40 Questions
What type of defense mechanism do plants have to prevent pest attacks?
Physical barriers
What is the main purpose of using Metarrhizium anisopliae in pest control?
To control insect pests
Which of the following microorganisms is used to control plant parasitic nematodes?
Paecilomyces lilacinus
What is the purpose of using Bacillus thuringiensis (Bt) in pest control?
To control insect pests
What is the purpose of suberized cells in plant defense?
To form a physical barrier against pests
What is the purpose of the Bt toxin in genetically modified crops?
To provide insect resistance
What is the name of the genetically modified papaya that is resistant to papaya ringspot virus?
Sunup
Which of the following microorganisms is used to control giant reed weed?
Arundo gall wasp
What is the name of the company that developed the Round-up Ready canola?
Monsanto
What is the function of phytoalexins in plant defense?
To respond to fungal infections
What is the purpose of genetic pest control method?
To control pests through genetic manipulation
What is the main purpose of using Trichoderma in pest control?
To control plant diseases
What is the purpose of systemic acquired resistance (SAR) in plants?
To provide long-term resistance to pathogens
Which of the following techniques is used in genetic pest control method?
Causing reproductive sterility in pests
What is the name of the genetically modified tomato that has delayed ripening?
FlavrSavr
What is the purpose of using Colletotrichum gloeosporioides in pest control?
To control sensitive jointvetch
What is the consequence of water hyacinth growth in tropical freshwater without CBC?
Freshwater being rendered useless
Which of the following is an example of an augmentative approach in biological control?
Trichogramma spp. used against many Lepidopteran insect pests
What is the main reason for using biological control agents?
Increasing resistance against pesticides
Which of the following is a consequence of the overuse of pesticides?
Increased dose and frequency of pesticide use
What is the name of the aquatic weed that is considered the world's worst?
Water hyacinth
What is the term for releasing natural enemies periodically or seasonally to reestablish a balance?
Inoculative approach
What is the consequence of using pesticides excessively?
Increased problems with residues in fruits and vegetables
What is the term for the massive production and release of natural enemies to control pests quickly?
Inundative approach
What is a crucial geographical requirement for an eradication zone?
Natural barriers or defensible borders
What is a limitation of the Sterile Insect Technique (SIT) due to the target pest's behavior?
Native females may recognize and refuse to mate with sterile males
What is an economic limitation of the Sterile Insect Technique (SIT)?
The cost of rearing, sterilizing, and releasing large numbers of insects
What is a characteristic of the lab-reared and sterilized male insects used in the Sterile Insect Technique (SIT)?
They are equally or more competitive than native males in mating with native females
What is required for the successful implementation of the Sterile Insect Technique (SIT)?
Knowledge of the pest's reproductive behavior, population dynamics, dispersal, and ecology
What is the primary function of the Cry protein in Bacillus thuringiensis?
To break down in the insect gut and release the toxin known as delta endotoxin
What is an alternative genetic strategy to the Sterile Insect Technique (SIT)?
Inherited/Delayed Sterility
What is the purpose of incorporating a virus coat protein in genetic engineering for disease resistance?
To cross protect the host plant from viral diseases
What is the term for a gene moved from one non-closely related species to another?
Transgenic
What was the first genetically engineered crop plant?
Tobacco
What is the definition of pesticides?
Any substance or product, including active ingredients, adjuvants and pesticide formulations, intended to control, prevent, destroy, repel or mitigate directly or indirectly, any pest
What is the name of the toxin released by the Cry protein in Bacillus thuringiensis?
Delta endotoxin
What is the purpose of using Plantibodies in genetic engineering for disease resistance?
To provide disease resistance to host plants
What is the year when Bacillus thuringiensis was approved for commercial sale?
1985
What is the function of 2-5A synthetase in genetic engineering for disease resistance?
To provide disease resistance to host plants
What is the purpose of incorporating a glyphosate degrading enzyme in genetic engineering for herbicide resistance?
To degrade glyphosate in the soil
Study Notes
Evolutionary Arms Race
- Plant defense mechanisms against pests:
- Physical barriers: thick, waxy cuticle, long, dense trichomes, sticky trichomes, suberized (corky) cells
- Chemical barriers: secondary metabolites (thousands of known compounds with varied and complex chemistry)
- Pests can develop resistance to plant defense mechanisms, leading to an evolutionary arms race
Genetically Modified Crops
- Examples of genetically modified crops:
- Canola with herbicide resistance (Glyphosate) - Round-up Ready
- Corn with herbicide resistance (Glyphosate) - SeedLink
- Flax with herbicide resistance (Sulfonylurea) - CDC Triffid
- Soybeans with herbicide resistance (Glufosinate)
- Corn with insect resistance (Bt toxin) - NatureGard
- Cotton with insect resistance (Bt toxin) - Bollgard
- Potatoes with insect resistance (Bt toxin) - NewLeaf
- Squash with disease resistance (Watermelon, zucchini, and cucumber mosaic viruses)
- Papayas with disease resistance (Papaya ringspot virus) - Sunup, Rainbow
- Tomatoes with delayed ripening - FlavrSavr
Biological Control
- Water hyacinth (Eichhornia crassipes) is the world's worst aquatic weed, threatening freshwater flora and fauna, increasing disease vectors, and hampering hydroelectric power, transport, and water supply.
- Biological control agents used to control water hyacinth:
- Mottled water hyacinth weevil (Neochetina eichhorniae)
- Approaches to implementing biological control agents:
- Periodical mass release of beneficials (augmentation approach)
- Inoculative approach: releasing natural enemies to reestablish balance
- Inundative approach: massive production and release of natural enemies to control pests quickly
- Periodical mass release of beneficials (augmentation approach)
Biocontrol Methods
- Reasons to use biocontrol methods:
- Increasing resistance against pesticides
- Higher dose and increased frequency of pesticide use
- Problems with residues in fruits and vegetables
- Examples of biocontrol methods:
- Insect pathogens: Metarrhizium anisopliae (green muscardine fungus), Beauveria bassiana (white muscardine fungus), Bacillus thuringiensis (Bt) against corn borer
- Microorganisms against plant pathogens:
- Fungus (Trichoderma) against various plant pathogens
- Fungus (Paecilomyces lilacinus) against nematodes
- Bacillus amiloliquefaciens against many plant diseases
- Microorganisms against weeds:
- Phytophthora palmivora against strangler vines
- Collectotrichum gloeosporoides f.sp.aeschenomene against sensitive jointvetch
- Arundo gall wasp against giant reed weed
Genetic Manipulation of Pests
- Genetic pest control methods:
- Causing reproductive sterility
- Incorporating new genes or alleles into the pest population (deleterious) or crop (resistance)
- Limitations of Sterile Insect Technique (SIT):
- Resistance: native females may refuse to mate with sterile males
- Economics: high cost of rearing, sterilizing, and releasing large numbers of insects
- Desirability of sterile males: lab-reared males may become less competitive over generations
- Knowledge about pest: understanding pest behavior, population dynamics, dispersal, and ecology
- Timing: synchronizing lab-reared insect development with wild population development
- Alternative genetic strategies:
- Inherited/Delayed Sterility: released insects are fertile but their progeny are sterile
- Genetic Engineering in Pest Management:
- Utilizes biotechnology to make plants resistant to specific pests
- Examples: Bt crops, herbicide-resistant crops, disease-resistant crops
Genetic Engineering in Pest Management
- Definition of terms:
- Transgenic: gene transfer between non-closely related species
- Cisgenic/Intragenic: gene transfer within same species or closely related species
- Subgenic: gene editing to amplify, delete, insert, silence, or repress genes
- First genetically modified crop: tobacco, approved in 1985
- Bacillus thuringiensis (Bt) produces crystalline (Cry) protein, which breaks down in insect gut and releases toxin
- Herbicide resistance:
- Incorporating soil bacterium gene that produces glyphosate-tolerant EPSPS
- Incorporating soil bacterium gene that produces glyphosate-degrading enzyme
- Disease resistance:
- Using virus coat protein as cross-protectant for host plant
- Using Plantibodies
- 2-5A synthetase, a class of proteins of mammalian origin, for engineering plant virus resistance
This quiz covers the different defense mechanisms that plants have evolved to protect themselves from pests, including physical and chemical barriers. Learn about the various ways plants defend themselves!
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