Plant Pathology Quiz: Yellow Rust Questions and Flashcards

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Questions and Answers

Which environmental conditions favor the development of the disease mentioned in the text?

Cold temperature and low humidity

Excessive rainfall and cloudy weather

Moisture stress and higher temperature (correct)

Dry soil and high temperatures

What serves as the primary source of infection for the pathogen in the disease cycle?

Seed-borne pathogen (correct)

Optimum nutrition

Seedling planting density

Rain splash and irrigation water

What is recommended to manage the disease in terms of seed treatment?

Treat seeds with Carbendazim or Thiram at 2/kg

Closer planting of seedlings

Use implements equipped with rain splash protection

Seed treatment with Trichoderma viride (correct)

Which disease is caused by Albugo candida according to the text?

White rust Signup and view all the answers

What is the effect of the disease on plant leaves initially?

Formation of circular brown necrotic spots Signup and view all the answers

How can sclerotia spread in the disease cycle?

Via irrigation water Signup and view all the answers

What is the pathogen responsible for loose smut of wheat?

Ustilago tritici Signup and view all the answers

How does loose smut of wheat primarily spread?

Through seed only Signup and view all the answers

Where does the pathogen responsible for loose smut of wheat remain in the plant?

In the seed embryo Signup and view all the answers

What is the appearance of the teliospores of the loose smut fungus?

Pale, olive brown, spherical to oval with echinulations Signup and view all the answers

How are teliospores of the loose smut fungus transformed to initiate infection?

By germinating readily in water to form a promycelium Signup and view all the answers

What characterizes loose smut of wheat in terms of its detection in the field?

Partially or completely replaces the spike with spores, making detection difficult Signup and view all the answers

What are the characteristic symptoms of Cotton leaf curl virus?

Upward and downward curling of leaves with thickening of veins Signup and view all the answers

What is the pathogen responsible for Cotton leaf curl virus?

Begomovirus Signup and view all the answers

How can the transmission of Cotton leaf curl virus be reduced?

Management of planting date Signup and view all the answers

What is the management strategy involving Paecilomyces farinosus in relation to Cotton leaf curl virus?

Eliminating alternate hosts Signup and view all the answers

How many sprays are recommended for managing Cotton leaf curl disease at 15-day intervals?

Four to five sprays Signup and view all the answers

What is the pathogen responsible for Fusarium wilt in lentils?

Fusarium oxysporum Signup and view all the answers

What is the characteristic symptom of angular leaf spot caused by the bacterium malvacearum?

Dark green spots on lower leaf surface Signup and view all the answers

Which stage of plant development is affected by seedling blight caused by malvacearum?

Seedling stage Signup and view all the answers

What is a common outcome of black arm symptoms caused by malvacearum on the plant's stem and branches?

Premature drooping off of leaves Signup and view all the answers

How does the infection progress in square rot / boll rot symptoms caused by malvacearum?

Dark black and sunken irregular spots appear on bolls Signup and view all the answers

What distinguishes vein blight or vein necrosis caused by malvacearum?

Blackening of veins and veinlets Signup and view all the answers

What is a key visual indicator that indicates the progression of angular leaf spot symptoms caused by malvacearum?

Reddish brown colour lesions Signup and view all the answers

What is the primary mode of transmission of the phytoplasma pathogen?

Through insects like aphids Signup and view all the answers

What is a key characteristic of phytoplasma in terms of their cell structure?

They have a rigid cell wall Signup and view all the answers

What is the main effect of phytoplasma colonization on plants?

Blocking of photosynthates from leaf to stalk and root Signup and view all the answers

What are the typical symptoms of ratoon stunting disease in sugarcane?

Stunted growth, reduced tillering, and yellowish foliage Signup and view all the answers

How does the disease cycle of phytoplasma start?

Through diseased setts and cutting knives Signup and view all the answers

What is the recommended management practice for controlling sugarcane diseases like ratoon stunting?

Eradicate diseased parts as soon as symptoms are seen Signup and view all the answers

Study Notes

Disease Cycle of Sclerotinia Stem Rot

The pathogen survives in soil and infected crop residues through sclerotia and pycnidia.
The pathogen is seed-borne and serves as a primary source of infection.
Soil-borne sclerotia also spreads through rain splash, irrigation water, and implements.

Management of Sclerotinia Stem Rot

Closer planting of seedlings should be avoided.
Optimum nutrition should be provided to maintain plant vigor.
Irrigation should be provided when the soil becomes dry and the soil temperature rises.
Seed treatment with Trichoderma viride or T.harzianum formulation at 5 g/kg seed is recommended.
In endemic areas, long crop rotation should be followed.

Important Diseases of Mustard

Alternaria blight is caused by Alternaria brassicae and/or Alternaria brassicola.
White rust is caused by Albugo candida.
Downy mildew is caused by Peronospora parasitica.
Sclerotinia stem rot is caused by Sclerotinia sclerotiorum.
Powdery mildew is caused by Erysiphe cruciferarum.
Bacterial blight/black rot is caused by Xanthomonas campestris.
Club root is caused by Plasmodiophora brassicae.

Alternaria Blight

The disease first attacks the lower leaves as small circular brown necrotic spots.
Many concentric spots coalesce to cover large patches, showing blightening and defoliation in severe cases.

Yellow Rust (Stripe Rust)

Caused by Puccinia striiformis.
Affects leave lamina, leaf sheath, and ears.
Spherical to ovate, containing 6-16 germ pores, bicelled, dark brown, and flattened at the top.
Pustules are small, oval, and arranged in rows or strips.

Loose Smut

Caused by Ustilago tritici.
Dissemination is exclusively through seed.
The entire inflorescence is commonly affected, appearing as a mass of olive-black spores.
The spike may be partially or completely replaced by spores, except the rachis which remains intact.

Bacterial Blight/Black Rot

Caused by Xanthomonas campestris.
The bacterium attacks all stages from seed to harvest.
Symptoms include seedling blight, angular leaf spot, vein blight or vein necrosis, black arm, and square rot/boll rot.

Leaf Curl Disease

Caused by Cotton leaf curl virus, a begomovirus of family Geminiviridae.
Symptoms include downward and upward curling of leaves, thickening of veins, and enation on the underside of leaves.
Management includes adjusting planting dates, eliminating volunteer perennial cotton and alternate hosts, using Paecilomyces farinosus, and applying neem leaf extract and neem oil.

Diseases of Lentil

Important diseases of lentil include Fusarium wilt caused by Fusarium oxysporum f.sp.
Ratoon stunting disease is caused by a phytoplasma.
Symptoms of ratoon stunting disease include stunted growth, reduced tillering, thin stalks with shortened internodes, and yellowish foliage.
Management of ratoon stunting disease includes eradicating diseased parts, avoiding selection of setts from diseased areas, pre-treating with hot water or hot air, and spraying with insecticides.

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Test your knowledge on Plant Pathology focusing on Yellow Rust caused by Puccinia striiformis with symptoms, characteristics, and dissemination methods.

Plant Pathology Yellow Rust Quiz