GENERAL PHYSIOLOGY AND TOXICOLOGY INTRODUCTION

Physiology

Study of how insects live and reproduce; focuses in the function of structures and organ system

Physiological Systems in Insects

1. Insect integument

2. Endocrine system

3. Muscular system

4. Respiratory system

5. Digestive system

6. Circulatory system

7. Nervous system

8. Excretory system

Toxicology

Study of harmful actions of chemicals on biological tissue; involves understanding chemical reactions and interactions

Insecticide toxicology

• Determination of tolerance levels of pesticide in man

• Selective toxicology of chemical on killing insects without affecting mammals
  

Absorption

Process by which chemicals crosses various membranes of a living organisms

Toxicity

Ability of pesticide to produce adverse effects

Acute Toxicity

Ability of chemical to do systemic damage as a result of one-time exposure to large amount

Types: Acute oral, Acute dermal, Acute inhalation

Chronic toxicity

harmful effects of chemical by long-term exposure which persist over a long period of time

LD50 (Lethal Dose 50)

Single dose of toxic substance administered by any route (except inhalation) that causes 50% death of animal population

LDLo (Lethal Dose Low)

Lowest dose reported to have caused death in humans/ animals

LC50 (Lethal Concentration 50)

Concentration in air that kills 50% of test animals administered as single exposure; route is inhalation

Dose

total amount of substance administered to, take up, absorbed by organisms

Response

Effect on the group of individuals that demonstrates effect in given time at given dose

Half life

Time required for reactant to reach a value that is the arithmetic mean of initial and final values (equilibrium)

Tolerance

Ability of organism to show less response to specific dose of chemical acquired

Insecticide use profile

Phil. Agriculture increased productivity in 1960’s because of improved agricultural inputs and infrastructure

Total agricultural inputs expenditure
Pesticide- 18.2%
Insecticide - 55%
Fungicides - 22%
Herbicide - 16%

Regulation of Fertilizer and Pesticide Industry

1. PD 1144 - merged fertilizer and pesticide industries

2. Fertilizer and Pesticide Authority (FPA)
   

Most commonly used insecticides in the Philippines

1. Organophosphate - Parathion, Malathion, Diazinon

2. Carbamates - Carbaryl (Sevin), Methomyl (Lannate)

3. Pyrethroids - (Ambush, Pounce)

Insecticide Importation in the Philippines

• Import of pesticide grew to 500% in 1972-1978

• FAO indicates steady rate of pesticide importation from 2010-2015 but uncreased up to 50% in 2015

• In 2020, Phil imported 363 million dollars in Pesticides, becoming 28th largest importer of Pesticides in the world