KEEPING PLANTS HEALTHY Unit E: MANAGING PESTS IN PLANTS

FIVE MAJOR CATEGORIES OF PESTS INSECTS NEMATODES DISEASES WEEDS RODENTS PEST: Anything that causes plants injury or damages them

CHARACTERISTICS OF INSECTS Insects have three pairs or 6 legs. Insects body is divided into three sections: head, thorax and abdomen.

FIVE TYPES OF MOUTH PARTS CHEWING : Bite off, chew and grind parts of plants; examples include grasshoppers, beetles and armyworms. PIERCING-SUCKING : Suck sap from a plant; examples include aphids, chinch bugs, thrips, squash bugs and leafhoppers.

Rasping-sucking – rasps or breaks surface and sucks the sap EX: thrips Siphoning – a coiled tube they dip into liquid food (nectar)

Sponging – have 2 spong-like structures that collect liquid food and move it into the food canal Ex: housefly

METAMORPHOSIS FOUR STAGES 1. EGG 2. LARVA – worms or caterpillars 3. PUPA 4. ADULT – flies, beetles, etc. Examples of insects with complete metamorphosis include moths and butterflies, beetles and boll weevils.

INCOMPLETE METAMORPHOSIS 1. EGG 2. NYMPH 3. ADULT EXAMPLE IS A GRASSHOPPER

Insects must be killed when that are actively feeding or moving on the plant.

WAYS INSECTS ARE BENEFICIAL IMPROVE THE SOIL - Allow air to enter the soil or bury decaying parts of plants: ants, wild bees and beetles. HELP POLLINATE PLANTS - Spread pollen from plant to plant: bees, butterflies, wasps and beetles.

DESTROY INSECTS - Attack and destroy harmful insects: lady beetles, dragon flies, wasps and ants.

Damage to plants by pests Insects – damage depends on types of mouthparts Chewing - parts of leaves eaten away Beetles – eat leaves, stems, flowers and fruit Cutworms – usually attach stems Caterpillars – larva of moths; eat young leaves and stem; make leaves curl Grasshoppers – eat all parts of the plant

Damage from Sucking insects Aphids – pierce and suck juices, called plant lice. Causes stunted growth and yellow spotted leaves. Sticky substance and black mold will appear on leaves, followed by ants eating the sticky stuff.

Sucking Mealy bugs – Pierce and suck from underside of leaves and in the leaf axils causing yellow appearance

Sucking Scale – appear as black or brown raised lumps attached to stems and underside of leaves causing yellow leaves and stunted growth

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

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

Plant Diseases Disease – a plant disorder caused by an infectious pathogen or agent 3 things needed for disease Host plant Disease causing organism or pathogen Favorable environment for disease

MAJOR TYPES OF PLANT DISEASES ENVIRONMENTAL 1. Nutrient deficiencies 2. Damage to plant parts 3. Chemical injuries 4. Pollution injuries 5. Weather 6. Naturally-occurring genetic abnormalities

PARASITIC 1. Fungi 2. Bacteria 3. Viruses 4. Parasitic plants – like mistletoe, lichens attach themselves to a host plant and suck food & life from it

Plant diseases must be identified before they can be treated Warmth and moist environment of greenhouses make plant diseases worse.

Blight Plants quickly turn brown or black as if they have been burned

Canker Causes open wounds on wood plant stems

Damping Off Damping off is a fungal diseases that causes young plants and seedlings to rot off at soil level.

Galls ~ round swellings or growths on plants.

Leaf spots ~ rings of different shades of brown, green or yellow that make spots on leaves.

Mildew ~ grows on leaf surface as white, gray or purple spots. Looks like powder.

Rot ~ cause plant to decay and die. Usually caused by excessive moisture

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

Smut ~ a black powdery disease that causes blisters that burst open releasing black spores.

Wilt ~ diseases that block the uptake of water in plant stems causing plants to wilt.

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.

Preventing plant diseases is better than treating the diseases.

PROBLEMS THAT WEEDS CAUSE Weed: Any plant growing in an unwanted area Keep plants from growing Waste nutrients Lower quality of crop Make harvesting harder Hiding place for insects and disease Look bad

CONDITIONS NEEDED FOR A PEST TO CAUSE PROBLEMS A PEST MUST EXIST A SUSCEPTIBLE PLANT THE RIGHT ENVIRONMENT

WAYS THAT PESTS DAMAGE PLANTS Pests chew holes in plants Pests attack the vascular system Pests attack the fruit Pests contaminate products Pests rob plants of food Pests damage land

Biological uses natural enemies such as birds, other insects, etc. Lady bugs – eat aphids, so they help the gardener control a bad insect Ways to control pests:

Chemicals using poisons: insecticides Contact poisons affect the insect’s nervous system and must come into contact with insect to be effective. Stomach poisons are sprayed on plant surfaces or are taken into the plant through absorption. The insect must eat or suck the poison to get it into the stomach. Most effective for chewing insects. SYSTEMIC POISONS - Poison is absorbed by the plant and when insects bites or sucks its juice, it gets poison. Systemic poisons are more effective for controlling sucking insects like scale. FUMIGANTS – poisonous gases released into greenhouse and insects breath the gases

WAYS TO PREVENT PEST PROBLEMS Use good seed Destroy diseased plants Use the right fertilizer Disinfect equipment Use good water Control animal movement Use chemicals properly Use tests to check for pests

CULTURAL PRACTICES Cultural involves sanitation, removing insect breeding and hiding areas and using insect resistant plant varieties. ROTATING CROPS ROGUING TRAP CROPPING BURNING USING RESISTANT VARIETIES

MECHANICAL METHODS OF PEST CONTROL Mechanical uses physical control such as insect traps using screens over fans and other openings and washing plants with soapy water. PLOWING MOWING MULCHING

PESTICIDES Chemicals used to control pest Insecticides - controls insects Nematocides - controls nematodes Fungicides - controls fungi Bactericides - used to control bacteria Herbicides - used to control weeds

TYPES OF HERBICIDES SELECTIVE HERBICIDES - Will only kill certain kinds of plants. NON-SELECTIVE HERBICIDES - Used to kill all vegetation where they are applied. TRANSLOCATED HERBICIDES - Absorbed into the plant and moved all through its parts; upset the growth process of weeds.

NON-CHEMICAL MEANS OF CONTROLLING PESTS BIOLOGICAL PEST CONTROL - Using living organisms to control pests. GENETIC METHODS - Develop crops that are resistant to pests

IPM INTEGRATED PEST MANAGEMENT is a planned process for controlling pests. Involves using a blend of pest control techniques in a planned program Field of crops is managed as an ecosystem IPM has fewer adverse effects on the environment.

SAFETY PRACTICES IN PEST CONTROL Use only approved pesticides Know the pesticide Use the pesticide with low toxicity Use pesticides only when needed Do not contaminate resources Wear protective clothing

SAFETY PRACTICES IN PEST CONTROL Wash the skin after contact Dispose of empty containers properly Apply in good weather Use the right equipment Know the emergency measures