Agriculture Entomology

1. Unit 1: Introduction to Entomology
Department of Agriculture- Plant Science
Sumnima Polytechnic Institute, Bhojpur

2. 1.1 Definition, Importance and Scope of Entomology
 Entomology is derived from two Greek words: Entomon meaning insects
and logy meaning study
 The meaning of entomology is the scientific study of insects
 Thus, entomology can be defined as the branch of zoology that deals with
the biology, taxonomy, physiology, ecology, behavior, and evolution of
insects
 Agricultural entomology is a sub-discipline of entomology, that focuses on
the relationship between insects and agriculture
 This branch of entomology is concerned with the study of insects that
affect crops and agricultural ecosystems.

3. Importance of Entomology
Entomology plays a crucial role in various aspects of human life, agriculture, ecology,
medicine, and beyond. Here are some key aspects highlighting the importance of
entomology:
1. Agriculture:
 Pest Management:
Entomologists study insect pests that affect crops and develop strategies for
effective pest management.
This includes the development of integrated pest management (IPM) programs
that use a combination of biological, chemical, and cultural control methods to
minimize the impact of pests on crops.
 Pollination:
Many crops rely on insects for pollination.
Understanding the role of different insect species in pollination is essential for
maintaining and enhancing agricultural productivity.

4. 2. Ecology:
 Biodiversity:
Insects represent a significant portion of global biodiversity.
Studying insect ecology helps scientists understand the interactions between insects
and their environments, contributing to our understanding of ecosystems and
biodiversity.
 Food Chains:
Insects often play vital roles in food chains, serving as prey for various animals.
Understanding these relationships is essential for maintaining balanced ecosystems.
3. Medicine:
Some insects, like mosquitoes and ticks, are vectors for diseases such as malaria,
encephalitis, dengue, etc.
Medical entomologists study these insects to develop strategies for disease
prevention and control.

5. 4. Conservation:
 Insects can act as indicators of environmental health.
 Monitoring insect populations can provide insights into the impacts of pollution, habitat
loss, and climate change, aiding conservation efforts.
5. Research and Education:
 Scientific Advancements:
Entomological research contributes to scientific knowledge and advancements.
Understanding insect physiology, behavior, and genetics can lead to discoveries
with applications in various fields.
 Education:
Entomology provides valuable educational opportunities, fostering an appreciation
for the diversity and importance of insects in the natural world.

6. 6. Economic Impact:
 Commercial Products:
Some insects are commercially valuable for products such as honey, silk, and
shellac.
Understanding their biology and husbandry is crucial for sustainable production.
 Biological Control:
Beneficial insects are often used for biological control of pests, reducing the need
for chemical pesticides and promoting environmentally friendly pest management
practices.

7. Scope of Entomology
The scope of entomology in Nepal can be diverse and impactful, considering the country's
rich biodiversity, agricultural significance, and the presence of insect-related challenges.
i. Pest Management: Nepal often faces severe agricultural damage by insects pests.
Entomology can be deployed to increase agricultural production and productivity
ii. Biodiversity Conservation: Nepal is home to diverse insect species. Entomology plays
crucial role in conservation of those species
iii. Disease Management: Insects are responsible for transmission of many diseases in
plants and animals. Scope of entomology lies in the management of such diseases
iv. Demand of Insect Products: Insects products like honey, silk, lac, venom, etc. have high
demand in national and international market. Entomology provides basis for
commercial rearing of economic insects to produce high value insect products
v. Education and Research

8. 1.2 General concepts of insect, pest and pesticides
Insect
 Insects are a class of invertebrates within the arthropod phylum, characterized by a
three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound
eyes, and two pairs of wings
 They are the most diverse group of animals on Earth, with over a million described
species
 Insects play crucial roles in ecosystems, including pollination, decomposition, and
serving as a food source for other organisms.
Pest
 A pest is an organism, usually an insect, plant, or animal, that poses a threat or
nuisance to humans, their activities, or their interests
 Pests can cause damage to crops, structures, livestock, or human health

9. 1.2 General concepts of insect, pest and pesticides
Pesticide
 Pesticides are substances or mixtures of substances intended for preventing,
destroying, repelling, or mitigating any pest
 This broad category includes insecticides (targeting insects), herbicides (targeting
weeds), fungicides (targeting fungi), and other chemicals designed to control or
eliminate pests

10. Assignment 1:
Write any five insect species and categorize whether they are beneficial
or harmful.
Preparation time: 5 minutes

11. 1.3 Harmful insects and beneficial insects
Beneficial Insects
 Beneficial insects are those that provide positive contributions to ecosystems,
agriculture, and human activities
 They play important roles in natural processes, provide essential services, and often
contribute to the well-being of plants, animals, and humans.
Here are some categories of beneficial insects:
 Pollinators: Examples: Bees, butterflies, moths, hummingbirds, beetles.
 Natural Predators: Examples: Ladybugs (Ladybirds), predatory beetles, lacewings,
predatory wasps, spiders.
 Decomposers: Examples: Dung beetles, ants, certain beetles.
 Biological Control Agents: Examples: Parasitoid wasps, certain nematodes.
 Industrially Important Insects: Examples: Honeybee, silkworm, lac insect, etc.

12. 1.3 Harmful insects and beneficial insects
Harmful Insects
 Harmful insects are those that have adverse effects on ecosystems, agriculture,
structures, or human health
 They may cause damage to crops, spread diseases, or pose a threat to various aspects
of human activities
Here are some categories of harmful insects:
 Crop Pests: Examples: Aphids, caterpillars, weevils.
 Disease Vectors: Examples: Mosquitoes, ticks
 Structural Pests: Examples: Termites, carpenter ants, cockroaches.
 Nuisance Insects: Examples: Flies, mosquitoes.

13. 1.4 Reasons for the dominance of insects over other animals
1. Adaptability and Diverse Habitats:
 Insects are highly adaptable to a wide range of environments, from deserts to rainforests, and
from freshwater to saltwater ecosystems
 Their ability to thrive in diverse habitats has contributed to their widespread distribution.
2. Reproductive Capacity:
 Insects generally have high reproductive rates.
 Many species produce a large number of offspring, enabling them to quickly colonize new areas
and exploit available resources efficiently.
3. Metamorphosis:
 Insects undergo metamorphosis, a process that involves distinct developmental stages (egg,
larva, pupa, and adult).
 This allows them to exploit different ecological niches during each stage of their life cycle,
increasing their chances of survival.

14. 1.4 Reasons for the dominance of insects over other animals
4. Small Size and Efficient Body Design:
 The small size of most insects allows them to exploit microhabitats, find shelter in various
environments, and access diverse food sources.
5. Flight:
 Many insects are capable of flight, which enhances their ability to disperse over long distances,
locate mates, find food, and escape predators
6. Feeding Diversity:
 Insects exhibit a wide range of feeding strategies, including herbivory, predation, parasitism,
and scavenging
 This dietary flexibility allows them to exploit various food sources, contributing to their
ecological success.

15. 1.4 Reasons for the dominance of insects over other animals
7. Specialized Mouthparts:
 Insects have evolved diverse mouthparts adapted to different feeding habit
 This specialization allows them to feed on a wide variety of plant and animal materials,
enhancing their ability to exploit different ecological niches.
8. Exoskeleton and Molting:
 The exoskeleton of insects provides structural support, protection, and serves as a barrier against
desiccation
 Molting allows them to grow and adapt to changing environmental conditions.
9. Rapid Evolution:
 Insects exhibit high rates of evolution, allowing them to adapt quickly to changing
environmental conditions, including the presence of new predators, competitors, or
environmental stressors.