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CIR1443 Strawberry Pest Management Strategic Plan (PMSP)1 Mark A. Mossler and O. Norman Nesheim2 1. This document is CIR1443, one of a series of the Food Science and Human Nutrition Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date January 2004. Revised July 2007. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. Mark A. Mossler, pest management information specialist. O. Norman Nesheim, Ph.D., professor and pesticide coordinator, Pesticide Information Office, Food Science and Human Nutrition Department, Cooperative Extension Service, UF/IFAS, Gainesville, 32611-0710. The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer's label. The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean APPENDIX Table 1. Efficacy ratings for pest management tools against invertebrate pests in Florida strawberry. Table 2. Toxicity of pest management tools to beneficials in Florida strawberry. Table 3. Indications for disease management products used on Florida strawberries. Executive Summary Florida ranks second in the U.S. in the production of strawberry, providing 15 percent of the total U.S. crop, and 100 percent of the domestically-produced winter crop. Because of the great value of winter strawberries and the high competition on either end of the production window, this crop is highly integrated in all aspects, especially pest management. However, the loss of methyl bromide and greater restrictions non remaining fumigants are the largest IPM consideration for this production system. Secondary pests (such as thrips) and emerging pests (such as whitefly, aphids, and birds) do exist for Florida strawberry producers. Additionally, resistance issues (generally for miticides and fungicides but also noted for a herbicide) exist in this production system. PMSP members expressed confidence that these issues may well be addressed by a combination of research, education, and regulatory actions. A revision to the PMSP meeting held in late 2003 was done to address mainlymainly addressed fumigant use issues that affect strawberry, but also other topics which have changed since then. The following were placed on the ATo Do@ list. Research 1. Examine efficacy of milbemectin on pest mites and thrips and toxicity to beneficial mites and beneficial thrips as well as phytotoxicity on current and potential Florida strawberry cultivars. 2. Conduct trials to identify cover crops that will reduce nematode populations. 3. Examine the possibility of using phage to manage angular leaf spot.
Strawberry Pest Management Strategic Plan (PMSP) 2 4. Examine the use of thiram as a bird feeding deterrent and devise new types of bird repellents. Education 1. Educate growers/scouts with regard to whitefly identification and sanitation, especially on transplants. 2. Educate growers to the issue that in some cases (e.g. Roundup7) a brand name associated with an active ingredient (such as glyphosate) may have something Anew@ in it (such as diquat) which will influence the overall performance of the application and may/may not be used on strawberry. Regulation 1. Determine if data exist that would allow a 2-day PHI for malathion and diazinon. 2. Refine planting window (currently 21 days) for dichloropropene, if possible. 3. Reduce the 110-day PHI for terbacil (Sinbar7) to 60 days. 4. Interact with registrant to facilitate state registration of clopyralid (Stinger7) in strawberry. Strawberry PMSP List of Attendees Strawberry Growers Joel Drawdy Aaron Grimes Carl Grooms Cammy Hinton Andrew McDonald Johnny St. Martin Ronnie Young Extension Personnel Jim Mertely, Gulf Coast Research and Education Center, UF/IFAS, 14625 CR 672, Wimauma, FL 33598. Tel. (813) 633-4131, email@example.com Curtis Nagle, Gulf Coast Research and Education Center, UF/IFAS, 14625 CR 672, Wimauma, FL 33598. Tel. (813) 634-0000 Alicia Whidden, Hillsborough County Extension Office, 5339 S CR 579, Seffner, FL 33584. Tel. (813) 744-5519 ext. 134, firstname.lastname@example.org Association Personnel Chip Hinton (no longer associated with FSGA), Florida Strawberry Growers Assoc., PO Box 2550, Plant City, FL 33564. Tel. (813) 752-6822, email@example.com Mike Aerts, Florida Fruit and Vegetable Association, 800 Trafalgar Ct., Suite 200, Maitland, FL 32794-8153, tel. (321) 214-5200 Research Personnel Roger Francis, Clemson University, firstname.lastname@example.org James Gilreath, Gulf Coast Research and Education Center, UF/IFAS, (retired 2006) Barbra Larson, Department of Entomology and Nematology, UF/IFAS, Box 110620, Gainesville, FL 32611. Tel. (352) 392-1901. Oscar Liburd, Department of Entomology and Nematology, UF/IFAS, Box 110620, Gainesville, FL 32611. Tel. (352) 392-1901 ext. 182, email@example.com Joe Noling, Citrus Research and Education Center, UF/IFAS, PO Box 111563, Lake Alfred, FL 33850. Tel. (863) 956-1151 ext. 262, firstname.lastname@example.org Jim Price, Gulf Coast Research and Education Center, UF/IFAS, 5007 60th St. E., Bradenton, FL 34203. Tel. (941) 751-7636 ext. 246, email@example.com Silvia Rondon (no longer associated with UF/IFAS), Department of Horticultural Sciences,
Strawberry Pest Management Strategic Plan (PMSP) 3 UF/IFAS, Box 110690, Gainesville, FL 32611. Tel. (352) 392-1928. Gisette Seferina, Department of Entomology and Nematology, UF/IFAS, Box 110620, Gainesville, FL 32611. Tel. (352) 392-1901. Governmental/Pest Management Centers Personnel Shani File (no longer associated with UF/IFAS) Southern Pest Management Centers, PO Box 110710, Gainesville, FL 32611. Tel. (352) 392-4721, firstname.lastname@example.org Mark Mossler, UF/IFAS FL Pest Management Center, PO Box 110710, Gainesville, FL 32611. Tel. (352) 392-4721, email@example.com Lora Lee Schroeder, EPA Region IV, 61 Forsyth St. SW, Atlanta, GA 30303. Tel. (404) 562-9015, firstname.lastname@example.org Registrant Personnel Jerry Nance, Dow AgroSciences. Tel. (863) 412-4410 Advisors Not Able to Attend Wilfred Burr, USDA/OPMP, 1400 Independence Ave. SW, Washington, DC 20250-0315. Tel. (202) 720-8647, email@example.com Charlie Meister, IR-4, PO Box 110720, Gainesville, FL 32611. Tel. (352) 392-2399 ext. 412, firstname.lastname@example.org Introduction Florida ranks second in the U.S. in the production of strawberry, providing 15 percent of the total U.S. crop, and 100 percent of the domestically-produced winter crop. In 2004-2005, 179,000,000 pounds of fresh berries valued in excess of $196 million were produced on 7,300 acres ($26,850/acre). Over the last 10 years, Florida strawberry growers have increased their acreage 20 percent and their production nvolume 15 percent, while income has increased by 75 percent. Approximately 95 percent of Florida=s commercial strawberry production acreage is located in Hillsborough and Manatee counties with the remainder in several other counties in both north and south Florida. For this reason, a Pest Management Strategic Plan (PMSP) meeting for the Florida strawberry industry was conducted at the Farm Bureau office nin Hillsborough County (Valrico), Florida. The revision to the plan was conducted by Extension specialists in 2007 to mainly address fumigant issues, but also weed control. Because of the great value of the crop as well as the initial investment, it has historically been recommended that Florida strawberries be grown only on full-bed plastic mulch, and that a fumigant be applied to the bed as the plastic is laid over it. However, due to the restrictions on plant back with some of the fumigant and herbicide alternatives to methyl bromide, growers must now consider soil pest problems over a nmonth before planting and make applications accordingly. Many producers are also now using or considering delivering fumigant in chemigation systems to reduce worker exposure. As of 2007, Methyl bromide, as of 2007, is only available only in a 50/50 mixture with chloropicrin, the latter whichand strawberry growers do not particularly favor the latter. Several principal varieties are cultivated in Florida and these varieties can change yearly. To avoid re-introduction of mites, nematodes and other pathogens to the treated beds, growers are encouraged to use only the best quality transplants available. Transplants are set in late September through early November. Overhead irrigation is used to help establish plants and protect them from frost while drip irrigation is nused after establishment. Following early vegetative growth, the cool nights and short days of winter stimulate the plant to produce flowers which, after pollination, develop into fruits ready for harvest in four to six weeks. This results in three or four crops of fruit from each plant (based on a 30-day cycle). Flowers are present on plants in production areas continuously from shortly after planting until the end of harvest, nbut there are typically two peak flowering periods each season, one in November or December, and the other in mid to late January. The average harvest period runs from late November through early April. Fruit are harvested by hand every two or three days throughout
Strawberry Pest Management Strategic Plan (PMSP) 4 the harvest season. Due to the frequency of harvest, preharvest intervals (PHIs) and restricted entry intervals (REIs) are important factors when ngrowers select pesticides for use on strawberries. Pesticides are applied exclusively by ground application equipment. Florida=s warm, humid climate is ideal for the development of many insect and mite, nematode, disease, and weed pests. Additionally, birds have become a yearly problem for three out of the last four years(three out of the last four years) rather than a sporadic pest by consumption and damage of nthe strawberries. All of these pests were discussed at the Florida strawberry PMSP meeting. Mites Spider mites of the family Tetranychidae (especially the two spotted spider mite) are always the main mite pests, and cyclamen mites (family Tarsonemidae) are a sporadic mite problem. Transplants that arrive in Florida have been growing in northern fields (generally Canada or North Carolina) for months and have been exposed to various pest pressures. These producers try their best to provide pest-free plants, but nmany newer chemistries registered for field use on strawberry are not available to nurseries. Florida growers are encouraged by Extension specialists to monitor the transplants upon receipt for mites as well as aphids, immature whiteflies, and diseases. Once the condition of the transplants is understood, growers should decide to seek healthier transplants or prepare for pesticidal treatment after overhead nwatering/establishment ends. The establishment period (approximately two weeks) when bareroot transplants are being irrigated overhead is the first period of pest management and Florida strawberry growers have very few chemical options because the irrigation water washes off the active ingredient. Consequently, any pest problems are often chemically unmanaged until the establishment period has ended. During this period, mites and nlepidopteran larvae are the key arthropod pests. Lepidopteran larvae that were small upon arrival of the transplants are mature by the time establishment ends, and uncontrollable by B.t. sprays at that point. Consequently, mature larvae are often treated with methomyl, even though methomyl is not compatible with a predatory mite program. It is not hard to see that initial transplant pest pressures set the stage as tofor nwhether a grower can use a beneficial mite program, as well as for the entire mite/insect management program for the growing season. However, registration of spinosad on strawberry has provided growers with a product that is less toxic to predatory mites than methomyl at roughly the same cost per acre. It was also noted by growers that weaker plants are infested by mites more quickly than stronger plants. The economic threshold for spider mites is presence of any life stage on five percent of the leaflets. In terms of chemical miticides, abamectin was being used (and possibly overused) just prior to the registration of bifenazate, hexythiazox, and etoxazole. Some growers were reporting resistance to abamectin. n These four active ingredients now make up the core of the spider mite chemical management system, although some growers not using predatory mites use bifenthrin and fenbutatin-oxide as miticides. Even though there appears to be many options for mite management, it should be noted that seasonal applications are limited to one for hexythiazox or etoxazole, two of bifenazate or fenbutatin-oxide, and four of nabamectin. Before the introduction of bifenazate, hexythiazox and etoxazole, when abamectin sensitivity was being questioned, Florida strawberry growers had an estimated 40 percent adoption of predatory mite programs. With the introduction of the new miticide chemistries, that rate has dropped to 25 percent, even though the two systems were roughly the same cost as reported by growers in attendance. Growers reported nthe desire to have Aclean plants@ rather than those with mites on them. Although predatory mite populations can withstand a few applications of certain insecticides (malathion, diazinon) over the season, one of the biggest impediments to the predatory mite program is that the liquid formulation of captan (used exclusively because the WP formulation leaves white residue) is toxic to predatory mites. Since captan is the nbackbone of the prophylactic fungicide program, it
Strawberry Pest Management Strategic Plan (PMSP) 5 is a certainty that predatory mites will be sprayed and may be reduced to non-efficacious levels by these sprays. Thiophanate-methyl was also reported by growers to be detrimental to predatory mites. For strawberry miticides, there are no carbamate, organophosphate, carcinogen, PHI, or REI concerns with the currently registered materials. Acequinocyl, a miticide receiving reduced risk chemical classification status, has also been registered for use in strawberry (two applications per year). Insects The three lepidopteran larvae that were reported as pests in the crop profile (Spodoptera frugiperda, S. eridania, Helicoverpa zea) were confirmed by growers as the main Aworm@ problems, with Abudworm@ (H. zea) as the most damaging. These are mainly early season pests, and the ramifications of their presence during establishment have already been described. Midand late-season insect pests include nthrips, aphids, and sap beetles. Sap beetles are a zero tolerance pest. Presence of larvae in a ripe strawberry can lead to rejection of the whole shipment. For those growers employing predatory mites, B.t. and spinosad are the preferential materials for Aworm@ management so that predatory mite populations are conserved. For those using exclusive chemical control, methomyl, spinosad, and bifenthrin are often used. Growers expressed desire to transition away from methomyl, as its the restricted status carries licensing and recordkeeping regulations with regards to nlicensing and recordkeeping. Additionally, it was announced in 2007 that methomyl would be withdrawn from the strawberry market. Similarly, there are other insecticides which may be phytotoxic due to strawberry variety, temperature, or incompatibility with other active ingredients. These active ingredients are: carbaryl, dicofol, naled, propargite, oils (petroleum and neem), soaps, and sulfur. Perhaps the best nexample of this is for the incompatibility between petroleum oil and captan/sulfur. In this case, the user is cautioned not to use oil in combination with or immediately before or after spraying with captan or any product containing sulfur. Statements discouraging sulfur use within four weeks of an oil application are also common on oil products. Consequently, growers face these constraints when deciding choosing an ninsect spray program. As strawberries begin to form on the plants, chemical cues radiate to surrounding natural areas. These cues attract adult sap beetles of mainlymainly from two different genera that deposit their eggs preferentially in rotting strawberries, although a few may be deposited in fresh strawberries. The most important steps to take to manage sap beetle problems are to pick all fruit as soon as they areit is mature and to not nleave behind any fermenting fruit. In addition to giving pickers incentive (money) to pull the rotting fruits, the fruit should also be taken out of the field. The second best practice is to drop them into the row middles, where they decay too quickly for the beetles to complete their life cycle. The pressure from sap beetles is most intense during the last month of production, when picking is most intense. The five active ningredients used to control sap beetle are bifenthrin, diazinon, pyrethrins, carbaryl, and malathion. But bBifenthrin and pyrethrins can be hard on predatory mites, and there are potential phytotoxicity issues with carbaryl, so diazinon and malathion are used more than the others for sap beetle control. However, the PHI for diazinon is five days and the PHI for malathion is three days. Since the picking is done at two day nintervals, growers expressed desire to have a PHI of two days for both diazinon and malathion. During tThe last month of picking is also a time in Florida when oak and citrus blooms are concluding. Flower thrips move from these locations into the strawberry fields. However, it has also been noted that the beneficial six-spotted thrips is present in substantial numbers in Florida if the insecticidal spray program is not too Ahard.@ Consequently, an effort should be made to educate growers regarding the ndifferences between these twobeneficial and pest thrips groups (beneficial or pest). When flower thrips do become problematic, spinosad, imidacloprid, or methomyl is used. Aphids (strawberry and melon) have become more persistent in localized areas than they have been historically. The presence of aphids and their cast
Strawberry Pest Management Strategic Plan (PMSP) 6 skins and sugary excretions on fruit are is objectionable to consumers and reduce quality of the fruit. Although there are several aphid predators in Florida, the most effective is a parasitic wasp. As with the six-spotted thrips, Ahard@ chemical programs can reduce the nlevel of parasitism and allow aphid populations to increase. Growers wishing to reduce aphids before naturally occurring predators and parasites have done so must rely on insecticides. A number of materials are efficacious on aphids, such as diazinon, malathion, methomyl, naled, azadirachtin, Beauveria bassiana, bifenthrin, and endosulfan. A potential emerging insect problem is whitefly (usually greenhouse whitefly). The biggest concern for Florida strawberry growers is that plant material from California will harbor the inoculum for major outbreaks in Florida. Consequently, Florida growers utilizing material from California should be educated on how to scout transplants for all whitefly life stages. For strawberry insecticides, there are no carcinogen or REI concerns with the currently registered materials. One concern in terms of IPM may be that there is only one efficacious compound (spinosad) for mature worms that will not drastically harm predatory mites. Methoxyfenozide and thiamethoxam have been recently registered on strawberry. Nematodes This arena of Florida strawberry pest management is in the greatest transition due to the phaseout of methyl bromide. Each year, the price of methyl bromide and chloropicrin content of the methyl bromide product increases. Currently, there is enough methyl bromide to last an estimated two years (2009). The only formulation available to growers in 2007 is one consisting of half methyl bromide and half chloropicrin nand it currently sells for $4 per pound. Even at a reduced methyl bromide rate of 150 pounds per acre using virtually impenetrable film (VIF) mulches, the cost of fumigation would be approximately $1,200 per acre. Florida strawberry growers have never particularly liked chloropicrin as a fumigant. As long as methyl bromide had beenwas the near exclusive constituent of the formulation, chloropicrin was not needed for soilborne pest and disease control. Generally, a higher weed pressure is observed as the percentage of chloropicrin increases in the fumigant mixture. Growers also believe that, with the 50/50 formulation, there nwill be a higher surviving percentage of nematodes after fumigation that will become unresolvable problems during the production season. Secondly, and probably as important as the loss of pest control activity, are the issues of worker complaints and the potential for off-site movement of a compound such as chloropicrin. Chloropicrin can be very unforgiving to workers who perform sloppy applications. The EPA is nalso proposing to implement requirements for substantial buffer zones surrounding fumigant treated fields. Consequently, research has more recently been directed towards pre-bed applications of fumigant, when workers are not around. Of all combinations of methyl bromide alternatives for strawberry in Florida, the best available is Telone7 C-35 applied pre-bed at 22 to 35 gallons per treated acre, 3 to 5 weeks prior to transplanting. To avoid the use of half-face respirators, Telone7 C-35 must be injected to flat soil to a depth of at least 12 inches. With the use of VIF mulch, fumigant rates can be reduced by 25 to 40 percent from maximum nlabeled broadcast application rates. In addition to the Telone7 C-35, a mixture of oxyfluorfen and napropamide applied to the beds during mulch laying has proven most effective in weed control. Oxyfluorfen has a 30-day pre-plant interval before transplanting. For fields with high sting nematode populations, a late summer application of Telone7 is recommended. Chemigation through drip irrigation is also a potential alternative which minimizes personal protective equipment and buffer requirements. Conducting the fumigation after the plastic is laid and irrigation is operational puts the majority of workers out of the field and the fumigant under the mulch. A major requirement of this is to have two drip tapes per bedded row to allow ample dispersion throughout the bed profile.
Strawberry Pest Management Strategic Plan (PMSP) 7 For strawberry nematicides, there are no carbamate, organophosphate, carcinogen, or REI concerns with the currently registered materials. Iodomethane (methyl iodide) is due to be registered for use in 2007. Diseases The key diseases reported by growers at the PMSP meeting were those listed in the crop profile, namely botrytis (gray mold) and Colletotrichum diseases (anthracnose, fruit rot, and crown rot). Other problematic and emerging diseases include angular leaf spot, powdery mildew, and Phytophthora diseases. Botrytis attacks strawberry fruit in all stages of development in the field and in transportation. Years in which conditions are cool and wet during the major bloom period (mid-January to mid-February) provide exceptional disease pressure on Florida strawberries. Thankfully, several new chemistries have been introduced to help manage this fungus and growers reported utilizing all of them (boscalid, cyprodinil + nfludioxonil, fenhexamid +/captan, pyrimethanil). However, the backbone of the prophylactic fungus control program is the rotation and use of captan and thiram. This is illustrated by the 2004 NASS survey data, which reported an average of 15 applications of captan and 7 applications of thiram. One of the characteristics of the newer materials for disease control are extensive label limitations. All of the new compounds mentioned above (as well as azoxystrobin and pyraclostrobin) have application limits per season. Azoxystrobin, pyraclostrobin, and fenhexamid are not to be used more than twice in a row without switching to an alternative mode of action. It is apparent that growers have a limited number of napplications of the new and much costlier fungicides. They view these as supplements to the backbone spray program of captan and thiram. There are three species of Colletotrichum fungus that affect Florida strawberry production, Colletotrichum fragariae, C. gloeosporioides, and C. acutatum. Fruit and root rot are generally caused by C. acutatum. Crown rot can be caused by the other two species. In fact, crown rot was the disease that led to the demise of the strawberry nursery industry in Florida. The strobilurin fungicides have shown to be most neffective in managing anthracnose fruit rot prophylactically. However, there was consensus among meeting members that growers were uncertain as to the maximum number of applications that should be made since limitations are either prescribed on a season, crop, or yearly basis. Extension publications produced since the initial meeting have helped to clarify this issue. Angular leaf spot is caused by the bacterium Xanthomonas fragariae. Transplants often arrive infected from the nursery. Cold, wet conditions (including overhead sprinkling for establishment or freeze protection) encourage disease outbreaks. Copper fungicides may negatively affect strawberry growth at full labeled rate, so growers use it sparingly at low rates. Powdery mildew is a sporadic/emerging fungal problem. The disease is typically managed with fall applications of myclobutanil, triflumizole, or thiophanate-methyl. However, thiophanate-methyl cannot be used by those growers using predatory mites, and resistance to myclobutanil is suspected by members of the PMSP meeting. Consequently, some growers are going back to sulfur for management, and others are nhaving success with potassium bicarbonate. Quinoxyfen has also been recently labeled and adopted for management of powdery mildew in strawberry. Two Phytophthora species (P. cactorum and P. citricola) occasionally cause crown rot and leather rot in Florida strawberries. Subsequent to the fumigant application, mefenoxam is applied early to control this fungus and fosetyl-Al and potassium phosphite are used later in the season because those two materials can be sprayed on the foliage. Field observations suggest that the causative agent of charcoal rot, Macrophomina phaseolina, may become a key disease after the loss of methyl bromide. This disease has been observed in portions of the strawberry field which did not receive sufficient or proper fumigation. It is a warm-season disease that may occur at either end of the Florida production season.
Strawberry Pest Management Strategic Plan (PMSP) 8 Other strawberry diseases are intermittent or incidentally controlled by applications intended to control target diseases. For strawberry fungicides, there are no IPM, PHI, or REI concerns with the currently registered materials. It appears that captan and thiram will remain labeled for strawberry foliar applications for the near future. Weeds Weed pressure has historically been one of the more difficult management aspects for Florida strawberry growers for several reasons. First, when methyl bromide is employed as the sterilant, the dormant weed seeds such as Carolina geranium and cut-leaf evening primrose are not inactivated. Since no treatment is capable of controlling weed emergence the entire strawberry season (six to seven months), these weeds nbecome midto late-season problems that impact quality and harvest efficiency. The desired effect of methyl bromide is that it does control the majority of yellow and purple nutsedge, which are considered the worst weeds in this crop. Since the methyl bromide alternatives (except for methyl iodide) don=t control nutsedge, these species as well as the aforementioned late season weeds will be a problem in rows nduring some or most of the season. Another consideration with respect to weeds is their ability to harbor spider mites. Soon after transplants are set, Carolina geranium seedlings appear. The potential for mite reinfestation is not great when the weed grows from transplant holes in the plastic mulch, because in that position miticide applications will kill resident mites on both the weeds and strawberry plants. However, this plant also grows in the row ends nand field perimeter, and these areas are not treated. Consequently, spider mites can reinfest fields from these plants after miticide residues have decreased. Herbicide research for strawberry has also lagged behind that of pepper and tomato due to the economic superiority of these two crops and the fact that some herbicides available to tomato and pepper growers are not and will not be available to strawberry growers. Results from solarization treatments were similar to those of the untreated control. Consequently, Florida strawberry growers have little experience with nnew herbicide alternatives. Herbicide resistance has also been observed in Florida strawberry production. Goosegrass in the row middles has become resistant to paraquat, due to heavy reliance on this single herbicide. Growers also reported potential glyphosate damage to strawberry plants due to transmission from shallow roots present in treated row middles. In addition to nutsedge and resistant weeds, other problematic weeds include npurslane, pusley, Carolina geranium, cut-leaf evening primrose, and eclipta. Dayflower is an emerging weed problem. Weed pressure in Florida strawberry production comes from two locations, in-bed and the row middles. There are several herbicides which currently provide a degree of control in most cases for row middles. As noted, weeds in the bedded portion of the field, historically managed by methyl bromide application, are now considered the weakest point of methyl bromide alternatives. The following points list the issues nwith each of the in-bed herbicide options: Napropamide (Devrinol7) appears to have reasonable early season efficacy for most weed species. Degradation leads to loss of weed control midto late-season with certain species more tolerant than others. Oxyfluorfen (Goal7 2XL) appears to manage troublesome weeds such as Carolina geranium and cut-leaf evening primrose, but the use is through fallow bed labeling, which requires a 30-day post application fallow. This length of time is too long between bed formation and transplanting, as mentioned in the nematode section. Like oxyfluorfen, newly registered flumioxazin (Chateau7) is supposed to be applied 30 days prior to bed formation. Terbacil (Sinbar7) appears promising but there is a label restriction (110-day PHI) that make this product almost useless for the Florida strawberry growing system. The residue work has been done and Extension specialists are trying to work with IR-4 to refine this label with respect to the PHI (proposed 60-day).
Strawberry Pest Management Strategic Plan (PMSP) 9 Newly registered materials for row middles include aciflurofen, carfentrazone, and pendimethalin. The remaining herbicides available for Florida growers are non-selective or grass-killing postemergence herbicides. It is expected that the napropamide/oxyfluorfen combination will be the one adopted fully by Florida growers as the methyl bromide products begin to be lost, as it is the most proven tandem at this point. One last consideration regarding herbicides (and especially Roundup7 products) is the addition of different active ingredients to established trade names. There is a new formulation of Roundup7 that offers weed control within 24 hours. This is accomplished by the addition of diquat to the glyphosate. Growers must be mindful that this type of addition has become more commonplace, and that they must examine the nlabel to make sure the products they need do not also contain an active ingredient not allowed on strawberry. Other than the aforementioned, there are no IPM or REI concerns with the currently registered materials. Clopyralid is labeled nationally for strawberry, but is not registered in the State of Florida due to groundwater concerns. Birds Bird predation of strawberries used to be viewed as a sporadic event, but in three of the last four years, bird predation losses have been substantial. The species primarily associated with this phenomenon are American robin, cedar waxwing, and crows. It is estimated that these birds consume approximately 400,000 flats of strawberries (over $2 million in losses). An extension specialist that who works with nvertebrate pests stated that the current technologies (propane cannon at a rate of one per ten acres or robin distress calls) have minimal effect, while twisted reflective ribbon (silver on one side/red on the other) may be slightly more effective. Additionally, audio devices are generally not acceptable since much of the growing area is now bordered by residential developments. Since the strawberry is a Anaked@ fruit, ntaste repellents such as methyl anthranilate (grape flavoring) and capsaicin (pepper) cannot be used. The specialist stressed that the most important aspect in trying to rid the field of birds is to try and scare them as soon as they start inhabiting the field. Flock presence draws in more birds. One interesting potential for taste aversion that may well fit nicely into the current pest management program is the application of thiram when a flock first starts to land in the field. This fungicide is known to discourage other vertebrate pests from feeding, and some growers have applied it when birds were densely standing in the field, but did not report any particular positive effects. Summary Based on the input of the members of the Florida strawberry PMSP, the following items have been placed on the ATo Do@ list. Research 1. Examine efficacy of milbemectin on pest mites and thrips and toxicity to beneficial mites and beneficial thrips as well as phytotoxicity on current and potential Florida strawberry cultivars. 2. Conduct trials to identify cover crops that will reduce nematode populations. 3. Examine the possibility of using phage to manage angular leaf spot. 4. Examine the use of thiram as a bird feeding deterrent and devise new types of bird repellents. Education 1. Educate growers/scouts with regard to whitefly identification and sanitation, especially on transplants. 2. Educate growers to the issue that in some cases (e.g. Roundup7) a brand name associated with an active ingredient (such as glyphosate) may have something Anew@ in it (such as diquat) which will influence the overall performance of the application and may/may not be used on strawberry. Regulation 1. Determine if residue data exist that would allow a 2-day PHI for malathion and diazinon.
Strawberry Pest Management Strategic Plan (PMSP) 10 2. Refine planting window (currently 21 days) for dichloropropene, if possible. 3. Reduce the 110-day PHI for terbacil (Sinbar7) to 60 days. 4. Interact with registrant to facilitate state registration of clopyralid (Stinger7) in strawberry.
Abbreviations: TSM=two-spotted spider mite FT=flower thrips SB=sap beetles FAW=fall armyworm SAW=southern armyworm CEW=corn earworm Abbreviations: TB=tobacco budworm SMC=saltmarsh caterpillar LCB=lesser cornstalk borer SLR=strawberry leafroller OLT=omnivorous leaftier TPB=tarnished plant bug Rating scale: E = excellent; G =good; F = fair; P = poor; Rating scale: ? = research needed; = not used; = used but not a stand alone management tool Table 1. Efficacy ratings for pest management tools against invertebrate pests in Florida strawberry. Pests Pest Management ToolsTSM Other Mites FT SB Aphids FAW SAW CEW TB SMC LCB SLR OLT TPB Whiteflies Frujt flies Mole Crickets Ants Slugs Registered materialsAbamectin GGFF F Acequinocyl E Azadirachtin FFFFFFFFGFFGF Bacillus thuringiensis GGGGGGG Beauveria bassiana PPPPPPPPPPPPP Bifenazate E Bifenthrin PFGPFFFFG P Boric acid Canola oil ... Carbaryl PF Chlorpyrifos ... Diazinon PGFGG Dicofol PG Endosulfan GFFFFF F Etoxazole E Fenbutatin-oxide G Fenpropathrin PFGFFFFFGGF Hexythiazox E Imidacloprid PE E Malathion PFGFFFF FPGStrawberry Pest Management Strategic Plan (PMSP) 11
Table 1. Efficacy ratings for pest management tools against invertebrate pests in Florida strawberry. Pests Pest Management ToolsTSM Other Mites FT SB Aphids FAW SAW CEW TB SMC LCB SLR OLT TPB Whiteflies Frujt flies Mole Crickets Ants Slugs Abbreviations: TSM=two-spotted spider mite FT=flower thrips SB=sap beetles FAW=fall armyworm SAW=southern armyworm CEW=corn earworm Abbreviations: TB=tobacco budworm SMC=saltmarsh caterpillar LCB=lesser cornstalk borer SLR=strawberry leafroller OLT=omnivorous leaftier TPB=tarnished plant bug Rating scale: E = excellent; G =good; F = fair; P = poor; Rating scale: ? = research needed; = not used; = used but not a stand alone management tool Metaldehyde Methoprene G Methoxyfenozide GGGGG Naled PFF Neem oil ... Paraffinic oil ... Insecticidal soap ... Propargite ... Pyrethrins + rotenone PF G Pyrethrins + piperonyl butoxideFFFPPPPGGGPEPP Pyriproxyfen E F E Spinosad G GGG EE SpiromesifenSulfurThiamethoxam G ENew Chemistries IR4 (P current IR-4 project)P Fenpyroximate EP Milbemectin G??G FStrawberry Pest Management Strategic Plan (PMSP) 12
Table 1. Efficacy ratings for pest management tools against invertebrate pests in Florida strawberry. Pests Pest Management ToolsTSM Other Mites FT SB Aphids FAW SAW CEW TB SMC LCB SLR OLT TPB Whiteflies Frujt flies Mole Crickets Ants Slugs Abbreviations: TSM=two-spotted spider mite FT=flower thrips SB=sap beetles FAW=fall armyworm SAW=southern armyworm CEW=corn earworm Abbreviations: TB=tobacco budworm SMC=saltmarsh caterpillar LCB=lesser cornstalk borer SLR=strawberry leafroller OLT=omnivorous leaftier TPB=tarnished plant bug Rating scale: E = excellent; G =good; F = fair; P = poor; Rating scale: ? = research needed; = not used; = used but not a stand alone management tool Cultural/Non-chemicalCertified pest-free plantsEFEG F Crop rotation FF F Removing ripe fruit from field G Resistant varieties EF Sanitation GGG GGGTraps Weed control GG Biological controlsBeneficial mites EPP Damsel bugs PPPPPPPP Big-eyed bugs P P Ground beetles PPPPPPP Lacewings P PPPPPPPP Ladybird beetles F F Minute pirate bugs PPF PPPPPPPP Parasitic wasps ?G FFFFFFFG Predatory midges P P Predatory thrips F?Strawberry Pest Management Strategic Plan (PMSP) 13
Table 1. Efficacy ratings for pest management tools against invertebrate pests in Florida strawberry. Pests Pest Management ToolsTSM Other Mites FT SB Aphids FAW SAW CEW TB SMC LCB SLR OLT TPB Whiteflies Frujt flies Mole Crickets Ants Slugs Abbreviations: TSM=two-spotted spider mite FT=flower thrips SB=sap beetles FAW=fall armyworm SAW=southern armyworm CEW=corn earworm Abbreviations: TB=tobacco budworm SMC=saltmarsh caterpillar LCB=lesser cornstalk borer SLR=strawberry leafroller OLT=omnivorous leaftier TPB=tarnished plant bug Rating scale: E = excellent; G =good; F = fair; P = poor; Rating scale: ? = research needed; = not used; = used but not a stand alone management tool Spiders PPPPPPPPP Syrphid fly larvae P FStrawberry Pest Management Strategic Plan (PMSP) 14
Toxicity scale: S = slightly toxic M = moderately toxic H= highly toxicToxicity scale: O=nontoxic ?= no data available Table 2. Toxicity of pest management t ools to beneficials in Florida strawberry. Beneficial Insects/ Mites Pest Management ToolsBeneficial mites Big-eyed bugs Damsel bugs Ground beetles Honeybees Lacewings Ladybird beetles Minute pirate Parasitic wasps Predatory midges Predatory thrips Spiders Syrphid fly larvaeRegistered materialsAbamectinMH MHMH MHAcequinocyl AzadirachtinSS S SBacillus thuringiensisSS S SBeauveria bassianaSS S SBifenazateSS S SBifenthrinHH H H HBoric acid Canola oilSS S SCarbarylSH H HChlorpyrifosHH H HDiazinonMH ? H HDicofolHS M ? M HEndosulfanHH H MEtoxazole Fenbutatin-oxideSS S SFenpropathrinHH H HHexythiazoxSS S SImidaclopridMH M? HMalathionMH H HStrawberry Pest Management Strategic Plan (PMSP) 15
Table 2. Toxicity of pest management t ools to beneficials in Florida strawberry. Beneficial Insects/ Mites Pest Management ToolsBeneficial mites Big-eyed bugs Damsel bugs Ground beetles Honeybees Lacewings Ladybird beetles Minute pirate Parasitic wasps Predatory midges Predatory thrips Spiders Syrphid fly larvaeToxicity scale: S = slightly toxic M = moderately toxic H= highly toxicToxicity scale: O=nontoxic ?= no data available Metaldehyde Methoprene Methoxyfenozide NaledHH ? ?Neem oil Paraffinic oilMS S SInsecticidal soapHH ? MPropargiteMH S? SPyrethrins + rotenone Pyrethrins + piperonyl butoxideMH SM? MHPyriproxyfenSS H SSpinosadMH MH? MHSpiromesifenSulfur SM SS SThiamethoxam?? ? ?New Chemistries IR4 (P current IR-4 project)P FenpyroximateHS ? HP MilbemectinMH MHMH MHStrawberry Pest Management Strategic Plan (PMSP) 16
Table 3. Indications for disease management products used on Florida strawberries Disease Management Product Angular leaf spot Anthracnoseacrown rot Anthracnoseafruit rot Anthracnosea root rotbBotrytis fruit rot Phytophthora diseases Powdery mildew Misc. leaf spots Azoxystrobin XXS X Captan X X X X Captan + fenhexamid X X X X Copper compounds X X Cyprodinil + fludioxonil X X Fenhexamid X Fosetyl-aluminum X Hydrogen peroxide Iprodione X Mefenoxam X Myclobutanil X X Potassium bicarbonate X Potassium phosphite X Pyraclostrobin X S X X Pyraclostrobin + boscalid X X X X Pyrimethanil X Quinoxyfen X Sulfur X Thiophanate methyl X X X X Thiram X Triflumizole X aAnthracnose diseases are caused by Colletotrichum species: C. fragariae and C. gloeosporioides (crown rot), C. acutatum (fruit rot, root rot) bAnthracnose root rot is suppressed by dipping bare root runner pl ants in solutions or suspensions of the indicated products jus t before planting X = used for control of indicated disease S = for suppression only of indicated diseaseStrawberry Pest Management Strategic Plan (PMSP) 17