University of Florida - IFAS Plant Disease Management Uses an Integrated Approach Exclusion Plant resistance Cultural controls Chemicals Microbiologicals 1

University of Florida - IFAS Integrated Plant Disease Management Exclusion Regulation of plant material at ports, city, county, state or country boundaries – federal and state rules Pathogen-free seed or plants Seed certification Meristem culture Cuttings from clean “mother” plant under sterile conditions 2

Don’t Pack a Pest University of Florida - IFAS Integrated Plant Disease Management Exclusion 3

University of Florida - IFAS Integrated Plant Disease Management Exclusion Where did all the impatiens go? Downy Mildew caused by Plasmopara obducens on Impatiens walleriana 4

University of Florida - IFAS Integrated Plant Disease Management Plant Resistance  Genetic Immunity is the rule in the plant kingdom If immunity does not exist, plant breeders develop cultivars with resistance to specific pathogens Constitutive and inducible defenses  Chemically or Biologically Induced Application of chemicals or biologicals to induce production of defense compounds  Adaptation Plant adaptation to site 5

University of Florida - IFAS Integrated Plant Disease Management Plant Resistance Graft susceptible top onto resistant root stock For Florida, roses grafted on 'Fortuniana' rootstock thrive Genetic 6

University of Florida - IFAS Integrated Plant Disease Management Plant Resistance Constitutive: continuous defenses; includes cell walls, waxy epidermal cuticles, bark, leaf hairs – physical and chemical barriers Inducible: defenses (chemicals or proteins) produced in response to invading pathogens; includes toxic chemicals, pathogen-degrading enzymes, deliberate plant cell suicide Genetic 7

University of Florida - IFAS Integrated Plant Disease Management Plant Resistance  Systemic Acquired Resistance (SAR) Activated when pathogen infects tissue Long-lasting systemic immunity, even in tissues not infected Relatively broad spectrum Usually associated with increase in phytohormone salicylic acid (SA) Genetic 8

University of Florida - IFAS Integrated Plant Disease Management Plant Resistance Chemically Induced Systemic Acquired Resistance (SAR) Use of SA or SA analogs can induce SAR-like responses Provides resistance in plant tissues beyond application site (systemic) Often referred to as “plant activators” Benzothiadiazoles (ex: Actigard) used for plant protection 9

University of Florida - IFAS Integrated Plant Disease Management Plant Resistance Biologically Induced  Systemic Acquired Resistance SAR) Weak viruses  Induced Systemic Resistance (ISR) Triggered by non-pathogenic plant growth promoting rhizobacteria Involves jasmonic acid and ethylene, rather than salicylic acid doi: /AEM Appl. Environ. Microbiol. Sept vol. 71, no. 9, pp doi: /tpc Plant Cell May 2013 vol. 25, no. 5, pp. 1489–

University of Florida - IFAS Integrated Plant Disease Management Plant Resistance Adaptation “Right Plant for the Right Site” temperate vs. tropical; cold induction dry vs. rainy soil type: sand vs. clay day length others? Genetic resistance can be overcome if site is not right for the plant species 11

University of Florida - IFAS Integrated Plant Disease Management Cultural Controls Crop rotation Alternate host eradication – for pathogens and vectors Sanitation of tools, equipment, potting containers, shoes, etc. Improved plant environment, especially water management, air circulation Nutrient management Soil treatment, such as solarization, tillage Mulches or other barriers 12

University of Florida - IFAS Integrated Plant Disease Management Chemical Controls Fungicides Bactericides Nematicides Insecticides Fumigants Seed treatments Soil treatments Root drenches Disinfecting tools Foliar sprays Trunk injections Trunk sprays Post-harvest use  For fungicides and bactericides, the “cides” is not accurate. Most suppress rather than kill.  There are no chemicals to use against plant viruses. 13

University of Florida - IFAS Integrated Plant Disease Management Chemical Controls From: Also see: Figure 1. U.S. Crop Protection Fungicide Use 14

University of Florida - IFAS YearFungicidePrimary Use 1637Brine (Salt)Cereal seed treatment 1755ArsenicCereal seed treatment 1760Copper sulfateCereal seed treatment 1824Sulfur (dust)Powdery mildew and other pathogens 1833Lime sulfurBroad spectrum foliar pathogens 1885Bordeaux mixtureBroad spectrum foliar pathogens 1891Mercury chlorideTurf fungicide 1900CuOCl 2 Especially Phytophthora infestans 1914Phenylmercury chlorideCereal seed treatment 1932Cu 2 OSeed and broad spectrum foliar diseases 1934Dithiocarbamates patentedBroad spectrum protectants 1940Chloranil, DichloneBroad spectrum seed treatment Integrated Plant Disease Management Chemical Controls (IN)Organic Fungicides: f f 15 From: Organic Materials Review Institute:

University of Florida - IFAS Integrated Plant Disease Management Chemical Controls FRAC CodeChemical ClassMode of action / inhibition Resistance risk 1BenzimidazolesBeta-tubulin assembly in mitosis (cytoskeleton and motor proteins)high 2DicarboximidesMAP/Histidine-kinase in osmotic signal transductionmedium-high 3Azoles, PyrimidinesC-14 demethylation in sterol biosynthesis in membranesmedium 4PhenylamidesRNA polymerase I (nucleic acid synthesis)high 5Morpholines^8 and ^7 isomerase and ^14 reductase in sterol biosynthesislow-medium 7CarboxamidesSuccinic acid oxidation (respiration)medium 9AnilinopyrimidineMethionine biosynthesis (amino acid and protein synthesis)medium 11StrobilurinsMitochondrial synthesis in cytochrome bc1 (respiration)high 16Various chemistryMelanin biosynthesis (two sites) in cell wallmedium 40Carboxylic acid amidesCellulose synthase (cell wall formation in Oomycetes)low-medium M1InorganicsMultisite contactlow M3DithiocarbamatesMultisite contactlow M5PhthalimidesMultisite contactlow Mode of action of some major fungicides classes, their FRAC code and resistance risk Fungicide Resistance Action Committee:

University of Florida - IFAS Integrated Plant Disease Management Chemical Controls From: 17

University of Florida - IFAS Integrated Plant Disease Management Microbiological Controls  Fungi: Trichoderma, Candida, Muscodor, Pythium, Ulocladium, Verticillium  Bacteria: Bacillus group, Streptomyces, Xanthomonas, Pseudomonas, Pantoea, Pasteuria, Agrobacterium, Paecilomyces, Burkholdaria

University of Florida - IFAS Integrated Plant Disease Management Microbiological Controls  Effective because they produce: Antibiotics Lytic enzymes Biocidal volatiles  Effective because they outcompete the pathogens Detoxification enzymes Iron-chelating siderophores 19

University of Florida - IFAS Integrated Plant Disease Management Microbiological Controls Bacillus subtilis strains: QST 713 MBI 600 GB03 FZB24 Registered by EPA as biopesticide 20

University of Florida - IFAS Plant Disease Management Uses an Integrated Approach Exclusion Plant resistance Cultural controls Chemicals Microbiologicals 21

University of Florida - IFAS 22 Is there a place for GMOs in our integrated plant disease management tool box? Integrated Plant Disease Management GMOs

University of Florida - IFAS Some diseases cannot be controlled with any currently available methods! 23 Integrated Plant Disease Management GMOs Florida Example: Bacterial Spot Disease of Tomatoes The Good, the Bad, and the Ugly: What the Future Could Hold for Bs2 Tomatoes