.alfalfa-hay.html ).
Use of chlorpyrifos has declined in the past two years (due to increased restrictions) but still it was used on 153,000 acres of alfalfa hay in California 2017 (CA-DPR Pesticide Use Report and Figure 3).
Figure 1. Alfalfa weevil larva, a key pest in California's alfalfa fields in the spring months (January-May), reducing yields and quality from feeding on the foliage. Chlorpyrifos has been widely used to control this pest, but in 2020, growers will need to look for alternatives. (Photo: Ian Grettenburger)
What are the alternatives? Unfortunately, there are few alternative products available for alfalfa weevil control specifically. Examples include pyrethroids like Warrior, Steward, Malathion and Entrust (spinosad used for organic production). These have their own limitations, both in terms of efficacy and environmental impacts.
Unfortunately, alfalfa weevils frequently reach economic damaging thresholds in California and many growers find it necessary to spray. There are some other aphid-specific insecticides that would help with aphids but not with alfalfa weevil.
The problem of pesticide resistance. Weevil resistance to pyrethroids is beginning to be a problem throughout the Western states, including select areas in California such as the intermountain and low desert production areas. With the loss of chlorpyrifos, the over-use of a single class of insecticide could be a major challenge.
It has been a long-standing recommendation of the UC Integrated Pest Management Program to rotate insecticide classes to prevent insecticide resistance, in addition to ONLY spraying when thresholds reach an economic level. However, the reductions in active ingredient possibilities may exacerbate resistance.
What drives the withdrawal of chlorpyrifos? Chlorpyrifos was on the way out nationally in 2017 under Obama, but the EPA decision was reversed suddenly in March 2017 as administrations changed (see blog: Chlorpyrifos ban Averted at Last Minute). Chlorpyrifos was subsequently limited by California EPA (and now banned) since it has been designated as a toxic air contaminant and associated with negative health effects in sensitive groups. Chlorpyrifos has been around for many years and used to control pests on a variety of crops, including alfalfa (primarily weevils), as well as on almonds, citrus, cotton, grapes and walnuts. Chlorpyrifos is marketed as Lorsban, Vulcan, Stallion, Cobalt, and Lock-On among others.
The agreement between DPR and manufactures states that:
- All sales of chlorpyrifos products to growers in California will end on Feb. 6, 2020.
- Users can continue to use chlorpyrifos products until December 31, 2020.
- Until then, all uses must comply with existing restrictions, including a ban on aerial spraying, quarter-mile buffer zones and limiting use to crop-pest combinations that lack alternatives.
- Product take-back will occur through normal business practices/channels – with outreach to growers to explain the terms of continued use.
A few products that apply chlorpyrifos in granular form (e.g. for cutworm control), will possibly be allowed to remain on the market (but not registered for use in alfalfa).
The need for alternatives. UC Cooperative Extension advisors and specialists throughout the state are working on developing alternatives to chlorpyrifos in many crops. This work is being supported through the current California state budget, which has appropriated more than $5 million in grant funding for the purpose.
- DPR will award more than $2.1 million in grants to fund projects that identify, develop, and implement safer, practical, and sustainable pest management alternatives to chlorpyrifos.
- CDFA will award approximately $2 million in grants to expand outreach about innovative, biologically integrated farming systems that reduce chemical insecticide inputs. Crops that have used chlorpyrifos will be a priority.
- CFDA will also fund approximately $1.5 million in research to develop alternatives to chlorpyrifos that provide safer, more sustainable pest management solutions.
Non-pesticide options. There are important non-pesticide approaches for weevil and aphid management, including grazing to reduce winter stem egg-laying, early harvest, and introduction of biological controls which are detailed in our IPM guidelines, http://ipm.ucanr.edu/. Additionally, scouting for pest numbers and predation (infected larvae which reduce impacts of the pests) are important tools.
Critical need for alternatives. However, in spite of many of these efforts, many growers have found it necessary to spray (Figure 3), and now will have to look hard for viable alternatives. Following UC IPM guidelines for managing pests, including selecting locally adapted varieties with high levels of pest and disease resistance, are important steps to managing pests and reducing reliance on pesticide use in alfalfa fields.
Figure 3. Map of Chlorpyrifos applications, CA, 2013-2017. Chlorpryifos has been used throughout the major alfalfa growing areas of California (Intermountain, Central Valley, and Desert) for many years, mostly for alfalfa weevil and aphid control - a practice which will wind down in 2020. Data: CA Pesticide Use Report.
This article was originally posted in Alfalfa & Forage News.