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Waves of Invasion
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Like their counterparts elsewhere, farmers and ranchers in Ventura County engage in constant battle against crop-destroying pests and pathogens. A wide range of insects, fungi, bacteria and viruses find their way into local fields, greenhouses and orchards, and some can destroy a farm’s productivity and profitability nearly overnight.
To fight back, growers employ a wide range of strategies. These include application of chemical pesticides and fumigants, as well as naturally occurring minerals, oils and other relatively benign materials that suppress pests and diseases. Many growers also rely on release of beneficial insects that prey on harmful insects.
Over the years, Ventura County growers have confronted, suppressed and adapted to numerous crop pests and diseases, including some that were thought initially to be unstoppable. But new ones are always arriving, and the pace of invasion has accelerated. Some of these new assailants pose an unprecedented threat to the survival of key elements in Ventura County’s rich agricultural landscape.
Asian Citrus Psyllid and HLB
Asian citrus psyllid (ACP) is an invasive, aphid-like insect pest. Although the psyllid (SIL-lid) is not a serious problem by itself, it can transmit a devastating bacterial disease to citrus trees. Known as Huanglongbing (HLB), the disease ruins the taste and appearance of citrus fruit, and eventually kills infected trees. There is no treatment or cure for Huanglongbing (wong-long-BING), and all commercially valuable varieties of citrus are vulnerable. If ACP and HLB reach Ventura County, and cannot be eradicated or contained, it is likely that the county will cease to be a significant producer of citrus fruit within a decade.
But the potential threat posed by ACP and the disease it transmits goes well beyond commercial citrus production and the jobs, income and tax dollars it generates. Tens of thousands of trees in residential yards also are at risk. They, too, will die if infected with HLB, meaning that this iconic element of the suburban Southern California landscape — the backyard orange, lemon, lime, grapefruit or tangerine tree — also might disappear from Ventura County.
Read the FAQ about ACP and HLB
Resource Links
Download ACP-HLB documents
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Laurel Wilt Disease in Avocados
Avocado growers have faced serious threats in the past, including thrips, mites and root rot, which threatened to destroy the industry in the 1940s and 1950s, until trees based on resistant rootstocks — and a cost-effective way of propagating them rapidly — were developed. But a new fungal disorder known as laurel wilt disease is making its way toward Southern California and could prove a more devastating foe.
Read the FAQ about laurel wilt disease
Resource Links
Download laurel wilt disease documents
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Charcoal Rot in Strawberries
In 2007 and 2008, the mysterious and sudden collapse of strawberry plants in several fields throughout Ventura County drew attention to a new disorder afflicting Ventura County’s No. 1 crop. Known as charcoal rot, it is caused by what was once regarded as a “minor” pathogen: Macrophomina phaseolina, a soil-borne fungus.
Strawberry plants infected by the fungus appear normal until fairly late in the season, when heavy fruit load coincides with a period of stress such as hot, dry weather. Within days, the affected plants begin to collapse. Symptoms consist of wilting of foliage, plant stunting, and drying and death of older leaves, though the central youngest leaves often remain green and alive. Plants can eventually collapse and die.
The fungus appears to have been kept in check when growers routinely fumigated fields with methyl bromide before planting, but restrictions on use of that potent chemical have prompted many growers to turn to alternatives. Fields afflicted by charcoal rot typically have been fumigated for several successive seasons with these less-potent materials.
Research is under way in Ventura County and other strawberry growing regions in California to identify resistant fruit strains and to develop strategies for control of the fungus.
Resource Links
Download charcoal rot documents
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Frequently Asked Questions
About ACP and HLB
Q. What is the Asian citrus psyllid?
A. The Asian citrus psyllid (ACP) is an aphid-like insect that feeds on the leaves and stems of citrus trees and related plants. Although the psyllid (SIL-lid) can damage plants, the real danger lies in its ability to transmit a deadly bacterial tree disease called Huanglongbing (HLB).
Q. What is Huanglongbing?
A. Huanglongbing (wong-long-BING) is a bacterial disease that kills all varieties of citrus trees. It is the most serious citrus plant disease in the world and once a tree is infected, there is no treatment or cure. Diseased trees produce bitter, inedible, misshapen fruit and eventually die. HLB has already destroyed citrus production in various parts of the world, including Florida, where the industry is now in rapid decline.
Q. How is HLB spread?
A. HLB can be spread by grafting infected plant tissue onto another plant, but it is more likely to be moved around by infected psyllids. Once a psyllid picks up the disease by feeding on an infected tree, it carries it for the rest of its life, spreading it from tree to tree as it feeds.
Q. What types of trees can be infected?
A. All types of citrus trees — including oranges, lemons, tangerines, limes, grapefruit, kumquats and plants closely related to citrus — can be infected with HLB.
Q. Where has the insect been found?
A. ACP has spread throughout Asia, India, parts of the Middle East, and South and Central America. It has also been found in Mexico, Hawaii, Texas, Louisiana, Georgia, Alabama, South Carolina and Florida. It arrived in Southern California in 2008 and has been found in San Diego, Imperial, Orange and Los Angeles counties. ACP has also been intercepted coming into California in packages of fruit and plants, including citrus, ornamentals, herbs and bouquets of cut flowers, shipped from other states and countries.
Q. How close is it?
A. ACP has been found in Van Nuys — just seven miles from the Ventura County line. Experts anticipate the psyllid’s arrival in Ventura County in 2010.
Q. Is the HLB disease in California?
A. Not as far as we know. It has been found in the states of Nayarit and Jalisco on the western coast of Mexico, about 1,000 miles south of Ventura County. Although the psyllid has been found in San Diego, Imperial, Orange and Los Angeles counties, testing has not found any insects or trees in California to be infected with the deadly disease. HLB likely will arrive in an infected citrus tree brought into the state, or by ACP picking it up from an infected plant in a region such as Florida and being transported into California by ship, truck, car or mail.
Q. What will happen if ACP and HLB invade Ventura County?
A. If ACP and HLB reach Ventura County, and cannot be contained or eradicated, it is likely that the county would cease to be a significant producer of citrus crops within a decade.
Q. What is at stake?
A. The economic stakes are high for everyone in Ventura County. Lemons, tangerines, oranges and grapefruit currently account for more than 24,000 acres (a quarter of the total irrigated agricultural land in the county) and generate at least $510 million a year in economic activity. Citrus also supports more than 7,000 local jobs, including on-farm employment, jobs in packinghouses and related businesses, and jobs in other sectors supported indirectly by agricultural activity. The county’s citrus industry also generates $19 million annually in indirect business tax revenue. Additional dollars and jobs are supported by that portion of the local nursery industry devoted to producing young citrus trees, which also would suffer severe impacts in the event that HLB and ACP are detected in Ventura County. Even those nurseries that specialize in other plants would face increased costs for inspection and certification required to ship potential host materials out of infected zones.
Q. I have citrus trees in my yard. Are they vulnerable?
A. Yes. They, too, will die if infected, meaning that iconic element of the suburban Southern California landscape — the backyard orange, lemon, lime or mandarin tree — will also disappear from Ventura County if ACP and HLB spread here. So far, all the ACPs found in California have been on backyard citrus trees in residential areas
Q. How does the psyllid spread?
A. ACP can spread throughout the state on infested citrus plants and close relatives of citrus – such as orange jasmine or Indian curry leaves – that arrive in airplanes, ships, trucks, cars or mail. Distribution of orange jasmine plants by retail nurseries was the main method of movement of ACP throughout Florida. Floral bouquets containing psyllid-infested orange jasmine have been intercepted coming into California from Mexico. Additionally, the psyllid could fly northward from Southern California and gradually spread throughout the state.
Q. If ACP is detected in Ventura County, what will happen?
A. If Asian citrus psyllid is detected locally, a quarantine zone will be established that encompasses an area within a 20-mile radius of the location of the find. Residents are prohibited from moving host plants and backyard fruit out of a quarantine zone. Growers cannot move host plants unless they have been inspected and certified as free of the pest and the disease, and they must commercially clean and pack fruit before it can be moved out of the zone. If the pest is detected in an urban area, the California Department of Food and Agriculture, working with the local agricultural commissioner, will launch a treatment protocol intended to eradicate the infestation.
Q. What does the treatment involve?
A. The treatment consists of application of two pesticides to all host plants within 400 meters of the infestation site. The materials are Cyfluthrin, a contact pesticide that kills psyllids directly, and Imidacloprid, a systemic pesticide that is applied to the soil and absorbed into the tissues of the plant. The pesticides are applied from the ground by trained applicators using hand sprayers. This allows them to target only potential pest hosts, and minimizes the chance that beneficial insects will be harmed.
Q. Are the pesticides dangerous?
A. Both are widely used and regarded as having low risk of adverse effects. Cyfluthrin is a synthetic pyrethroid, chemically similar to a naturally occurring insecticide found in chrysanthemum petals. It breaks down rapidly in sunlight, with a half-life of 48 to 72 hours, and is effective when applied at rates much lower than other commonly used pesticides. It is a skin and eye irritant, but is considered to have low toxicity in humans because it is broken down and eliminated from the body very quickly. The principal negative environmental effects are toxicity to bees and other beneficial insects. Imidacloprid is approved for use on trees producing edible fruit — the pesticide does not pass from the stem into the fruit — and although it is considered moderately toxic, the literature contains no account of human poisoning. It has a half-life of 48-190 days in soil, and is not considered a risk to groundwater. Although toxic to birds and bees, it is not considered a threat to them when applied directly to soil.
Q. Aren’t there alternatives to chemical pesticides, such as organic treatments or biological controls?
A. In order to prevent ACP from becoming established in Ventura County, it is necessary to eradicate any new population immediately upon discovery. Although some organic formulations may kill psyllids, they do not do so swiftly and completely enough to eradicate an invasive population. And although there are some natural predators that feed upon psyllids, these also do not work quickly and thoroughly enough to eliminate 100 percent of the newly detected pests.
Q. Why is it necessary to kill them all? Can’t we just live with them?
A. If the HLB disease is not present, that might be an option. But if the disease arrives in Ventura County and finds a local population of ACP, the infection will spread quickly. It only takes a single infected psyllid to carry the disease-causing bacteria to a new tree. Because there is no treatment or cure for the disease itself, the only way to halt it is to attack the insects that spread it and prevent them from becoming established in Ventura County.
Q. Should I spray my trees now?
A. At the present time, state and local experts are recommending only that owners of citrus trees inspect them frequently for possible infestation by the Asian citrus psyllid. The pest is not currently known to be in Ventura County, so there is little to be gained by applying pesticides as a preventative measure. If you do suspect that one or more of your trees has been infested, please report your suspicion immediately using the state's toll-free hotline, (800) 491-1899. An inspector will collect samples, and if the presence of Asian citrus psyllid is confirmed, the state will apply appropriate pesticides to eradicate the infestation. These materials are more effective than those available to homeowners, and will be applied safely by trained professionals.
Q. What can I do?
A. If you have citrus trees, inspect them frequently for the psyllid, and report suspected finds promptly to the Agricultural Commissioner’s Office at (805) 933-2926, or the CDFA hotline at (800) 491-1899. You should also refrain from moving plants and fruit from one area of the state to another, and you can make sure to buy citrus trees and other landscaping plants only from legitimate retail or wholesale outlets that follow state and federal guidelines for inspection and certification. Information about how to identify ACP and HLB is provided by the downloadable flyers, bookmarks and other materials found on this website.
Q. What should I be looking for when I inspect my trees?
A. There are three life stages of the psyllid: eggs, nymphs and adults. Eggs are elliptical and difficult to see without a magnifying glass. Eggs can be laid singly or in small clusters on tender new growth. They are white when laid, and turn bright orange or yellow as they mature. Nymphs are orange and stay flat against the plant surface. They produce long, waxy filaments that direct honeydew away from their bodies. Nymphs move readily if disturbed but generally spend most of their time feeding on plant juices close to the site where they were born. Adult psyllids are winged and capable of flying considerable distances. Adult psyllids are 0.1 to 0.2 inch in length, with a brown body. Their body usually rests at a slant or 45-degree angle to the host leaf or stem. Adult psyllids may look like aphids, but they are fast-moving jumpers. They may be found on either the upper or lower surface of the leaf, or along the stem, but are almost exclusively found on new growth.
Q. Are there other symptoms of ACP infestation?
A. Yes. High populations of psyllid nymphs and adults can cause permanent deformation of newly formed citrus leaves and shoots. The tender young growth becomes twisted and stunted, and may appear burned. Honeydew produced by nymphs and adults allows growth of sooty mold that coats leaves. Ants, attracted by the honeydew, may be observed visiting ACP-infested stems and leaves at the tips of branches.
Q. When should I inspect my trees?
A. Any time is a good time, but new ACP infestation is most likely to occur when citrus trees are producing new growth, which typically occurs from spring through fall.
Q. What is being done to stop the insect?
A. The California Department of Food and Agriculture (CDFA) has established quarantine zones in areas where the psyllid has been found, and is trying to eradicate the infestation. County agricultural commissioners, CDFA and the U.S. Department of Agriculture, along with industry groups such as the Citrus Research Board, are working together on increased surveying and trapping. Additionally, the Citrus Research Board is setting up diagnostic laboratories at several locations in the state to enable mass testing of psyllids and plant material for the disease. Inspection of cargo at international ports, state lines, airports and mail-sorting facilities has been ramped up to intercept the insect.
Q. What is being done locally?
A. The state has placed traps in urban neighborhoods, and the Citrus Research Board has placed them in commercial orchards, in the hope of detecting ACP quickly if it arrives. In addition, the Farm Bureau of Ventura County, working in cooperation with the Agricultural Commissioner’s Office, recently convened the Ventura County ACP-HLB Task Force. The mission of the Task Force is to coordinate an education and outreach program intended to alert Ventura County residents to the threat posed by the Asian citrus psyllid, and to mobilize broad public support for efforts to exclude, detect and eradicate the pest. Task Force activities include presentations by trained speakers to elected officials and civic groups; distribution of educational materials to the general public; hosting of educational workshops for growers, shippers, pest control advisors and homeowners; and preparation of materials for print, radio and online distribution.
Q. How do I arrange for a speaker to give a presentation about ACP-HLB to my club, homeowners association, organization or community group?
A. Call the Task Force at (805) 535-8641 or send email to taskforce@farmbureauvc.com.
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Laurel Wilt Disease – Frequently Asked Questions
Q. What causes laurel wilt disease?
A. Laurel wilt disease is caused by a fungus, which is carried by the redbay ambrosia beetle. When a beetle carrying the fungus bores into a tree, the fungus spreads and begins digesting the wood, disrupting the flow of water and nutrients. Within six months after a tree is infected, it wilts and dies.
Q. Is the disease in Ventura County?
A. Not yet, but it is spreading rapidly throughout the United States. It was first detected in May 2002 near Savannah, Georgia. By 2008, it had spread along the coast of South Carolina, Georgia and Florida. It is currently in the avocado orchards around Miami.
Q. Is there a cure or treatment?
A. No. Infected trees must be cut down and burned. It burning is not allowed, the tree must be cut down, chipped and left to decompose in place. Moving any part of an infected tree, even if it has been chipped, can spread the fungus.
Q. How is it spread?
A. Like many other invasive pest-disease complexes, laurel wilt and the redbay ambrosia beetle are being moved around the country by humans. They can be spread in wooden packing materials such as shipping crates, as well as potted plants, firewood, logs and wood chips.
Q. Does it affect other trees?
A. Yes. Laurel wilt disease affects all plant species in the family Lauraceae, which includes avocados, California bay, and about 2,000 other species of woody shrubs and trees.
Q. Where did it originate?
A. The redbay ambrosia beetle is native to Asia and is the 12th new species of ambrosia beetle known to have been introduced unintentionally into the United States since 1990. The associated fungus is in the same class of fungi as those that cause Dutch elm disease.
Q. What is being done to stop it?
A. There are no proven management strategies for preventing the development of laurel wilt disease. Early removal of infested trees and limiting movement of infested wood may help slow the spread. Field trials evaluating the effectiveness of certain pesticides are being conducted in Florida and Georgia.
Q. What can I do?
A. Report any suspicious trees to the Agricultural Commissioner’s Office at (805) 933-2926, or the California Department of Food and Agriculture at 1-800-491-1899. Don’t bring wood or wood products into Ventura County from areas known to be infested. Don’t purchase or obtain native Lauracae plants or avocado trees from an area known to have the pest and disease.
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ACP-HLB Links
Ventura County ACP-HLB Task Force on Facebook
Hungry Pests Coalition
USDA Animal and Plant Health Inspection Service
Citrus Research Board
California Department of Food and Agriculture
Florida Department of Agriculture
Invasive Species Council of California
University of California information site in Spanish
“Excluding A Bad Citrus Pest From California” (video)
“Detecting Asian Citrus Psyllid” (video)
“How to scout for the Asian Citrus Psyllid and Greening Disease” (video)
“Huanglongbing de los Cítricos” (video)
ACP-HLB Downloads
FAQs
University of California backgrounder on ACP
University of California backgrounder on HLB
Information card in English
Information card in Spanish
ACP-HLB flyer in English
ACP-HLB flyer in Spanish
ACP-HLB bookmark in English
ACP-HLB bookmark in Spanish
California quarantine map
National quarantine map
Laurel Wilt Disease Links
UC Riverside Center for Invasive Species Research
University of Florida Extension
USDA National Forest Service
Georgia Forestry Commission
UC Cooperative Extension-Ventura
Avocadosource
Laurel Wilt Disease Downloads
FAQs
Article from Western Farm Press
Laurel wilt overview from Institute of Food and Agricultural Sciences
Laurel wilt workshop summary from University of Florida Extension
Charcoal Rot Links
California Strawberry Commission
University of California
Charcoal Rot Downloads
Farm Bureau Newsletter article about strawberry collapse
UCCE paper on fumigant trials
University of Florida paper on charcoal rot
El Psílido Asiático de los Cítricos y la HLB
El psílido asiático de los cítricos (ACP, por sus siglas en Inglés), es un insecto invasivo, parecido a los áfidos. Aunque el psílido no constityue un problema serio por si mismo, puede transmitir una enfermedad bacteriana devastadora para los cítricos, conocida como Huanglongbing (HLB). Esta enfermedad arruina el sabor y la apariencia de las frutas y eventualmente mata a los árboles infectados. No existe cura ni tratamiento para esta enfermedad y todas las variedades comerciales de cítricos son vulnerables. Si el ACP y la HLB llegan al Condado de Ventura y no podemos erradicarlas o contenerlas, es muy probable que en un término de diez años, el condado deje de ser un productor importante de cítricos.
La amenaza potencial del ACP y la enfermedad que transmite, van mucho mas allá de la producción comercial de cítricos, y los empleos, ingresos e impuestos que genera. Miles de árboles en las areas residenciales tambien están en riesgo. Esos árboles tambien pueden morir si resultan infectados con la HLB, lo que significa que este elemento importante del paisaje del sur de California – los árboles de naranja, limón, lima, toronja y mandarina en los patios traseros – tambien pueden desaparecer del Condado de Ventura.
Preguntas frecuentes acerca del ACP y la HLB
P. Qué es el Psílido Asiático de los Cítricos?
R. El psílido asiático de los cítricos (ACP, por sus siglas en Inglés), es un insecto parecido a los áfidos que se alimenta de las hojas y tallos de los cítricos y plantas relacionadas. Aunque el psílido puede dañar las plantas, el peligro real está en su capacidad para transmitir una enfermedad bacteriana, mortal para los árboles, que se llama Huanglongbing (HLB).
P. Qué es Huanglongbing?
R. Huanglongbing (HLB) es una enfermedad bacteriana que mata todas las variedades de árboles de cítricos. Es la enfermedad mas seria de los cítricos en el mundo y una vez que un árbol es infectado, no existe tratamiento o cura. Los árboles enfermos producen frutas amargas, malformadas e incomibles y eventualmente mueren. La HLB ya ha destruido la producción de cítricos en varias partes del mundo, incluyendo la Florida, donde la industria está decayendo rápidamente.
P. Cómo se disemina la HLB?
R. La HLB se puede distribuir al injertar tejidos enfermos de una planta en otra planta sana, pero es mucho mas probable que se disemine por la acción de psílidos infectados. Una vez que el psílido es infectado con la enfermedad al alimentarse en un árbol enfermo, la lleva en si por el resto de su vida y la distribuye de árbol en árbol a medida que se alimenta de ellos.
P. Que tipos de árboles se pueden infectar?
R. Todos los tipos de cítricos se pueden infectar, incluyendo los limones, mandarinas, limas, toronjas, kumquats y otras plantas relacionadas con los cítricos.
P. Donde se ha encontrado el insecto?
R. El ACP se ha diseminado a traves de Asia, India, partes del Oriente medio y America Central y del Sur. También se ha encontrado en Mexico, Hawaii, Texas, Lousiana, Georgia, Alabama, Carolina del Sur y Florida. Llegó al sur de California en el año 2008 y ya se ha encontrado en los condados de San Diego, Imperial, Orange y Los Angeles. Tambien se ha interceptado el ACP en California en paquetes de frutas y plantas, incluyendo cítricos, ornamentales, hierbas y ramos de flores cortadas, provenientes de otros estados y paises.
P. Que tan cercano está?
R. El ACP se ha encontrado en Van Nuys – a solo siete millas de la frontera con el Condado de Ventura. Los expertos predicen que el psílido llegará a Ventura en el año 2010.
P. Está en California la HLB?
R. No hasta donde sabemos. Se ha encontrado en los estados de Nayarit y Jalisco en la costa occidental de Mexico, aproximadamente 1,000 millas al sur del Condado de Ventura. Aunque se ha encontrado el psílido en los condados de San Diego, Imperial, Orange y Los Angeles, no se han encontrado en ninguna de las muestras recolectadas ni insectos ni árboles contaminados con esta enfermedad mortal. La HLB llegará seguramente por medio de un árbol de cítricos infectado traido a nuestro estado, o por medio de un ACP contaminado con la enfermedad en alguna región como la Florida y traido a California ya sea por correo, carro, camión o barco.
P. Qué pasará si el ACP y la HLB invaden el Condado de Ventura?
R. Si el ACP y la HLB invaden el Condado de Ventura, y no se pueden contener o erradicar, es muy probable que el condado deje de ser un productor importante de cítricos en menos de una década.
P. Qué está en peligro?
R. Los riesgos económicos para todos en el Condado de Ventura son altos. Los limones, mandarinas, naranjas y toronjas cubren actualmente mas de 24,000 acres (un cuarto del area total agrícola irrigada en el condado) y generan por lo menos $510 millones por año en actividad económica. Los cítricos soportan mas de 7,000 empleos locales, incluyendo empleos en los ranchos, en las empacadoras y negocios relacionados y también trabajos en otros sectores apoyados indirectamente por esta actividad agrícola. La industria cítrica del condado genera $19 millones anualmente en ingresos indirectos por impuestos. La industria local de viveros, dedicada a producir arbolitos de cítricos tambien genera una cantidad adicional de dinero y empleos, los cuales tambien sufririan un impacto severo si se detectan en el Condado de Ventura el ACP y la HLB. Aún aquellos viveros que se especializan en la producción de otras plantas tambien afrontarian costos de producción mayores debido a las inspecciones y certificaciones requeridas para poder transladar fuera de las zonas infectadas materiales hospederos potenciales.
P. Yo tengo árboles de cítricos en mi patio. Tambien estan en peligro?
R. Si. Sus árboles tambien pueden morir si resultan infectados, lo que quiere decir que ese elemento importante del paisaje del sur de California - los árboles de naranja, limón, lima o mandarina – tambien desaparecerán del Condado de Ventura si el ACP y la HLB se diseminan aqui. Hasta ahora, todos los ACPs que se han hallado en California han sido encontrados en árboles de cítricos en los patios traseros de zonas residenciales.
P. Cómo se disemina el ACP?
R. El ACP se puede distribuir a traves de todo el estado en plantas de cítricos o relacionadas con los cítricos, como el jazmin naranja o las hojas del curry Hindú que estén infectadas . Estas pueden llegar en aviones, barcos, camiones, carros o el correo. La distribución de plantas del jazmin naranja por parte de los viveros, fue el principal método de movimiento del ACP en Florida. En California se han interceptado ramos de flores que contenian jazmin naranja infectado provenientes de Mexico. Adicionalmente, el psílido tambien puede volar hacia el norte desde el sur de California y diseminarse gradualmente por todo el estado.
P. Que pasaría en el Condado de Ventura si se detecta el ACP?
R. Si se detecta localmente el psílido asiático de los cítricos, se establecerá una cuarentena que cubra un área de 20 millas alrededor del sitio donde se localizó el hallazgo. Se prohibirá a los residentes mover frutos o plantas hospederas fuera del area de cuarentena. Los productores no podrán mover plantas hospederas a menos que se hayan inspeccionado y declarado libres del insecto y de la enfermedad, tambien deberán limpiar y empacar comercialmente la fruta antes de que se pueda mover fuera de la zona. Si se detectan el insecto o la enfermedad en un area urbana, el Departamento de Alimentos y Agricultura de California (CDFA, por sus siglas en Inglés), en conjunto con el Comisionado de Agricultura local, organizarán un protocolo de tratamiento dirijido a erradicar la infestación.
P. En que consiste el tratamiento?
R. El tratamiento consiste en la aplicación de dos pesticidas a todas las plantas hospederas que se encuentren en un círculo de 400 metros (1200 pies) alrededor del sitio de la infestación. Los materiales son: Ciflutrin, un insecticida de contacto que mata a los psílidos directamente, e Imidacloprid, un pesticida sistémico que se aplica al suelo y es absorbido por los tejidos de la planta. Personal entrenado aplicará estos pesticidas usando aplicadores manuales, lo que les permitirá aplicar solo a las plantas hospederas y minimizar de esta manera el impacto a los insectos benéficos.
P. Son peligrosos estos pesticidas?
R. Ambos pesticidas se usan ampliamente y se considera que tienen un bajo riesgo de efectos adversos. El ciflutrin es un piretroide sintético derivado de los crisantemos. La luz del sol lo desintegra rapidamente y tiene una vida media de 48 a 72 horas. Es efectivo aun cuando se aplica en dosis mucho menores que otros pesticidas usados comunmente. Es irritante si entra en contacto con los ojos o la piel pero se considera que tiene una toxicidad baja en los humanos porque se desintegra y se elimina del cuerpo muy rápidamente. El principal efecto negativo ambiental es su toxicidad para las abejas y otros insectos benéficos. El imidacloprid está aprobado para uso en árboles que producen frutas comestibles – el pesticida no pasa del tallo a la fruta – y aunque se considera moderadamente tóxico, no hay ningún reporte en la literatura de envenenamiento de humanos. Tiene una vida media de 48 a 190 dias en el suelo y no se considera un riesgo para las aguas subterráneas. Aunque es tóxico para las aves y las abejas, no se considera peligroso para ellas cuando se aplica directamente al suelo.
P. Existen otras alternativas diferentes al uso de pesticidas químicos tales como tratamientos orgánicos o control biológico?
R. Para prevenir que el ACP se establezca en el Condado de Ventura, es necesario erradicar cualquier población nueva tan pronto como se descubra. Aunque algunas formulaciones orgánicas pueden matar a los psílidos, estas no lo hacen de una manera suficientemente rápida y completa como para erradicar una población invasora. Y aunque existen algunos depredadores naturales que se alimentan de los psílidos, tampoco trabajan suficientemente rápido y completamente como para eliminar el cien por ciento de las plagas detectadas recientemente.
P. Porqué es necesario matar a todos los insectos? No podemos convivir con ellos?
R. Si la enfermedad HLB no está presente, esa podría ser una opción. Pero si la enfermedad llega al Condado de Ventura y encuentra una población local de ACP, la infección se esparcirá rápidamente. Sólo se requiere un insecto infectado, para transladar la bacteria que causa la enfermedad a un nuevo árbol. Como no existe ningún tratamitento o cura para la enfermedad misma, la única forma de detenerla es atacar el insecto que la transmite y evitar que se establezca en el Condado de Ventura.
P. Qué se está haciendo para detener al insecto?
R. El CDFA ha establecido zonas de cuarentena en las áreas donde se ha encontrado el psílido y está tratando de erradicar la infestación. Los Comisionados de Agricultura de los Condados, el CDFA y el Departamento de Agricultura de los Estados Unidos, en conjunto con grupos tales como la Junta de Investigación en Cítricos (CRB, por sus siglas en Inglés), están trabajando conjuntamente para aumentar los muestreos y la colocación de trampas. Adicionalmente, la CRB está estableciendo laboratorios de diagnóstico en diversos lugares en el estado para facilitar el muestreo masivo de psílidos y material vegetal para detectar la enfermedad. Para interceptar el insecto también se ha aumentado la inspección de carga en los aeropuertos internacionales, lineas fronterizas estatales, aeropuertos locales y sitios de manejo de correos.
P. Qué se está hacienda localmente?
R. El estado ha puesto trampas en las areas urbanas, y la CRB las ha puesto en los campos de producción comercial, con la esperanza de detectar rápidamente el ACP cuando llegue. Ademas, el Farm Bureau del Condado de Ventura, trabajando en colaboración con la oficina del Comisionado de Agricultura, formaron recientemente el Comité de Trabajo del Condado de Ventura para el control de ACP-HLB. La misión de este Comité de Trabajo es coordinar un programa de educación y promoción destinado a alertar a los residentes del Condado de Ventura acerca del peligro que representa el psílido asiático de los cítricos, y mobilizar el apoyo amplio del público hacia los esfuerzos para excluir, detectar y erradicar la plaga. Este comité sigue el modelo del exitoso Comité de Trabajo contra la mosca de la fruta establecido en 1994 para preparar al condado durante la infestación de la mosca del mediterráneo. Las actividades de este Comité de Trabajo incluyen presentaciones por parte de personal capacitado a los oficiales elejidos y grupos cívicos; distribución al público en general de materiales educativos; realización de sesiones de trabajo con productores, distribuidores, consejeros privados para el control de plagas y dueños de casa; y preparación de materiales para distribucion por medio de los medios escritos, radio e internet.
P. Qué puedo hacer yo?
R. Si usted tiene árboles de cítricos, inspeccionelos frecuentemente, si encuentra o sospecha haber encontrado el psílido informe rápidamente a la Oficina del Comisionado de Agricultura al teléfono (805) 933-2926, o a la linea de emergencia del CDFA al teléfono (800) 491-1899. Usted tambien debe evitar mover plantas y fruta de un area del estado a otra y debe asegurarse de comprar árboles de cítricos y otras plantas para jardin solo en los sitios de distribución que siguen las guias estatales y federales para la inspección y certificación. Usted encontrará información adicional sobre como identificar el ACP y la HLB en los materiales que puede imprimir desde nuestro sitio en la internet.
Sitios web
Huanglongbing de los Cítricos (video)
Universidad de California
Junta de Investigación de Cítricos
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