General Physiology

• Physiology is the scientific study of the normal function in living systems.
• Pesticides are almost ubiquitously available in developing countries and, usually at prices affordable even to poor farmers.
• A sub-discipline of biology, its focus is in how organisms, organ systems, organs, cells, and biomolecules carry out the chemical or physical functions that exist in a living system.
• Physiology is divided into animal physiology, plant physiology, cellular physiology, microbial physiology, bacterial physiology, and viral physiology.
• Toxicology is a branch of biology, chemistry, and medicine (more specifically pharmacology) concerned with the study of the adverse effects of chemicals on living organisms.
• Toxicology also studies the harmful effects of chemical, biological and physical agents in biological systems that establishes the extent of damage in living organisms.
• The relationship between dose and its effects on the exposed organism is of high significance in toxicology.
• Factors that influence chemical toxicity include the dosage (and whether it is acute or chronic); the route of exposure, the species, age, sex and environment.
• Abiotic factors are conditions of the environment which adversely affect the health and productivity of plants.
• Abiotic factors include unfavourable climatic conditions such as drought, too high or too low temperature, poor texture or toxic properties of the soil, deficiency or surplus of soil moisture, nutrients and elementary metals and pollution of the environment.
• Biotic factors are animal and microbial organisms that include insects, mites, nematodes, snails, birds and larger animals such as rabbit and wild boars.
• Major pests are chronic pests under prevalent conditions at various growth stages of the crop and cause considerable damage.
• Occasional pests occur irregularly and locally and cause sporadic outbreaks.
• Secondary, induced or potential pests are pests which come to the fore as a result of a particular action such as spraying of broad spectrum residual insecticide that also kills their natural enemies.
• Natural enemies include higher predatory animals such as birds and bats, predatory or parasitic species of insects, mites and nematodes, and infectious species of fungi, bacteria and protozoa and viruses.
• Economic injury level (EIL) is when the pest population is large enough to cause crop losses costing more than the control.
• Crop protection aims at the prevention and limitation of damage and loss from injurious organisms in agriculture, horticulture and forestry.
• Factors contributing to the differences in ET include variety and age of the crop, location, previous damage received, simultaneous infestation of other pests, and agronomic practices such as plant spacing, fertilizer levels and irrigation.
• Host plant resistance is the capability of the host to hinder the growth and activity of a parasite or phytophagous and to limit the reproduction of a virus.
• Cultural control in IPM includes crop rotation, phytosanitation, adequate cultivation practices, intercropping or mixed cropping.
• Economic threshold (ET) is the pest population at which measures should be taken to prevent pest numbers from reaching the economic injury level.
• Integrated Pest Management (IPM) is an economically justified and sustainable system of crop protection, consisting of a combination of cultural, biological, genetical and chemical control methods that aims at maximum productivity with the least possible adverse consequences for the environment.
• Preventive control measures in IPM include quarantine and regulatory control, and pest-free propagation material.
• Crop protection science is the study of the factors which threaten planted crops and the ways and means to provide protection in the pre-harvest and post-harvest stages.
• Natural control is the collective action of environmental factors, physical and biotic that maintain numbers of pest populations within certain upper and lower limits over a period of time.
• Factors that must be considered also include market value of the crop, cost of pesticide application, expected income of growing another crop instead, and weight of negative health, social and environmental effects.
• Applied control includes a whole range of practices developed or modified by man, that becomes necessary when natural control factors fail to control pests.
• Advantages of chemical control include generally being effective and reliable means for controlling pests and diseases and preventing losses in the field and in the storage.
• The proper preventive use of pesticides, such as the disinfection of soils and seeds and the protective spraying of fungicides are indispensable methods in modern plant protection.
• Herbicide resistance plants and transgenic plants resistant to virus are examples of transgenic plants.
• Pesticides can be applied either as a preventive treatment to protect crops or stored products against infection by diseases of infestations by animal pests or as curative treatment to destroy or limit population development of noxious organisms.
• Insect pathogenic symbionts of plants are a type of hypervirulent baculoviruses.
• Most pesticides demonstrate a fast activity, by which serious infections and outbreaks can be limited or possibly even controlled.
• Pesticides have played and will continue to play a great role in increasing agricultural production and in securing the supply of food and fibers needed by the people of the world.
• The use of pheromones, hormones and growth regulators is a method of biotechnology like genetic manipulation, in vitro regeneration, transformation system, hybridoma technology.
• No technical solutions, other than the use of pesticides are yet known, with regard to a number of problems in intensive agriculture, horticulture, household pest and rodent control and storage protection.
• Chemical control consists of the application of botanical or inorganic or organic synthetic compounds that have a killing, inhibiting or repulsive effect on injurious organisms threatening mankind, animals and plants.
• It is essential that the reasons for using pesticides and the consequences of misusing them can be carefully analyzed in order to obtain maximum benefit from their application, while at the same time preventing and remedying their possible hazardous effect on non-target organisms and the environment.
• Chemical control is effective under very diverse ecological conditions and it is less dependent on the scale of the operation than the various forms of cultural and biological control.
• Transgenic plants possessing insect resistance are another type of transgenic plants.