Pest, Disease and Weed Management
Integrated pest management (IPM) is the framework: prevention, monitoring, thresholds, and a hierarchy of controls from cultural and physical to biological and, last, chemical. Candidates must understand the difference between pests, diseases and disorders (abiotic problems such as nutrient deficiency, frost or herbicide damage). Learn to diagnose: identify the organism or cause, assess distribution and pattern, and check for signs (spores, frass, webbing) and symptoms (spots, wilts, galls).
Know the main groups: insects (chewing, sucking, borers), mites, nematodes, fungi, bacteria, viruses and phytoplasmas. Understand disease triangles (host, pathogen, environment) and how to break the cycle. Weeds: know classification (grass, broadleaf, sedge), life cycle (annual, biennial, perennial), and control methods (cultural, mechanical, biological, chemical). Understand herbicide selectivity, mode of action, resistance management and the importance of rotating groups.
Traps: treating a disorder as a disease; spraying when thresholds are not reached; and misidentifying a beneficial insect as a pest. Always confirm identification before treatment.
Worked rule of thumb: follow the IPM sequence - identify, monitor, set a threshold, then choose the least disruptive effective control. If a plant shows uniform yellowing across a bed, suspect an abiotic cause before a pathogen.