INTRO TO HORT

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INTRO TO HORT

• CHAPTER 7
• Biological Enemies of Horticultural Plants

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Biological enemies

• Discuss the economic effects of pests
• List the categories of organisms that are pests
• Distinguish among pests on the life cycle
• Distinguish among pests on feeding habits

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weeds

• They compete for nutrients
• Harbor pests
• Eyesore to the landscape
• Costly to remove
• Increase cost of production
• Reduce quality and market value
• Some are poisonous
• Clog waterways

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Types of weeds

• Annual
• Summer germinate spring, then seed
• Winter germinate in fall, then seed in spring
• Biennial- germinate one year then over winter and
  seed the following
• Perennial hard to get rid of

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control

• Biological
• Chemical
• Cultural

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Parasitic plants

• Epiphytes autotrophic (photosynthesizing)
• Hemiparasites depend on water and nutrients,
  mistletoe
• Parasites lack structures to make food and
  dependent on host, dodder

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Common weeds

• Canada thistle
• Bindweed
• Dandelion
• Milkweed
• Crabgrass
• Cocklebur
• Johnson grass

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Insects

• 800,000 species
• Insecticide
• Metamorphosis transformation

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chewing

• Leaves, petals, stems, fruits, flowers, roots
• Defoliating, boring, mining, feeding on roots
• Include caterpillars, grubs, grasshoppers,
  beetles,

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Sucking and piercing

• Suck out plant fluids
• Aphids, scales, mealy bugs, thrips, leaf hoppers
• Curling up or puckering of leaves
• Bleaching of leaves
• Usually hidden from eye sight

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Other insects

• Mites, spiders, millipedes, centipedes
• Colorado potato beetle, cucumber beetle
• Cutworms
• Cabbage looper
• Corn earworm, squash vine borer

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diseases

• Pathogen organism that causes disease
• Saprophyte lives on dead or nonliving tissue

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fungi

• Lives in the roots 75 does
• 250,000 species
• 22,000 cause plant disease
• Many are useful to humans and plants mushroom,
  fermented beverages, bread, wine, cheese, and
  beer
• Most easy to control

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bacteria

• Three shapes, spherical, rod like, spiral
• Very few cause plant problems
• But they are difficult to control
• Do not tolerate high temperatures
• Cause rots, cankers, spots, wilts,
• temperatures 125 degrees for ten minutes can kill
  them

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viruses

• Like living organisms only when found inside cell
  of plant or animal
• Microscopic, can be transmitted from plant to
  plant
• Mainly by insects
• Stunt growth, yellowing of leaves, loss of vigor,
  
• Resistant cultivars

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Other pests

• Rabbits, mice, gophers, bats, moles
• Birds
• Nematodes unsegmented roundworms
• snails and slugs

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How disease occurs

• Parasitism lives on or in another
• Has a host for food
• Pathogenicity abnormal physiological activities
  and physical degeneration

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Words to know

• Inoculation coming into contact
• Infection growth and multiplication
• Dissemination spread by air, water, insects,
  etc
• Resistance ability of overcome a pathogen

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summary

• In Chapter 9 we will discuss in more detail about
  how to prevent insects and diseases