Plant Disease Types and Symptoms

Plant Disease Types and Symptoms - e. Parasitic Plants...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Pathology 9/2/10 1. Parasitic Plants a. Depend on other plants for nutrients b. Lack chlorophyll so no photosynthesis c. Some lack roots and so obtain water from other plants d. Have structures that allow penetration of host tissues e. Most serious- witch weed i. Small plant with red or yellow flowers 1. Attacks corn, sugar cane, rice, tobacco, cowpeas in Africa, asia, and Australia 2. Causes plants to wilt and die prematurely a. Losses can be up to 100% 2. Inoculum – any pathogen part or stage capable of initiating infection a. Fungi – mycelia, spores i. Some survive for hours while others for years ii. Some can swim iii. Sources: air, water, soil, insects, animals, seeds/planting material b. Bacteria – bacterial cells (can swim), spores (Gram positive) i. Sources: air, water, insects, seeds/planting material, animals c. Viruses – virus particles i. Sources: insects, seeds/planting materials ,soil, bacteria, fungi, nematodes d. Nematodes – eggs and juvenile stages
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
i. Sources: soil, water, seeds/planting material
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: e. Parasitic Plants seeds i. Sources: soil f. Biotroph: Obligate parasite (needs host alive) g. Necrotroph: Kills host 3. How pathogens cause disease a. Toxins (necrotrophic) poisonous compounds produced by fungi and bacteria i. Toxins may produce disease symptoms 1. Active in low concentrations 2. Kill plant cells and allow pathogens to feed b. Growth regulators (biotrophic) compounds that regulate plant growth patterns i. Pathogens may produce hormones that stimulate or retard plant growth c. Plant disease suppressors compounds that suppress plant defense mechanisms d. Proliferation multiplication in host tissues disrupt normal cell function 4. Symptoms of Plant Diseases a. Necrosis collapse and death of plant cells leaving lesions/cankers/blights/etc. b. Hyperplasia/Hypertrophy Overgrowths of tissue c. Hypoplasia/Hypotrophy Undergrowth of tissue...
View Full Document

Page1 / 2

Plant Disease Types and Symptoms - e. Parasitic Plants...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online