What’s Wrong With Your Plants and Why?

1. What’s Wrong With Your Plants and Why? Tony Glover Regional Extension Agent

2. Diagnosis Can Be Tricky Without All The Facts

3. Abiotic vs. Biotic Problems • Abiotic – non-living agent (non-infectious). • Extreme temperatures • Excess or deficient water, light or nutrients • Soil compaction, soil grade changes • Damage from cultural practices: herbicides, fertilizers, pruning, mulching

4. Abiotic vs. Biotic Problems • Biotic – living agent (infectious). • Pathogens - parasitic microorganisms that cause disease (fungi, bacteria, viruses, phytoplasma) • Pests – insects, mites, nematodes or mammals feeding on or damaging plants.

5. Abiotic vs. Biotic Problems Symptom Progression • Biotic disease – symptoms progress and nearby plants become infected. • Abiotic disease – generally a lack of symptom progression. Does not spread. • Exception – nutritional deficiency symptoms progress slowly. Abiotic disease – Herbicide Injury

6. What’s Wrong? Biotic or Abiotic

7. Steps in Problem Diagnosis • Know the Plant • Inspect the Site and Look for Patterns • Look for Symptoms or Signs • Examine cultural practices and weather conditions • Identify Potential Causes • Consult Resources and Reach Diagnosis

8. Steps in Problem Diagnosis Know the Plant • Identify the species and cultivar affected • Know what problems commonly affect the species. For example: • Red Maple – Phyllosticta Leaf Spot, gloomy scale • Flowering Dogwood – Powdery Mildew, spot anthracnose

9. Steps in Problem Diagnosis Know the Plant • What’s normal for specific plant? Fall Needle Drop on White Pine

10. Steps in Problem Diagnosis Know the Plant • Look at the Whole Plant (foliage, stems, branches, leaves, and roots) • Note the color, size, and thickness of the foliage • Check the trunk and branches • Examine the Roots

11. Check the Trunk and Branches • Look for wounds, cankers, exit holes and other clues Pitch Tubes on Bark, Southern Pine Beetle

12. Check the Trunk and Branches • Sapsucker damage to sugar maple • Don’t mistake sapsucker damage for borer exit holes

15. Check the Trunk and Branches But…

16. Girdling Roots

17. Girdling Injury

18. Planted too deep

19. Deep Planting or Covered Later • Check for flare at base of trunk

20. Girdling Roots • Girdling roots are a common problem with trees that are planted too deep

21. Too Much Mulch Over The Root Ball • Problems caused by too much mulch • Keeps trunk tissue wet • Can increase rodent damage • Mulch can intercept rain and irrigation • Can keep poorly drained soils too wet • Can encourage surface roots • Can encourage development of stem girdling roots

22. Planted too deep Old root system has died

23. Steps in Problem Diagnosis Inspect the Site and Look For Patterns • Determine prevalence of problem. • Large area, all plants – generally abiotic. • Scattered, localized – generally biotic. • Check for distribution of symptoms. • Uniform – generally abiotic. • Random – generally biotic. • Are the symptoms/patterns related to geography? (soil, low spot, etc) • Is the damage limited to one type of plant? • Multiple plant species - often abiotic • One species – often biotic

24. Observation of Field PatternsAbiotic Problem • Symptoms distributed in a large area. Damage pattern is uniform. Gas leak from building

25. Observation of PatternsRandom vs. Uniform Leaf Spot (Fungal) Marginal Leaf Scorch

26. Observation of Field PatternsRandom vs. Uniform Oak Nutrient Deficiency Boxwood Phytophthora Root Rot

27. Observation of Field PatternsRandom vs. Uniform Random Patches Uniform Stripes Bermuda spring dead spot Fertilizer application problems

28. Steps in Problem Diagnosis • Know the Plant • Inspect the Site and Look for Patterns • Look for Symptoms and/or Signs • Examine Cultural Practices and Weather Conditions • Identify Potential Causes • Consult Resources and Reach Diagnosis

29. Look for Symptoms and/or Signs • Symptoms - plant reactions or alterations of a plant’s appearance due to a disease or disorder. • Signs - actual presence of the pathogen, it’s parts or by-products seen on a diseased host plant.

30. Symptoms

31. Signs

32. Steps in Problem Diagnosis • Know the Plant • Inspect the Site and Look for Patterns • Look for Symptoms and/or Signs • Examine Cultural Practices and Weather Conditions • Identify Potential Causes • Consult Resources and Reach Diagnosis

33. Steps in Problem Diagnosis Examine Cultural Practices and Weather Conditions • Ask questions - Collect as much background information as possible • When was the problem noticed? • Was the damage sudden or gradual? • Has the problem spread? • How old are affected plants? • What cultural practices have been performed recently? Herbicide Sprays?

34. Hail Damage

35. Steps in Problem Diagnosis • Identify Potential Causes • Consult Resources and Reach Diagnosis • Get Laboratory Assistance • Take samples (plant, soil) • Don’t forget pictures

36. Most Common Diseases of 2009Ornamentals • Phytophthora Root and Crown Rot • Boxwood, Juniper, Hydangea, Leyland Cypress, Pansy, Petunia, • Fungal Leaf Spots (Oak Leaf Blister, Anthracnose, and other leaf spots) • Armillaria Root Rot • Oakleaf Hydrangea, Cotoneaster • Pythium Root Rot • Pansy and other flowers • Powdery Mildew • Dogwood, Crape Myrtle, Rose • Botryosphaeria Canker /Dieback • Leyland Cypress, Japanese Maple, Cleyera • Bacterial Leaf Spots • Basil, Begonia, Oakleaf Hydrangea, English Ivy • Azalea Leaf Gall • Sooty Mold • Various Trees and Shrubs (Hackberry Woolly Aphid)

38. Diseases Caused by Phytophthora Some of the most economically important and damaging diseases on woody plants in the Southeast, USA, and worldwide The name Phytophthora derives from Greek and literally means “plant destroyer.” Cause problems annually Notorious Phytophthora diseases include rhododendron root rot, sudden oak death, and potato late blight. Particularly serious in or following “wet” years Diseases often are associated with wet or saturated soils

40. Phytophthora 101 Phytophthora species resemble fungi but are not. They are most closely related to aquatic organisms, such as brown algae and diatoms. Phytophthora organisms are often referred to as ‘water molds’ because they do need water to complete their life cycle. This group of organisms produces swimming spores .

41. Disease Cycle: Phytophthora Root Rot

42. Some Trees and Shrubs Attacked • Abies – fir • Acer – maple • Arbutus – madrone • Betula – birch • Buxus – boxwood • Camellia – C. japonica • Castanea – chestnut • Cedrus – cedar • Cercis – redbud • Chamaecyparis - false cypress • Citrus - orange, lemon, etc. • Cornus – dogwood • Cryptomeria -Japanese cedar • Cupressus - cypress • Elaeagnus • Eucalyptus • Fagus – beech • Ficus - fig • Forsythia • Ilex - holly • Juglans—walnut • Juniperus –juniper • Kalmia – laurel • Malus - apple

43. More Trees & Shrubs Attacked... • Pieris – andromeda • Pinus – pine • Platanus – sycamore • Prunus - cherry, plum, etc. • Pseudotsuga - Douglas fir • Pyrus - pear • Quercus – oak • Rhododendron - rhododendron, azalea • Robinia – locust • Rosa - rose • Rubus - raspberry • Syringa - lilac • Taxus - yew • Thuja - arborvitae • Tsuga - hemlock • Vaccinium - blueberry • Viburnum -arrowwood • Ulmus – elm

44. Phytophthora as Pathogens of Woody Plants They can attack all parts of the plant Blight & dieback on shoots & foliage —uncommon Cankers on stems & trunk —e.g., “bleeding” cankers – occasionally Root & crown rots — most common

45. Symptoms—Above Ground • Appear after roots are diseased • Chlorosis & yellowing of the foliage • very slight at first, then becoming obvious • Stunted growth • Overall wilting & decline • Cankers - orange/red/brown discoloration • on stems and trunk • distinct margin between healthy & diseased tissues • Plant death

46. Phytophthora Foliage Blight

47. Trunk and Stem Cankers “bleeding” cankers - maple

48. Trunk and Stem Cankers “bleeding” cankers - Oak outer bark inner bark Photo: Bruce Moltzen, Missouri Department of Conservation

49. Symptoms—Below Ground • Must expose roots for examination • this usually requires digging! • need to know what healthy roots look like! • Reduced root volume/lack of feeder roots • Roots discolored - red, brown, dark brown • healthy roots are white or off-white • Cortex sloughing/root rot • Cankers on root crown • may move up stem above ground

50. Boxwood - Cortex sloughing/root rot