1. Introduction to Insects

2. Phylum Arthropoda
(jointed appendages, exoskeleton, etc.)
• Class Insecta (most numerous and
diverse group of organisms)
• Class Arachnida
• Class Crustacea
• Etc. (centipedes, millipedes, etc.)
Spiders – often beneficial as predators
Mites – some plant pests, some predators

3. Insects vs Arachnids (Mites,
Spiders)

4. Insect Life Cycles
• 1. Simple metamorphosis
• 2. Complete metamorphosis
• 3. Some exceptions
• #1 and #2 apply to most agricultural pests

5. Simple Metamorphosis
Egg
Nymphs
Adult
– has full-size wings,
functional reproductive
system

6. Simple Metamorphosis
Nymphs
InstarInstar
Molt Molt

7. Simple Metamorphosis
Egg
Nymphs
Adult
– has full-size wings,
functional reproductive
system
Usually 4-6
instars, resemble
adults, smaller
size
Same food and environment for nymphs and adults

8. Complete Metamorphosis
Egg Pupa
Larva
– several instars,
important feeding stage
Adult
– very different
from larva
Corn Earworm

9. Complete Metamorphosis
• Life stages are important because
ecology, food habits, and management of
different stages can be different
• Example: butterflies and moths
• Larva – feeds as damaging caterpillar
• Adult – beneficial as plant pollinator

10. Survey of insects – Major groups
(orders) of ag pests or beneficial
predators and parasites
• Beneficial insects:
• Predators, parasites
• Pollinators
• Recyclers of OM

11. Survey of insects – Major groups
(orders) of ag pests or beneficials
• Dragonflies
• Orthoptera and relatives (mantids, roaches)
• Thrips
• True bugs (Hemiptera)
• Piercing-sucking insects (Homoptera)
• Beetles
• Nerve-winged insects (Neuroptera)
• Butterflies and moths
• Bees, wasps, and ants
• Flies
• Etc.

12. Survey of Insects
• Dragonflies --- beneficial predators of
flying insects
• Praying mantids --- beneficial predators
• Roaches --- recycling in some ag systems
• Grasshoppers, Crickets --- can be serious
ag pests

13. Tawny Mole Cricket

14. Thrips
Thrips
palmi

15. Thrips
• Almost microscopic in size, fringed wings
• Beneficial pollination in flowers
• Most are plant pests
• Some carry plant viruses

16. Virus Vectors
• Vector = carrier of virus
• Viruses in plants
• Transmitted by insects, etc.
• Vector feeds on infected plant acquires
virus feeds and passes virus to other
plants

17. True
Bugs
• Squash bug
• Note typical
appearance

18. True Bugs
• Piercing-sucking mouthparts
• Some important pests, e.g., stink bugs
• Some predators

19. Piercing-Sucking Insects
• Piercing-sucking mouthparts to feed on
plants
• Formerly Homoptera, often included with
true bugs
• Many important plant pests
• Some transmit viruses
• Aphids, cicadas, whiteflies, scale insects,
leafhoppers, etc…

20. Green Peach Aphid
• Very abundant as plant pests

21. Whitefly Adult
• Common underneath leaves

22. Sooty Mold - Silverleaf
• Important sign of whiteflies, etc…

23. Beetles
• Pepper Weevil

24. Beetles
• Very many species
• Many pests – weevils, larvae of some
types are grubs or wireworms
• Many beneficials – Lady beetles, ground
beetles, tiger beetles

25. Nerve-Winged Insects (Neuroptera)
• Brown Lacewing

26. Lacewing Larva Eating Whiteflies
• Beneficial predators

27. Butterflies and Moths
• Pests – many kinds of caterpillars
• Beneficial as pollinators

28. Bees, Wasps, Ants
• Beneficial as pollinators
• Many are important as predators and
parasites
• Many different kinds of wasps, most nearly
microscopic
• Parasitoids – microscopic wasps, lay
eggs in body of pest (e.g., caterpillar), or
even in egg

29. Flies
• Many different kinds, difficult to distinguish
– different flies do different things:
• Important pests of livestock
• Beneficial as pollinators
• Beneficial as predators
• Some are parasitoids
• Some are plant pests (leaf miners)

30. Leafminers
• Larvae of some flies, some moths

31. Many Important Pests of Livestock
• Flies, Lice, Fleas, etc…

32. Important Insect Relatives
• Mites -- some beneficial predators
• Mites – some livestock pests
• Mites – some plant pests
• Spiders – Very important as predators
(much underrated) in agroecosystems

33. Mite Damage on Leaf

34. Spider Mites
• Note characteristic webbing

35. Management of Insect Pests

36. Insecticides and Acaricides
• +++ effective, detailed knowledge of pest
biology not needed
• +++ reliable, fast-acting
• +++ quick response to emergency
situations
• - - - non target effects
• - - - $ and energy costs
• - - - high expectations

37. Biological Control
• Control by living organism or natural
product of living organism
• Hyperparasitism
Caterpillar Tachinid fly Parasitoid Wasp

38. Biological Control
-- Two Approaches
• Introduced = add control agents to
ecosystem (many good examples with
introduced pests)
• Introduced: classical (new agent) vs
augmentation (agent already present)
• Natural = favor increase of naturally
occurring control agents (manipulate
environment, cropping systems)

39. Biological Control
Many possible organisms:
• Predators (often not specific)
• Parasites
• Diseases (parasites)
Fungi
Bacteria
Viruses
Parasitoids (often highly specific)
Entomopathogenic nematodes

40. Host Plant Resistance
• Interfere with host finding, feeding, pest
nutrition, timing of life cycles, etc…
• Hairs on leaves, sticky, etc.
• Alkaloids in plants deter insects
• Crop cultivars/genotypes selected for
resistance to pests

41. What is Biological Control
and What Is Not ???

42. What is Biological Control?
• Predators
• Parasites
• Diseases

43. What is Biological Control?
• Predators
• Parasites
• Diseases
• Bacterial disease of insects caused by
Bacillus thuringiensis (BT)

44. What is Biological Control?
• Bacterial disease of insects caused by
Bacillus thuringiensis (BT)
• Allow bacteria to produce spores with
toxin in lab, isolate BT toxin, and spray it
on pests

45. What is Biological Control?
• Bacterial disease of insects caused by
Bacillus thuringiensis (BT)
• Allow bacteria to produce spores with
toxin in lab, isolate BT toxin, and spray it
on pests
• Transgenic plants that produce BT toxin
(Bt corn, Bt cotton)

46. What is Biological Control?
• Resistant plants as biological control
agents
• Plants with alkaloids
• Pyrethrum = natural plant alkaloid

47. What is Biological Control?
• Resistant plants as biological control
agents
• Plants with alkaloids
• Pyrethrum = natural plant alkaloid
• Isolate pyrethrum from plants and use it

48. What is Biological Control?
• Resistant plants as biological control agents
• Plants with alkaloids
• Pyrethrum = natural plant alkaloid
• Isolate pyrethrum from plants and use it
• Make synthetic pyrethrum
• Pyrethroid = pyrethrum analog, similar chem
structure

49. Environmental Heterogeneity
• Crop genetics (uniform genotypes vs mix)
• Vegetation diversity vs pest dispersal
• Vegetation diversity as reservoir for
natural enemies

50. Plant Health
• +++ Healthy plant can withstand some
insect damage
• - - - High N can increase insect growth
and reproduction

51. Attractants and Repellents
• Attractant, e.g., pheromone (sex or
aggregation) useful for:
• Sampling and monitoring (important use
for quarantine detection, regional
monitoring)
• Attracting insects to traps
• Confusing normal life processes and
patterns

52. Cultural Practices
• Crop Rotation
• Weed control of virus hosts
• Sanitation and cleanup of crop residues
(affected overwintering of boll weevil)
• Timing of planting dates (winter wheat,
Hessian fly)
• Others (sterile males, etc.)

53. For most effective insect
management, usually need
to know biology and habits
of individual insect pests

54. References
• Text: Ch 10, pp. 201-208; Ch.11, pp. 219-222.
• Metcalf C.L., W.P. Flint, and R.L. Metcalf. 1962.
Destructive and Useful Insects. McGraw-Hill,
NY.
• Metcalf, R.L., and W.H. Luckmann. 1994.
Introduction to Insect Pest Management. John
Wiley & Sons, NY.
• Images from UF Dept. Entomology &
Nematology – Featured Creatures:
• http://creatures.ifas.ufl.edu