Papaya Mealybug(Paracoccus marginatus)

Papaya Mealybug (Paracoccus marginatus)

• Adult female is yellowish segmented, flattened oval, about two millimetres long covered with mealy wax.

• a number of short waxy filaments projecting around the margin.

• The ovisac is well developed and visible underneath the posterior part.

• Sometimes the wax looks like cotton wool and oozes drops of fluid.

• The adult male is pinkish and about one millimetre long, with well-developed wings each marked with a small basal vein.

• can easily be distinguished from Maconellicoccus marginatus (Green), the pink hibiscus mealybug, because papaya mealybug females have eight antennal segments, in contrast to nine in the latter.

Papaya Mealybug (Female)

Paracoccus marginatus

Adult maleand

female

Host plants

o Papaya

o Avocado

o Citrus

o Mango

o Cherry

o Pomegranate

o Hibiscus

o Cotton

o Tomato

o Eggplant

o Peppers

o Beans

o Peas

o sweet potato.

• The papaya mealybug is polyphagous and feeds on over 55 plants in more than 25 genera.

• Economically important host plants include

Symptoms Papaya mealybug: sucking insect that injects a toxic substance into the leaves while feeding. They are generally observed as clusters of cotton-like masses on leaves, stems or fruit and symptoms caused by infestation are as follows:

• Leaf chlorosis, deformation or crinkling due to toxins

• Premature aging of leaves, flowers and fruit causing these plant parts to drop under severe infestation

• Fruits may fail to develop normally and may be unusually small. Affected fruit may shrivel and drop.

• Flowers may be distorted or fail to open. Petals may be malformed or blemished.

• Sooty mould formation due to honeydew excretions by mealybugs

• Thick, waxy coating on leaves, stems and fruit under heavy infestation

Symptoms on Papaya

Biology

• Adult female deposits up to 600 eggs into her ovisac over a period of one to two weeks.

• The eggs hatch ten days later and the crawlers disperse.

• There are 4 instars in the females and 5 in the males.

• The fifth instar male is a pupa in which the nymph undergoes metamorphosis into a winged adult

Economic impact

• causes serious damage to papaya, other tropical fruit and ornamentals such as Annona and Hibiscus spp.

• Mealybugs suck sap and infestations can cause crinkled and twisted leaves, reduced fruit development or reduced quality of fruit.

• Heavy infestations excrete honey dew, resulting in development of sooty mould which can also reduce yield and plant growth.

• Due to the potential damage on papaya and wide host range the economic impact is considered to be High.

Management 

• none are currently registered specifically for control of papaya mealybug.

• Active ingredients acephate, carbaryl, chlorpyrifos, diazinon, dimethoate, malathion, and white mineral oils.

• Typically, twice the normal dose is applied when treating for mealybugs because mealybugs are protected by thick waxy, cottony sacs, and often are concealed inside damaged leaves and buds.

• only partially effective and require multiple applications.

• Furthermore, problems with insecticide resistance and non-target effects on natural enemies make chemical control a less desirable control option

Chemical control

Physical control

• Destruction of all heavily infested plant parts on the spot

• Avoiding transportation of infested plant material

• Avoiding pruned, infested plant parts being left unattended

• Spraying plants near houses and in home gardens with a soap + kerosene oil + water mixture

• Use of botanical pesticides to treat agricultural crops in home gardens

• Wrapping polythene/spongy tapes impregnated with insecticides around tree trunks to exclude ants from the canopy

Biological control• Four genera of encyrtid endoparasitoid wasps specific to mealybugs were

collected as potential biological control agents:

• Acerophagus papayae 

• Anagyrus loecki 

• Anagyrus californicus

• Pseudaphycus sp

• All four wasps were observed parasitising second and third instars of the papaya mealybug, and Acerophagus papayae was the dominant species.

• All four have since been mass-reared and released

• A fifth collected species was later reared and identified as Pseudleptomastix mexicana 

Other natural enemies of the papaya mealybug include

• Cryptolaemus montrouzieri

• other lady beetles,

• Lacewings (Chrysoperla rufilabris)  

• Hoverflies (Pisyrphus balteatus).

Natural enemies

Lacewing

Chrysoperla rufilabris

Hoverfly

Acerophagus papaya

Released @ 250/acre

• Papaya Mealybug in India

• Papaya mealybug found in August 2008

• Parasitoids introduced in August 2010

• Controlled by February 2011

THANK YOUReference:• http://entnemdept.ufl.edu/• Miller DR and Miller GL 2002 Redescription of Paracoccus marginatus Williams and Granara de Willink• http://creatures.ifas.ufl.edu/ fruit / mealy bugs / papaya_mealybug.htm• http://www.bugwood.org/