|Some Key Words of Entomology:
As few words as possible of entomological jargon are used in the different areas of Entomology. These are as follows:
Frass : solid insect excrement.
Honeydew : a sweetish liquid excrement produced by certain insects, especially aphids and scale insects.
Pitch tubes: hardened resin with a tube-like or balled form on the outside bark of pine trees infested by pine bark beetles.
Cocoon : a covering, composed partly or wholly of silk, spun by a larva to protect the enclosed pupa.
Checklist of Insect Damage:
Usually, evidence of damage caused by insects can be found on or in most trees, especially older trees. If such damage is seen on or in a tree a land owner is faced with a decision ; what to do? To complicate matters, insects may or may not be present. To assist the reader in making the decision of what to do, a control section is included for all pests discussed in this book. In most cases an insecticide or fungicide will be only one of several options available to the landowner. A chemical solution to the problem is not always the best or first to use. Cultural or physical control options may be the best choice.
Fruits: Mines, Premature drop, Damaged seed, Chewed,Galls, Holes,Abnormal shape etc.
Leaves: Discolored, Curled, Spotted, Galls, Notched (LuvRKvUv), Holes, Mines, Skeletonization, Defoliation, Disfiguration with excrement (gjZ¨v‡M †Pnviv cwiewZ©Z nIqv)
Twigs/Buds: Girdled (my›`i K‡i †cuwP‡q KvUv), Galls, Mines, Pruned, Wilted twigs, Discolored, Holes, Enlarged buds
Stem: Mines in bark or cambium, Borer channel into wood, Chewed bark, Galls, Pitch masses (cy‡iv Ges AvVv‡jv c`v_©), Fine sawdust, Holes.
Roots: Girdled, Galls, Mines, Chewed, Borer tunnels into wood, Mines in bark or cambium
This brief history of the interactions of humans and insects dating from the adoption of agriculture since 10,000 years ago and its inherent ecological disruptions.
The high hopes following World War II for relief from the bondage of insects through the use of chemical insecticides such as DDT proved unrealistic. After then chemical pest control became popular due to its quick knock down effect.
Gradually agriculture scientists realized the curse & negative impact of chemical pest control system. Subsequently Integrated pest management (IPM) is developed. In this system, multiple control technologies are used, with the additive effect being to hold insect injury at acceptable levels, while avoiding excessive environmental insult.
Entomologists are also facing new challenges from invasive species brought on by the increased international movement of people and goods in the global economy, and by global warming, which threatens to dramatically alter the geographic ranges of plant and animal species, including agricultural crops and their pests, as well as vectors of human and animal pathogens.
It is estimated that insects make up 75% of the known animal kingdom.
Because insects occupy almost every terrestrial niche, they interact with humans in countless ways that accord them status as “pests.”
During Greek civilization in the time of Aristotle (384-322 B.C.) the orderly study of biology began with his speculations. Aristotle’s vision of rationality lay dormant for centuries until the Renaissance.
The scientific revolution of the 16th and 17th centuries marked the beginning of modern science and included mathematics, mechanics, and astronomy but had little impact on biology.
Not until the 17th and 18th centuries was entomology advanced as a field of study within zoology. Anton van Leeuwenhoek (1632-1723) used the microscope to extend the power of the human eye. He was obsessed with the study of detail, including the morphology and specialized organs of insects. His revelations established insects as proper subjects for scientific study.
Francesco Redi (1626-1697) demonstrated in 1668 that insects arose not from spontaneous generation but from eggs laid by fertilized females.
Jan Swammerdam (1637- 1680) did superb anatomical work on insects, including the honey bee. Carl Linnaeus Systema Naturae (10th Ed., 1758) is the foundation stone of zoological nomenclature.
He greatly simplified insect classification by using insect wings (hence the suffix -ptera, meaning wing, for most order names) as the basis for classification. Another great naturalist, Rene Antoine Ferchault de Reaumur (1683-1757), infused a new perspective into the emerging study of insects. He deplored the confusion that existed regarding metamorphosis, distribution, and “industries” of insects. His(Rene Antoine Ferchault de Reaumur)six volumes of Memoires pour Servir a l’Histoire des Insectes (1734-1742) with their exacting attention to morphology and function, complete with accurate drawings, established a new standard of excellence. The work of Linnaeus and Reaumur provided the templates for orderly classification and elucidation of fundamental and applied aspects of entomology. The next step in the unfolding of the biological sciences was a great one: the publication in 1859 of Charles Darwin’s (1809-1882) theory, On the Origin of Species. This event placed conceptual biology in a new light. In a single stroke, Darwin’s work challenged the natural theology that had dominated biological thought for three centuries.
Darwin provided a new way of viewing biology. Intense debate followed the publication of Darwin’s theory.
Entomology like zoology has developed as study of natural history and taxonomy. Till about 1930 the subject was morphological all over the world.
In the present century investigation of all known phases of entomology progressed and expanded at a remarkable rate. Certain phases or definite events attracted widespread popular attention at various times. Each of these was stimulus to further expansion in the following brief remarks.
Medical & Veterinary Entomology:
The foundation for modern medical and veterinary entomology was laid by Louis Pasteur, a French microbiologist who formulated the theory of microbial causation of disease, based on his work with the silkworm, Bombyx mori in 1887.
Josiah Nott, a Mobile, Alabama, physician, proposed (1848) that the causative agents of malaria and yellow fever were transmitted by mosquitoes.
In 1897, Ronald Ross demonstrated the occurrence of the malaria parasite in mosquitoes that fed on a human patient whose blood contained the parasite, thus leading to the elucidation of the epidemiology of malaria.
In 1889, Theobold Smith discovered the causative agent of Texas cattle fever and the cattle tick, Boophilus annulatus, was the vector. Their work paved the way for tick prevention and development of the cattle industry in the southern United States.
The experiences in control of insects of agricultural, medical, and veterinary importance were unprecedented and left no region untouched. These experiences revealed the social, political, biological, economic, and environmental dimensions of insect problems.
The fundamental principles of insect control for the future included the following areas:
(1) Taxonomic knowledge of the vast insect fauna is a prerequisite for detection and development of control programs;
(2) international commerce barriers to the dispersal of insects;
(3) introduced species, uninhibited by their natural controls, often become major pests in their new habitat;
(4) the economic well-being of vast regions of the nation is vulnerable to insect attack;
(5) intervention at the national & international l level is required for insect problems beyond the scope of individual area;
(6) alterations of ecosystems trigger changes in patterns of insect behavior;
(7) the use of insecticides requires federal regulations to protect the user, the public, and the environment; and
(8) sound programs of insect control.
During the last decade of 19th century and up to the present, many insects of foreign origin became established various countries of the world and produced catastrophic damage to agriculture. The gypsy moth threatened to wipe out fruit and other tree in UK from 1889 – 1900’s. The destructive cotton ball weevil had invaded the entire cotton belt between about 1895 – 1920;the European corn borer loomed as a possible serious pests to the Mid Western corn crop in the early 1930’s and so on.
Each of these `battles’ between Entomologist and new insect enemy brought forth discoveries of new insecticides, equipment or methods need intensive study.
The research advances in the fundamental field followed very closely the demands of economic entomologist for more and better information about economic insect, suspected species or related forms. With such a stimulus the number of research works increased steadily and the growth and scope of teaching increased with it.
In the century progress in the insect Taxonomy, Physiology ,Embryology, and other fundamentals fields followed a definite pattern. In the more recent years researches with insect played a vital role of increasing importance in contributing information and ideas of general biological interest. This is especially true in biochemistry ,physiology behavior , ecology, biogeography and evolution.
Changing Entomological Economics:
In 1945 and 1946 the commercial introduction of the new synthetic insecticide DDT heralded a revolution in the economic Entomology. Up to that time effective control of insect pests by insecticides had been a relatively expensive undertaking because the necessary dosages of insecticides were high and the control often only moderately satisfactory.
DDt and later discovered synthetic insecticides such as benzene hexachloride, dieldrin, organic phosphate and other proved to so effective in such small dosages that the cost of pest control was lower. This opened a new area of pest control .Difficulties being encountered in plant toxicity, insecticide-resistant of insects and drastic ecological changes.
The subject Entomology which deals with forest pests is regarded as `Forest Entomology . Depletion of forest combined with the great need for forest products particularly building materials and paper have focused attention on the importance of forest as a vital part of the national economy. In this setting forest entomology has ` come of age’. The enormous depredation caused by insects are now well realized with the result that this field is receiving increased support from government agencies and private industries.
The usefulness of these entomological advances has been evolved monetary changes in the farm economy. Especially in irrigated areas and areas of relatively abundant rainfall , the per unit value of crops risen steadily. This investment includes increased application of fertilizer, increased use of better and more expensive seed and more and better mechanized farm equipments. As a result the farmer has a greater monetary stake in each acre and is able and willing to spend more for insect control in order to protect his investment.
What Role Do Insects Play in Agriculture?
Eat parts of plant, causing weakened growth and production
Eat parts of plant that we eat, spoiling crop
Spread diseases that weaken or kill the plant
Eat or parasitize harmful insects, keeping their populations in check.
Produce Marketable Products (honey, wax, silk)