Crop Protection Reviewer PDF

CROP PROTECTION REVIEWER DEFINITION Entomology - branch of Zoology which deals with insects and how they interact with their environment, and other species; the study of insects. Insects - are animals belonging to phylum Arthropoda or simply arthropods. Most abundant and diverse group o...

CROP PROTECTION REVIEWER DEFINITION Entomology - branch of Zoology which deals with insects and how they interact with their environment, and other species; the study of insects. Insects - are animals belonging to phylum Arthropoda or simply arthropods. Most abundant and diverse group of organisms on earth. Are segmented, bilaterally symmetrical and possess hard chitinous exoskeleton and paired jointed appendages PRODUCTS FROM INSECTS Apiculture - refers to the rearing of honeybees (Apis mellifera), originally for honey, wax and other products (royal jelly, swarms) Sericulture - refers to the rearing of silkworm (Bombyx mori) for the production of silk Shellac - sticky brown resinous substance produced from the thick scale of the lac insect (high quality polish, manufacture of insulators, buttons, sealing wax, hairsprays) Cochineal - is a red dye produced from the dried and powdered bodies of the cactus mealybug (used in foodstuff coloration, cosmetics). Chitin - act as anticoagulant or haemostatic agent for tissue repair in humans INSECTS - living organisms mainly characterized by having the following characteristics: 1. Exoskeleton - a general characteristic of arthropods external skeleton that supports and protects an animal’s body 2. Three pairs of legs - generally the distinguishing characteristics of insects among other arthropods 3. Three distinct body parts - Head (bears a pair of antennae, eyes, and mouthparts) - Thorax (bears wings - 1 or 2 pairs and the legs-some are legless and has additional legs)  - Abdomen (bears 11 abdominal segments, spiracles, and reproductive system) The insect body wall-composed of three parts 1. Epidermal cell - cellular layer of the body wall; secretes molting fluid involved in the growth process 2. Cuticle non-cellular layer of the body wall; covers the entire body surface and also lines the insects' air tube lining, salivary glands and parts of the digestive tracts. 3 layers of cuticle: - Epicuticle - outermost thin layer which contains cuticulin, wax, and cement. - Exocuticle - middle part which gives the cuticle its characteristics strength and resilience; It is formed of chitin (a resistant substance insoluble to water, alcohol, alkali, and dilute acids. - Endocuticle - innermost thick layer of cuticle 3. Basement membrane - separates body wall from internal organs Importance of Entomology 1. Economically important as pests, and natural enemies 2. Bio-indicators 3. Medical and Veterinary Importance BASIC ANATOMY OF INSECTS GENERAL MORPHOLOGY INSECT HEAD ORIENTATION Prognathous - mouthparts projected forward; head horizontal Examples: termites, ground beetle Hypognathous - mouthparts located ventrally; head vertical Examples: grasshoppers, roaches, mantids, larvae of moths and butterflies Opisthognathous - mouthparts directed backwards Examples: cicada, bugs, leafhoppers MAIN STRUCTURES MOUTHPARTS Mouthparts vary in type depending on the kind of food the insects eat. Labrum – the “upper lip”; serves as a cover; flap-like structure Maxillae- the “pincers”; used to steady the food; has 5 segmented palp which is sensory for taste; used for mastication and lie directly behind the mandibles Labium- the “lower lip”; serves as the lower cover, posterior to the maxillae Mandibles- hard, powerful cutting jaws; tooth-like structure used for chewing, grinding, tearing orpinching-off solid food Heavily sclerotized, paired and unsegmented Hypopharnyx - a central tonguelike which drops from the membranous floor of the head, and bears the opening of the salivary ducts. TYPES OF MOUTHPARTS 1. Chewing-sucking mouthparts (Honeybees) - Characterized by the presence of both mandibles and proboscis. - MANDIBLES act as “teeth” to chew, manipulate wax, clean other bees, bite pests. - PROBOSCIS is mainly used for sucking nectar, water, or for exchanging food with other bees “Trophallaxis” 2. Piercing-sucking mouthparts (Mosquito, True bugs) - Characterized by the union of mandibles and maxillae into needle-like structure called “stylet” and is enclosed by labium - The labrum acts like a tongue and is used to suck the blood - pierce tissues and suck juices from them 3. Sponging mouthparts (house fly) - End portion of labellum terminates in a spongy pad where the fly uses to “slurp” food. - mandibles and maxillae are non- functional and the remaining parts form a proboscis with a sponge-like apex called labella. 4. Siphoning mouthparts (Moths & Butterfly) - Common to adult Lepidopterans - Proboscis is a modified maxillary galea; union of paired galea which form a tube during feeding used to suck up nectar. - When not in use, proboscis coils up and held close to the underside of the head 5. Chewing mouthparts (Majority of Insects) - Common to adult Lepidopterans - the mandibles cut off and grind solid food, and the maxillae and labium push it into the esophagus 6. Rasping Sucking - has a cone-shaped beak formed from clypeus, labrum, parts of the maxillae and labium. ANTENNAE - Elongated, segmented structures of varying designs and sizes - used for sensory purposes and sometimes for defense Three main parts: 1. Scape - basal segment 2. Pedicel - second segment 3. Flagellum - whiplike part beyond the pedicel TYPES OF ANTENNAE a. Setaceous (Latin: seta [bristle]) - bristlelike, segments taper distally Examples: green leafhopper, damselfly, dragonfly b. Filiform (Latin: filum [Thread]) - threadlike, segments nearly uniformly cylindrical in size Examples: grasshoppers, crickets, roaches, tigerand ground beetle c. Moniliform (Latin: monile [necklace] - beadlike, segments similar in size and nearly spherical in shape. - Example: termites d. Serrate (Latin: serra [saw]) - sawlike, the distal half or 2/3 of the antennal segments more or less triangular. Example: click beetles e. Pectinate (Latin: pectin [comb]) - comblike, most segments with long slender lateral process Example: fire- colored beetles f. Clavate (Latin: clava [Club]) - clubbed, segments gradually increase in diameter distally Example: ladybird beetle g. Capitate (Latin: caput [Head]) - having a head, terminal segments suddenly enlarged Example: sap beetle h. Lamellate (Latin: lamella [thin plate]) - leaflike, terminal segments expanded laterally to form rounded lobes Example: june beetle i. Geniculate (Latin: genu [knee]) - elbowed, the first segment is long and the following segments are small and going off at an angle to the first Examples: ants, chalcid wasps, bees j. Plumose (Latin: pluma [feather]) - feathery, most segments with whorls of long hair Example: male mosquitoes k. Aristate - the last segment enlarged and bears a conspicuous dorsal bristle called arista Example house fly l. Stylate - the last segment with an elongated terminal style like or finger like process, the style Example: robber fly, snipe fly m. Flabellate (Latin: flabellum [Fan]) - Similar to a folded paper fan - Found in several insect groups (Coleoptera, Hymenoptera, Lepidoptera)