Presentation on theme: "Plant Diseases and Insect Pests"— Presentation transcript:
1Plant Diseases and Insect Pests Disease - any kind of injurious abnormalityPhysiological (environment)Other living organisms (pathogens)Pathogen - biological agent that causes the injuryInsectsBacteriaFungiVirusesNematodesMiscellaneous
2Plant Diseases and Insect Pests Parasite - an organism that derives nourishment from another living organismHost - an organism that provides nourishment to anotherObligate parasite - organism that can only survive on the living hostHost range - list of several different plants that some parasites can feed off of
3Plant Diseases and Insect Pests Bacteria - one-celled organisms that enter through wounds and cause rotFungi - multi-celled organisms that either are saprophytes or parasites. Ex: molds, mildew. Cause decay of plants
6Bacterial disease control? Start with clean pots & potting media & toolsStart with clean seed or healthy transplantsUse drip irrigation or water in the morning so the extra water on the surface of the leaves evaporates by eveningAntibiotics now exist for injecting into trees but treatment is costly and the effects temporary. There are no antibiotic spray treatments.
9Fungal disease control? Start with clean pots & potting media & toolsStart with clean seed or healthy transplantsUse drip irrigation or water in the morning so the extra water on the surface of the leaves evaporates by eveningFungicides do exist. They can be used as a liquid drench, spray or powder.
15Plant Diseases and Insect Pests Viruses - infectious particles made-up of nucleic acids (typically RNA in plants) with a protein coat. In the plant cell, the protein coat comes off and the RNA uses the plant cell to reproduce itself. These are obligate parasites.
31How Plants are Damaged Damage by: Direct feedingSecretion of toxic substancesSecondary organism enters the woundSymptom - plant’s response to attack (wilt)Sign - structures produced by the attacking organism (webs, tunnels, etc.)
34Spread of Insects and Disease Diseases and insects are spread to plants by:WaterWindInsectsAnimals (including people) Ex: TMVMachineryPlants are more susceptible to disease and insect attack when they are stressed (water or temperature)