Plant Diseases & Pest Management Test - 1

Banana Freckle is a disease caused by the fungus Guignardia musae (telomorph) or Phyllosticta musarum (anamorph). Generally, the causal agent of disease is referred to as Guignardia - Phyllosticta Symptoms include yellowing of the tissue and formation of small dark brown spots on the leaves and fruit.

 Within the spots, conidia or pycnidia can be found. Banana Freckle is easily propagated and spread from plant to plant by rain splash and movement of infected tissue or fruit.

Management of the disease consists of cutting out infected leaves, the paper bag method, fungicide application, and proper sanitation techniques

The correct answer is option (2) It is also known as ring disease.

Key Points

• The bacterial Blight of Rice is caused by bacteria which affects rice production badly.
• This disease is commonly spread by wind and rain.
• Millions of hectares of rice are infected annually with this disease.
• Wilt of Potato disease is also known as Ring disease because the brown ring is formed on Xylem.
• The factor of the Wilt of Potato disease is Pseudomonas Solonacearum bacteria.

The correct option is 4 i.e.All of the above.

• Sugarcane is a tropical plant.
• Therefore, it requires a year of warm weather to reach maturity.
• It survives in the areas having a temperature of 20° to 26°C 
• It requires an average rainfall of 150 cm for its cultivation.

Diseases of sugarcane:

The correct answer is Imbalanced and excessive use of chemical fertilizers.

Explanation:

• The concept of integrated nutrient management in agriculture was initiated mainly because of imbalanced and excessive use of chemical fertilizers, increasing prices of chemical fertilizers, Imbalance in the NPK consumption, pollution hazard of chemical fertilizers, Deterioration in soil health and its physical properties and biological activity.  
• Integrated Nutrient management system is promotion and maintenance of soil fertility for sustainable crop productivity through optimum use of all resources of nutrients like organic, inorganic and biological in an integrated manner appropriate to farming situation.
• The key principle of integrated nutrient management is Improvement of soil fertility and productivity on sustainable basis through appropriate use of fertilizers and organic manures.
• Integrated nutrient management emphasis the use of all the essential nutrients from different sources like organic manures, green manures, bio-fertilizers, chemical fertilizers, bio-fertilizers, legume crops, locally available plant resources in a balanced proportion for sustainable soil health and productivity.

Additional Information

Objectives of INM 

• Reducing dependence on chemical fertilizers.
• Maintaining productivity on sustainable basis without affecting soil health.
• Conserving locally available resources & utilize them judiciously.
• Maintaining soil health by providing balanced nutrients through different nutrient sources.
• Reducing the gap between utilised nutrients & nutrients harvested by the crop.
• Improving physical, chemical & biological properties of soil.
• Reducing the ill effects of continuous use of only inorganic chemical fertilizers.
• Increasing the fertilizer use efficiency (FUE).
• Improving the economical status of farmers.

Explanation:

• Microorganisms are harmful in many ways. Some of the microorganisms cause diseases in human beings, plants and animals.
• Such disease-causing microorganisms are called pathogens.
• Several microorganisms cause diseases in plants like wheat, rice, potato, sugarcane, orange, apple and others. The diseases reduce the yield of crops.
• The disease Yellow vein mosaic of bhindi is caused by a Virus called the Begomovirus. It is transmitted by an insect - Whitefly.
• The disease is characterised by mosaic-like yellowing of veins & veinlets of leaves.

Additional Information 

Correct Answer: Option 3-  Ranikhet

The correct answer is A - (3), B - (4), C - (2), D - (1).

Key Points

Citrus canker:

• It is caused by the bacterium Xanthomonas citri subsp. citri.
• It affects the leaves, twigs and fruit of citrus plants causing the leaves to drop and unripe fruit to fall to the ground.
• All types of citrus are affected by the disease.

Red rot of sugarcane:

• ​It is caused by the fungus Colletotrichum falcatum.
• It attacks the leaf midribs, stubble rhizomes, and stalks of the sugarcane plant.
• The leaves of the upper portion of the plant become pale or dark red and ultimately drop down.
• The stem splits and many red-coloured longitudinal streaks are formed on it.

Krishnakant disease of potato:

• It is also known as Black Heart Disease.
• Blackheart occurs primarily in storage when the tubers do not receive enough oxygen.
• Blackening of the tuber centre follows acute oxygen deficiency associated with either low temperature in confined storage or high field soil temperatures.
• The tissue dies from the inside out and turns jet black.

S​ahu disease of wheat:

• The spot blotch disease of wheat (Sahu Disease) is caused by Bipolaris sorokiniana, which is an anamorph (teleomorph Cochliobolus sativus).
• The disease mainly occurs in warm humid wheat-growing regions, and the Eastern Gangetic Plains (EGP) of South Asia is a hotspot.

The correct answer is Boron.

• Symptoms:
• When turnips are boron deficient, brown, water-soake d areas develop in the root, normally in the outer regions of the xylem.
• These symptoms give rise to the various names for the deficiency such as “brown heart,” “water core,” and “Raan."
• In severe cases, the central tissue may break down and the root becomes hollow. 
• Keeping quality is poor and affected roots lose weight through loss of moisture in storage.

• Management:
• Typical recommended ranges for boron boradcast soil application for turnips is 1-1.3 kg of Boron/acre.
• Normal plant analysis levels for the best quality and marketability have leaf boron levels in the 25-60 ppm range.

• The environmental effects of pesticides describe the broad series of consequences of using pesticides.
• The unintended consequences of pesticides is one of the main drivers of the negative impact of modern industrial agriculture on the environment.
• Pesticides, because they are toxic chemicals meant to kill pest species, can affect non-target species, such as plants, animals and humans.
• Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, because they are sprayed or spread across entire agricultural fields.
• Other agrochemicals, such as fertilizers, can also have negative effects on the environment.
• The negative effects of pesticides are not just in the area of application.
• Runoff and pesticide drift can carry pesticides into distant aquatic environments or other fields, grazing areas, human settlements and undeveloped areas.

•  Alternatives to heavy use of pesticides, such as integrated pest management, and sustainable agriculture techniques such as polyculture mitigate these consequences, without the harmful toxic chemical application.