Plant Protection Dept. 3rd Stage Students Practical Forest Insects Mr. Hazim S. Ahmed and Mrs. Dlpak B. Yaba Lecture 05 Piercing-sucking Insects: All types of these insects have piercing and sucking mouth parts whether in nymphal stage or in adult stage. Their effects on the forest trees are not very clear in comparisons with that in the leaf eating insects.
Damages: 1) Direct damage: by sucking plant juices. 2) Indirect effect: transition of viral diseases or fungal disease or bacterial disease. 3) Mechanical damage: resulted from eggs laying.
(1) Brocaded poplar bug, Monosteira unicostata Order: Homoptera Family: Tingidae Description: The adult its color is brownish grey, the wings are grey in color contain spots, the upper surface of the abdomen is dark brown in color and the lower surface is lighter in color. The important differential between male insect and the female is that the terminal segments in the abdomen of the male are relatively narrow while in the female are wide and more circular. The nymphs pass through five nymphal instars covered by dark hairs and clavate thoracic hairs while the antennae and legs covered by fine hairs.
22 Plant Protection Dept. 3rd Stage Students Practical Forest Insects Mr. Hazim S. Ahmed and Mrs. Dlpak B. Yaba Damage: The first symptoms of infestation by this pest is the presence of scattered small spots with yellowish green color, located on the middle region of the leaf and as the infestation increases, these spots enlarges and the leaf color tend to become yellow and also covered by insect feces or secretions, their color is dark brown and moldy or sticky texture. Leaf defoliation occurs in the severe infestation.
(2) Shield bug, Apodiphus amygdali Order: Hemiptera Family: Pentatomidae
Description: Adult can reach a length of about 15mm and a width of about 8mm. The females are slightly larger than the males. Body is oval, convex dorsally, blackish brown, densely speckled with yellow ocher spots. The pronotum has dentate and concave lateral margins. On the head and pronotum there is a short ocher or yellowish longitudinal line. The connexivum shows black and yellowish spots. The long legs and antennae are gray-brown to black.
23 Plant Protection Dept. 3rd Stage Students Practical Forest Insects Mr. Hazim S. Ahmed and Mrs. Dlpak B. Yaba Damage: Imago and nymphs of these large bugs suck on the stems, leaves and immature fruits of various deciduous trees and are considered an agricultural pest. They mainly feed on plum, apricot, apple, olive, pear and pistachio. They attack also silver poplar, Turkish pine, field elm and silver willow.
(3) Forest cicada, Cicadetta montana Order: Homoptera Family: Cicadidae
Description: Females have a body measuring about 50mm in length, the males being much smaller. It has transparent wings with prominent veins, folded over the back when at rest, and a dark slate-grey or black body with dull orange rings around the abdomen. The legs are marked with dull orange as are the leading edges of the wings.
The males have the ability to produce special sounds recognized or familiar by the peoples who live in the forest.
Damage: Most of the damage are because of the feeding behavior of the nymphs which suck root sap (juice) and also the juices of shoot system, but the great damage is due to the egg laying in the small branches and large branches (branches + twigs).
24 Plant Protection Dept. 3rd Stage Students Practical Forest Insects Mr. Hazim S. Ahmed and Mrs. Dlpak B. Yaba (4) Olive psyllid, Euphyllura olivina Order: Homoptera Family: Psyllidae
Description: The adults are light tan in color, 2.5mm long and strong jumpers. Forewings are marked with a few small dark spots.
The eggs are oval in shape, 0.3mm long, pale yellow, and attached to the substrate by a pedicel.
Nymphs are flat, green to tan, and secrete a white waxy coating that covers the entire colony. There are five nymphal stages (0.4mm to 1.5mm long).
Damage: Trees that are heavily infested can have yield losses of 30 to 60%. The olive psyllid damages trees through direct feeding on buds, flowers, tender shoots, and small fruit and also through the production of honeydew, which increases sooty mold development. During olive flowering and fruiting, psyllid waxy secretion causes flower and small fruit drop and yield reductions. Large populations may retard the growth of young trees.
25 Plant Protection Dept. 3rd Stage Students Practical Forest Insects Mr. Hazim S. Ahmed and Mrs. Dlpak B. Yaba (5) Oak leaf aphid, Tuberculatus annulatus Order: Homoptera Family: Aphididae
Description: Adults are yellowish or green with pale antennae apart from black bands at the tips of the segments. The adult winged viviparae are very variable in colour ranging from yellowish, greyish-green or pink to purple in summer.
Damage: Generally abundant on oak (Quercus), and developing in scattered colonies along the major veins on the underside of the expanded leaves. Infestations often occur on young trees in parks, gardens and nurseries but cause little or no damage, although infested foliage may become contaminated by honeydew and sooty moulds.
26 Plant Protection Dept. 3rd Stage Students Practical Forest Insects Mr. Hazim S. Ahmed and Mrs. Dlpak B. Yaba (6) Oriental scale, Aonidielia orientalis Order: Homoptera Family: Diaspididae
Description: The adult scale is circular and flat in shape, almost white to pale brown or yellow, with yellow to dark brown molt (exuviate) positioned more or less centrally, and measure 1.0-1.4mm in length when slide- mounted.
Damage: The nymphs and adults sucks plant juice from the small stems and branches and then extends to the shoot system, fruits and seeds, leaves falls, growth delay, and the death of young trees.
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