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Vol.6, No. 3 Looking at the Future for Nurserymen Phil Rucks, President Our citrus nursery industry appears to finally be stabilizing after an unfortunate turbulent market the past few years. New citrus plantings have subsided greatly, thus limiting tree demand to service primarily resetting needs. With the market settling there appears to be a whole new front of pest and diseases on the horizon with Florida in their sights. Unfortunately, some have invaded here recently with the detection of the Asian strain of citrus canker in Dade County, and the brown citrus aphid (BCA) in Dade and Broward counties. Many more pest problems can be expected with the increased trade and travel of foreigners to Florida from abroad. This aphid will rapidly spread existing Florida severe citrus tristeza virus (CTV) strains to remaining sour orange (S/O) rooted trees in our industry. Following this inoculation comes destruction to plantings on S/O affecting 20% of our production acreage with the combination of the BCA and citrus nursery propagations containing severe CTV strains being planted throughout the industry, will ultimately accelerate the demise of S/O. Today, the nursery industry still does not have a self protection program intact that can deal with the constant aggression of industry threatening diseases and pests. A practical mandated nursery tree registration program has been recommended from industry organizations and is also under consideration in the nursery industry. This program will preserve our future in screening and preventing any harmful disease from further spreading in our industry. If we don't take the initiative to protect ourselves then it could lead to the destruction of our Florida citrus industry. It's not a matter of when it's going to happen, it's a matter of what's going to happen. Protect your livelihood, support the mandatory tree registration program. DPI Update Mike Kesinger, Chief I have been asked what benefit a mandatory budwood protection program would have for a small nursery? The Budwood Protection Program will actually be a good deal for the smaller nurseries because of the subsidized testing of the scion grove trees. The nurseryman has only the responsibility of the tristeza test, the cheapest test of all. The state will do other testing of scion grove trees at no expense to the nursery. The viroid tests, psorosis virus complex and tatterleaf virus tests have been given a value of $175 per tree and is on the low end of actual costs. So in reality the majority of testing expense is picked up by the state for scion grove trees. I believe without this subsidized testing program in place, nurserymen would have to start testing all their source trees from a liability stand point. Lawyers and growers are not hesitant to file lawsuits over diseased trees, with compensation going much deeper than tree replacement costs. Growers are starting to demand disease free trees and have been holding nurserymen accountable for groves planted with pathogen infected trees. I don't believe using the excuse of not knowing that your source trees carried a graft-transmissible pathogen will hold water with the testing technology available. No one can just look at a tree a say it's healthy or doesn't carry a disease if they are planted on tolerant rootstocks. Once disease free, always disease free is a irresponsible way to view source trees. I'd like to prophesy that if we don't test our sources today, that the liability factor will require testing trees as they leave the nursery tomorrow. I think everyone knows that would be a financial nightmare. It's much cheaper to test at the point of origin. Implementation of the mandatory Budwood Protection Program is planned to begin July 1, 1996. Major highlights and steps to consider in implementing the mandatory Budwood Protection Program are: 1). All propagators of commercial citrus nursery stock must make application to the Citrus Budwood Protection Program. There is no application fee. All current participants may keep their current participant numbers but they must fill out a new application form so we will have a complete update of addresses, contact persons, phone and fax information. 2). Beginning July 1, 1996 all propagating material (budwood) must originate from a registered source tree, which would be a scion, increase, parent or foundation tree. 3). All budwood must be witnessed and have a bud cutting report submitted. We have a training program to authorize nurserymen to witness their own budwood cutting and to fill out budwood cutting reports. 4). Seed must originate from a registered scion grove tree or a seed source tree. A non DPI originating seed source tree of the genus Poncirus or a hybrid of poncirus must be tested once for psorosis virus at cost to the nurseryman. This would include non-Division of Plant Industry Swingle and carrizo sources. Current psorosis charges are $ 60 per test. It would be advantageous to obtain tested budwood and establish seed sources in scion groves to avoid the psorosis indexing costs. 5). Record Keeping: The nursery plat requirement has been dropped. What will be required, as in most other countries, is that a nursery journal or log be keep at the nursery for the purpose of keeping track of and locating nursery propagations. This will allow nurseries flexibility in record keeping formats, but in no way is meant to diminish the quality of the program or eliminate good record keeping. Records shall be available at the nursery for examination when inspected or if problems arise. All propagations must be tagged or labeled in the nursery as in the current budwood program, so as to be able to trace any propagations back to the original budwood source tree. Nursery inventories must reflect bud cutting reports. Annual inventories will be compared to bud cutting reports received. The nursery plat is only required for trees intended for use in a scion grove or increase block. If you order budwood for scion grove or increase block use, please let our office know at the time the budwood is ordered so we can send you a plat form. Beginning January 1, 1997 Citrus Tristeza Virus testing is implemented. All source trees must have a CTV test by this date. This is the date that no further propagation of sour orange decline CTV isolates may continue. The window of opportunity for CTV testing is October through May, as current test results are of optimal accuracy when night time temperatures are cooler. It is imperative to have your trees tested prior to the implementation date of Jan 1, 1997 to determine how many budwood source trees you will have in compliance after testing. The importance of knowing the status of your trees can not be over stated in the management of your nursery. If large numbers of your scion trees fail to qualify due to severe CTV isolates, arrangements must be made to find alternative sources of budwood. The implementation dates are quickly approaching and clean budwood sources should be established now. In some years demand is less for certain varieties and all source trees may not be utilized. It will be possible to place a source tree in reserve status for a year by not having a tristeza test run. However, the annual source tree registration fee of $2 must be paid every year to maintain them in the budwood program. Viroid tests will be ongoing even when the tristeza test is skipped. A source tree not kept current in the budwood protection program will have to undergo complete re-indexing to be reinstated at a current cost of $175. As you can see it will be to your advantage to pay the $2 annual source tree registration fee for scion grove trees each year to keep the tree under inspection and to avoid paying complete virus indexing costs. We are ready to start testing additional scion trees for the exocortis viroid. We would like nurserymen to have tristeza tests done on their trees before we start the viroid testing. If you desire 50 free exocortis viroid tests, please submit a list of your top 50 priorities along with the CTV test results from a commercial lab and we will start testing your scion trees in the order we receive the test results. All manufactures have to have a supply of raw material to produce their products. Foremost in the planning and budgeting process for manufactures is a constant stable supply of raw material. It should be no different in our business and our source trees should not be an after thought. Too often budwood sources take second place to fruit production. If you would sit down and put a pencil to the value of budwood to your livelihood, the nursery business, you may consider giving source trees a greater priority in terms of allotting land and giving care. The transition to a mandatory budwood protection program should go smoothly if everyone starts preparing now and registers their trees now before the mandatory program is implemented. Final Workshop on the Mandatory Citrus Budwood Protection Program Held October 17, 1995 Richard Gaskalla Draft 5 of the proposed rules to adopt mandatory requirements for testing citrus propagation material for viruses and viroids prior to its use is now available. These rules are in response to an initiative by citrus nurserymen and citrus production managers to develop a quality citrus tree program. A final workshop on these rules was held October 17, 1995, in the Ben Hill Griffin Auditorium at the IFAS Citrus Research Center in Lake Alfred, 700 Experiment Station Road. The major requirements in this rule chapter are summarized as follows: 1) Commercial citrus nursery stock must be propagated from a registered parent, foundation, scion, or increase block tree effective July 1, 1996. 2) Dooryard citrus nursery stock must be propagated from a dooryard source tree which has been annually tested at the nurserymen's expense for severe isolates of citrus tristeza virus (CTV) effective January 1, 1998. 3) Parent trees must be tested at the nurserymen's expense annually by January 1, 1997, for severe isolates of CTV and once every six years for psorosis, citrus viroids, and tatterleaf virus. 4) Scion trees must be propagated from parent or foundation trees, be tested at the nurserymen's expense annually for severe isolates of CTV by January 1, 1997 and tested for psorosis, citrus viroids, and tatterleaf virus by the Division of Plant Industry as needed and at its expense. 5) Increase block trees must be propagated from parent, foundation, or designated scion trees (those tested negatively for citrus exocortis viroid within the past 6 years) which have tested negatively for severe strains of CTV within the past 12 months. They can be used as budwood sources for 24 months with no additional testing and for nine more months if tested for CTV. 6) Annual registration fees for source trees are $5 per parent tree, $2 per scion tree, $1 per seed source tree, $1 per dooryard source tree, and $2 per 100 increase trees. 7) Exemptions are made for calamondins and citrus for out-of-state sale, and lime sales for five years following rule implementation. If you want a copy of this draft, please contact Connie Riherd at the Division of Plant Industry, Post Office Box 147100, Gainesville, Florida 32614-7100, phone 904-372-3505. Asian Strain of Citrus Canker Confirmed in Dade County Bob Rouse The following information was taken from several memos over the past few weeks by Richard Gaskalla, Director, FDACS, DPI. On September 28, 1995, during a routing inspection of a fruit fly trap in the Westchester community of Miami, an environmental specialist with DPI found a grapefruit tree highly suspect with the Asian strain of citrus canker. On October 20 Florida Agricultural Commissioner Bob Crawford announced that the Asian or "A" strain of citrus canker had been confirmed on residential citrus trees in the Westchester section of Miami. The outbreak is approximately 1.5 miles from Miami International Airport and encompasses about 13.5 square miles of residential area. Crawford designated a zone of about 100 square miles -- encompassing Westchester, Sweetwater, West Miami, Airport West, Virginia Gardens, Coconut Grove and portions of South Miami, Kendall and Miami Springs -- to be placed under quarantine as a precaution to prevent further spread of the disease. No commercial citrus groves are affected. The first incidence of this highly virulent bacterial disease known as the Asian strain of citrus canker was introduced into Florida in 1910. It rapidly spread throughout the Gulf states and a total of 20 million trees were destroyed in that epidemic. It took until 1933 to eradicate the disease from Florida. The disease next appeared in 1986 in portions of Manatee, Pinellas, Sarasota and Hillsborough counties and, in 1990, in one Highlands County citrus grove. The last detection was in 1992 on a single tree in Manatee County. Eradication was declared in January 1994. Brown Citrus Aphid Found in Florida The brown citrus aphid was found November 3 on an orange tree in Fort Lauderdale during a routine inspection of fruit fly traps by a USDA inspector. As of November 28th, a total of 43 infested sites in extreme Southeastern Florida (not including the Keys) have been discovered. The brown citrus aphid is slightly larger than other aphid species that feed on citrus. It is usually found in large dark-brown populations on new citrus growth, with feeding taking place mainly on leaf mid-rib and green stems. It causes young leaves and stems to die prematurely. The aphid is capable of building up large populations quickly, with new generations produced every 6-8 days under favorable conditions. DPI's Entomology circular # 194, The Brown Citrus Aphid, Toxoptera citricida (Kirkaldy) (Homoptera: Aphididae), contains more information on the brown citrus aphid as well as graphics to assist in identification. Points to remember: 1). Host plants are citrus or close relatives. This aphid is not known to attack anything else. 2). New flush is usually colonized. No need to search old leaves. 3) Wingless adults are very shiny black. Only one other species has shiny black adults and it is quite rare. 4) Antennae of wingless adults look similar to the black citrus aphid, expect that segments I, II, and III (closest to the head) are black. The Division of Plant Industry requests that any suspected aphids be sent to it for identification. Report them to the nearest Division of Plant Industry office for collection and identification of.: Call (800) 282-5153. The Risk Assessment of Brown Citrus Aphid Group, decided that, due to the wide distribution of the brown citrus aphid in Broward and Dade counties, no insecticide treatment would be applied to detections in residential locations. Inspections will be expanded to cover adjoining counties. Regulatory measures will be immediately implemented to reduce the risk of artificial long distance spread. This will require some type of treatment before plants leave citrus nurseries. Even though the feeding damage to citrus by this pest is a serious concern, an even greater threat is its ability to very effectively transmit the citrus tristeza virus (CTV) complex from virus-infected to non-infected citrus trees. Not only can the aphid spread CTV strains currently known to exist in Florida, there is fear that this insect could eventually spread severe stem-pitting forms found in other parts of the world but not currently known to occur in Florida. Info-Book for Citrus Nurseries for only $35 The California Citrus Nursery Advisory Board has developed an Info-Book for Citrus Nurseries. The book has 236 pages plus two extension publications on citrus. The book is designed to provide a single source of essential and supplemental information for the operation of California citrus nurseries. The book is useful as a handy reference on laws, regulations and other trade information. The price of $35 includes shipping and handling. Please make checks payable to: Cashier, CDFA and mail your order to: Attn: Parm Randhawa Calendar of Events
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