| TALKING
SHOP: California Conference on Biological
Control and Organic Production, July 15 to 17, UC Berkeley By Don Lotter, Ph.D. |
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Posted August 3, 2004: Every year the evidence builds to show that biological control and agroecological and organic methods could supply most of what we need to grow all of our food. A conference at the International House at UC Berkeley from July 15-17 covered research being done at the University of California, all over the state, on biological pest management and research related to organic production systems. The three-day conference devoted two days to biological control in general, with a third day devoted to general organic farming systems research. The subject of cutbacks in research funds was brought up repeatedly as a severe constraint by the researchers at the conference. Those of us who work in this area have a huge obstacle: a mainstream scientific, government, and media community that has been completely swept away by proprietary biotechnological approaches to food production. Nearly all of the agroecological techniques we use, many described below, are non-proprietary, that is, they can’t be patented. Therefore the private sector, with its enormous investment capital, is not interested in funding us. The proprietary biotechnology sector gets huge amounts of this money, easily in the tens of billions. The problem is that they are also getting our much smaller pool of public, federal funding, taking somewhere in the ballpark of 85% of agricultural research funds. We, the agroecologists and biological control specialists, with only farmers and consumers as our backers and beneficiaries, literally get thrown the crumbs. There is a building awareness that public moneys, federal tax dollars, should be devoted to research on non-proprietary approaches to food production and not to proprietary technologies that already have huge sources of funding in the private sector. After all, the agroecological approach will likely provide most of the solutions to food production constraints in the future. Below I review the conference presentations, many of which are good examples of what I mean when I talk about non-proprietary approaches to agriculture. All in all, the conference was very informative, showing an impressive amount of organic-relevant research coming out of the UC system. But despite the results from the researchers discussed below, most are looking at cutbacks in their funding. Biofumigation, part 1. Krishna Subbarao of the UC Davis reviewed his research on using cruciferous cover crops to reduce diseases, known by some as biofumigation. Broccoli is particularly effective on the Verticillium wilt fungus, V. dahliae. His early observation is that the numbers of certain actinomycetes and bacteria increase by 100- to 1000-fold. Each cruciferous crop has its own type of glucosinolate, and broccoli’s is effective on V. dahliae. Biofumigation, part 2. Oleg Daugovish of UC Cooperative Extension, Ventura County, described how “biofumigation” with yellow and oriental mustard cover crops reduced citrus nematode and Phytophtora root rot by 90%. Biofumigation may not be the correct term, as Daugovish noted that beneficial fungi such as Trichoderma have been found at much higher levels in the mustard treated soils. This does not occur when the soil is fumigated with chemicals. Mustard cover crops are now commonplace in the Salinas Valley. Mustard’s effects on weed seed germination can be significant in the lab, but field trials have not shown significant results. The mustards had no effect on Verticillium, contrary to the significant effect that its cousin broccoli (all are Brassicaceous) had on this pathogen. Tripping up the thrips threat. Mark Hoddle of UC Riverside has reduced the emergence of thrips by half from soil under avocado trees by mulching with compost. As with many orchard pests, thrips pupates in the orchard soil. Predatory mites, Collembolans, beetles, and entomopathogenic fungi and nematodes may be responsible for the reduction in thrips. He saw higher levels of the entomopathogenic fungus Beauvaria bassiana in the mulched soils. [Entomopathogenic is a big word that simply means that these fungi and nematodes are a threat to insects.] Soils that suppress plant parasites. J. Ole Becker of UC Riverside discussed the development of soils that are suppressive to plant parasitic nematodes. This type of suppressiveness, such as of cyst nematode in sugar beet, develops only after five or six years of growing the same crop in the same soil. The suppressiveness is transferable with small amounts of soil from one soil to another, and appears to be microbiological. This may explain some of the rationale behind such agricultural approaches as Natural Agriculture practiced by Shinji Shumeikai, in which a crop is grown year after year in same plot. And now a word about the politics of research … The inimitable Miguel Altieri of UC Berkeley discussed the importance of the balancing of both the diversity of the plant community and soil fertility in maintaining the integrity of agroecosystems. He reviewed research on insect predation on pest crops as affected by soil nitrogen. Altieri then threw in a few references to the uselessness and harmfulness of transgene crops, to which the other University of California panelists later responded with carefully worded statements putting themselves as neutral to or advocating transgenics. University faculty here seem to be under intense, albeit indirect, pressure to advocate for – or at least take a neutral stance on – transgenics. A case in point is Ignacio Chapela. He was denied tenure this spring despite near-unanimous support from experts within Berkeley and around the world. This follows his critique of a $25 million research agreement between the university and Novartis, and then his publication of research showing that transgenic DNA has contaminated native corn in Mexico. Cultivating beneficial insects. William Chaney of UC Cooperative Extension in Salinas discussed insectary plants which provide nectar for beneficial insects in vegetable crops. (Many beneficial insects have a nectar feeding stage, after which they lay eggs on neighboring plants, such as crops. When the larvae emerge they feed voraciously on aphids and other pestiferous insects.) According to Chaney and other presenters, the criteria for selecting insectary plants are: attractiveness to beneficial insects; an early and long bloom period; low potential to host crop viruses; ability to out-compete weeds; low potential to become a weed; low attractiveness to pest species; and low cost of seed and establishment. His preferred mixture is sweet alyssum, seed coriander, buckwheat, and a cereal. The cereal acts as a windbreak and as a host for beneficial insect alternate prey. Sweet alyssum has really taken off in the Salinas Valley and coastal areas of California as an insectary plant for vegetable crops, planted as about 5% of rows or crop land. Syrphid flies, of numerous species, also known as hover flies, have become the prime beneficial insect to attract. One of the notable observations that Chaney mentioned was that aphid flare-ups have resulted from applications of spinosad, the new organically approved pesticide (Entrust®), a classic effect of pesticides. This may be due to the killing of the syrphid fly’s host, the aphid, leaving the syrphid without a food source, or due additionally to the soap’s lethality on syrphid flies. Spinosads have been taking some organic pest control programs by storm. Very little work has been done in the area of the effects of organically approved pesticides on beneficials. Habitat management for pest control. Ramy Colfer, who did his Ph.D. at UC Davis at the same time and in the same department as I did, and who now works for Mission Organics in Salinas, the largest grower of organic salad mix, described his work with insectary plants and habitat management for pest control. He plants every 20th row of lettuce to sweet alyssum, makes sure it blooms as early as possible, and has successfully reduced lettuce aphid infestations to where crop loss has been 1% or less – quite an accomplishment in an industry that routinely writes off entire fields to aphid infestations. Ramy also found that organically approved insecticidal soaps caused aphid flare-ups. You know that a revolution in pest management is happening when the pest management specialist of a big Salinas Valley produce company shows a photo of a young, aphid-infested romaine lettuce plant, and says “I don’t worry about this anymore because I know the beneficial insects will catch up and eat them all. Is it allowed organically? Ray Green of the California Department of Food and Agriculture clarified the different ways to determine if a substance applied to organic crops is in or not in compliance with the USDA National Organic Program (NOP) if it hasn’t yet made the OMRI list. Green’s first caveat, which elicited laughs was: “All natural compounds are allowed unless prohibited; and all synthetics are prohibited unless allowed.” In California, any one of the following criteria generally make it safe to apply a material, if the material:
Stink bug strategies. Les Ehler of Entomology at UC Davis described how to reduce stink bug problems by manipulating the farmscape. In California, where the consperse stink bug, one of many types of stink bugs around the US, is a problem, elimination of winter habitat and early season food sources are the keys. Blackberry patches are particularly important winter habitat. Brassicaceous weeds, such as mustards and wild radish, are important early season food sources and need to be kept down. Organic pest control products: costly to develop. Barat Bisabri of Dow AgroSciences reviewed the development of their spinosad products, Entrust® and GF-120 NF®. Entrust, is a spray, now well-known to many organic growers, and GF-120 NF is a bait, now being used to effectively control the olive fruit fly, the Mediterranean’s worst olive pest, which invaded California’s olive groves several years ago. Bisabri noted that the actinomycete that spinosad compounds are isolated from was found in an abandoned rum distillery in the Caribbean in 1982. The product was licensed in 1997, making it a 15-year lag from discovery to commercial release of product, typical of the industry. Four criteria need to be satisfied, according to Bisabri, in order to develop new pest control products: efficacy; IPM friendliness; resistance manageability; and environmental profile. Few new organic products are on the horizon because of the high development costs and small organic market. The impact of organic insecticides on beneficials. Marshall Johnson of Entomology at UC Riverside presented the results of a survey of research on the lethality effects on parasitoid and predator natural enemies of two of the most common organic insecticides: spinosads and neem/azadirachtin materials. He found that most beneficials were negatively affected (86%). Most affected were the parasitoids by spinosads; these somewhat less so by the neem products. Neem had a relatively greater effect on predators than spinsads. The entomopathic microbes Beauvaria and Bt had less of an effect on beneficials than the other two compounds. “N” gets boost from compost. Willy Horwath of UC Davis reviewed organic matter in organic farming systems, noting that when composts are applied just before or following cover crop incorporation, there is a catalytic effect on nitrogen release. The compost stimulates the active organic fraction in the disked-in cover crop biomass to release N. “N” boost, part 2.” Mark Gaskell of UC Extension also discussed organic matter management for N supply to organic crop systems. The peak N demand period for crops generally lasts for 30-60 days starting 25-40 days after seeding. Gaskell maintains that keeping a soil nitrate level of a minimum of 20 ppm is important. Again, the importance of cover crops as an N-releasing base, on top of which is put the organic fertilizers, was emphasized. The application of organic fertilizers could be reduced from 220 to 120 kg/ha of N with a cover crop base. (These numbers seemed high to me, and since nitrogen nutrition is such an important part of organic farming, I called compost expert Ralph Jurgens of New Era Farm Services in Tulare, CA, who has many organic farmer clients. Jurgens concurred that the compost application rates of 100 to 200 kg/ha of N are high. This would be on the order of 25-50 tons per hectare of composted manure, which generally averages 2-3% N. Phosphorus overloading from composts and manures has become a problem, and N availability and release rates from organic sources are not well-understood. Jurgens gets enough N to the crop using cover crops and much lower rates of compost applications - around 3-5 tons per hectare per year. Much still needs to be sorted out in the area of compost, cover crops, and crop nitrogen needs.) Best cover crops. Eric Brennan of USDA-ARS Salinas, California, the first USDA scientist whose job is dedicated to organic crop systems, discussed his research on three cover crop factors: seed cost, seeding density, and weed competitiveness. He planted a legume-rye mix, mustard alone, and rye alone, each at 1x and 3x recommended rates. He found that the 1x legume-rye allowed 20 times more weed biomass than any of the other treatments. The 3x rates of all of the cover types had about twice the early season (November) biomass, which is good for sequestering nitrogen and preventing nitrate leaching. By late season (February) the biomass had equalized between the two seeding rates. Another problem with the legume-rye blend is that the legume ends up with only about 10% of the total biomass compared to rye, which means that little N is likely being fixed into the system; yet the legume accounts for 90% of the cost of the seed. Organic peach management. Janine Hasey of UC Cooperative Extension, Yuba City, discussed her research on peach orchard floor management. Subclover plus soft chess were good floor covers, providing adequate N. She noted that, in regards to transitioning to organic, it is easier to transition an existing peach orchard than to start an orchard as organic, mostly because of the effect of the mature canopy on reducing weeds. Organic research funding review. Sean Swezey, director of the UC Sustainable Agriculture Research and Education program, reviewed the sources of funds going into organic agriculture at the federal and state (CA) levels. Federal programs are:
Swezey made an interesting comment that California’s organic value at the farm gate is $350 million, while the organic processors declared a value of $5 billion – an approximate 15-fold value increase – putting the value-added aspect of organics in perspective. Of course, the comparison doesn’t take into account that processors import some organic products for processing, but the statistic is still illustrative. Strawberry suction reduction. Swezey also reviewed his research on the lygus bug in organic strawberries. Currently, large organic growers use large vacuum machines to suck up the pest. Swezey showed that alfalfa as a trap crop, planted every 16th row, is so attractive to the lygus bug that just vacuuming the alfalfa rows gave better control of the lygus than entire-field vacuuming, and reduced vacuuming by 75%. What are the research needs of organic? Mark Lipson of the Organic Farming Research Foundation reviewed research needs for organic systems and noted that the weak areas of research have been in plant breeding (see my upcoming article on horizontal disease resistance breeding in Mexico) and in livestock management. Strong areas of research on organic systems have been on soil quality and biological control of pests. Organic numbers, part 1. Karen Klonsky, agricultural economist at UC Davis, reviewed California’s organic statistics. The highest grossing organic commodity is grapes, followed by lettuce, carrots, strawberries, and tomatoes. Rice is tops in acreage, followed by grapes. In the last ten years, the number of farmed acres grew much faster than the number of growers increased. This has been driven by two things – the expansion of existing farms, and the higher relative growth recently of organic grain and field crops, such as rice, which have larger acreages per farm than vegetable and fruit crops. California has kind of a “developing country” situation in that large growers, making up 3% of total farmers, produce 55% of crop value, while small growers, making up 50% of all growers, produce only 2% of total value. Organic numbers, part 2. Desmond Jolly of UC Davis, summarizing the sociology of California’s organic farmers showed that, on the average, organic farmers are more educated (61% vs. 37% are college grads), and use computer technology at nearly twice the rate of their conventional counterparts. Soda bottles vs. the olive fruit fly. Paul Vossen of UC Extension in Sonoma County described how low-tech soda bottle traps for the olive fruit fly, developed in Spain using Torula yeast as an attractant, were the best and lowest cost of all traps tested. The spinosad bait product GF-120®, tested separately, was effective also. Organic herbicides not great. Karen Baumgartner of USDA-ARS Salinas compared the organic herbicide Matran®, a vinegar and clove oil based product, with other treatments, including Roundup®, showing that organic herbicides have a long way to go to catch up with the Monsanto product. Matran was most effective on broadleaved weeds. Sub-surface irrigation reduces weeds. Tom Lanini of UC Davis discussed his research on the effectiveness of sub-surface drip emitters for nearly eliminating weed seed germination in dry summer areas like California. The drip emitters are buried 10 inches deep. In regular sprinkler and furrow irrigation systems he tested pre-irrigation
to germinate weeds, which are then disked. He found that 110 to
130 degree days (about six days, averaging 30° C, with a base
calculation temperature of 10° C) was optimum to get them up
before disking them in. |
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