Use of resistant varieties in ipm is which kind of method
Answers
Answered by
1
Recognizing there are entire courses and books on the subject of plant resistance to crop pests, this lecture will cover only the essential aspects of the topic. The role of plant resistance as a direct control tactic in insect integrated pest management (IPM) will be emphasized. Two case studies of the use of insect-resistant varieties as a component of an IPM strategy will be provided.
Ecological Results of Agriculture: In contrast to natural ecosystems, most agricultural crop production systems are ecologically unstable, non-sustainable, and energy dependent. Man has through plant domestication and cultivation practices interfered in many ways with species diversity and natural defense mechanisms of plants. Cultivated crops originated from genetically diverse plant types. However, crop plants are now grown in large, genetically homogeneous stands, a practice that decreases genetic and species diversity and increases the likelihood of economically significant insect pest infestations. Defense mechanisms of plants are re-created in resistant plants. Plant defense mechanisms include escape in space and time, incompatible biological associations, physically and chemically derived barriers, and accommodation by replacement or repair of damaged plant parts. By re-creating plant defenses, genetic resistance to insect pests plays, in an environmentally compatible manner, a vital role in the attempt to enhance ecological stability in agricultural crops.
An IPM Direct Control Tactic: Plant resistance to insects is one of several cultural control methods. Cultural control methods involve use of agronomic practices to reduce insect pest abundance and damage below that which would have occurred if the practice had not been used. In IPM, plant resistance to insects refers to the use of resistant crop varieties to suppress insect pest damage. Plant resistance is intended to be used in conjunction with other direct control tactics.
Definition of an Insect-Resistant Plant: Definitions of an insect-resistant plant are many and varied. In the broadest sense, plant resistance is defined as "the consequence of heritable plant qualities that result in a plant being relatively less damaged than a plant without the qualities." In practical agricultural terms, an insect-resistant crop cultivar is one that yields more than a susceptible cultivar when confronted with insect pest invasion. Resistance of plants is relative and is based on comparison with plants lacking the resistance characters, i.e., susceptible plants.
Effect of Insect Pest-Plant Host Relationship: Insect-resistant crop varieties suppress insect pest abundance or elevate the damage tolerance level of the plants. In other words, insect-resistant plants alter the relationship an insect pest has with its plant host. How the relationship between the insect and plant is affected depends on the kind of resistance, e.g. antibiosis, antixenosis (non-preference), or tolerance.
Antibiosis resistance affects the biology of the insect so pest abundance and subsequent damage is reduced compared to that which would have occurred if the insect was on a susceptible crop variety. Antibiosis resistance often results in increased mortality or reduced longevity and reproduction of the insect.
Antixenosis resistance affects the behavior of an insect pest and usually is expressed as non-preference of the insect for a resistant plant compared with a susceptible plant.
Tolerance is resistance in which a plant is able to withstand or recover from damage caused by insect pest abundance equal to that damaging a plant without resistance characters (susceptible). Tolerance is a plant response to an insect pest. Thus, tolerance resistance differs from antibiosis and antixenosis resistance in how it affects the insect-plant relationship. Antibiosis and antixenosis resistance cause an insect response when the insect attempts to use the resistant plant for food, oviposition, or shelter.
Advantages to the Use of Inse
Ecological Results of Agriculture: In contrast to natural ecosystems, most agricultural crop production systems are ecologically unstable, non-sustainable, and energy dependent. Man has through plant domestication and cultivation practices interfered in many ways with species diversity and natural defense mechanisms of plants. Cultivated crops originated from genetically diverse plant types. However, crop plants are now grown in large, genetically homogeneous stands, a practice that decreases genetic and species diversity and increases the likelihood of economically significant insect pest infestations. Defense mechanisms of plants are re-created in resistant plants. Plant defense mechanisms include escape in space and time, incompatible biological associations, physically and chemically derived barriers, and accommodation by replacement or repair of damaged plant parts. By re-creating plant defenses, genetic resistance to insect pests plays, in an environmentally compatible manner, a vital role in the attempt to enhance ecological stability in agricultural crops.
An IPM Direct Control Tactic: Plant resistance to insects is one of several cultural control methods. Cultural control methods involve use of agronomic practices to reduce insect pest abundance and damage below that which would have occurred if the practice had not been used. In IPM, plant resistance to insects refers to the use of resistant crop varieties to suppress insect pest damage. Plant resistance is intended to be used in conjunction with other direct control tactics.
Definition of an Insect-Resistant Plant: Definitions of an insect-resistant plant are many and varied. In the broadest sense, plant resistance is defined as "the consequence of heritable plant qualities that result in a plant being relatively less damaged than a plant without the qualities." In practical agricultural terms, an insect-resistant crop cultivar is one that yields more than a susceptible cultivar when confronted with insect pest invasion. Resistance of plants is relative and is based on comparison with plants lacking the resistance characters, i.e., susceptible plants.
Effect of Insect Pest-Plant Host Relationship: Insect-resistant crop varieties suppress insect pest abundance or elevate the damage tolerance level of the plants. In other words, insect-resistant plants alter the relationship an insect pest has with its plant host. How the relationship between the insect and plant is affected depends on the kind of resistance, e.g. antibiosis, antixenosis (non-preference), or tolerance.
Antibiosis resistance affects the biology of the insect so pest abundance and subsequent damage is reduced compared to that which would have occurred if the insect was on a susceptible crop variety. Antibiosis resistance often results in increased mortality or reduced longevity and reproduction of the insect.
Antixenosis resistance affects the behavior of an insect pest and usually is expressed as non-preference of the insect for a resistant plant compared with a susceptible plant.
Tolerance is resistance in which a plant is able to withstand or recover from damage caused by insect pest abundance equal to that damaging a plant without resistance characters (susceptible). Tolerance is a plant response to an insect pest. Thus, tolerance resistance differs from antibiosis and antixenosis resistance in how it affects the insect-plant relationship. Antibiosis and antixenosis resistance cause an insect response when the insect attempts to use the resistant plant for food, oviposition, or shelter.
Advantages to the Use of Inse
Similar questions