Báo cáo nghiên cứu khoa học " CITRUS INSECT PEST AND THEICITRUS INSECT PEST AND THEIR NATURAL ENEMIES " docx

Phyllocnistis citrella Stainton Leafminer usually occur in the early rain season and young shoot stage... Phyllocnistis citrella Stainton Life cycle  Eggs are laid at night, a female ca

CITRUS INSECT PEST AND THEIR

NATURAL ENEMIES

Hồ Văn Chiến, Lê Quốc Cường, Lâm Thị Mỹ Nương

Southern Regional Plant Protection

Compiling based on Citrus pests and their natural enemies - Integrated pest

management in Australia edited by Dan Smith, GAC Beattie & Roger Broadley

(Phyllocnistis citrella Stainton)

 1) symptom

(Phyllocnistis citrella Stainton)

•Adult

Egg and larva

Pupa

Life Cycle

Second instar

Third instar Pupa

Pre-pupa

Pupa in pupal chamber

Eggs

(Phyllocnistis citrella Stainton)

Leafminer usually occur in the early rain season and young shoot stage.

(Phyllocnistis citrella Stainton)

Life cycle

 Eggs are laid at night, a female can laid more than

50 eggs their life (as many as 20 eggs per night)

 The flat, slightly oval eggs are about 0.3 mm long and look like tiny water droplets on the leaves Eggs are deposited singly, on the undersides of leaves near the midrib, usually at the base of the leaf Young leaves 10-20 mm in length are preferred sites for egg laying

(Phyllocnistis citrella Stainton)

 Hatching can occur within a day, and the young larva immediately burrows under the leaf surface.

 Each pale-green larva tunnels a characteristic, sinuous, silvery mine in the leaf, with a raised parchment-like skin lined centrally with dark excreta Larva never leave their mines to form other mines or move between lower and upper sides of leaves Damage is caused by the larvae as they mine immature foliage Twisted and curled leaves are generally the first symptom noticed.

 Larva stage is about 5-6 days The pre-pupa and pupa are about 6 days and then adults emerge

The leaves growth stages and their symptom

Aphids ( Toxoptera sp.)1) Symptom

Aphids

( Toxoptera aurantii Boyer de Fonscolombe)

 Aphids are dark brown or black and about 2 mm long They live on the young leaves and shoots with high density They feed on plant sap, using their sucking mouthparts They produce a sugary liquid (honeydew), on which sooty mould grows, and can transmit plant viruses.

 Aphids may be winged or wingless, depending on the state of their food supply and their density

 Damage: deformation, flower drop, sooty mould, reduced fruit set, distortion of young leaves and shoots.

winged Adult

(Aleurodicus dispersus)

 1) Symptom

Whitefly (Aleurodicus dispersus)

 Citrus whitefly usually occur on undersides of young leaves , they are 2.5 mm long, with white powdery wings Adult look like small moths, they are related to scale insect

 Adult will fly out in swarms if foliage is disturbed

 The eggs are yellow and oval-shaped with white powdery wax, underside the young leaves or fruits, and circular egg laying pattern

Whitefly (Aleurodicus dispersus)

2) Life cycle

 The larvae settle in group on the underside of leaves At first they are flat and resemble scale crawlers feeding and developing beneath a protective waxy covering Both adults and nymphs produce sticky honeydew on which sooty mould grows, and transmitting virus diseases

 Three growth stages are followed by a pupa and then winged adult The pupae are often found on leaf midribs and look like young soft brown scale There are at least 5 to 6 generations per year

Whitefly

Citrus Hopper

Citrus Hopper

1) Shape and habits

wings are tent-like shape Citrus Hopper can occur on mango also;

 They are pale green to white, with small red spot in the middle of each forewing, and usually a red border on the forewings Citrus Hopper are usually green, and covered with small yellow spots Both adult and larvae are mobile,

skipping short distances when disturbed Adult are weak fliers

 Four growth stages are followed by adult The complete life cycle takes 1 to 2 months There are about 3 to 6 generations per year.

Citrus Hopper

2) Life cycle

Spined citrus bug

1) Shape and damage symptoms

prominent spine on each shoulder of the

thorax Both nymphs and adults of

plant-feeding species cause plant and fruit damage with their sucking mouthparts The bug pierce the rind of fruit at any stage causing drying

and brown staining of segments, gumming and fruit drop In ripe fruit, damage is often not

evident until the fruit is cut open Young fruit fall readily after attack They can cause total crop loss

Spined citrus bug

Damage symptoms

Spined citrus bug

2) Life cycle

 The big citrus butterfly has the wing span of about 130

mm (75 cm for small one) Wings of the male are black with white markings, while the hind wings of the female are brightly marked with white, orange and blue.

Citrus butterflies

eggs Adults

Citrus butterflies

Citrus butterflies

2) Life cycle

 Butterfly lay eggs singly on the tip of the

young leaves The eggs of species are

yellow, spherical and 2-2.5 mm in diameter

 The larvae pass through 5 instars, settle and feeding on young leaves before pupating in

an upright position attached to a citrus twig

by silken pad at the tail end, and a fine silken girdle at the waist

 The complete life cycle takes 2-3 months

There are at least 3 generations per year

Citrus butterflies

 2) Life cycle

Fruit fly

(Bactrocera dorsalis)

1) Shape and damage

 Fruit fly attack on citrus and the others fruits

such as apple, papaya, mango, plum, guava , so they occur almost garden fruit Adult fruit flies are about 7mm, they can fly tens of km; larvae are cream to white maggots without legs, the

last-stage larvae are about 8 mm The area

around the ‘sting’ yellows and often clear or

brown gum exudes from the sting Stung mature fruit become infested fruit maggots and rot, and may drop from the tree They can cause total

crop loss

 They can cause total crop loss

Fruit fly

(Bactrocera dorsalis)

 1) Shape