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3 http://www.bing.com/videos/watch/video/monarch-butterfly-metamorphosis/242142B9588E878D68A9242142B9588E878D68A9 http://www.bing.com/videos/watch/video/monarch-butterfly-pupation/4CA8292A29F610D1DA5B4CA8292A29F610D1DA5B

4  http://bugguide.net/index.php?q=search&keys =caterpillars http://bugguide.net/index.php?q=search&keys =caterpillars

5  All factors present disease can result  Methods of control can modify the triangle Susceptible Host Disease No Disease Host PathogenEnvironment

6  Biotic factors (biological in origin)  Fungi  Bacteria  Viruses  Nematodes  Phytoplasmas  Abiotic factors (non-biological)  Weather  Environmental pollutants

7  Largest pathogen group  Over 200,000 known species of fungi  More than 8,000 cause plant diseases  Reproduce by asexual and sexual means  Spores are like seeds

8  Powdery Mildew  White coating on plant  sprinkled with powdered sugar  Group of diseases  Host specific  Environmental conditions correct (high humidity)

9  Rust  Rusty-orange powdery pustules  Easily removed by rubbing leaf  Can produce 4 types of different spores  Alternate hosts (Cedar-apple rust fungus)

10  Symptom  Abnormalities in a plant  Give us a sense if fungus or other pathogen  Spots  Roughly circular NECROTIC (dead area)  Lesions  Irregular shaped spots  Lesions can have yellow halos  Blight  Spots or lesions enlarge and merge

11 Black Spot of Elm, Gnomonia ulmea

12  Lesions  Often delimited (bordered) by veins  Angular appearance  Fungal lesions more irregular shape

13 Alternaria leaf blight caused by Alternaria solani (left) and Septoria leaf blight caused by Septoria lycopersici (right)

14  Cankers  Lesions on stems, branches or trunks  Sunken and discolored  Outer bark fallen away

15  Rots  Destruction and disintegration of a large portion of the plant  Affected areas are discolored and soft  Crown rots  Root rots Southern blight Sclerotium rolfsii

16  Fruit Rots  Start as dry rots  Secondary microorganisms (bacteria) begin and lead to soft, slimy rots  Pytophthora fruit rot of pumpkin

17  Wilts  Indicate plant is not getting water  Plants have a droopy appearance  Root rots  Root system decayed, no longer absorb water Cineraria with root rot Pythium

18  Wilts  Vascular wilt invades the xylem (water conducting tissue)  Vascular discoloration or browning  Xylem changes from whitish color to brown, green or gray color Verticillium Bacterial Wilt of Cucumber carried by Cucumber Beetle

19  Second most important group of plant pathogens  Spots  Lesions  Blight  Rots  Vascular wilts  Galls

20  Galls  Bacterial infections can cause galls to form  Bacterium induces gall formation by injecting it’s own DNA into a plant cell Crown gall

21  Reproduce by taking over host reproductive machinery  Often associated with insect vectors  Reproduction can take place in vector  Can be transmitted mechanically  Grower handling issues  Plants rubbing together

22  Mosaic  Mottling  Leaf and Fruit Distortions  Ringspot

23  Mosaic  Classic symptom  Blotchy light and dark green coloring on leaves  Poinsettia mosaic virus

24  Rose Mosaic Virus  Interesting lines and patterns

25  Mottle  Blotchy coloring occurs on flowers of other colored flower parts

26  Some cases of viral infections can be highly desirable  Tulips

27  Leaf and Fruit Distortions  Leaves are narrow or “strappy”, thicker then normal  Leaves are curled and twisted  Fruit has warts (yellow raised bumps) Zucchini

28  Ringspot  Concentric ring patterns on fruit or leaves  Papaya ringspot

29  Odd bacteria like organisms  Much smaller than bacteria, need an electron microscope  Transmitted by insects usually leafhoppers  Leafhoppers are phloem feeders

30  Virescence  Brooming  Fasciation  Twisting and Distortion

31  Virescense  Normally colored plant parts are green  Brooming  Plant parts become overly branched and bushy

32  Brooming - Ash Yellows

33  Fasciation  Flattening of plant parts Maple branch

34  Twisting, Distortion and Virescence  Cosmos with Aster Yellows

35  Parasitic worms  Very complex compared to other pathogens  Usually seen only with a light microscope  Reproduce by eggs

36  Nematodes  Identified by extracting from soil or infected plant material  Non-pathogenic vs. pathogenic nematodes  Pathogenic have a stylet  Modified tooth that punctures and feeds on plant tissue

37  Gall formation by nematodes  Nematode tunnels into the root  It’s saliva stimulates plant root cells to divide

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39  Nutritional abnormalities  Pesticide exposure  Environmental pollutants  Adverse weather conditions

40  Abnormalities are called INJURIES  Discolortion  Yellowing  Chlorosis  Reddening

41  Yellowing at margins of leaf  lack of molybdenum  General yellowing  lack of nitrogen  Leaf veins remain green and leaf blades turn yellow  lack of iron or manganese  Reddening of foliage  lack of phosphorus

42  Molybdenum deficiency on poinsettia  Yellowing at margins

43  Pesticide exposure  Curling and cupping  Geranium exposed to the herbicide 2,4-D

44  Pesticide exposure  Twisting  Tomatoes exposed to the herbicide 2,4-D

45  Pesticide exposure  Distortion  Rose exposed to a phenoxy-type herbicide  Symptoms similar to viruses and phytoplasmas  Gather information

46  Pesticide exposure  Fungicide use can cause marginal burning  Follow the label directions

47  Environmental Pollutants  Contaminants in water or the air  Marginal bronzing on Shefflera due to exposure to sulfur dioxide

48  Environmental Pollutants  Lesions on Dracena from high levels of fluoride in water or fluoride gas  Paper thin lesions, concentrated at margins

49  Environmental Pollutants  Browning of arborvitae due to dog urine

50  Environmental Pollutants  Cold injury  Candles starting to grow and cold weather comes  Gather information

51  Environmental Pollutants  Heat injury  High temps can cause tissue damage

52  Environmental Pollutants  Adverse weather conditions  Winter injury  Air temps rise but soil temps are cold  Plant begins growing but the roots can’t get water to the foliage  Plant desiccates and dies

53  Environmental Pollutants  Adverse weather conditions  Drought stress, reddening of branches

54  Plant Disease Diagnostics Clinic  http://www.plantpath.wisc.edu/pddc/index.html http://www.plantpath.wisc.edu/pddc/index.html  Soil and Plant Analysis Lab  Nutritional disorders  http://uwlab.soils.wisc.edu/ http://uwlab.soils.wisc.edu/

55 Slides in power point are copy write:  1999 by the Board of Regents of the University of Wisconsin System doing business as the division of Cooperative Extension of the University of Wisconsin Extension


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