Đề tài citrus insect pest and theicitrus insect pest and their natural enemies

CITRUS INSECT PEST AND THEIR NATURAL ENEMIES Hoàà Vaênê Chieáán, Leâ Quoâ áác Cöôøøng, Laâm Thâ ịMỹ 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 Leafminer (Phyllocnistis citrella Stainton)  1) symptom Leafminer (Phyllocnistis citrella Stainton) Leafminer •Adult Leafminer Egg and larva Leafminer Pupa Life Cycle Adult First instar Second instar Third instar Pupa Pre-pupa Pupa in pupal chamber Eggs Leafminer (Phyllocnistis citrella Stainton) Leafminer usually occur in the early rain season and young shoot stage. 2). Life cycle  The complete life cycle takes 14-17 days or times longer.  Most adults live for less than a week, female moths start laying eggs about 24 hours after mating. Leafminer (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. Leafminer (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. Aphids 2). Life cycle There are probably 25-30 generations per years. The most important known of vectors tristeza virus to citrus plant. It is very dangerous for citrus grower nymph wingless Adult winged Adult Whitefly (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 (Colgar peracutum Walker) Citrus Hopper (Colgar peracutum Walker) 1). Shape and habits  Citrus Hopper is about 10 mm long. When at rest their 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 Citrus Hopper (Colgar peracutum Walker) 2). Life cycle  The eggs of species are laid in oval shaped masses about 50 eggs. The eggs masses are about 5 mm in diameter. At first eggs are white, but they darken near hatching.  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 (Rhynochocoris poseidon Kirkaldy) 1). Shape and damage symptoms The spined citrus bug 15-20 mm long with a 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 (Rhynochocoris poseidon Kirkaldy) Damage symptoms Spined citrus bug (Rhynochocoris poseidon Kirkaldy) 2). Life cycle Citrus butterflies (Papilio demoleus L.) 1). Shape  There are many species butterflies on citrus; the fully grown larva of the big citrus butterflies is 70 cm long(and 50 cm for small one), they are brown to olive green in color, with a reddish band near the front.  Larvae of both species have rows of small fleshy spines on the body.  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 (Papilio demoleus L.) eggsAdults Citrus butterflies (Papilio demoleus L.) Larvae Adult and pupa Citrus butterflies (Papilio demoleus L.) 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 (Papilio demoleus L.)  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