Crop Protection: Insects and Products

Crop Protection Reviewer

• Entomology is the branch of Zoology that studies insects and their interaction with the environment and other species.

• Insects are arthropods, a diverse group of segmented, bilaterally symmetrical animals with a hard, chitinous exoskeleton and jointed appendages. They are the most abundant group of organisms on Earth.

Products from Insects

• Apiculture is the rearing of honeybees ( Apis mellifera) for honey, beeswax, and other products like royal jelly.

• Sericulture involves the rearing of silkworms (Bombyx mori) to produce silk.

• Shellac is a sticky brown resinous substance produced from the lac insect's scale. It is used in various products, including polishes and sealing wax.

• Cochineal is a red dye extracted from the dried bodies of the cactus mealybug. It finds use in food coloring and cosmetics.

• Chitin is a component of insect exoskeletons. It is also used as an anticoagulant in humans for tissue repair.

Insects

• Exoskeleton: Arthropods (including insects) have an external skeleton that supports and protects their bodies.

• Three Pairs of Legs: This is a defining characteristic of insects that distinguishes them from other arthropods.

• Three Distinct Body Parts: Insects have a head, thorax, and abdomen.

• Head: Bears antennae, eyes, and mouthparts.

• Thorax: Bears wings (one or two pairs) and legs.

• Abdomen: Bears abdominal segments, spiracles, and the reproductive system.

General Insect Morphology

• Body wall: Composed of three parts

• Epidermal cells: Secrete molting fluid in the growth process.

• Cuticle: Non-cellular layer that lines the body surface and various internal structures.

• Epicuticle: Outermost, thin layer.

• Exocuticle: Middle layer for strength and resilience.

• Endocuticle: Innermost, thick layer.

• Basement membrane: Separates the body wall from internal organs.

• Importance of Entomology:

• Economically important as pests & natural enemies.

• Bio-indicators

• Medical & Veterinary importance

Insect Mouthparts

• Mouthparts vary depending on the insect's diet.
• Chewing-sucking (honeybees): use mandibles for manipulating food and a proboscis for sucking.
• Piercing-sucking (mosquitoes): mandibles and maxillae form a needle-like stylet for piercing and sucking.
• Sponging (houseflies): spongy pad at the end of the labellum for slurping.
• Siphoning (moths and butterflies): a tube-like proboscis formed from modified mouthparts for sucking.
• Chewing (most insects): mandibles for cutting and grinding food.
• Rasping-sucking: cone-shaped beak.

Antennae

• Antennae are sensory structures used for detecting various stimuli—e.g. smells, vibrations, wind.
• Three parts: scape, pedicel, flagellum.
• Types: Setaceous, filiform, moniliform, serrate, pectinate, clavate, capitate, lamellate, geniculate, plumose, aristate, and styliate.