Proposed pistachio marketing agreement to
help fund UC variety development
Greg Northcutt, Contributing Writer
It’s happened all too frequently to California pistachio grower Tom Coleman. Walking in his Fresno County orchards on an early spring morning, he discovers dozens of three-five-year-old trees with two-foot-long sticks clipped off the ends of branches – the tell-tale sign of thieves who have made off with budwood to start their own orchards. Based on reports from other growers, Coleman says his aren’t the only trees targeted this way. In fact, such incidences have been increasing over the last few years in response to the brisk demand for new trees to capitalize on the booming market for pistachio nuts, he adds. The buds from the pilfered sticks are wrapped in damp towels and kept on ice to keep the wood fresh for no more than a day or two. The buds are carved out and slid into the bark of rootstock to form a new pistachio tree. Done properly, removal of the budwood doesn’t damage the parent tree. In fact, this procedure is used commonly by commercial budders. However, obtaining budwood without permission is not only wrong but it’s actually harming the pistachio industry. It reduces funding for public research and development of improved pistachio varieties, says Coleman, who also serves as chairman of the California Pistachio Research Board (CPRB). Almost all new commercial pistachio acreage in the U.S. is grown from UCB#1 seed or rootstock. This hybrid of Pistacia atlantica (female) X Pistacia integerrima (male) was developed by UC researchers for resistance to Verticillium wilt and vigorous growth. Licensing fees from the sale of the seed or rootstock of this hybrid, as well as the budwood of the UC-developed varieties - Golden Hills (female), Lost Hills (female) and Randy (male), help support the work of the university’s researchers and breeders in producing, testing, and distributing disease-tested plant propagation material, including pistachio cultivars. Pistachio trees produced by commercial nurseries from tissues or clones are not subject to the University of California licensing fee. The price of UCB#1 seed purchased under license from UC Foundation Plant Services is $1 per seed. The price for UCB#1, Golden Hills, Lost Hills, and Randy budwood is $50 for a budwood stick (about 6 inches long) with no less than four buds each. Grafting budwood of Golden Hills, Lost Hills, and Randy is also subject to a licensing fee of $1 per bud. Coleman, who farms several thousand acres of pistachio trees, prefers to start his orchards from seed. “I think growing a tree from seed rather than planting a pre-budded tree produces the most vigorous tree,” says Coleman. He buys the UCB#1 seed from the FPS, paying the $1 dollar per seed licensing fee. After the seed is planted and grown to about 18-inches in height at several nurseries, Coleman plants the trees in his fields. Once five-feet tall, he hires a commercial budder to graft them with buds from wood removed from Coleman’s blocks of Golden Hills and Randy trees. In addition to paying for these budding services, Coleman pays $1 per bud to the budder who then pays the licensing fee for the buds to the University of California. Over the last few years, however, the demand for UCB#1 seed has far outpaced the supply, says Coleman. As a result, growers typically receive only a fraction of the amount of the seed they order from FPS. Coleman says this shortfall has contributed to the increased number of unlicensed growers. Last year, Coleman paid $250,000 for the UCB#1 seed purchased from FPS. “It’s not fair for growers like me who pay for this UCB#1 seed or budwood when others don’t. And, it’s not fair to the industry.” Coleman can understand why some growers may be tempted to avoid paying the licensing fee. However with the industry’s rapid growth in recent years, some newer growers may not be aware of the licensing fee rules. One grower even asked me if the fee for budwood was a requirement or a donation,” says Coleman. This is why Coleman and a small group of other pistachio industry leaders are proposing a California marketing agreement designed to encourage more growers to pay the licensing fees to help fund UC’s development of improved varieties. Coleman says, “A marketing agreement is a way to provide legal standing for this proposed program.” The CPRB, for example, is a California state marketing order, authorized in December 2007 through a grower referendum. The order operates under the oversight of the California Department of Food and Agriculture. The CPRB uses mandatory assessments, paid by pistachio growers, to fund research on pistachio propagation, production, harvesting, handling, and preparation for market, and to provide educational opportunities and materials for pistachio growers. The marketing agreement Coleman and his colleagues propose would be similar to current marketing orders for California’s citrus, grape, and strawberry industries. These orders help control quality and disease resistance of plant parent material except that the agreements are voluntary but binding on the signatories. Pistachio nurseries and commercial budders participating in the proposed pistachio marketing order would agree to use only UC-licensed rootstock and budwood and budwood with the exception of their own proprietary varieties. “I could see members of this agreement assessing themselves a relatively small fee to pay for reviewing the records of each other to check for compliance with the UC licensing program,” Coleman says. A listing of these licensed growers and budders would be available to the public. “This way any grower buying foundation material from an unlicensed producer would risk buying seed, rootstock, or budwood that might not meet the quality and disease resistance standards of those developed by the University of California,” Coleman explains. His group plans to put the proposed marketing agreement to a vote of pistachio nurseries and budders this fall.
Wise nitrogen management key to
pistachio tree health, productivity
Greg Northcutt, Contributing writer
A pistachio tree requires far more supplemental nitrogen (N) than any other single nutrient to maintain proper health and productivity. For example, a thousand pounds of mature pistachio nuts, including the hulls, contain about 28 pounds of nitrogen. However, keeping a tree supplied with the right amount of nitrogen is more complicated than simply replacing the N removed when the nuts are harvested, says Craig Kallsen, reports University of California Cooperative Extension farm advisor for Kern County in his January 2016 Kern Pistachio Notes newsletter. He points out that fertilizing with N or other required elements don’t feed or fatten up a plant with the nutrients. Instead, the nutrients enable the plant to use the energy in carbohydrate, the food produced by photosynthesis, to maintain the photosynthetic and respiration systems, grow the plant, and produce reproductive structures including pistachio nuts. Not all N applied as fertilizer to the tree produces the nut crop. Some is directed to growing new leaves and shoots. And some of it never makes its way into the tree. Soil-applied N may be tied up in organic matter or lost through denitrification by soil-borne organisms. Nitrogen in the soil can also be lost in surface runoff or washed out of the soil profile through leaching, especially if leaching is used to reduce soil salinity levels. If we progressively fail to replace fertilizer elements removed at harvest, used in tree growth, and otherwise lost during crop production, then the soil is being depleted and is becoming less productive,” Kallsen explains. At the same time, the tree may be getting some N from other sources other than fertilizer applications. This can include nitrogen-containing molecules from vehicle exhaust, other human-related activities, and electric storms washed out of the atmosphere in rain. N in irrigation water can reduce the need for annual N fertilizer requirements on a pound for pound basis, Kallsen adds. Allowing fallen leaves and shredded pruning to decay in the orchard can also provide trees with N. Another factor complicating N fertilizer needs is the alternate-bearing habit of pistachio trees, he notes. Typically, but not always, a high yielding on-year is followed by a lower-yielding off-year. So, should a grower increase the amount of N applied during the on-year and reduce during the off-year? Research suggests that fertilizing the pistachio crop on a two-year basis, as opposed to a single-year basis, may have merit, says Kallsen. In this study, the total N demand of the trees was very similar between the on- and off-years. During the on-year, 85 percent of the total N uptake went to the nuts. But, the researcher found that 67 percent of the N went to the canopy during the off-year. These data suggest that in the off-year the tree is growing the leaf canopy for light capture and associated carbohydrate production and storing N that is utilized for nut production during the on-year,” Kallsen says. The application of similar quantities of N during the on and off-years, in combination with maintaining more manageable tree size through pruning, may help mitigate large swings in alternate bearing. To reduce N pollution from fertilizer applications, the goal is to apply enough N to produce the maximum crop possible under existing environmental limitations, while minimizing the amount of residual N remaining in the soil after leaf drop in the fall, Kallsen notes. This is especially important in salty soils where extensive salt leaching will occur during the winter or in areas with high winter and spring rainfall, There is no point in providing more fertilizer than is necessary for the crop to maintain optimal light interception, and its eventual conversion into energy by the leaf canopy, per unit of ground area,” he says. Kallsen recommends testing soil N level in the spring to help estimate how much of the nutrient is available in the soil rooting profile for the upcoming season. Some of this can be counted toward the annual N fertilizer requirement. If leaf testing in August reveals high N levels, this usually suggests high N storage in the tree plus high residual N levels in the soil. Both of these conditions suggest that N fertilization rates can probably be reduced significantly the following year without danger of reducing yields,” says Kallsen. Good record keeping can greatly assist the grower in adjusting current N applications based on historical N fertilization, leaf and soil N levels, and crop yields. If post-harvest soil-N levels are increasing year over year, and yields are optimal, N fertilization rates can probably be reduced.
Research maximizing Navel orangeworm management in
There are three legs to the stool where control of the Navel orangeworm sits, says Brad Higbee, director of entomology research for Wonderful Orchards. And one of those legs has grown shakier over time the use of a particular class of prized chemicals that was highly effective and relatively inexpensive. Higbee and David Haviland, University of California integrated pest management advisor in Kern County, discussed the challenges to managing pyrethroid use against the Navel orangeworm (NOW) and other pests. Both also talked of another leg of the stool – “Sanitation, sanitation, sanitation,” Haviland said. And Higbee emphasized the third leg, another weapon in his arsenal as he seeks to keep NOW at bay: mating disruption. The men pointed out that repeated pyrethroid use has fostered resistance in pests, and both advocated making certain that different classes of pesticides are used. Higbee said, “A 2015 field was treated with Warrior and at most we killed 30 percent (of adults exposed to residue). Five or six years ago, we would have killed all of them. We’re seeing a reduction in the efficacy of pyrethroid products.” He said permethrin has little impact on NOW, and pyrethroid tank mixes are now required. Higbee believes in “loading up on residues” close to harvest. In discussing IPM and pyrethroids, Haviland said they still have some efficacy and their price remains low. “I’m not here to say, ‘Don’t use pyrethroids.’ Just don’t use them more than necessary. Don’t spray if you don’t have to.” When spraying, he adds, use a high label rate “enough to kill.” Haviland said the most important spray timing – in order of importance – is at hull spray, after hull split, and at early split. He recommends monitoring for damage, taking into account how many nuts are expected to fall off naturally and whether beneficials including phytocoris – “which can also be a bad guy” – pose a problem. If you can preserve the phytocoris, particularly during the early May window, it may be best, so it can eat the eggs of NOW’s first generation, Haviland says. Higbee said application of pesticides can be challenged by the fact “intimate contact with larvae and eggs” is required. He said they are only on the hull, and adequate coverage is difficult to achieve. Reaching nuts higher in the tree is a challenge. Higbee said the tolerance for damage from NOW has become lower and lower. “My marching orders are 1 percent or less.” “It makes sense to do as much as you can,” Higbee said. But he said it is especially hard to predict risk of NOW damage in pistachios where pest populations tend to be higher than in almonds. “We’ve looked at no sanitation and full sanitation,” he said. “Full always lowers damage. But we don’t know if we do nothing, how much damage we will have.” He said mummies on the ground pose the greatest risk, and that mowing and disking are equally good at destroying mummies. Sweeping the orchard floor also helps. Higbee says the NOW moth is highly mobile and can travel more than half a mile per night. Enlisting help from neighbors in treatment helps bolster effectiveness. As pistachio prices have risen in recent years, he says it could pencil out to use more costly chemicals and other approaches and be worthwhile as growers shoot for damage of 1 percent or less of the crop. The cost per acre, Higbee says, can amount to $5 to $10 (per acre) for pyrethroids, $40 to $50/acre for new chemistries, and $120/acre for mating disruptions. And growers also benefit from processor incentives to achieve low damage levels. At the same time that some earlier popular pyrethroids have shrunk in usage in recent years, the nut acreage where mating disruption is used has risen. In 2013, this amounted to 32,000 acres using NOW mating disruption. It grew to 60,000 in 2014, and to an estimated 120,000 acres in 2015. Higbee expects it will reach 200,000 acres this year – in both almonds and pistachios. The worldwide registration for mating disruption products rose dramatically from 1978-2008. When Higbee first started using a sex pheromone for mating disruption in pistachios, he said, “I wasn’t crazy about it. It doesn’t work well in high populations, and populations were higher in pistachios than in almonds. But we did it and it worked well.” Higbee is also part of an industry task force looking at a way to add a fourth leg to the stool of NOW control. This leg includes a pilot project in the experimental stage that would draw on facilities previously used to rear, sterilize, and release massive numbers of sterile pink bollworm moths. This project seeks the release of millions of sterilized NOW moths, and would likewise work best when populations of the sterile pest are low. Meanwhile, Higbee touts successes of mating disruption, saying it can help reduce NOW damage “generally by 50 percent.” “The best fit currently is in orchards where current insecticide programs are not sufficient,” he said. “It’s most effective when added to an existing insecticide program.” In some cases, it can reduce the number of sprays needed. Pheromones can be provided in micro-capsules, hand applied, or in timed-released puffers. The capsules are applied at between 10-100 per acre. Hand-applied passive release devices are applied at 100-200 per acre. Puffers are used at 1-2 per acre
Gill’s mealybug in pistachio, does the spray pay
To spray or not - that’s a question that often plagues pistachio growers faced with pests including Gill’s mealybug, which may or may not wreak economic havoc on their crop. And that’s where David Haviland, University of California integrated pest management advisor for Kern County, comes in. Haviland has published a paper with the Journal of Economic Entomology which presents a formula for determining the economic injury level that might or might not be tolerated by a grower. The paper is based on several factors, including the treatment cost, the expected price per pound for the crop, and the anticipated yield. It’s a matter of “does the spray pay?” Haviland said. It could be that if an infestation is just beginning and a grower is trying to prevent spread, it might be best to be more aggressive, he adds. The economic injury level formula adds the cost per acre for control with the anticipated yield in pounds per acre and the anticipated price, and then divides it by 0.094. The result will be the economic injury level per cluster in May. As the cost goes up and the price and yield drops, there may be a greater tolerance for the number of mealybugs per cluster. Haviland says a higher payment per pound of around $4 means the threshold for treating the pest “is really low.” The ideal treatment timing is around June 1, or 10 days or so earlier when temperatures are higher. Haviland said adult females emerge in late April or May, “and that’s when you monitor the number of mealybugs per cluster.” They can be found when the old wood connects with new growth - basically where the bud was. Among the pesticides effective on the pest are Centaur (Buprofezin), Movento (Spirotetramat), Assail (Acetamiprid), and Admire (Imidacloprid). Haviland said Admire is not as effective as the others but it is inexpensive and has no application costs when used in drip systems. Admire, he says, might not be the best choice in a bad infestation, but if the level is creeping back it can be used for suppression. Haviland said Centaur, Assail, and Movento are all “extremely good.” Another good product he shared is Closer, which has been re-named Sequoia, a Dow AgroSciences product where the registration was pulled. Dow is seeking product re-registration. Movento is costly, Haviland said, but researchers have learned it can be used at lower rates, six ounces rather than nine ounces, shaving one-third off the cost. The pest was introduced into Tulare County in the mid-to-late 1990s. It spread slowly initially, reaching 2,000 acres in 2004 in at least five counties and was also found in almonds and wine grapes. By 2005, 3,000 acres were infested. There were 6,000 aces infested by 2007. And pesticide reports indicate treatment on 80,000 acres in California by 2013. “Perhaps 100,000 acres have mealybug today,” Haviland said. Gill’s mealybugs are roughly ½ to 1/5 inch in length and pinkish grey in color. The pest is often covered with white wax secreted from a pore. “They muck up the clusters,” Haviland said. He explained that they “intercept carbohydrates intended for kernel development.” Smaller kernels mean less weight and less splitting. “The small kernel is never big enough to push them open,” Haviland said, “and the biggest problem is closed shell nuts.” The pest can cause shell staining and an increase in adhering hulls with later harvests. But it has no association with aflatoxin. Pistachio growers should be cautious not to confuse Gill’s mealybug with grape mealybug. Grape mealybug is sometimes found on pistachios, but does not cause economic damage but requires treatment. Grape mealybug has four slender white tails. The female Gill’s mealybug has two broad white tails. When poked, adult females of grape mealybug extrude a bright red liquid through structures called ostioles towards both the rear and front of the top of the body. Gill’s mealybug does not extrude such a liquid. Mealybug feeding produces large amounts of honeydew that results in black sooty mold that can reduce photosynthesis. The most common predators of mealybugs in pistachios are brown lacewing and lady beetle whose larva resembles a mealybug. One way to peg problem areas is to check trees before dormancy in the fall and look for sooty mold and leaves and for mealybugs within clusters. Note those locations for further evaluation the following spring.