CBRC SET A

100問 • 1年前

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Cadang-cadang disease which is caused by Coconut cadang-cadang viroid (CCCVd) becomes widely distributed in the central Philippines. Because of this, strict enforcement of quarantine regulations by concerned government agencies on the safe movement of coconut germplasm from infected areas is heightened to prevent its further spread to disease-free areas. The name Cadang-cadang is derived from the Bicol term 'gadan-gadan' which means

Dying

Coffee rust is a major disease of coffee affecting farmers. Coffee rust is dominant in what coffee producing province?

batangas

Black Sigatoka is caused by which pathogen?

Mycosphaerella fijiensis

True of the characteristics of fungi

Eukaryotic

The presence of different nuclei in the same mycelium is.

Heterokaryon

A group of substances secreted by pathogens that interfere with the permeability of photoplast membrane.

toxins

Which is NOT among the five (5) major genera of phytopathogenic bacteria?

Bacillus

Clustering of roots, flowers, fruits, or twigs around a common focus?

Fasciation

Common isolation method of bacterial plant pathogens from plant tissues?

Serial dilution

Citrus greening or mottling is now believed to be caused by:

bacteria

In rice, it causes a disease known as bakanae or "foolish seedling" disease, characterized by:

seedling elongation

How does Fusarium oxysporum cause wilting in bananas?

Fungi blocks water and nutrient uptake in the vascular system

Which of the following is the best reason why there will be severe symptom development in rice tungro infected rice plants?

Due to the presence of RTSV in infected plants

True of False: Manipulating one or more factors in the disease triangle can help control plant diseases.

true

Refers to the quantitative amoufal of disease that an isolate of a given pathogen can cause in a given group of plants in terms of size of lesions or number of lesions

virulence

Plant pathogenic bacteria can arrive at the ports of entry in the host plant. Which of the following allows this phenomenon?

The presence of bacterial flagellum for motility

Which of the following is a characteristic of viroids?

Absence of capsid protein

Why are Streptomyces considered as atypical plant bacterial pathogen?

Its spore germination results in filamentous colonies

A crop with adequate yield despite extensive nematode infestation exhibits which of the following?

Tolerance

Soil fumigation to control Moko disease of banana falls under what method of control?

physical control

Which of the following is considered as an exclusion method for management of plant diseases?

Rouging of virus-infected plants

With the use of insecticides to control a persistently transmitted plant virus, the following is/are NOT expected effect/s?

Negligible decrease in the rate of disease spread

A seed infected with a virus is an important source of infection since the seed introduces the virus

the virus into the crop at all stages of the crop

For root knot and cyst nematodes, this is also known as the infective stage

2nd stage juvenile

Koch's postulates, one of the four criteria is re-isolation, which states that:

The microorganism must be re-isolated from the inoculated, diseased individual and matched to the original microorganism

The damage due to the formation of ice crystals within cells

freezing injury

Which of the following is a form of susceptible response by the plant to a virus infection?

relatively fast appearance of severe symptoms

A virus is different from a viroid in that the viroid is composed of

stranded RNA alone with short bases

Consider the disease complex situation between Pratylenchus sp ( a nematode) and Fusarium sp. (a soil-borne fungal pathogen). Which of the statements below is NOT correct? Situation A: Plants Infected with Pratylenchus alone = 25% crop yield Situation B: Plants Infected with Fusarium alone = 50% crop yield Situation C: Plants Infected with Pratylenchus sp and Fusarium sp: 10% crop yield Situation D: Uninfected plants: 75% crop yield

It would be enough to control only Pratylenchus

The permanent nurse cells induced by root-knot nematodes in roots are called

giant cells

The permanent nurse cells induced by cyst nematodes in roots are called

syncytia

You observed that your rice plants manifested sheath blight symptoms. Which of the following best describes the pathogen that caused this disease?

A known non-spore forming fungus

In manifested sheath blight symptoms, what is the scientific name of the pathogen that inflicts the said disease?

Rhizoctonia solani

Why do mollicutes have different shape compared to a typical plant pathogenic bacteria?

They are rich in teichoic acid

What is the advantage of using polymerase chain reaction (PCR) in plant virus identification?

It allows determination of nucleic acid base sequencing of the virus

True of bacterial conjugation

Compatible bacteria exchange plasmids through sex pilus

Bacteria utilizes the following process that results in variability, EXCEPT:

None of the above

Which of the following is NOT an/are expression of variability among pathogens?

None of the following

A reaction that results in infection is also known as

compatible

Which of the following is TRUE about the gene-for-gene theory

R genes are generally dominant

According to the gene-for-gene theory which of the following is TRUE?

Avr genes - present in pathogens - no infection

TRUE of plant disease cycle

This has 2 parts - pathogenesis and saprogenesis

Which of the following phenomena corresponds to the 1st step of the disease cycle?

A fungal spore dispersed by wind then lodged at the surface of the host plants leaf

Which of the following reflects the survival phase of the inoculum in the disease cycle?

production of endospores

Some bacteria produce__ as their structures when unfavorable conditions occur.

Endospore

Sclerotial bodies are produced as__ structures by what species of fungi?

survival structures - Rhizocionia solant

Disease cycles classified as monocycles are characterized by:

Slow disease incidence rate

Which of the following is a NOT eukaryote?

Serratia marsecens

Which of the following spores is most likely favored to germinate in Cordillera Administrative Region?

Puccinia coronate

In which soil conditions favor fungal pathogens to germinate?

Soils with pH of 5

Pathogens that destroy chloroplasts exhibit what mechanism of pathogenicity?

Reduction of plant's photosynthetic capacity

Corn smut is a fungal disease that causes swellings (galls) on ears, leaves, stalks, and tassels of sweet and field corn. Which of the following best explains the symptoms caused by the fungal pathogen?

Ustilago maydis is able to produce indole-3-acetic acid efficiently from tryptophan

These substances are produced by plant pathogens which are toxic only to hosts of the pathogen producing the toxin. Which of the following is an example?

HC toxin

Select the correct pathogen and its corresponding toxin

Helminthosporium carbonum - HC toxin

Host plants have pre-formed resistance. Which of the following shows the pre-formed resistance of plants against plant pathogens?

Presence of glandular hairs secrete alkaloids

These are naturally occurring chemicals that bind to sterols in fungal cell membranes; alters permeability

Saponins

Induced resistance is defined as resistance that is active in the presence of inducers. Which of the following is an example of induced resistance?

SA pathway

Which of the following is produced in incompanbie reactions between a pathogen and a host plant

Localized plant cell death at the site of inoculation

Which of the following favors plant disease epidemics to occur?

All of the above

In disease epidemics, there are two types of diseases - one that shows compound interest and one that shoes simple interest. Which of the following correctly describes and matches each type of disease cycle?

Powdery mildew - compound interest

Which of the following assessment methods is best to use for rice tungro disease?

Disease incidence

This is computed by dividing the number of infected plants by the total number of plants multiplied by 100

Disease incidence

This is used to answer the question "How often the disease occurs in the locality" ?

Plant disease prevalence

All the following are the goals of plant disease survey EXCEPT:

To properly guide farmers in making decisions on plant disease control

The utilization of some physical component of the environment, such as temperature, humidity, or light, to the detriment of pathogens is under what principle of plant disease control

Eradication

This method is used to conserve moisture and organic matter and reduce erosion in the soil

Mulching

This refers to a mixture of several lines with similar agronomic characteristics but with different genes for resistance

Multiline varieties

Philippine Liberica is known locally as ?

Barako

Fungi in the Philippines reproduce mainly by?

asexual spores

Main means of reproduction in bacteria

binary fission

The genetic material of bacteria

deoxyribonucleic acid

This structure regulates the transport of materials into and out of the cell

Cell membrane

Common bacterial plant pathogen in the philippines that produces yellow and mucoid colonies in ordinary culture media

xanthomonas

Quiescent or latent infection is often associated with

anthracnose

In the absence of plants in field, fungal pathogens will not survive in

human beings

Who clearly demonstrated that fungi are the cause, and not the result of plant diseases?

De Bary

If juveniles and adults are motile during all life cycle stages but may be either within or inside of roots, a plant parasitic nematode is called as

migratory ectoparasite

Education, quarantine, using certified planting materials, checking suspect materials before planting and clearing equipment are examples of what type of management of plant parasitic nematode:

Prevention

In nematology, a variety is said to be resistant if it:

Suppresses the multiplication of nematodes

The early works of plant diseases due to viruses were based on the simple fact that they are

Very infectious and cause mosaic/mottle symptoms

Which of the following is a barrier to virus movement through the plant?

movement out of the vascular tissue into the parenchyma of an invaded leaf

Which life stage of the nematode will NOT be killed by a systemic nematicide?

Eggs

The most important group of vectors of plant viruses, both in terms of number of the viruses they transmit and the economic importance of the diseases these viruses cause, is/are the following except:

beetles

The early definitions of a virus mentioned which of the following characteristics?

smaller than the poresize of bacterial filters

A virus that does NOT persist in its insect vector

is lost after molting of the vector

An example of a disease due to lack of oxygen

black heart of potato

A unique air pollutant that can cause premature senescence

Ethylene

A disease which is aggravated by the presence of root knot nematode

bacterial wilt of tomato

Which of the following is not caused by a fungus?

tobacco mosaic

Crop loss assessment methods may be done using any of the following EXCEPT:

comparison of yield between different varieties without disease

Some pathogens produce either host-selective toxins or non-host-selective toxins to be able to successfully infect living plant cells. Which of the following is a host selective toxin produced by plant pathogen?

Victorin

These are a structurally diverse group of proteins produced by the plant that are toxic to plant pathogens. One example is chitinase, which is toxic to invading fungal pathogens.

Pathogenesis-related proteins

You were required to leave at the airport the planting materials you carried from abroad. What principle of plant disease control was applied?

Exclusion

Race-specific resistance is also called

vertical resistance

The phenomenon wherein genetically susceptible plants do not become infected because the three factors necessary for disease (susceptible host, virulent pathogen, and favorable environment) do not coincide and interact at the proper time or for sufficient duration.

immunity

Ralstonia solanacearum, the pathogen for bacterial wilt of solanaceous crops cause disease to plants through this:

Production of profuse EPS which clogs the xylem vessels of the host

The first report of insect transmission of a plant virus in the country dates back to 1926 when Gerardo O. Ocfemia reported transmission of a plant virus by Pentalonia nigronervosa. What is the particular virus disease?

Abaca bunchy top

Refers to the possesion of both functional male and female reproductive organ

hermaphroditic

Refers to the quantitative amount of disease that an isolate of a given pathogen can cause in a given group of plants in terms of size of lesions or number of lesions

virulence

100

The following are the climatic factors except one, which can cause symptoms that may br confused with crop damages brought about by pests and pathogens

Fertilizer burn

CLSU

Gante, Sherlane R. · 100問 · 1年前

CLSU