Insects - Anatomy
•Insects▫Small animals that have three body regions
and three pairs or six legs.▫The three body regions are….
Head Thorax Abdomen
Insects - Mouthparts
•Chewing▫Tear, chew or grind food.
▫Parts of leaves eaten away.
▫Example: Grasshoppers Beetles.
Insects - Mouthparts
•Piercing-sucking▫Punctures plant & sucks sap.
•Rasping-sucking▫Rasps or breaks surface and suck sap.▫Example: Thrips
Insects - Mouthparts
•Siphoning▫Have a coiled tube they dip into liquid food
such as nectar and draw it in.•Sponging
▫Have two sponge-like structures that collect liquid food and move it into the food canal.
▫Example: Housefly
Chewing Insects
•Caterpillars▫Larva of moths and butterflies and are fuzzy
or hairy.▫Eat young leaves and stems.▫Roll up in leaves making the leaves curl.
Sucking Insects
•Aphids▫Pierce & suck
juices.▫Known as plant lice.▫Cause stunted
growth and yellow spotted leaves.
▫Causes sticky substance and black mold which attracts ants.
Sucking Insects
•Mealybugs▫Pierce and suck from underside of leaves
and in leaf axils.▫Causes yellow appearance and sticky
secretions.
Sucking Insects
•Scale▫Appear as black or brown raised bumps
attached to stems and underside of leaves ▫Causes yellow leaves and stunted growth.
Sucking Insects
•Thrips▫Chew & then suck
plant tissue causing it to become speckled or whitened, leaf tips to wither, curl up or die.
Sucking Insects
•Whiteflies▫Feed on underside
of young leaves causing yellowing.
▫They will look like flying little white specks when plants are shaken.
Mite Damage
•Mites▫Aren’t insects
because they have 8 legs.
▫Attack underside of leaves causing gray to grayish-green spots.
▫Severe infestations cause webbing.
Controlling Insects
•Insects must be killed when they are….▫Actively feeding or moving on the plant.
Chemical Control
•Contact Poisons▫Affect the insect’s nervous system and must
come into contact with insect to be effective.
Chemical Control
•Stomach Poisons▫Are sprayed on
plant surfaces or are taken into the plant through absorption.
▫Insect must eat or suck the poison to get it into the stomach for this method to be effective.
Chemical Control
•Systemic Poisons▫Absorbed by the
plant and then ingested by the pest when it feeds.
▫More effective than stomach poisons for controlling sucking insects.
Chemical Control
•Fumigants▫Poisonous gases released into an enclosed
place so that insects breathe the gases.
Cultural Control•Involves sanitation, removing insect
breeding and hiding areas and using insect resistant plant varieties.
Mechanical Control
•Using physical controls such as….▫Insect traps. ▫Using screens
over fans & other openings.
▫Washing plants w/ soapy water.
Natural Methods
•Using natural barriers to control insects such as….▫Rivers▫Woods▫Mountains▫Predators
Combining Methods
•Using a combination of control methods is called….▫Integrated Pest Management (IPM) or….▫Integrated Control
Conditions Needed for a Disease•Three conditions are necessary for a
disease in a plant.▫Host plant▫Disease causing organism or pathogen
must be present.▫Favorable environment for disease
organism to develop.
What Causes a Disease??
•The groups of pathogens are….▫Bacteria▫Fungi▫Viruses▫Parasitic plants
Mistletoe Dodder Lichens
FUNGI
Controlling Diseases
•Warm temperatures and moist conditions in greenhouse plant production make most horticulture plant diseases worse because….▫Environmental conditions that support disease-
causing pathogens.•Preventing plant diseases is better than
treating the diseases.•Plant diseases must be identified before
they can be treated.
Plant Diseases – Damping Off
•A fungal disease that causes young plants and seedlings to rot off at the soil level.
Plant Diseases – Leaf Spots
•Rings of different shades of brown, green, or yellow that make spots on leaves.
Plant Diseases – Mildew
•Grows on leaf surfaces (both upper & lower) as white, gray or purple spots.
Plant Diseases – 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.
Plant Diseases – Rust
•Causes small spots on leaves that resemble yellow, orange, brown or red rust mainly on the underneath side of leaves.
Plant Diseases – Smut
•A black powdery disease that causes blisters that burst open releasing black spores.