Organic Approaches to Organic Approaches to Disease ControlDisease Control

George DrieverGeorge Driever

Area Pest Management SpecialistArea Pest Management Specialist

Cooperative Extension ServiceCooperative Extension Service

Oklahoma State UniversityOklahoma State University

Plant pathogensPlant pathogens

FungiFungi BacteriaBacteria VirusesViruses PhytoplasmsPhytoplasms NematodesNematodes

Host

Environment

Time

Pathogen

Disease

DISEASE TRIANGLE

Identifying Diseases by SymptomsIdentifying Diseases by Symptoms

Fungi – spots, lesions, blights, yellowing of Fungi – spots, lesions, blights, yellowing of leaves, wilts, cankers, rots, fruiting bodiesleaves, wilts, cankers, rots, fruiting bodies

Bacteria – water-soaking, spots, wilts, rots, Bacteria – water-soaking, spots, wilts, rots, blights, cankers, exudates, galls, yellowingblights, cankers, exudates, galls, yellowing

Viruses – mottling, leaf and stem distortions, Viruses – mottling, leaf and stem distortions, stuntingstunting

Phytoplasms – similar to virus symptomsPhytoplasms – similar to virus symptoms Nematodes – stunting, dying plants Nematodes – stunting, dying plants

Difficulties in IdentificationDifficulties in Identification

Plant pathogens are very smallPlant pathogens are very small Similar symptoms between bacteria and fungi Similar symptoms between bacteria and fungi

and between fungal groupsand between fungal groups Field diagnosis is difficultField diagnosis is difficult Multiple pathogens may be present at the same Multiple pathogens may be present at the same

time.time. Multiple symptoms may be presentMultiple symptoms may be present

Methods of Disease ControlMethods of Disease Control

CulturalCultural

ChemicalChemical

BiologicalBiological

Cultural Disease ControlCultural Disease Control

Develop soil rich in organic matterDevelop soil rich in organic matter Plant on raised bedsPlant on raised beds Plant tolerant or resistant varietiesPlant tolerant or resistant varieties Crop rotation Crop rotation Plants adapted to areaPlants adapted to area Plant at proper depth (below crown or graft)Plant at proper depth (below crown or graft) Use only thoroughly composted materialUse only thoroughly composted material

Cultural Disease Control cont’dCultural Disease Control cont’d

Soil pH adjustmentSoil pH adjustment Improve air circulation by staking, trellis Improve air circulation by staking, trellis

or pruningor pruning Remove weeds: carry disease, circulationRemove weeds: carry disease, circulation Water in the morning Water in the morning Avoid high angle sprinklersAvoid high angle sprinklers Do not over fertilizeDo not over fertilize Remove diseased plants and destroyRemove diseased plants and destroy

Exclusion of DiseaseExclusion of Disease

Certified disease free plantsCertified disease free plants Prevent introduction of diseased plants or soilPrevent introduction of diseased plants or soil Disease free water sourceDisease free water source Control insects that can carry diseaseControl insects that can carry disease Soil solarizationSoil solarization

Chemical ControlsChemical Controls

Hydrated LimeHydrated Lime Lime sulfurLime sulfur CoppersCoppers Horticultural OilsHorticultural Oils Essential OilsEssential Oils BicarbonatesBicarbonates AntibioticsAntibiotics

Hydrated LimeHydrated Lime

pH adjustmentpH adjustment Component of Bordeaux mixtureComponent of Bordeaux mixture

Lime SulphurLime Sulphur

Use as a protectant dust or spray to control Use as a protectant dust or spray to control some fungal or bacterial diseasessome fungal or bacterial diseases

Helps control peach leaf curl, rust, powdery Helps control peach leaf curl, rust, powdery mildew (PM), brown rotmildew (PM), brown rot

Lilly Miller Poly Sul Lime Sulfur – Calcium Lilly Miller Poly Sul Lime Sulfur – Calcium Polysulfide – 28.7% Polysulfide – 28.7%

Generic and other brands availableGeneric and other brands available

CoppersCoppers

Controls some fungi and FireblightControls some fungi and Fireblight Free Cu - Copper sulfate: Bordeaux mixtureFree Cu - Copper sulfate: Bordeaux mixture Fixed Cu - copper hydroxide, copper oxide, Fixed Cu - copper hydroxide, copper oxide,

copper oxychloride, copper octanoatecopper oxychloride, copper octanoate Kocides – restricted use, requires licenseKocides – restricted use, requires license Safer Garden fungicide – Cu 12% or 0.4% : Safer Garden fungicide – Cu 12% or 0.4% :

rust, scab, brown spot, black spot, othersrust, scab, brown spot, black spot, others

CopperCopper

Bonide Liquid Cu – Cu octanoate 0.08% : PM, Bonide Liquid Cu – Cu octanoate 0.08% : PM, rust, black spot, late blight, othersrust, black spot, late blight, others

Bonide Copper Garden Dust – copper sulfate Bonide Copper Garden Dust – copper sulfate and rotenone for fruits, garden, and flowersand rotenone for fruits, garden, and flowers

Lilly Miller Cueva Cu soap – Cu octanoate Lilly Miller Cueva Cu soap – Cu octanoate 0.08%: PM, DM, gray mold, blight, spots0.08%: PM, DM, gray mold, blight, spots

Many other brandsMany other brands

Horticultural oilsHorticultural oils

Mostly controls foliar insects, but also peach leaf Mostly controls foliar insects, but also peach leaf curl, and some other fungicurl, and some other fungi

Dormant, suffocating, summer oilsDormant, suffocating, summer oils Fungus Pharm – soybean oil plus Rosemary oil Fungus Pharm – soybean oil plus Rosemary oil

0.1%0.1%

Essential OilsEssential Oils

Neem oil – up to 70%: many brands that Neem oil – up to 70%: many brands that control insects, mites and some fungi such as control insects, mites and some fungi such as PM, rust, scab, leaf spots, anthracnose and PM, rust, scab, leaf spots, anthracnose and black spotblack spot

Green Light Organic fungicide – Rosemary Green Light Organic fungicide – Rosemary Oil 0.2%: anthracnose, blights, gray mold, Oil 0.2%: anthracnose, blights, gray mold, PM, DM, leaf spots, scab, rusts, othersPM, DM, leaf spots, scab, rusts, others

BicarbonatesBicarbonates

Potassium Bicarbonate – disrupts cell Potassium Bicarbonate – disrupts cell membrane K balancemembrane K balance

Bi Carb - K bicarbonate: PM, othersBi Carb - K bicarbonate: PM, others

Safer 3 in 1 – K salts: PM Black spot, leaf Safer 3 in 1 – K salts: PM Black spot, leaf spots, rusts for seed, transplants or established spots, rusts for seed, transplants or established plantsplants

Sodium Bicarbonate ?Sodium Bicarbonate ?

AntibioticsAntibiotics

Streptomycin sulfate – many brands for Streptomycin sulfate – many brands for agricultural use to control bacteria, fireblightagricultural use to control bacteria, fireblight

Fertilome Fireblight spray : also for bacterial Fertilome Fireblight spray : also for bacterial wilt, stem rot, leaf spots and crown gallwilt, stem rot, leaf spots and crown gall

Tetracycline - fireblightTetracycline - fireblight

Antagonists/ CompetitorsAntagonists/ Competitors

Trichoderma harziumTrichoderma harzium is the most researched is the most researched Many others are being looked atMany others are being looked at

Biological ControlsBiological Controls

Bacillus subtillusBacillus subtillus

Seranade Garden Disease Control – control Seranade Garden Disease Control – control and suppressionand suppression

Streptomyces griseoviridisStreptomyces griseoviridis – Pythium, – Pythium, Botrytis, Fusarium, Alternaria, Phomopsis, Botrytis, Fusarium, Alternaria, Phomopsis, slightly on Phytopthora, Rhizoctoniaslightly on Phytopthora, Rhizoctonia

Pythium oligandrumPythium oligandrum DV 74 – hyperparasite DV 74 – hyperparasite in testing on many pathogenic fungiin testing on many pathogenic fungi

Nematode ControlNematode Control

ExclusionExclusion Resistant varietiesResistant varieties Crop rotationCrop rotation Cover cropsCover crops

Grain Rye (Elbon rye) for root knotGrain Rye (Elbon rye) for root knot SolarizationSolarization

Take Home MessageTake Home Message

PlanPlan Keep recordsKeep records ScoutScout Learn disease symptomsLearn disease symptoms Be proactive in controlBe proactive in control