Kelly Young Horticulture Agent University of Arizona Cooperative Extension, Maricopa County
1. Yes 2. No 50% 50% 1 2
1. Determine what is normal for the plant 2. Inquire about irrigation practices 3. Identify the plant 4. Recommend corrective pruning 5. Go to a big-box nursery department and ask for a product recommendation 20% 20% 20% 20% 20% 1 2 3 4 5
1. Poor pruning 2. Insects 12% 12% 12% 12% 12% 12% 12% 12% 3. Fungus 4. Improper irrigation 5. Bacteria 6. Virus 7. Parasitic plants 1 2 3 4 5 6 7 8 8. Nematodes
1. Insufficient irrigation 17% 17% 17% 17% 17% 17% 2. mites 3. fungus 4. Poor pruning practices 5. Nutrient deficiency 1 2 3 4 5 6 6. Pine beetles
25% 25% 25% 25% 1. Bacteria, fungi, viruses 2. Water, high temps, shade 3. Host, pathogen, favorable environment 4. Salinity, fungus, high ph 1 2 3 4
20% 20% 20% 20% 20% 1. Nitrogen deficiency 2. Iron or zinc deficiency 3. Overwatering 1 2 3 4 5 4. Underwatering 5. All of the above
Problem: My date palm isn t producing dates. Never attempt to diagnose a disease over the phone, even if you are 99% sure.
B COTTONWOOD IN WINTER BERMUDAGRASS IN WINTER
All three factors must be present for disease to occur Susceptible Host Disease Favorable Environment Causal Agent
Full or partial sun Alkaline or acid soil Frequent fertilizer Pollinator
Are all species affected? Location on the property Location on the plant Sudden onset Gradually over time
Weather conditions Temperature Humidity Wind Hail Light Soil conditions: Moisture Texture Structure Ph Salinity Depth
Beneficials Predatory nematodes Mycorrhizae Nitrogen fixing bacteria Parasites Root-knot nematodes Predators rabbits
Change in the appearance of functioning of the plant as a result of the disease Chlorosis Wilting Stippling Interveinal chlorosis
Actual evidence of the causal agent Mycelia, frass, spores, ooze
QUEEN PALM GARDENIA
Over pruning Over watering Under watering (or not watering properly) Too much or too little light Over fertilizing ph or salinity issues
Abiotic Corrected with deep winter irrigations
Animals: Insects,mites, nematodes Parasitic plants Fungi Bacteria Protists Virus
Symptoms: Small, stunted Chlorotic Wilt even when amply watered during warm weather Poor fruit set Fruits small Presence of knots on roots
Cotton (Texas) foot rot Only affects dicots Affects over 2300 plant spp. Symptoms: wilting and rapid death during hot months, dead leaves remain attached to plant
Occurs in smooth bark trees Sunburn - overpruning
Pose hazards Transmitted through wounds Mostly attacks dead cells Once conch visible the damage is extensive No treatment Ganoderma
Caused by Erwinia If lesion is small, remove and disinfect with 10% bleach
Caused by Agrobacterium tumefaciens
Occurs in tomato, peppers, spinach and beans, melons and squash Transmitted by beet leafhopper Leaves curl upward Develops in spring after wet year
Mostly affects cucurbits Whitefly transmitted
Systemic Acquired Resistance Attack by certain pathogens triggers series of events Whole plant responds
All three factors must be present for disease to occur Susceptible Host Disease Favorable Environment Causal Agent
Remember, Talk with most client, problems discuss plant are from choice, placement and care Bad plant choice Bad plant location Bad plant care If disease is still suspected, submit sample to MG diagnostics Don t try to diagnose over the phone If you believe you have ruled out the above submit sample for submission If diagnostic group can t solve problem, client will be advised to submit a sample to Tucson for diagnosis
1. Determine what is normal for the plant 2. Inquire about irrigation practices 3. Identify the plant 4. Recommend corrective pruning 5. Go to a big-box nursery department and ask for a product recommendation 20% 20% 20% 20% 20% 1 2 3 4 5
1. Poor pruning 2. Insects 12% 12% 12% 12% 12% 12% 12% 12% 3. Fungus 4. Improper irrigation 5. Bacteria 6. Virus 7. Parasitic plants 1 2 3 4 5 6 7 8 8. Nematodes
1. Insufficient irrigation 17% 17% 17% 17% 17% 17% 2. mites 3. fungus 4. Poor pruning practices 5. Nutrient deficiency 1 2 3 4 5 6 6. Pine beetles
25% 25% 25% 25% 1. Bacteria, fungi, viruses 2. Water, high temps, shade 3. Host, pathogen, favorable environment 4. Salinity, fungus, high ph 1 2 3 4
20% 20% 20% 20% 20% 1. Nitrogen deficiency 2. Iron or zinc deficiency 3. Overwatering 1 2 3 4 5 4. Underwatering 5. All of the above
University of Arizona Extension Plant Pathology: http://cals.arizona.edu/plp/plpext/ The American Phytopathological Society: http://www.apsnet.org/education/introplantpath/ Top.html Western Plant Diagnostic Network: https://www.wpdn.org/