Interiorscaping

1
Interiorscaping

• Chapter 7

2
Causes of Infectious Plant Diseases

• Plant pathogen living disease causing agent
• Examples are bacteria, viruses, fungi, nematodes
• Most are microscopic
• Parasites living on the plant
• Causes abnormal processes

3
Diseases vs. pathogens

• Diseases do not spread from plant to plant
• Pathogens do spread

4
Naming of plant disease

• Plant most commonly affected
• Plant part affected
• How the part is affected
• Name of pathogen

5
Disease triangle

• Host plant that is susceptible to the infection
• Pathogen itself
• Environmental conditions that are favorable

6
Control of disease

• Nature of the agent
• How Long has the disease been present
• What control measure economically feasible

7
Control principles

• Exclusion to prevent pathogen from being
  introduced
• Eradication elimination of the pathogen from an
  area
• Protection placement of a protective barrier
  between plant and pathogen (fungicide)
• Resistance use of plants that are resistant to
  pathogens

8
Exclusion and resistance practices

• Purchase pathogen free plants
• Acclimation and installation care plants not
  weakened
• Eradication discard and replace infected plants

9
IPM

• Integrated pest management using more than one
  practice to control diseases

10
powdery mildew

• Powdery mildew A. violet, begonia, grape ivy,
  jade plant, kalanchoe, mums
• Look whitish appearance on leaf surface
• Leaf distortion, browning, crusty lesions

11
control

• Keep susceptible plants away from cld air drafts
• Never water late in the day
• Avoid drought stress
• Use appropriate fungicide

12
Anthracnose leaf blights

• Schefflera, aglaonema, croton, dracaena, hedera,
  cissus, philo, pothos, monstera,
• Spotted or blighted areas on leaves petioles,
  stems, brown with tiny black spots
• Bulls eye look on tissue

13
control

• Resistant plants
• Plant spacing
• Irrigation
• Soilless media
• Handling procedures

14
Fungal leaf spots

• Dracaena, sansevieria, yucca, palms
• Spots can be reddish brown on young foliage, dry
  rot, cankering at the base of leaves
• Can look like fluoride and high soluble salt
  damage
• Spots also brown to black, sunken and purple
  margin

15
control

• No splashing of water
• Trim out infected areas
• Disease free material
• fungicides

16
Root and crown rots

• A. violet, aglonema, hedera, cissus, syngonium,
  pilo, schefflera
• Wilted foliage, yellowing, drop off, blackened
  and softened roots
• String like roots

17
control

• Good drainage of media
• Fungicides
• Sterile media used
• Leach to rid of soluble salts

18
Soil borne pathogens

• Pythium
• Phytophthora
• Cylindrocladium
• Wilting, yellowing of lower leaves

19
control

• Disease free plants
• Favorable root environment
• Soil free growing media
• Integrated maintenance
• Soil drench fungicides

20
Canker and dieback

• Caused by fungi that produce localized dead areas
  in bark and cambium tissues of twigs, branches,
  and trunks
• Dead tissue is oval to elongate, 1-2 inches to 1
  long
• Takes many years to develop
• Girdling then decline, dieback, death of branch

21
Plants affected

• Dracaena
• Araucaria
• Ficus
• Spathphyllum

22
control

• Stress management - imbalances
• Wound infections
• fungicides

23
Bacterial diseases

• Spread from a point of infection
• Leaf spot or stem lesion
• Water-soaked
• Oily spotting
• Blighting of foliage
• Yellow halo with brown center
• Leaf yellowing
• Soft rotted area, with odor

24
control

• chemical protectants
• Picking off diseased plant parts
• Tissue-cultured propagated plants
• Sanitary growing conditions
• Spread from plant to plant by hands, tools,
  splashing water

25
Virus diseases

• Exist in living cell of plant
• Tiny bodies, that infect, multiply,
• Abnormal green and yellow patterns in leaves
• Mosaics, ring-spotting, yellow spots with rings,
  distortion of young leaves, veins thick and
  translucent

26
control

• Show up in cool weather
• Will disappear in hot weather
• No chemicals available
• Good insect control
• Good cultural practices

27
Susceptible plants

• Mosaic virus on dieffenbachia
• Mosaic virus on Maranta
• Ghost Ring on Schefflera
• Spotted wilt virus on many plants

28
Nematode diseases

• Tiny microscopic roundworms
• Plant parasites causing disease
• Cause dead, brown to black areas between leaf
  veins
• Worse on older foliage
• Root feeding nematodes overall poor plant health
• Plant stunting, yellowing, tiny root swellings

29
control

• Nematicides
• Remove any specimens infested
• Avoid splashing water
• Do not use soil probes or shovels without
  disinfecting

30
Susceptible plants

• Foliar nematode on Ficus, begonia, peperomia
• Root knot nematode on Schefflera, Pothos,
  Maranta, Philos, Sansevieria
• Burrowing nematode Chamaedorea, Maranta, Philos

31
conclusion

• There are many diseases that affect indoor plants
• To know for sure, have a sample tested by a
  laboratory