Integrated pest management Study Guide

📖 Core Concepts Integrated Pest Management (IPM) – A strategy that blends chemical and non‑chemical tactics to keep pest damage below an economically acceptable level while protecting the agro‑ecosystem. Action Threshold – The pest density at which control must be implemented to avoid exceeding the economic injury level. Economic Injury Level (EIL) – The pest population at which the cost of damage exceeds the cost of treatment. Degree‑Days – Cumulative temperature units (°C·day) used to predict pest development stages; helps time interventions. Preventive Cultural Practices – Crop‑selection, sanitation, and beneficial micro‑organism additions that keep crops healthy and less attractive to pests. Monitoring – Regular scouting, trapping, and record‑keeping to track pest numbers and biology. Mechanical Controls – Physical methods (hand‑picking, barriers, traps, tillage) used before chemical options. Biological Controls – Use of natural enemies or microbial insecticides (e.g., Bacillus thuringiensis, entomopathogenic fungi). Release Strategies Augmentative – Periodic addition of natural enemies. Inoculative – Small initial release for long‑term suppression. Inundative – Massive release for rapid, short‑term knock‑down. Responsible Pesticide Use – Apply only when needed, target the pest’s vulnerable life stage, and match formulation/technique to the crop. --- 📌 Must Remember IPM prioritizes cultural → mechanical → biological → chemical controls. Action thresholds are species‑ and site‑specific; exceeding them triggers the decision process. Maintaining pests below thresholds reduces selection pressure for resistance. Degree‑days = Σ (daily avg. temp – developmental base temp) → predicts when larvae, eggs, etc., appear. EIL formula (when provided): \[ \text{EIL} = \frac{C}{V \times D \times I} \] where C = control cost per unit area, V = market value per unit, D = damage per pest, I = injury per pest. (Only conceptual – not given in outline.) Three Reductions, Three Gains (SE Asia) = cut seed, fertilizer, pesticide → boost yield, quality, farmer income. Sterile Insect Technique = release sterile males → suppress reproduction without chemicals. --- 🔄 Key Processes Scouting & Monitoring Visual inspections, traps, degree‑day calculations, record pest species & life stages. Determine Thresholds Compare observed pest density to the pre‑set action threshold (or EIL). Decision‑Making If threshold crossed → evaluate cultural → mechanical → biological → chemical options. Select & Implement Intervention Choose the most economical, least disruptive tactic (e.g., resistant variety, barrier, augmentative release, targeted pesticide). Evaluation Assess control efficacy, side effects, and cost; adjust thresholds or tactics for the next cycle. --- 🔍 Key Comparisons Action Threshold vs. Economic Injury Level Action Threshold: practical trigger for control. EIL: economic break‑even point; may be higher than the action threshold. Augmentative vs. Inoculative vs. Inundative Release Augmentative: repeat additions, medium numbers. Inoculative: small early‑season release, long‑term effect. Inundative: huge one‑time release, immediate knock‑down. Biological vs. Chemical Controls Biological: relies on living enemies or microbes; slower, sustainable. Chemical: fast‑acting, higher resistance risk; used as last resort. Cultural vs. Mechanical Controls Cultural: long‑term preventive (varieties, sanitation). Mechanical: direct physical removal or disruption after pest presence is detected. --- ⚠️ Common Misunderstandings “IPM means no pesticides.” – False; pesticides are used only when needed and in a targeted way. “Thresholds are universal.” – Each pest‑crop‑environment combo needs its own threshold. “Biological controls are always safe.” – Introduced organisms can become non‑target pests if mis‑applied. “Degree‑days are optional.” – Ignoring them can mistime interventions, reducing effectiveness. “Resistant varieties eliminate need for monitoring.” – Resistance can break down; scouting remains essential. --- 🧠 Mental Models / Intuition IPM Decision Pyramid – Imagine a pyramid: Base = Cultural, then Mechanical, then Biological, and Apex = Chemical. Move up only when lower layers fail. “Threshold as a Stoplight” – Green (below threshold, no action), Yellow (approaching, prepare), Red (above, act). Degree‑Day Clock – Treat accumulated degree‑days like a clock hand that points to the next vulnerable pest stage. --- 🚩 Exceptions & Edge Cases Action thresholds may be set without economic calculations in structural pest management (e.g., termite monitoring). Certain high‑risk pests (e.g., invasive species) may require pre‑emptive chemical control even below threshold. In organic systems, “chemical” options are limited to botanicals or microbial insecticides, shifting the decision hierarchy. --- 📍 When to Use Which Choose Cultural when a resistant variety, proper sanitation, or beneficial microbes can keep pest pressure low. Select Mechanical if pest numbers just exceed the threshold and a quick physical removal is feasible (e.g., hand‑picking, traps). Apply Biological when a natural enemy is present or can be released effectively; prefer inoculative for long‑term, inundative for sudden outbreaks. Reserve Chemical for: Situations where other tactics have failed or are impractical, and When the pest is in a vulnerable life stage identified via degree‑days. --- 👀 Patterns to Recognize Spike in pest catches coinciding with a specific degree‑day accumulation → time for targeted spray or release. Decline in pest numbers after introduction of a flower strip or trap crop → indicates effective habitat diversification. Re‑emergence of pest after pesticide use → classic sign of resistance resurgence. Consistent low pest counts across seasons → suggests successful cultural/preventive measures. --- 🗂️ Exam Traps Confusing Action Threshold with EIL – Threshold is a management trigger; EIL is a break‑even economic point. Assuming “biological = always safe” – Question may ask for potential non‑target impacts. Mix‑up of release types – Inoculative = small & early, Inundative = large & immediate, Augmentative = repeat & moderate. Choosing pesticide first – IPM exam questions test the hierarchy; picking chemicals before cultural/mechanical is usually wrong. Degree‑day calculation omitted – If a question gives temperature data, expect you to compute degree‑days to decide timing. ---