Báo cáo Nghiên cứu khoa học Fruit Fruit fly (Bactrocera dorsalis)

Fruit fly (Bactrocera dorsalis) 2). Life cycle  The adult female fly feeds up to a week on protein, e.g. on bacteria growing on plant surfaces, and on sugars, e.g. in honeydew and nectar, before laying eggs.  Eggs are white, banana-shaped and 1 mm long. They are deposited in batches of 10- 12 into the spongy albedo of the fruit. The rind puncture is not visible at first, but later a yellow area develops around the‘sting’site. Fruit fly (Bactrocera dorsalis) 2) Life cycle  Eggs hatch in 2-3 days and the larvae borrow into the fruit pulp. The number of larvae per fruit varies from one to 12 or more. Larvae complete their development in about 10 days. They then drop to the ground to fined a suitable place to pupate. Pupation occurs in the soil and can take about 7- 9 days. Pupae are brown, barrel-shaped and about 4-5 mm long. They are over 6 generations per years. Fruit fly 2) Life cycle egg egg Life cycle of fruit fly Mealybug (Pseudococcus sp.)  1). Shape Mealybugs (Pseudococcus sp.)  1). Shape and damage symptoms Mealybugs (Pseudococcus sp.)  1). Shape and damage symptoms  There are many species attack on citrus plant. Although shape is different, habits and symptoms are similar. The adult female mealybug is a slow- moving, and covered by a thin coating of white, mealy wax which extent into filaments around the edge of the body.  Eggs hatching are small one and move flexility. If larvae without pupae stage would be adults female and vice versa. Mealybugs (Pseudococcus sp.)  1). Shape and damage symptoms  Adult males are tiny, delicate winged insect with long tail filament.  Juveniles and adults seek out sheltered sites: under the fruit calyx, inside the navel of fruit, between touching fruit and leaves, in curled leaves attacked by citrus leafminer and inside cracks and crevices in bark.  Mealybug excrete sticky honeydew that is good medium for the growth of sooty mould and other fungi. Mealybugs (Pseudococcus sp.) 2). Life cycle “Citrophilous”  Citrophilous mealybug female lay about 500 eggs in a cottony egg sac, and hatch within a few days. There are three moults in females and four in male.  The complete life cycle takes about 2 months and there are 3-4 generation per years. Mealybugs (Pseudococcus sp.) 2). Life cycle “Citrophilous” Mites Panonychus citri 1). Shape and damage symptoms  The group mites attack on citrus include 8 species. However, red mite occur and cause damage popular almost citrus garden in Mekong delta area.  The adult female red mite has oval body, and is 0,5 mm long. The body is purple-red color with long white bristle on the back and sides, the pale legs. The adult male is smaller than female and legs are longer than one. Mites 1). Shape and damage symptoms  Citrus red mite feeds on citrus fruit, leaves (young and old) and green twigs. The maturing leaf is preferred, and most damage occurs on the upper surface, makes leaf curved, spotted grey scarring of the rind. Citrus rust mite (Phyllocoptruta oleivora) Mites  1). Rind damage on fruit caused by citrus red mite Mites 2). Life cycle  The adult female citrus mite lays 20-40 eggs at rate of 2-3 per day. The egg is bright red and spherical, 0,13 mm diameter. Eggs are commonly deposited along the midribs of the leaves. Newly hatched larvae are red and have 6 legs. They develop through two further nymphal stages with 8 legs before reaching adulthood. From egg to adult can takes about 2-8 weeks depend on temperature and humidity, the adult female live about 18 days. There are 8-10 generations per years. Thrips (Thysanoptera) 1). Shape and damage symptoms  There are 5 species of thrips caused damage on Citrus. Thrips are small with two short antennae, and rapid moving when disturbed. Adult thrips are about 3-4 mm; however, some one grow to length of about 12 mm. Wings of thrips are narrow with a fringe of long hairs on the hind edge, and other are wingless. Thrips 1). Shape and damage symptoms Thrips have mouthparts adapted for sucking and rasping. Flowers are often favoured feeding sites, but thrips also feed on developing fruit and young leaves. Heavy infestations of thrips cause twisting and grey scarring of young foliage similar to the damage cause by broad mites; ring scarring around the stem end of a navel on fruit. Thrips  1). Shape (Scirtothrips dorsalis Hood) (Megalurothrips kellyanus) (Chaetanaphothrips orchidii) (Heliothrips haemorrhoidalis Thrips  1). Damage symptoms Thrips (Scirtothrips dorsalis Hood) 2). Life cycle  Thrips often laid into soft tissue on very young fruit near the calyx, or in young leaves (near the midrib or main vein), eggs are 0.3 mm long. Adult female lay about 2-3 eggs a day. Larvae develop through two stages to become a propupa. They complete life cycle takes about 5 weeks. Thrips adult can live 3 months. There are about 6 generations per year They can attack many other fruit, beside citrus. Thrips (Scirtothrips dorsalis Hood) 2). Life cycle propupa Fruitpiercing moths (Rhytia hypernestra) Shape and damage symptoms Fruitpiercing moths (Rhytia hypernestra)  Belong to Noctuidae, the adult moths fly to orchards during the night to suck juice from ripening fruit, and they rest outside the orchards by night. Adult fruitpiercing moths are large and stout-bodied with a wingspan of 100 mm. There are many species in the Mekong Delta, But the yellow-orange, with black patches or spots are popular. Larval hosts include native vines Fruitpiercing moths (Othreis fullonia (Clerck)  The larvae feed on native vines for about 3 weeks, through 5 stages before forming a dark-brown pupa within a delicate silk cocoon between webbeb leaves. After 3 weeks, adults emerge from the pupa. Beside citrus the moths can attack many other fruit tree. There are about 2-4 generations per year. Psyllids (Diaphorina citri) 1). Shape and biological characteristic * Eggs are very small with slight yellow, pear shaped. They usually laid on young leaves and buds * Psyllids larvae are small, oval shaped, new hatching with yellow (second and third instar) and yellow-brown (fourth and five instar), with 2 small wings Psyllids (Diaphorina citri) 1). Shape and biological characteristic Adult: 2.5- 3 mm long; brown dark body, wings have light brown color. Head is acute and brown color, red eyes. When they are on the leaf, the body of the psyllid will post the angle about 40 0. Adult Psyllids are 2,5-3 mm long Eggs Psyllids (Diaphorina citri)  Larvae Adult 2. Morphology and Life cycle  After mating, the Female start laying eggs in the tissue of buds, or young shoots which are not yet open. A female can lay more than 200 eggs.  Eggs are yellow, oval shape 0.3 mm long. egg period 2-11 days.  After hatching, young nymph can move for some distance, and the color of body is yellow or green. The nymph has 5 instars to become adult which take 12-22 days.  Adult can live 15 –45 days  The life cycle of psyllid is about 30-75 days; Average about 40 days.  There are about 12-14 generations per year.