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Hort 1217 Introduction to Pest Management

All arthropods possess. Exoskeleton - a hard protective covering around the outside of the body (divided by sutures into plates called sclerites) Segmented body - that allows movement Jointed limbs and jointed mouthparts - that allow extensive specialisation Bilateral symmetry - whereby a central

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Hort 1217 Introduction to Pest Management

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    1. Hort 1217 Introduction to Pest Management Arthropod morphology Arthropod anatomy Basic arthropod physiology

    2. All arthropods possess Exoskeleton - a hard protective covering around the outside of the body (divided by sutures into plates called sclerites) Segmented body - that allows movement Jointed limbs and jointed mouthparts - that allow extensive specialisation Bilateral symmetry - whereby a central line can divide the body into two identical halves, left and right Ventral nerve chord - as opposed to a vertebrate nerve chord which is dorsal Dorsal blood vessel

    3. All insects possess 3 body segments 6 legs 1 pair antennae Most adults have wings

    5. Insect Thorax The insect thorax is divided into three parts: prothorax (pro=first) mesothorax (meso=middle) metathorax (meta=last) Each of the three thoracic segments contains one pair of legs. Wings are found only on the meso- and metathoracic segments.

    7. Insect head The head bears: The eyes; compound & ocelli Antennae Mouthparts Composed of a series of segments Specialized for: Food gathering & manipulation Sensory perception Neural integration

    9. Variations on the Insect Head Insect heads may have one of three different orientations based on the position of the mouthparts Directed downward = hypognathous Directed forward = prognathous Positioned in the posterior region of the head = opisthognathous

    11. Five Primary Parts of the Insect Mouth Mandibulate The clypeus (liplike sclerite) The upper lip or labrum (longitudinally) Two jaw-like structures, or mandibles (right angles to the body) The maxillae (sing. maxilla)(right angles) The lower lip or labium (longitudinally)

    13. Insect Mouthparts Haustellate Primarily used for sucking up liquids Broken down into two subgroups Those that possess stylets and those that do not Stylets are needle-like projections used to penetrate plant and animal tissue Long siphoning proboscis

    15. Adaptations of Mouthparts

    16. The Antennae Antennae vary greatly among insects, but all follow a basic plan: segments 1 and 2 are termed the scape and pedicel, respectively. The remaining antennal segments (flagellomeres) are jointly called the flagellum.

    17. The Antennae

    18. Antennae Functions Almost exclusively in sensory perception Some information: Motion & orientation Odour Sound Humidity And a variety of chemical cues (pheromones, kairomones, allomones, synomones)

    20. Insect Wings Insects have evolved many variations of the wing. Wing venation is a commonly used taxonomic character, especially at the family and species level.

    21. Insect Wings Halteres are an extreme modification among the order Diptera (true flies), in which the hind wings are reduced to mere nubs used for balance and direction during flight.

    22. Insect Wings Elytra (sing. elytron) are the hardened, heavily sclerotized forewings of beetles (Order Coleoptera) and are modified to protect the hind wings when at rest.

    23. Insect Wings A variation of the elytra is the hemelytra. The forewings of Hemipterans are said to be hemelytrous because they are hardened throughout the proximal two-thirds (approximately), while the distal portion is membranous.

    24. Insect Legs The fore-legs are located on the prothorax, the mid-legs on the mesothorax, and the hind legs on the metathorax. Each leg has five major components, listed here from proximal to distal: coxa (p1. coxae), trochanter, femur (p1. femora),tibia(p1.tibiae),tarsus (p1. tarsi).

    25. Insect Leg

    26. Types of legs

    29. Abdominal Appendages

    30. Adult Internal Morphology

    31. Digestive & Excretory Systems The digestive system (sometimes referred to as the alimentary canal) should be easily seen It is a long tube-like structure that runs from the mouth to the anus and is centrally located within the body cavity, or hemocoel The primary function of the foregut is to begin the breakdown of food particles The midgut is the major area of digestion and absorption The hindgut functions in water and solute reabsorption and waste excretion

    32. Digestive & Excretory Systems

    33. Circulatory system Insect circulatory systems are said to be “open”, Insect blood (called hemolymph) flows relatively “freely” throughout the hemocoel. Only one vessel is present in the insect circulatory system: the dorsal vessel. Posteriorly, the dorsal vessel acts as the heart, pumping hemolymph forward into the anterior region, where it acts as the aorta and dumps the hemolymph into the head. It flows posteriorly and is returned to the heart via ostia, which are small slits in the heart region of the dorsal vessel designed for hemolymph uptake.

    34. Circulatory system

    35. Nervous System To view the ventral nerve cord, examine the ventral region of the grasshopper for something that resembles a railroad track running from the head posteriorly to the abdominal region. The “railroad track” is made up of two nerve cords (connectives) that run longitudinally with a series of node-like ganglia. The anterior most region of the ventral nerve cord is called the subesophageal ganglion. Just dorsal to that structure is the insect “brain”.

    36. Nervous System

    37. Respiratory System The insect respiratory system is made up of a series of tubes that originate from spiracles (openings of the exoskeleton that allow for gas exchange) and extend throughout the body. Internally, the tubes, or trachea, appear as thin white lines throughout the hemocoel and are particularly noticeable surrounding internal organs. Trachea deliver oxygen to internal organs and tissues.

    38. Respiratory System

    39. FEEDING HABITS CHEWING DAMAGE RASPING-SUCKING DAMAGE PIERCING-SUCKING DAMAGE

    40. CHEWING DAMAGE: Entire Leaf Blade, only tougher midvein remains Distinct Portions of Leaf Missing, notches cut from leaf margin, circular holes cut from margin of leaf, small randomly scattered holes in leaf Leaf Surfaces Damaged: "Skeletonization" of leaf surface. Leaves "rolled“, tied together with silken threads or rolled into a tube

    41. CHEWING DAMAGE Leaf Miners Feed Between the Upper and Lower Leaf Surfaces Petiole and Leaf Stalk Borers burrow into the petiole near the blade or near the base of the leaf. Tissues are weakened and leaf falls in early summer. Twig Girdlers and Pruners Borers Feed under the Bark in the cambium tissue or in the solid wood or xylem tissue Root Feeders, chewed areas of roots

    42. SUCKING DAMAGE In addition to direct mechanical damage from feeding, some phloem-feeding insects cause damage by injecting toxic substances when feeding. This can cause symptoms which range from simple stippling of the leaves to extensive disruption of the entire plant.

    43. SUCKING DAMAGE Insect species which secrete phytotoxic substances are called toxicogenic (toxin-producing) insects. The resulting plant damage is called "phytotoxemia" or "toxemia". Spotting or Stippling result from little diffusion of the toxin and localized destruction of the chlorophyll by the injected enzymes at the feeding site.

    44. SUCKING DAMAGE: Leaf curling or Puckering - More severe toxemias such as tissue malformations develop when toxic saliva causes the leaf to curl and pucker around the insect. Systemic Toxemia - In some cases the toxic effects from toxicogenic insect feeding spread throughout the plant resulting in reduced growth and chlorosis.

    45. SUCKING DAMAGE: General (uniform) "stippling" or flecking or chlorotic pattern on leaf Random Stipple Pattern on leaf Leaf and Stem "distortion" associated with off-color foliage Galls, Swellings on leaf and stem tissue Damaged Twigs = Split: Damage resembling split by some sharp instrument Root, Stem, Branch Feeders - General Decline of Entire Plant or Section of a Plant

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