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. What is an insect?
Small animals that have three body regions and three pairs of legs equaling six legs
Body regions
head
thorax
abdomen

3. Types of Insects
The five types of mouthparts are important in identifying and controlling insects.
Chewing
Piercing
Rasping
Siphoning
Sponging

4. Chewing Insects Insects tear, chew or grind food Examples grasshopper
beetle

5. Piercing Insects
Punctures plant and sucks the sap

6. Rasping insect
Rasps or breaks surface and sucks sap
Example
thrips

7. Siphoning insects
Have a coiled tube they dip into liquid food such as nectar and draw it in
Example
butterfly

8. Sponging Insects
Have two sponge-like structures that collect liquid food and move it into the food canal
Example
housefly

9. Life Cycles Complete metamorphosis has four stages egg
larva-worms or caterpillars
pupa
adult-flies, beetles, etc.

10. Life Cycles
Incomplete metamorphosis has three stages
egg
nymph
adult

11. Life Cycles

12. Chewing Insects Parts of leaves are eaten away beetles cutworms
caterpillars
grasshoppers

13. Chewing Insects Beetles Cutworms
eat leaves, stems, flowers, fruit and nuts
Cutworms
usually attack stems, but may eat other plant parts

14. Chewing Insects Caterpillars Grasshoppers
larva of moths and butterflies
fuzzy or hairy
eat young leaves and stems
roll up in leaves making leaves curl
Grasshoppers
eat all parts of plants

15. Sucking Insects
Aphids
Leaf bugs
Mealy bugs
Scale
Thrips
Whiteflies

16. 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

17. Aphids

18. Leaf Bugs Cause plants to look unhealthy
plants will lose their normal color and wilt

19. Leaf Bugs

20. Mealy Bugs
Pierce and suck from underside of leaves and in leaf axils causing yellow appearance and sticky secretions

21. Mealy bugs

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

23. Scale

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

25. Thrips

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

27. Whiteflies

28. Mites Attack underside of leaves causing gray to grayish-green spots
severe infestations cause webbing

29. Mites

30. Plant Diseases

31. Diseases
A disease is a plant disorder caused by an infectious pathogen or agent

32. Diseases There are 3 conditions necessary for diseases in plants
host plant
disease causing organism or pathogen must be present
favorable environment for disease organism to develop

33. Pathogens There are four groups of pathogens bacteria fungi viruses
parasitic plants (attach to plants)
mistletoe
dodder
lichens

34. Blight
Causes plants to quickly turn brown or black as if they had been burned

35. Blight

36. Canker
Causes open wounds on woody plants

37. Canker

38. Damping off
A fungal disease that causes young plants and seedlings to rot off at soil level

39. Damping Off

40. Gall
Swellings or growths on plants

41. Leaf Spots
Rings of different shades of brown, green or yellow that make spots on leaves

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

43. 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

44. Mosaic

45. Rots
Cause plant to decay and die

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

47. Rust

48. Smut
A black, powdery disease that causes blisters that burst open releasing black spores

49. Smut

50. Wilt
A disease that blocks the uptake of water in plant stems causing plants to wilt

51. Wilt

52. Controlling Pests and Diseases

53. Disease Control
Preventing plant diseases is better than treating the diseases
Plant diseases must be identified before they can be treated

54. Environment
Warm temperatures and moist conditions in greenhouse plant production make most horticulture plant diseases worse because of environmental conditions that support disease-causing pathogens

55. Controlling Insects
Insects can be controlled using the following methods:
biological
chemical
cultural
mechanical
natural
quarantine

56. Biological Control
Uses natural enemies such as birds, other insects, etc.

57. Chemical Control The use of pesticides or insecticides
Insects must be killed when they are actively feeding or moving on the plant

58. Chemical Control Contact poisons Fumigants
affect the insect’s 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

59. 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.

60. Cultural Control
Involves sanitation, removing insect breeding and hiding areas and using insect resistant plant varieties

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

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

63. Quarantine
Physically isolates insects from healthy plants

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