Unit 1�INTRODUCTION

CLASS 11

AGRICULTURAL ENTOMOLOGY

IMTIYAZ AHMAD KHAN

DEFINITION�The term entomology is derived from two Greek words. Entomon means an insect and logos means to study. Thus, the term entomology means study of insects. REVEREND WILLIAM KIRBY (R.W KIRBY) is known as father of entomology.�* The term ‘insect’ is derived from the Latin word insectum which means ‘cut into’.�* Among 20 phylum of animal kingdom, arthropoda is the biggest one and comprises the class insecta, which is the largest and complicated group of insects.�* Agricultural entomology is a subdivision of Entomology which is the study of field crops, fruit and vegetable pests. It is the branch of entomology concerned with the harmful and beneficial effects of insects on agricultural practices.��

IMPORTANCE�* Two third of all the animal world is represented by insects. Knowing insects therefore gives us the better exposure about the natural fauna.��* Insects are most fascinating living things. They have amazing shapes, sizes, feeding habits, development processes etc. Study about them is a fascinating thing.��* They cause about 35% of loss to agriculture. Immagine the loss in terms of revenue and it's significance in the context of food hungry world.��* Insects are key factors in maintaining natural equilibrium. They do amazing services as herbivores, parasites, predators, pollinators, vectors, scavengers, seed transmissiors, soil dwellers etc.��* Insects are important link in nature's food chain.�

* They produce useful substances like silk, honey, wax, lac, colchicine, colors, dyes, medicines etc.��* They are equally important in the fields of human health, animal health, forestry, etc.��* Insects are hugely economically important in agriculture. They can be beneficial as pollinators and decomposers, or they can be detrimental as pests and vectors of plant diseases.��* Insects are excellent models for physiological and population processes. For example, the common fruit fly, Drosophila melanogaster, has been used as a model species in genetic studies.��* Insects are vectors of many plant diseases across the world. Understanding the biology of insects is key to understanding the diseases that they carry and spread.

UNIT- 2�INSECTS�����

CHARACTERISTICS OF INSECTS�* The body is bilaterally symmetrical and triploblastic(3 embryonic cell)�* Insects have a chitinous exoskeleton ( A nitrogen-containing polysaccharide that is a tough, protective, semitransparent substance), a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.��* Thorax consists of 3 segments i.e. pro, meso and meta, thorax consists of one pair of legs in each segments.��* Abdomen is comprised of 7-11 segments.�* Metamorphosis is common phenomenon in insects.�* Reproduction is usually sexual, sometimes viviparous and parthenogenesis.�� * The alimentary canal is tubular in structure which opens anteriority into mouth and end into anus.�� * Sense organs which are usually present in insects include compound eyes(vision), auditory(hearing), olfactory(smell), tactile(touch)etc.

�������������������

Fig:- Body parts of an insect

Economic Importance (Beneficial And Harmful) Of Insects� A- Beneficial Insects� 1- Insects and insects product in the food�Insects are an abundant food supply for several animals like frogs, snakes and small fishes, etc depend on insects for food.� 2- Insects as a scavenger�Some insects such as houseflies, silverfish, termites, maggots, dung-beetles, etc. feed upon waste material like a dead and decaying matter of insects and plants, thus act as scavengers and remove dead and decaying materials from the environment.� 3- Insects as pollinators for flowers�Some beneficial insects act as the pollinator for several flowers, it means transfer pollen grain from the anther of one flower to the stigma of the same or another flower of the same species.� 4- Insects in medicine�Some insects used as medicine, such as Cochineal insects contain carminic acid, used for the treatment of whooping cough. Cantharidine oil obtained from bristle beetles serves as a hair restorer. Bombax mori is used for treating leucorrhoea and chronic diarrhea

5- Insects in biological Pest control�Some beneficial insects feed on another insect which damage crops, these beneficial insects feeding on harmful insects are used as biological pest controller.�6- Productive insects� a- Honey producing insect:-  by the honey bee “Apis” � b- Bee-wax producing insect:-  by the honey bee “Apis” � c- Silk producing insects:- by Bombyx mori and other silkworms � d- Lac producing insects:- from female lac insects (Tachardia lacca) � e- Dyes:- � Dyes such as tannin, cochineal, and crimson lake are obtained from dried bodies of certain scale insects living on cacti.��Note :-� •Example of positive behaviors:-Pollination, Preying on harmful insects �•Example of negative behaviors:-Damaging vegetation, plant growth, diseases �

B- Harmful insects� 1- Pest of plants, fruits, and stores grains�Insects feed on several parts of green plants and crops, such as leaves, stems, buds, flowers, fruits, and seeds.�•Flea Beetles:- Attack on crops such as mustard and rapeseed. �•Green Worms:- feed on vegetation causing dramatic damage�•Stink Bugs:- Eat quickly and feed on a variety of fruit,) vegetables and plants �•Grass Hoppers:- Attack and eat wild plants, crops, and ornamental plants.� 2- Household pests�Several insects are living in our house, and annoy ourselves, such as mosquitoes, bedbug, may suck our blood and disturb us.�3- Disease carriers or an intermediate host of several pathogens�a- Anopheles mosquitoes�b- Sand fly (Phlebotomus)�c- Housefly (Musca)�� ***(classification of insect is in hand written note)

Thank you�����