問題一覧
1
Fungi in the Philippines reproduce mainly by?
asexual spores
2
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
3
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
4
True of False: Manipulating one or more factors in the disease triangle can help control plant diseases.
true
5
Bacteria utilizes the following process that results in variability, EXCEPT:
None of the above
6
The presence of different nuclei in the same mycelium is.
Heterokaryon
7
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
8
For root knot and cyst nematodes, this is also known as the infective stage
2nd stage juvenile
9
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
10
Which life stage of the nematode will NOT be killed by a systemic nematicide?
Eggs
11
In which soil conditions favor fungal pathogens to germinate?
Soils with pH of 5
12
True of bacterial conjugation
Compatible bacteria exchange plasmids through sex pilus
13
TRUE of plant disease cycle
This has 2 parts - pathogenesis and saprogenesis
14
The damage due to the formation of ice crystals within cells
freezing injury
15
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
16
Citrus greening or mottling is now believed to be caused by:
bacteria
17
Which of the following assessment methods is best to use for rice tungro disease?
Disease incidence
18
This is computed by dividing the number of infected plants by the total number of plants multiplied by 100
Disease incidence
19
Which of the following is considered as an exclusion method for management of plant diseases?
Rouging of virus-infected plants
20
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
21
Coffee rust is a major disease of coffee affecting farmers. Coffee rust is dominant in what coffee producing province?
batangas
22
Who clearly demonstrated that fungi are the cause, and not the result of plant diseases?
De Bary
23
Which of the following is a NOT eukaryote?
Serratia marsecens
24
Common bacterial plant pathogen in the philippines that produces yellow and mucoid colonies in ordinary culture media
xanthomonas
25
Which of the following is a form of susceptible response by the plant to a virus infection?
relatively fast appearance of severe symptoms
26
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
27
A virus that does NOT persist in its insect vector
is lost after molting of the vector
28
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
29
According to the gene-for-gene theory which of the following is TRUE?
Avr genes - present in pathogens - no infection
30
The early definitions of a virus mentioned which of the following characteristics?
smaller than the poresize of bacterial filters
31
How does Fusarium oxysporum cause wilting in bananas?
Fungi blocks water and nutrient uptake in the vascular system
32
These are naturally occurring chemicals that bind to sterols in fungal cell membranes; alters permeability
Saponins
33
In manifested sheath blight symptoms, what is the scientific name of the pathogen that inflicts the said disease?
Rhizoctonia solani
34
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
35
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
36
Which of the following spores is most likely favored to germinate in Cordillera Administrative Region?
Puccinia coronate
37
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
38
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
39
A crop with adequate yield despite extensive nematode infestation exhibits which of the following?
Tolerance
40
All the following are the goals of plant disease survey EXCEPT:
To properly guide farmers in making decisions on plant disease control
41
This refers to a mixture of several lines with similar agronomic characteristics but with different genes for resistance
Multiline varieties
42
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
43
Select the correct pathogen and its corresponding toxin
Helminthosporium carbonum - HC toxin
44
Pathogens that destroy chloroplasts exhibit what mechanism of pathogenicity?
Reduction of plant's photosynthetic capacity
45
Main means of reproduction in bacteria
binary fission
46
Why do mollicutes have different shape compared to a typical plant pathogenic bacteria?
They are rich in teichoic acid
47
Which of the following is TRUE about the gene-for-gene theory
R genes are generally dominant
48
Refers to the possesion of both functional male and female reproductive organ
hermaphroditic
49
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
50
The permanent nurse cells induced by root-knot nematodes in roots are called
giant cells
51
A disease which is aggravated by the presence of root knot nematode
bacterial wilt of tomato
52
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
53
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
54
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
55
Race-specific resistance is also called
vertical resistance
56
Common isolation method of bacterial plant pathogens from plant tissues?
Serial dilution
57
An example of a disease due to lack of oxygen
black heart of potato
58
The genetic material of bacteria
deoxyribonucleic acid
59
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
60
Disease cycles classified as monocycles are characterized by:
Slow disease incidence rate
61
A group of substances secreted by pathogens that interfere with the permeability of photoplast membrane.
toxins
62
Which of the following is a characteristic of viroids?
Absence of capsid protein
63
Black Sigatoka is caused by which pathogen?
Mycosphaerella fijiensis
64
Which is NOT among the five (5) major genera of phytopathogenic bacteria?
Bacillus
65
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
66
A virus is different from a viroid in that the viroid is composed of
stranded RNA alone with short bases
67
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
68
Soil fumigation to control Moko disease of banana falls under what method of control?
physical control
69
Which of the following favors plant disease epidemics to occur?
All of the above
70
You were required to leave at the airport the planting materials you carried from abroad. What principle of plant disease control was applied?
Exclusion
71
This structure regulates the transport of materials into and out of the cell
Cell membrane
72
Crop loss assessment methods may be done using any of the following EXCEPT:
comparison of yield between different varieties without disease
73
Philippine Liberica is known locally as ?
Barako
74
The permanent nurse cells induced by cyst nematodes in roots are called
syncytia
75
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
76
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
77
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
78
This method is used to conserve moisture and organic matter and reduce erosion in the soil
Mulching
79
Which of the following is not caused by a fungus?
tobacco mosaic
80
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
81
This is used to answer the question "How often the disease occurs in the locality" ?
Plant disease prevalence
82
True of the characteristics of fungi
Eukaryotic
83
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
84
Sclerotial bodies are produced as__ structures by what species of fungi?
survival structures - Rhizocionia solant
85
A unique air pollutant that can cause premature senescence
Ethylene
86
Why are Streptomyces considered as atypical plant bacterial pathogen?
Its spore germination results in filamentous colonies
87
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
88
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
89
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
90
In rice, it causes a disease known as bakanae or "foolish seedling" disease, characterized by:
seedling elongation
91
Which of the following is NOT an/are expression of variability among pathogens?
None of the following
92
Which of the following reflects the survival phase of the inoculum in the disease cycle?
production of endospores
93
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
94
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
95
Quiescent or latent infection is often associated with
anthracnose
96
Some bacteria produce__ as their structures when unfavorable conditions occur.
Endospore
97
In the absence of plants in field, fungal pathogens will not survive in
human beings
98
In nematology, a variety is said to be resistant if it:
Suppresses the multiplication of nematodes
99
A reaction that results in infection is also known as
compatible
100
Clustering of roots, flowers, fruits, or twigs around a common focus?
Fasciation