Transcript File
Pests & Diseases Insects - Anatomy • Insects ▫ Small animals that have three body regions and three pairs or six legs. ▫ The three body regions are…. Head Thorax Abdomen Parts of the Insect Life Cycle of Insects • Complete metamorphosis ▫ Egg ▫ Larva Worm Caterpillar ▫ Pupa ▫ Adult Flies Beetles Life Cycle of Insects • Incomplete metamorphosis ▫ Egg ▫ Nymph ▫ Adult 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 Insect Damage • Damage depends on type of mouthparts. Chewing Insects • Beetle ▫ Eat leaves, stems, flowers, fruit and nuts. Chewing Insects • Cutworms ▫ Usually attack stems, but may eat other plant parts. 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. Chewing Insects • Grasshoppers ▫ Eat all parts of plants. 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 • Leaf Bugs ▫ Causes plants to look unhealthy. ▫ Lose their normal color and wilt. 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 Controlling Insects • Insects must be killed when they are…. ▫ Actively feeding or moving on the plant. Biological Control • Using natural enemies such as…. ▫ Birds ▫ Other insects. ▫ Etc. Chemical Control • Using pesticides or insecticides (chemicals). 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 Quarantine • Physically isolating insects from healthy plants. Combining Methods • Using a combination of control methods is called…. ▫ Integrated Pest Management (IPM) or…. ▫ Integrated Control Plant Diseases What is a Disease??? • A plant disorder caused by an infectious pathogen or agent. 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. The Disease Triangle What Causes a Disease?? • The groups of pathogens are…. ▫ ▫ ▫ ▫ Bacteria Fungi Viruses Parasitic plants Mistletoe Dodder Lichens FUNGI Parasitic Plants MISTLETOE DODDER LICHENS Controlling Diseases • Warm temperatures and moist conditions in greenhouse plant production make most horticulture plant diseases worse because…. ▫ Environmental conditions that support diseasecausing pathogens. • Preventing plant diseases is better than treating the diseases. • Plant diseases must be identified before they can be treated. Plant Diseases – Blight • Cause plants to quickly turn brown as if they had been burned. Plant Diseases – Canker • Causes open wounds on woody plant stems. Plant Diseases – Damping Off • A fungal disease that causes young plants and seedlings to rot off at the soil level. Plant Diseases – Galls • Round swellings or growths on plants. 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 – Rot • Causes plants to decay & die. 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. Plant Diseases – Wilts • Disease that blocks the uptake of water in plants stems causing it to wilt.