Bellringer-October 7, )Name 3 different causes of why a plant might become diseased (think hard): 2)What is the difference between biotic and abiotic? 3)For the picture below, list as many observations you can make about this plant.

Aquaponics Plant Diseases and Deficiencies

Definitions Plant Pathology – The study of plant diseases Plant Disease – Any physiological or morphological change in a plant that results in abnormal appearance or development Pathogen – An organism that causes disease Symptom – Abnormal appearance of a plant Sign – Appearance of the actual pathogen (fruiting bodies, spores, hyphae etc.)

Components of a Plant Disease Conducive Environment Susceptible Host Virulent Pathogen

Disease Classes Abiotic (not transmissible) – Caused by something that is not alive, like over-watering – Damage from chemicals, weather, mechanical – Nutritional problems Biotic (transmissible) – Caused by something that is alive, like a bacteria – Pathogens-parasitic microorganisms that cause diseases – Pests-insects, mammals, or other plants feeding on or damaging plants

Causes of Abiotic Disease Environmental – freezing, flooding, drought, light, wind, hail Cultural – mechanical damage, planting problems Chemical – fertilizers, herbicides, pets Physiological Disorders – abnormal growth due to genetic and/or environmental interactions

Causes of Biotic Diseases (Pathogens) Fungi Bacteria Viruses Nematodes Parasitic Plants

How do symptoms progress? Biotic disease- symptoms progress and nearby plants become infected. Abiotic disease- generally a lack of symptom progression – Exception-nutritional symptoms progress slowly.

Observe Patterns

Underdevelopment

Overdevelopment

Leaf Spots Cause – Fungi, bacteria, insects, mites, or abiotic factors Symptoms – Circular yellow or brown and dead spots on the leaf

Fungal Blight Fungus causes black dead spots on leaves or fruit Blight= rapid death or die back

Wilts Cause – Fungi or bacteria Signs and Symptoms – Vascular Plugging, wilted leaves and shoots

Galls Cause – Fungi, bacteria, insects, mites, nematodes, and abiotic factors Symptoms – Abnormal proliferation of plant tissue specific to a certain plant part; swelling

Rusts Cause – Fungi Signs and Symptoms – Fungal spore masses on leaves and stems

Cankers Cause – Fungi or bacterial infection resulting in dead, non- growing areas on stems and branches Signs and Symptoms – Dark sunken areas with distinct margins on stems

Root Rot Cause – Fungi and bacteria Signs and Symptoms – wilting, stem discoloration, dead roots

Mildew Cause – Fungi Symptoms – yellowing blotches on leaves, hyphae and fruiting bodies on surface

Abiotic: Blisters

Plant Deficiencies Definition Nutrient shortage or unavailability to plant that results in a physiological reaction

What are the 9 essential macronutrients? – C, H, O, N, P, S, Ca 2+, K +, Mg 2+ Deficiency in nutrients causes specific symptoms – Ex: yellow leaves without Mg +2 The most common deficiencies are those of N, K +, and P

Healthy Phosphate-deficient Potassium-deficient Nitrogen-deficient

Symptoms Chlorosis - condition in which leaves produce insufficient chlorophyll. Chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. Necrosis - browning and dieback of leaf edges and tips, sometimes extending into the leaf between the major veins. Can be caused by numerous factors that restrict the flow of water to the leaves and lack of nutrients.

Chlorosis

Reddening

Different Soil pH = different nutrient availability

How to Diagnose Deficiencies…

Disease Control Select plant material adapted to environment Buy disease-free seed and healthy plant material. Plant disease-resistant varieties when available. Choose plants that fit the site. Keep plants healthy. Control PESTS. Use chemical control with care.

How to fix a deficiency problem Check soil pH Apply a quality general use fertilizer or manure/compost

Exit Slip-October 7, )List 3 biotic diseases and 3 abiotic diseases. Explain the cause and appearance of the diseased plant. 2)Describe the symptoms of a plant with the following nutrient deficiency: a)Nitrogen b)Phosphorus