1. Beneficial and Harmful Insects
Plant Pest
Beneficial and Harmful Insects

2. Objectives Compare and Contrast complete and incomplete metamorphosis.
Identify and describe beneficial insects.
Identify and describe harmful insects.
**For this lesson you will need to take notes on the different insects mentioned**

3. Introduction Plants naturally have inherited problems
These plants rarely can be cured.
The best way to avoid this is to choose plants best adapted for the region.
Florida has more different kinds of insects that any other state.

4. Introduction (continued)
Most insects are NOT harmful to our plants.
Harmful insects are harmful due to:
Feeding Habits
Breeding
Shelter Habits

5. Insect Lifecycles Complete Metamorphosis
Metamorphosis: when insects pass through several stages during development.
Complete Metamorphosis
4 stages: Egg, Larva, Pupa, Adult
Examples:
Butterflies
Mealworms
Ladybugs

6. Incomplete Metamorphosis
3 Stages:
Egg
Nymph
Adult
Examples:
Stinkbugs
Earwigs
Grasshopper
Cockroaches

7. Beneficial Insects
Less than one half of one percent are actually pests.
Many beneficial insects feed on insects that are pests.
Example: Spiders, Assassin Bugs, Praying Mantids, Lacewings, Parasitic Wasps

8. Ladybeetles Florida’s most beneficial insect!!
Both adults and larva prey on Aphids
Adults: oval, red and black, or black/yellow
Adult eating Aphid Full Grown Larva Ladybeetle Eggs

9. Praying Mantids Very large insects (up to 2” in length)
Can be either green or brown
Front legs modified for grasping prey
Feed on flies, honeybees, crickets & moths
Adult Praying Mantis Egg case (ootheca) and Larva

10. Assassin Bugs Generally black or brown (can be bright)
Found on foliage where they attack prey
Caterpillars are their favorite lunch!!
Typically ambush their prey.

11. Lacewings Commonly found on grasses, row crops, shrubs and trees.
Feed on Aphids which nicknames them “Aphidlion”
Green with copper eyes

12. Parasitic Wasps Extremely important insects!!
Very small (1/8”) and go unnoticed
They lay eggs on the body of a host insect
Immature stage consumes the host
Prey on:
Scales, Whitefiles, Aphids, Leafminers and caterpillars

13. Spider Rarely Bite Humans!
Predaceous, feed on a wide variety of insects
Paralyze their prey with a venom bite
Most use webs but most beneficial spiders do not spin webs.
Examples: Wolf, Jumping and Crab

14. Insects as Pests (Harmful)
Pests of plants are typically divided into groups according to the way they damage plants
Most insects damage plants with their mouthparts.
Piercing-Sucking Mouthparts
Chewing Mouthparts (Foliage Feeding Insects)

15. Piercing Sucking Mouthparts
Tube like mouthpart which inserts into a food source
Plant, other insect, humans etc.
Cause damage to plants:
Stunting
Yellowing
Often are not affected by exterior pesticides as they feed on the interior of leaves

16. Chewing Mouthparts
Feed on leaves, flowers and also attack the roots of plants.
Mouthparts move side to side similar to scissors.
Examples include:
Caterpillar
Beetle
Grasshopper
Katydids

17. Scales (p.s.) Most serious pests on many ornamental plants.
Many species of soft and hard scales in Florida.
Cause yellow spots to appear on the top sides of leaves
Secrete a waxy covering over their bodies when mature making them hard to control.

18. Mealybugs (p.s.) Pests to foliage plants, annuals and perennials.
Excrete honeydew which serves as medium for fungus.
Soft bodied Scale
Common on:
Azalea
Coleus
Croton
Cactus

19. Aphids (p.s) Pear shaped Will infest any plant
Cause damage by sucking out plant juices
Transmit viral diseases
Mostly female and reproduce without mating
Each produce 50 – 100 daughters which reproduce in 8 days!!

20. Whiteflies Common on ornamental plants Resemble moths
Plants become pale or spotted
Can transmit viruses
Deposit eggs on underside of leaves
Eaten by Lady Beetles and lace wings

21. Lacebugs (p.s.) Brown with clear wings.
Damage on top side of leaf as white specks
Shiny black spots of excrement on underside of leaves
Cause damage to:
Azalea
Hawthorns

22. Thrips (p.s) Very small and slender Remove plant juices
Life cycle takes 2-4 weeks
Foliage feeders
Infested plants have stippled appearance and small brown specks.

23. Caterpillars (ch) Immature stage of moths/butterflies
Vary in color and hair stinging rose 
Devour foliage leaves holes and irregular areas or can strip leaves completely

24. Grasshopper and Katydid (ch)
Consume large quantities of foliage on ornamentals
Adults lay eggs clumped together in pods (in soil)
1 complete life cycle per year
Feeding habits vary greatly

25. Beetles (ch) Hard shelled insect
Chew off parts of the foliage or flowers of many plants.
Mostly active at night.
Larvae feed on the roots or bore through stems and branches.

26. Plant Insect Awareness Project:
Most people are unaware of the harms and benefits of the many insects that reside in Florida.
You are to create a Public Awareness Poster and insect model for your specific insect.
This is a two part project:
Part 1: Create a poster displaying facts about either your Beneficial or Harmful insect
Part 2: Create a model of the insect using a variety of materials.

27. Plant Insect Awareness Project
Things to include on your poster:
Life cycle of insect
Description of insect
Harms or Benefits
Where found (plants)
Things to include for your insect model:
Needs to be actual model of insect!!
Including proper mouthparts, legs, body segments, eyes, etc.
You may use a variety of materials (clay, foam, putty, food, straws etc. )
Points for the project are as follows:
-Pest Awareness Poster: 25 points
-Pest Model: points
Total Points: 40 points

28. List of possible insects:
Harmful:
-Scales
-Mealybugs
-Aphids
-Whiteflies
-Lacebugs
-Thrips
-Caterpillars
-Grasshoppers
-Katydids
-Beetles
Beneficial:
-Ladybeetles
-Praying Mantids
-Assassin Bugs
-Lacewings
-Parasitic Wasps
-Spiders