美国大学家庭园艺学课件1：害虫

Nematode damage on tomato
Nematode damage on carrot
Foliar nematodes
Hosta
Zinnia
How Plants are Damaged
• Damage by:
– Direct feeding – Secretion of toxic substances – Secondary organism enters the wound
• Symptom - plant’s response to attack (wilt)
• Sign - structures produced by the attacking organism (webs, tunnels, etc.)
Symptom = wilt
Webbing = sign
Insect Life Cycle
Egg
Adult
Larvae = feeding stage
Pupae
Topical insecticides
• Liquid soap • Pyrethroids • Rotenone • Neem oil • Rubbing alcohol
Liquid soap
• These include chewing insects:
– Caterpillers – Beetles
• These include sucking insects:
– Aphids – Leafhoppers – Scale – Mealybug – Thrips
Insects!
• Have 6 legs • 3 body regions • Wings as an adult
– Neem oil (active ingredient = azadirachtin)
Pyrethrum
Pyrethrum
Rotenone
ห้องสมุดไป่ตู้
Rotenone - for fishing
Rotenone
Rotenone & Pyrethrin
Rotenone & Parkinson’s
Neem Oil
Rubbing alcohol - topical
Synthetic insecticides
Systemic insecticide
Systemic insecticide
Systemic insecticide
Systemic insecticide
Garden Pests
Plant Diseases and Insect Pests
• Nematodes - unsegmented worms that feed on roots and create wounds for bacteria and fungi to enter
Nematode damage on tomato
• Plants are more susceptible to disease and insect attack when they are stressed (water or temperature)
Insects!
• There are 4,000-5,000 insect pests of cultivated plants
Spread of Insects and Disease
• Diseases and insects are spread to plants by:
– Water – Wind – Insects – Animals (including people) Ex: TMV – Machinery
Liquid soap
Pyrethroids
Control of Insects & Disease
• Organic pesticides
– Pyrethrum from Chrysanthemum cinerariaefolium
– Rotenone is extracted from many tropicals legumes such as Derris elliptica, Lonchocarpus nicou, Tephrosia vogelii . "Ichtyotoxic", which means toxic to fish and other cold blooded animals