Abiotic Diseases

8/2/2019 Abiotic Diseases

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Dr. Sushovan Bera

Associate Professor

Jogamaya Devi College


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Biotic (transmissible) ~30%

Abiotic(not transmissible) ~ 70%


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Environmental:(freezing,flooding,drought,light, wind, hail etc.)

Cultural:(mechanical damage, planting problems etc.) Chemical:

(fertilizers, herbicides, pesticides & others)

Physiological Disorders:(abnormal growth due to genetic and/orenvironmental interactions)


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Soil moisture :a. Low soil moisture Stunting, pale green / yellow

coloration, less flower & fruits death.i) Drought : Reduced growth, scorched leaf,defoliation death.ii) Excessive soil moisture Tree suffer slowly than

field crop, root system poorly develop, fibrous rootsget damaged, pale coloration of leaves, lack of vigor,wilt [ CO2 accumulation & anaerobic respiration ]

b. Soil texture Affect water retaining capacity; in bothhard & course soil stunted growth due to poor rootgrowth occurs.

c. Soil reaction Around neutral & acidic pH

preferable; unfavourable pH alter mineral uptakeSymptom expression.[ High acidity:- use lime; Highalkalinity:- usesulphur or irrigate to wash]


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Temperature:

High : Leaf scorching, sun scald, discoloration,water soaked appearance etc.

[ inactivate enzymes adverse biochemicalreaction death]

Low : Damage shoot tips, affected tissue becometranslucent black dry up; freezingtemperature form ice crystals.

Relative humidity:

Low RH Scorching / shriveling of fruits,wilting, premature shedding fruits.


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Lack of oxygen: Cells die due to sub-

oxidation & anaerobic respiration.

Black heart of potato, Brownining of

apple etc.

High light: Water soaked spots, sun scald,

brown and reddish brown coloration of

leaf.


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Sulphur dioxide: Water relations of cells

disrupted, cells collapse, mesophyll

damages chlorosis, water soakedspots.

Hydrogen fluoride: Rapid plsmolysis andinternal cell collapse burnt

appearance.

Ozone : Affect palisade cells, watersoaked spots appear,finally mottling &

chlorosis.


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Chlorine: Bleached, necrotic interveinal area,

scorching of leaf margins . Ethylene: Stunting, abnormal development

of leaf, early senescence of flowers

fruits. Photoactive pollutants:

NO2 + O2sunlight O3 + NO

O3 + (NO + un-burn hydrocarbon) = O3+PAN

Peroxy acyl nitrate (PAN) leads to banding effects

on leaf, injury around stomata & mesophylltissue.


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Iatrogenic disease produced byappropriate therapy for another

disease, usually occurring as aside effect of pharmacologicalagents.


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Phytotoxic effects can range from slightburning or browning of leaves to death of

the plant. Sometimes, the damage appears as

distorted leaves, fruits, flowers or stems.

Damage symptoms vary with pesticidesand the types of plant that has been affected.

Plant damage can be caused by the a.i.,solvent in formulations, impurities,

condition of plant at the time of treatment. High temperature can speed up

phytotoxicity.


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Deformed cotton leaf

Paraquot injury of apple

Glyphosate damage to apple

tree

Glyphosate damage tocucumber plant

Dimethoate injury Kresoxim injury


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Growth Regulator inhibitors Photosynthesis inhibitors Pigment inhibitors Seedling growth inhibitors

Root inhibitorsShoot inhibitors

Cell membrane disruptors Lipid synthesis inhibitors Amino acid synthesis inhibitors


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a. Leaf and stemmalformations

b. In broad leaf plants stemscurl, twist and droop.

c. Leaves are cupped, crinkledor have a drawstring

appearance caused byirregular growth of the leafedges.


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Yellowing between leaf

veins , in veins, yellowing andthen browining of leafmargins , finally death.

Specking, spotting andyellowing or bronzing of

leaves.


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a.Leaves turn yellow or whiteand then often translucent.

b.New growth is yellow towhite with sometimes a hintof purple or pink.

c.These symptoms can befound on cotyledons to thenewest leaves of susceptible

plants.


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ROOT INHIBITORS:(e.g. Dinitroaniline: Benetin, Oryzalin)

a. Stunted growth with purple

discoloration because roots cannot take up enough phosphorus.b. Root system appear stubby &

thick, especially lateral roots.

c. Callus tissue formed on the plantstem near the soil surface.


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Shoot inhibitors:( e.g. Acetamide : Acetachlor, Butachlor)

a. Improper leaf unfurling, buggy,

whipping(tightly rolled leaves), leaf wrinkling.b. In broad leaf plants, the midrib may draw inthe leaf edge in drawn string effect.

c.Leaf puckering.

d. Stunting.


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a.Plants rapidly turn yellow or

pale and look water soaked,then dry up.

b.Specks of burned tissue on

non-target vegetation.c.Leaf burn and red stem.


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a.Symptoms develop slowly within14 days.

b.Initial injury is seen where thenewest leaves are developing.

c.Base of new leaves become

mushy, has a rotted appearance.d.Reddish blue pigmentation maybe observed on stem, stemsheath, leaf margins and / or leaf

blade.


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a.Plants treated with

glyphosate or sulphosateturn yellow in 5-7 days,then turn brown & dies in10 14 days.

b.An individual plant mayhave dead tissue, yellowtissue and green tissue atthe same time.


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Nutrient deficiencies:

Nitrogen- Poor growth, pale green coloration,drying of flower & fruits.

Phosphorus- Poor growth, stunting, bluishgreen/ brown coloration of leaf.

Sulphur- Small leaf, light yellowing of leaf etc.

Potassium- Die back, premature senescence. Manganese- Chlorosis, premature senescence,

stunting.


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General chlorosis.

Chlorosis progresses from lightgreen to yellow.

Entire plant becomes yellowunder prolonged stress.

Growth is immediately restrictedand plants soon become spindlyand drop older leaves.

Drying of flower & fruits.


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Poor growth, stunting

Leaves appear dull, dark

green, blue green, or red-purple, especially on theunderside, and especially at

the midrib and vein. Petioles may also exhibitpurpling. Restriction in

growth may be noticed.


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Leavessmall,uniformly light

green, followed byyellowing and poorspindly growth.

Uniform chlorosisdoes not occur


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Leaf margins tanned, scorched, or

have necrotic spots (may be smallblack spots whichlater coalesce). Margins become brown and cupdownward.

Growth is restricted and die backmay occur. Mild symptoms appear first onrecently matured leaves.

Premature senescenceBlotchy ripening oftomato:Green & Yellow areamerging into Red


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Chlorosis is less markednear veins.

Some mottling occurs ininterveinal areas.

Chlorotic areas eventuallybecome brown, transparent, ornecrotic. Symptoms may appear later

on older leaves. Stunting prominant Premature senescence


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Calcium- Poor root growth,terminal buds maydie distortion & curling of leaf, pitting of fruitsetc.

Iron- Chlorosis, brown spots, drying &

shedding of leaves. Boron- Stunting, chlorosis & necrosis of leaf,

heart rot symptoms.

Zinc- Short internodes, chlorosis purplish

necrosis. Copper- Leaf and twig necrosis

Magnesium- Chlorotic mottling & browning etc.


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Poor root growth Growing points usuallydamaged or dead (die back). Margins of leaves developing

from the growing point are firstto turn brown. Distortion and curling of leaf

Pitting of fruits


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Distinct yellow or whiteareas appear between veins,

and veins eventuallybecome chlorotic.

Symptoms are rare onmature leaves

Brown spots, drying andshedding of leaves


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Young, expanding leavesmay be chlorotic, necrotic ordistorted followed by death ofgrowing points.

Internodes may be short,especially at shoot terminals,hence, stunting.

Stems may be rough,cracked, or split along thevascular bundles.

Heart rot symptoms occur


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Leaves may be abnormally small ,withchlorosis purplish necrosis.

Internodes are shortened.


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Leaves wilt, becomechlorotic, then necrotic.

Wilting and necrosisare not dominantsymptoms.

Twig necrosis notuncommon


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Marginal chlorosis or chlorotic

blotches which later merge.

Leaves show yellow chloroticinterveinal tissue on some species,reddish purple progressing to

necrosis on others.

Younger leaves affected withcontinued stress.

Chlorotic areas may becomenecrotic, brittle, and curl upward.

Symptoms usually occur late in

the growing season.


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Thank you

Documents

Abiotic Diseases