Common pests and diseases in mangoes and their control

Diseases

1. Algal leaf spot Cephaleuros virescens

Green algae (Cephaleuros spp.)

Algal leaf spot

Symptoms

Orange rusty spots on both upper and lower leaf surfaces which may coalesce to form large irregularly shaped patches; scraping away the orange spots reveals a grayish discoloration of the leaf lamina underneath

Cause

Alga

Comments

Disease affects many fruit trees in the tropics; infection is unsightly but often harmless

Management

Ensure that trees are properly pruned and fertilized to promote vigor; remove all weeds from around tree bases; employ a wider tree spacing to increase air circulation around the trees; badly infested trees can be treated with copper containing fungicides

2. Anthracnose Colletotrichum gleosporioides

Category : Fungal

Mango anthracnose leaf symptoms (2)

Anthracnose symptoms on mango

Anthracnose symptoms on mango fruit

Mango anthracnose leaf symptoms

Anthracnose symptoms on mango

Anthracnose symptoms on mango fruit

Anthracnose symptoms on mango

Anthracnose symptoms on mango fruit

Symptoms

Small, dark spots on flowers; spots coalesce to cover entire panicle; infected flowers dropping from tree; dark flecks or spots with yellow halo on young leaves; dark, irregular, sunken lesions on fruit; fruits dropping from tree before ripe

Cause

Fungus

Comments

Disease emergence favored by wet conditions; serious disease of mango wherever it is grown

Management

Susceptible mango varieties should be protected with fungicide in commercial production and the timing of the applications are critical to successful control; appropriate fungicide should be applied during flowering and fruit development

3. Phoma blight Phoma glomerata

Symptoms

Angular or irregular brown lesions on old leaves; lesions may develop gray centers and dark margin; withering leaves; defoliation of tree

Cause

Fungus

4. Pink disease Erythricium salmonicolor

Symptoms

White, silk-like threads at forks of branches which coalesce to form a pink crust during wet conditions; twigs and branches above this site may be killed and foliage will begin to dry out and die; orange pustules may be present on infected bark

Cause

Fungus

Comments

Pink disease is a destructive disease of mango grown in the wet areas

Management

If pink disease is identified the recommended treatment is an application of an appropriate fungicide which can be applied by spraying or painting onto infected bark with a paintbrush

5. Powdery mildew Odium mangiferae

Powdery mildew symptoms on mango leaf (2)

Powdery mildew symptoms on mango panicle

Mango powdery mildew: leaf symptoms

Powdery mildew symptoms on mango leaf

Symptoms

Gray-white powdery growth on leaves, flowers and/or fruit; curled, distorted shoots; fruit aborted and dropping from tree

Cause

Fungus

Comments

Found in all mango growing regions; outbreaks sporadic but can be severe

Management

Fungicides are very effective at controlling powdery mildew if applied at the first sign of the disease; chemical sprays only need be applied at flowering and fruit set

6. Sooty mold Several species of fungus

Premature aging and death of leaves

Sooty mold on leaves and twigs

Sooty mold on mango leaves

Symptoms

The leaves, twigs, inflorescence and fruits are covered with shiny black and sticky growth of fungal mycelium. The sooty mold won’t cause any direct infection to plants, but it may effect the photosynthetic process which may cause premature aging and death of leaves. Also plants may show stunted growth.

Cause

Fungus

Comments

Sooty mold mainly develops on honey dew secreted by sap sucking insects like whiteflies, aphids, leaf hoppers, scale insects, mealybugs and psyllids. Also this insects are always associated with ants.

Management

1. If plants are small wash mold with strong stream of water

2. Spraying starch also removes sooty mold

3. Control sap sucking insects

4. Also keep the trees free from ants by applying a sticky compound around the trunk .

7. Bacterial black spot (Bacterial canker) Xanthomonas campestris

Category : Bacterial

Bacterial black spot of mango caused by X. citri pv. mangiferae indicae

Bacterial canker on mango

Symptoms

Angular, water-soaked spots on leaves which coalesce and turn black; black cankerous lesions on stems which crack and exude a gummy substance; irregular black lesions on fruits which extend into the flesh and exude gum; fruits dropping from plant

Cause

Bacterium

Comments

Bacterial black spot is found in most tropical and subtropical areas where mango is grown

Management

Provide windbreaks for plants; prune out infected twigs; protective sprays of copper during wet weather help to protect plants from the disease

Pests

Category : Insects

1. Fruit fly; Ceratitis cosyra
Bactrocera obliqua
Bactrocera frauenfeldi
Anastrepha spp.

Predation of fruit fly larvae (third larval instar) by weaver ants

Adult fruit fly (Bactrocera obliqua) on mango fruit

Fruit fly, Bactrocera jarvisi on mango fruit

Fruit fly maggot (Anastrepha spp.) feeding on mango pulp

Adult fruit fly (Bactrocera frauenfeldi)

Symptoms

The adult female flies lay egg just under the skin of semi repine fruits. The maggots develop and feed inside the fruit, causing the flesh to turn brown and soft which emits foul smell. This damage also act as entry site for fungal and bacterial pathogens.

Cause

Insect

Comments

The mature maggots fall out of the fruits and pupate in soil. This make the cycle to repeat itself if the weaver ants are not controlled.

Management

1. Collect the fallen fruits and destroy them.

2. Also harvest fruits early to reduce flies damage .

3. Use traps to monitor fruit flies. Traps can be purchased in the market or one can prepare themselves. Take plastic container with lids (one quarts yogurt container is fine). Drill holes (10 to 16 holes) that are 3/16-inch in diameter around the upper side of the container. Add 1 to 2 inch of pure apple cider vinegar (not flavored one) and a drop of unscented liquid dishwashing soap into the container. Hang the container in shade near berry trees before fruits ripening and check the traps frequently for flies. Change the vinegar every week. 5. Spraying protein bait under leaf surface attract flies to single spot which make easier to kill them.

4. If infestation is severe spray suitable insecticide.

2. Mango hoppers Idioscopus clypealis
Idioscopus nitidulus
Amritodus atkinsoni

Mango leafhopper (Amritodus atkinsoni)

Leaf hopper on new mango leaf

Symptoms

Reduced plant vigor; sticky substance coating leaves; may be a growth of sooty mold on sticky residues; curling and drying leaves

Cause

Insects

Comments

Insect emergence favored by shady and humid conditions

3. Mango mealybugs; Drosicha mangiferae

Mealybugs on mango fruit

Mealybugs infestation on twigs and leaves

Mango infested with mealybug

Symptoms

Both nymphs and female insects sucks sap form all parts mango tree (i.e., tender leaves, shoots and inflorescence). The infected inflorescences may dry up affecting the fruit set and may cause fruit drop. Severely infected plants may show wilting and thereby affect fruit setting.

Cause

Insect

Comments

a. Mealybugs lay eggs in soil near tree trunk.

b. The mealybugs secrete the honey dew which causes sooty mold.

c. It feeds on wide range of plant species.

Management

1. Collect and burn fallen leaves and twigs.

2. Flooding orchard with water during October kills egg present in soil. Also deep ploughing in November exposes egg to sunlight.

3. After hatching the nymphs start climbing tree and suck sap. To avoid this band the tree trunks with polythene sheet (400 gauge, 30 cm wide) at a height of about 30 cm from the ground level and apply grease at the lower edge of band. Or you can use Funnel Type Slippery Traps.

4. To control insects already on tree you can spray fish oil rosin soap or azadirachtin (neem products).

5. Also soil application of the spores of the fungus, Beauveria bassiana helps in reducing mealybug population. 6. If infestation is severe you can spray suitable insecticides

3. Mango tree borer Batocera rufomaculata

Adult mango tree borer (2)

Adult mango tree borer

Symptoms

Mango tree borer damage may first be noticed as circular holes in the bark. This damage indicates that the tree has been attacked by borers which have chewed exit holes in the wood. Mango tree borers feed on the bark of twigs and chew green growing tips; when feeding damage is severes, branches may be killed and the main stem of the tree may collapse; insect frass (feces) collects in cracks in the bark and around the base of the tree; holes become visible in the bark.

Cause

Insect

Comments

Mango tree borers are a pest of mango trees in many parts of Asia, Africa, Central America, the Caribbean and the Solomon Islands; female tree borers lay their eggs in an incision made in damaged mango bark; larvae bore through the wood as they feed and eventually pupate within the tree; adult insects emerge from an exit hole that they cut in the wood. adult insects are 25–55 mm long with distinctive long antennae which extend the length of the body

Management

Application of appropriate insecticide to the trunk and branches of the tree when adult insects are present acts to kill any eggs and larvae that are present; insecticide applied to growing twigs and green shoots may deter adult feeding; probing injury sites with a knife or piece of wire can help to destroy larvae and eggs

4. White Mango Scale Aulacaspis tubercularis

Mango scale

Scale infestation on mango leaves (also occurrence of sooty mold due to scale infestation)

Female and male scale insects

Symptoms

Scale insects suck the sap from leaves, branches and fruits which causes defoliation, drying up of young twigs, poor blossoming and also affect the quality of fruits by causing conspicuous pink blemishes. Infestation of young plants results in retard growth. In case of severe infestation the fruits may fall prematurely, whereas the mature fruits are reduced in size. Another major problem with scale insect is the development of sooty mold due to honeydew secretion.

Cause

Insect

Comments

The insect have wide host range and can be seen in all mango growing countries like Ghana, Kenya, Madagascar, Mozambique, South Africa, Tanzania, Uganda, Zimbabwe, Australia, China, India, Indonesia, Malaysia, Pakistan, Philippines, Sri Lanka, Taiwan, Thailand, Japan, Egypt, Iraq, Israel, Italy and in many South American countries.

Management

Remove the infested plant parts and burn them. Spraying emulsive oil or suitable insecticides at recommended quantity will helps in reducing scale population.

Source; Plant village