Pest On CITRUS fruits – Lemon, Orange, etc – Free Online Studymaterial

Insects

CITRUS

Lime tree borer or orange borers Chelidonium cinctum (Cerambycidae: Coleoptera)

  • This is a major and highly destructive pest in South India. 
  • Wilting of twigs and stems, gum exudations and wood powder accumulation on ground below are symptoms of attack.
  • Adult is dull metallic green to dark violet with a yellow band across the middle of the elytra. 
  • Eggs are laid at angles of twigs or thorns. A female lays 30-50 eggs. EP lasts for 11-12 days. 
  • Hatching grub cuts a cork-screw-shaped tunnel around the twig, bores into twig or stem, and grows by feeding on the terminal tissues. Larval period lasts for 10 months.
  • It pupates in the tunnel for 3 weeks. Total life cycle occupies one year. 
  • Adult emerges from pupa in April and May and remains within the pupal chamber for a long time. 

Chloridolum alcamene (Cerambycidae: Coleoptera)

  • It is a sporadic pest of citrus in Coorg and Assam. 
  • Adult is a shining blue beetle. Grub causes serious damage by boring into the branches and stem.

Anoplophora versteegi (Cerambycidae: Coleoptera)

  • Grub feeds on upper sapwood for few days and then tunnels towards the centre of the stem. Adult is a sluggish beetle and feeds on leaves. 

Bark caterpillar Indarbela tetraonis (Metarbelidae: Lepidoptera) 

  • It also feeds on citrus, mango, guava, jamun, loquat, mulberry, pomegranate, drumstick, litchi, aonla, rose and a number of forest and ornamental trees.

Citrus psyllid Diaphorina indica (Psyllidae: Hemiptera)

  • Adult is small, with a brown band in the apical half of fore wings. 
  • Nymphs are flat, louse-like and orange–yellow, and seen congregated in large number on young leaves and buds. 
  • They suck cell sap. Leaf buds, flower buds and leaves wilt and die. 
  • Fruits fall off prematurely. 

Citrus black fly Aleurocanthus woglumi (Aleyrodidae: Hemiptera)

  • It is a serious pest of citrus fruits, especially of sweet orange. In addition, avocado, grapevine, mango, guava, pear, plum are also attacked. 
  • Adult fly is dark orange with smoky wings. 
  • Nymphs are scale like, shiny black and spiny and bearded by a white fringe of wax. They feed on cell sap 
  • It results in the curling of leaves and also premature fall of flower buds and developing fruits.

Citrus white fly Dialeurodes citri (Aleyrodidae: Hemiptera)

  • Adult is a minute insect. Wings are long and extend beyond tip of abdomen.
  • Both wings and body are completely covered with a white waxy powder. 
  • Nymph is pale yellow, with purple eyes and is marginally fringed with bristles. 
  • Both nymphs and adults suck cell sap from leaves, which curl over, dry and fall off. Honeydew excreted by nymphs is a very good medium for the growth of a sooty mould, which interferes with photosynthesis. Thus, the trees deteriorate further. 

California red scale or Citrus red scale Aonidiella aurantii (Diaspididae: Hemiptera)

  • It also feeds on acacia, Eucalyptus, fig, grape, rose, willow, and many other plants. Scales are active throughout the year, but maximum during autumn.
  • Scales infest leaves, branches and fruits by covering them.
  • They feed on plant juice and devitalize the plants and inject a toxic substance into the plant sap. Yellow spots appear at the point of feeding on leaves, twigs or fruits. When there is a severe infestation, all the leaves turn pale. 

Cottony cushion scale Icerya purchasi (Margarodidae: Hemiptera)

  • It is a sucking pest popularly known as citrus Fluted Scale or Cottony Cushion Scale. It is also recorded in apple, almond, walnut, peach, apricot, fig, grapevine, guava, and pomegranate, etc. 
  • Adult female is a flat, oval brown to reddish-brown, soft-bodied scale, which lays large, white, fluted egg-sac. 
  • Full-grown larva is broadly oval and reddish brown to brick red in colour. Males are rare, and reproduce by parthenogenesis. 
  • Leaves and twigs turn pale and then fall prematurely. Heavily infested young shoots and small nursery plants are also killed. 

Citrus mealy bug Pseudococcus filamentosus (Pseudococcidae: Hemiptera) 

  • Alternate host plants are Cactus spp., ferns, begonia, gardenia, poinsettia and other flowers. 
  • Nymphs are amber coloured with a whitish waxy coating and filaments. 
  • They feed on cell sap and the plants become pale, wilted and the affected parts eventually die. 

Citrus leaf miner Phyllocnistis citrella (Gracillariidae: Lepidoptera)

  • It is a serious pest of citrus nurseries in Tamil Nadu.  
  • Adult is a tiny moth. Front wings have brown stripes and prominent black spots along the tips. Hind wings are pure white and both pairs are fringed with hairs. 
  • Larvae mine into leaf tissue cause damage by making zig-zag silvery mines in young leaves. On older leaves, brownish patches are formed.
  • Full-grown larva is pale yellow or pale green with light brown well developed mandibles. 

Citrus caterpillar/ lemon butterfly Papilio demoleus, P. polytes (Papilionidae: Lepidoptera)

  • Caterpillars cause damage by eating leaves. It can feed and breed on all varieties of cultivated or wild citrus. 
  • Full-grown caterpillar is yellowish green, has a small horn-like structure on the dorsal side of the last body segment. 
  • Adult is a large beautiful butterfly. 
  • Young larvae feed only on fresh leaves and terminal shoots. 
  • Habitually, they feed from margin inwards to midrib. 
  • In later stages, they feed even on mature leaves and entire plant is defoliated. 
  • Heavily attacked plants bear no fruit. 

P. polytes: It shows sexual dimorphism in adults. Males are with dark black wings with a diagonal row of yellow spots. Females are smaller with greyish black fore wings and red-tinged hind wings.

Fruit piercing moths Othreis fullonia, O. materna and O. ancilla (Noctuidae: Lepidoptera)   

  • Fruit piercing moths are minor pests of citrus, mango, grapes and apple, and are distributed throughout India.
  • Unlike other moths and butterflies, they cause damage in adult stage. With the help of its strong, proboscis with backwardly curved teeth; moth punctures fruit for sucking juice. Bacterial and fungal infections take place at the site of attack. Whole fruit turns yellow.
  •  It drops from tree and looks like a premature fruit. In severe cases of infestation, all fruits are lost. 
  • Activity of moth can be recognized from the characteristic pin-hole damage in citrus and other fruits. 
  • Moths are nocturnal and are not seen during the day. 
  • They lay eggs on a number of wild plants and weeds, namely Tinospora cordifolia, Cocculus pendulus and C. hirsutus, which are found growing near citrus orchards. Larvae are semi loopers and have a stout appearance. Their velvety dark-brown back ground long with other patterns make them cryptic. They have distinct eye spots on head; yellow or red lateral spots and a dorsal hump on the last segment of body. 
  • A full-grown larva, when disturbed, assumes a characteristic snake like posture by curving round head and raising hind part of its body. It makes a pupal case by webbing together pieces of leaves and soil particles. Pupa is thickset and is dark reddish brown. This stage lasts about two weeks.

  Citrus leaf roller Psorostichya zizyphi (Gracillariidae: Lepidoptera)

  • It is a common pest in wet months. Larva webs together and folds leaves and feed from within on the epidermis first and on the whole leaves later.It pupates in the leaf folds. 

Black citrus aphids Toxoptera aurantii (Aphididae: Hemiptera)

  • This is a specific pest of citrus plants attacking at the time of flowering. It infests leaves and tender branches which become stunted or mal formed. 

Pentatomid bugs Cappoea taprobanica (Pentatomidae: Hemiptera)

  • It is a common pest in hills of Tamil Nadu. Nymphs crowd together and feed by sucking juice from tender fruits and grow to maturity in a month. Infested fruits fall prematurely.

Thrips Thrips nilgiriensis (Thripidae: Thysanoptera)

  • Nymphs and adults feed on leaves and on surface of fruits. Surface of the infested fruits becomes discoloured and cracked. 

Citrus mite Paratetranychus citri (Tetranychidae: Acarina) 

  • It also infests sweet-orange, lemon, grapefruit, and sour lime. Mites are destructive pests of citrus plantations. Injury to leaves, tender fruits and green bark is caused by their constant feeding on chlorophyll, resulting in a speckled appearance of leaves. Heavy infestation results in a complete defoliation, especially of the young nursery plants. Affected fruits become yellow and remain undersized.

Citrus fruit rust mite Phyllocoptruta olivora

  • This is observed in South India. Mites are vagrants on the undersurface of leaves and fruits of citrus species. The infestation causes browning of leaves and fruits turn pale-brown and sickly.

Leave a Reply