PPrt 132 Introduction.pdf

PPrt 132 General Physiology and Toxicology Introduction Learning outcomes To understand what insect physiology and toxicology is all about To familiarize with the common terminologies used in insect physiology and toxicology Introduction Definition of terms 1. Physiology...

PPrt 132 General Physiology and Toxicology Introduction Learning outcomes To understand what insect physiology and toxicology is all about To familiarize with the common terminologies used in insect physiology and toxicology Introduction Definition of terms 1. Physiology -sum total of processes tending to the maintenance and replication of a living organism taken as a group of metabolic systems. focuses in the function of structures and organ systems Insect physiology is the study of how insects live and reproduce. Physiological Systems in Insects Insect Integument Endocrine System Muscular System Respiratory System Digestive System Circulatory System Nervous System Excretory System 2. Toxicology Study of harmful actions of chemicals on biological tissue Involves an understanding of chemical reactions and interactions, and understanding of biological mechanisms  3. Insecticide toxicology a sub-discipline of medical toxicology Does not include clinical diagnosis or treatment of humans affected by insecticides Includes studies on: determination of tolerance levels of pesticide in man establishing a logical basis for selective toxicology of a chemical on killing insects but without affecting mammals in particular Insecticide Toxicologists are actually interested on: the effect of insecticide not only to insects but to any organism the elucidation of the mechanism of action of toxicants differences on the inhibitory actions of toxicants metabolic fate of toxicants in insects Terminologies in Toxicology 1. Absorption-a process by which a chemical crosses various membranes of a living organism. 2. Toxicity-ability of a poison (pesticide) to produce adverse effects. 3. Acute Toxicity- ability of a chemical to do systemic damage as a result of one-time exposure to large amount Types: acute oral, acute dermal or acute inhalation Terminologies in Toxicology 4. Chronic Toxicity- harmful effects of chemical by long-term exposure which persist over a long period of time. 5. LD50(Lethal Dose 50)- a single dose of a toxic substance administered by any route (except by inhalation) that causes 50% death of an animal population 6. LDLo(Lethal Dose Low)- lowest dose of a substance reported to have caused death in humans or animals  7. LC50(Lethal Concentration 50)- is the concentration of a material in air that kills 50% of a group of test animals administered as single exposure in a specific period. Used when the route of administration is by inhalation expressed as parts of material per million parts of air (ppm) Acute Toxicity measures and warnings 8. Dose- total amount of a substance administered to, taken up, or absorbed by an organism, organ, or tissue 9. Response- the proportion of an exposed population with a defined effect on the proportion of a group of individuals that demonstrates a defined effect in a given time at a given dose rate. 10. Half life- time required for the concentration of a reactant in a given reaction to reach a value that is the arithmetic mean of its initial and final (equilibrium) values. 11. Tolerance- ability of an organism to show less response to a specific dose of a chemical that it demonstrated on a prior occasion (acquired) Concept of Insect Physiology and Toxicology A successful pest and pesticide management program requires understanding of physiology and toxicology considering the pests, people and crops Why Insect Physiology? Insects provide an ideal mechanism to study general physiology of other animals to understand its basic principles To study physiology one must: have a proper understanding of the principal processes and peculiarities of insects proper discussion on the structures involved goes hand in hand with anatomy and ecology  Although insect physiology does not provide directly the means to control insect pests Yet, the rational application of control strategies is often dependent on knowledge of physiology of insect involved Insecticide Use Pattern Insecticide use profile Increased productivity in Phil. Agriculture started in 1960’s as a consequence of improved agriculture infrastructure and massive increase in agricultural inputs (fertilizers and pesticides) and introduction of HYV.  Pesticides comprise 18.2% in total agricultural inputs expenditure Insecticides constitute approximately 55%, fungicides 22% and herbicide 16% of the pesticides used Pesticides are for rice, corn, vegetables and plantation crops Regulation of Fertilizer and Pesticide Industry PD 1144 merged the fertilizer and pesticide industries Fertilizer and Pesticide Authority (FPA) Provides rules to prevent unlawful sale and use of fertilizers, pesticides and other agricultural chemicals Most commonly used insecticides in the Philippines Organophosphates e.g Parathion, Malathion, Diazinon Carbamates e.g Carbaryl (Sevin), Methomyl (Lannate) Pyrethroids e.g Permethrin (Ambush®, Pounce®)  Such insecticides are mostly used in vegetables, banana and rice Due to larger production area of cultivation, rice gets the largest gross amount of insecticide applications in the Phil. Although insecticides are also used intensively in vegetables Farmers use pesticide at Increased quantity Higher/stronger concentration Increased frequency of application Even mix several kinds together (“cocktail”) (To combat pest population that have already developed resistance) Insecticide Importation in the Philippines Import of pesticide grew to 500% in 1972-1978 FAO data indicates a steady rate of pesticide importation from 2010-2015 but increased up to 50% in 2015.  In 2020, Philippines imported $363M in Pesticides, becoming the 28th largest importer of Pesticides in the world. (https://oec.world/en/profile/bilateral-product/pesticides/reporter/phl)  In 2020, Pesticides was the 60th most imported product in Philippines. Philippines imports Pesticides primarily from: China ($109M), Indonesia ($60.4M), Malaysia ($2 7.7M), India ($18.9M), and South Korea ($18.6M).