KEEPING PLANTS HEALTHY

Unit E: MANAGING PESTS IN PLANTS

FIVE MAJOR CATEGORIES OF PESTS

INSECTSNEMATODES

DISEASESWEEDS

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. EGG2. LARVA – worms or caterpillars3. PUPA4. ADULT – flies, beetles, etc.Examples of insects with complete metamorphosis include moths and butterflies, beetles and boll weevils.

INCOMPLETE METAMORPHOSIS

1. EGG2. NYMPH3. 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 awayBeetles – eat leaves, stems, flowers and fruitCutworms – usually attach stems Caterpillars – larva of moths; eat young leaves and stem; make leaves curlGrasshoppers – 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.

SuckingMealy bugs –

Pierce and suck from underside of leaves and in the leaf axils causing yellow appearance

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

SuckingThrips

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

WhitefliesFeed 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 agent3 things needed for disease

Host plantDisease causing organism or pathogenFavorable environment for disease

MAJOR TYPES OF PLANT DISEASES

ENVIRONMENTAL1. Nutrient deficiencies2. Damage to plant parts3. Chemical injuries4. Pollution injuries5. Weather6. Naturally-occurring genetic abnormalities

PARASITIC1. Fungi2. Bacteria3. Viruses4. 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 treatedWarmth and moist environment of greenhouses make plant diseases worse.

BlightPlants quickly turn brown or black as if they have been burned

CankerCauses 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 makespots on leaves.

Mildew ~ grows on leaf surface as

white, gray or purplespots.

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 rustmainly on the underneath

side of leaves.

Smut ~ a black powdery disease that causes blisters that

burst open releasingblack spores.

Wilt ~ diseases that block the uptake of water in plant

stems causing plantsto wilt.

Mosaic ~ caused by viruses that make the leaves have

irregular mottled areaswith 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 growingWaste nutrientsLower quality of cropMake harvesting harderHiding place for insects and diseaseLook bad

CONDITIONS NEEDED FOR A PEST TO CAUSE

PROBLEMSA PEST MUST EXIST

A SUSCEPTIBLE PLANT

THE RIGHT ENVIRONMENT

WAYS THAT PESTS DAMAGE PLANTS

Pests chew holes in plantsPests attack the vascular systemPests attack the fruitPests contaminate products Pests rob plants of foodPests 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 seedDestroy diseased plantsUse the right fertilizerDisinfect equipmentUse good water Control animal movementUse chemicals properlyUse tests to check for pests

CULTURAL PRACTICES Cultural involves sanitation,

removing insect breeding and hiding areas and using insect resistant plant varieties.ROTATING CROPSROGUINGTRAP CROPPINGBURNINGUSING 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

PESTICIDESChemicals used to control pestInsecticides - controls insectsNematocides - controls nematodesFungicides - controls fungiBactericides - used to control bacteriaHerbicides - used to control weeds

TYPES OF HERBICIDESSELECTIVE 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

IPMINTEGRATED PEST MANAGEMENT is a planned process for controlling pests.Involves using a blend of pest control techniques in a planned programField of crops is managed as an ecosystemIPM has fewer adverse effects on the environment.

SAFETY PRACTICES IN PEST CONTROL

Use only approved pesticidesKnow the pesticideUse the pesticide with low toxicityUse pesticides only when neededDo not contaminate resourcesWear protective clothing

SAFETY PRACTICES IN PEST CONTROL

Wash the skin after contactDispose of empty containers properlyApply in good weatherUse the right equipmentKnow the emergency measures