Pests and Diseases

1
Pests and Diseases

• 28.00 Examine distinguishing characteristics of
  pests so as to determine best management
  practices.
• 29.00 Compare methods of control of
  horticulture plant pests.

2
Types of Insects

• The six types of mouthparts are important in
  identifying and controlling insects.
• Chewing
• Piercing
• Rasping
• Siphoning
• Sponging
• Sucking

3
Chewing Insects

• Parts of leaves are eaten away
• beetles
• cutworms
• caterpillars
• grasshoppers

4
Piercing Insects

• Punctures plant and sucks the sap
• Brown Stinkbug

5
Rasping insect

• Rasps or breaks surface and sucks sap
• Example
• Thrips

6
Siphoning insects

• Have a coiled tube they dip into liquid food such
  as nectar and draw it in
• Example
• butterfly

7
Sponging Insects

• Have two sponge-like structures that collect
  liquid food and move it into the food canal
• Example
• housefly

8
Sponging Insects

• Have two sponge-like structures that collect
  liquid food and move it into the food canal
• Example
• housefly

9
Sucking Insects

• Suck on underside of leaf (usually young) to
  collect nutrients
• Example
• Spider mites
• Aphids
• Squash Bug

10
MOST COMMON INSECT ISSUES
11
Aphids
12
Aphids

• Pierce and suck juices
• known as plant lice
• cause stunted growth and yellow spotted leaves
• causes sticky substances and black mold
• will attract ants

13
Aphids
14
Leaf Bugs
15
Leaf Bugs

• Cause plants to look unhealthy
• plants will lose their normal color and wilt

16
Leaf Bugs
17
Mealy bugs
18
Mealy Bugs

• Pierce and suck from underside of leaves and in
  leaf axils causing yellow appearance and sticky
  secretions

19
Mealy bugs
20
Thrips
21
Thrips

• Chew and then suck causing plant tissue to become
  speckled or whitened, leaf tip to wither, curl
  up, or die

22
Thrips
23
Whiteflies
24
Whiteflies

• Feed on underside of young leaves causing
  yellowing
• will look like flying little white specks when
  plants are shaken

25
Whiteflies
26
Mites
27
Mites

• Attack underside of leaves causing gray to
  grayish-green spots
• severe infestations cause webbing

28
Mites
29
Plant Diseases
30
Scale

• Appear as black or brown raised lumps attached to
  stems and underside of leaves causing yellow
  leaves and stunted growth

31
Scale
32
Blight

• Causes plants to quickly turn brown or black as
  if they had been burned

33
Blight
34
Canker

• Causes open wounds on woody plants

35
Canker
36
Damping off

• A fungal disease that causes young plants and
  seedlings to rot off at soil level

37
Damping Off
38
Gall

• Swellings or growths on plants

39
Leaf Spots

• Rings of different shades of brown, green or
  yellow that make spots on leaves

40
Mildew

• Grows on leaf surfaces--both upper and lower--as
  white, gray or purple spots

41
Mosaic

• Caused by viruses that make the leaves have
  irregular mottled areas with patterns ranging
  from dark green to light green to yellow to white

42
Mosaic
43
Rots

• Cause plant to decay and die

44
Rust

• Causes small spots on leaves that resemble
  yellow, orange, brown or red rust mainly on the
  underneath side of leaves

45
Rust
46
Smut

• A black, powdery disease that causes blisters
  that burst open releasing black spores

47
Wilt

• A disease that blocks the uptake of water in
  plant stems causing plants to wilt

48
Wilt
49
Smut
50
Controlling Pests and Diseases
51
Disease Control

• Preventing plant diseases is better than treating
  the diseases
• Plant diseases must be identified before they can
  be treated

52
IPM

• A combination of control methods is called
  Integrated Pest Management or integrated control.

53
Controlling Insects

• Insects can be controlled using the following
  methods
• biological
• chemical
• cultural
• mechanical
• natural
• quarantine

54
Biological Control

• Uses natural enemies such as birds, other
  insects, etc.

55
Chemical Control

• The use of pesticides or insecticides
• Insects must be killed when they are actively
  feeding or moving on the plant

56
Chemical Control

• Contact poisons
• affect the insects nervous system and must come
  into contact with the insect to be effective
• Fumigants
• poisonous gases released into an enclosed place
  so that insects breathe the gases

57
Chemical Control

• Stomach poisons
• sprayed on the plant surfaces or are taken into
  the plant through absorption.
• The insect must suck the poison to get it into
  the stomach for this method to be effective.
• Systemic poisons are more effective for
  controlling sucking insects.

58
Cultural Control

• Involves sanitation, removing insect breeding and
  hiding areas and using insect resistant plant
  varieties

59
Mechanical Control

• Uses physical control such as insect traps, using
  screens over fans and other openings, and washing
  plants with soapy water.

60
Natural Control

• Methods include natural barriers such as rivers,
  woods, mountains and predators to control insects.

61
Quarantine

• Physically isolates insects from healthy plants

62
IPM

• A combination of control methods is called
  Integrated Pest Management or integrated control.