The current control measures for pests’ attacking mango still relies on the use of pesticides. Most insecticides and fungicides are applied as calendar spray in an excessive manner resulting to pest resistance, elevation of minor pests to major ones, destruction of natural enemies and contamination of environment. In addition, pesticides are expensive and have caused in increased production inputs.
Many of these problems can be minimized though Integrated Pest Management (IPM). This involves these of alternative measures in combination, to minimize pests.
The IPM strategies make use of cultural management (pruning, cultivation, sanitation, proper nutrition to enhance vigor and fruit bagging) conservation of beneficial insects (pollinators and bio-con agents) and proper pesticide management.
This brochure on IPM for mango production emphasizes prevention of pests through destruction of source and prevention of its spread.
INSECTS
Circular-white back borer
Common names: Circular-white back borer,
Leaf cutting beetle
Scientific name: Callimetropus sp
Parts Affected: Young twigs and terminal leaves
Destructive stages: Adults and larvae
Description: This is a long-horned beetle and has very similar habits to the twig borer/cutter. The adult scrapes the bark of young twigs causing the death of terminal parts. The insect is easily identified by the circular white mark on the back of its body. Aside from destroyingthe twigs, the insect also cut the leaves of mango especially those on the tips of the shoots, hence, the name of “leaf cutting beetle”. Pile of cut leaves on the ground is a common indication of the presence of the insects.
Prevention/control
Like the twig borer, adults of the circular white-back borer are attracted to young leaves of mango or flushes for egg laying. Insecticides recommended for a twig borer infestation can also be used to protect trees from circular white back infestation. To prevent or minimize damage, spray the whole canopy with Karate at 1 ½ tbsp per 16 L water. Repeat application after one month, especially during flushing. Other pyrithroids can be used.
Green beetle
Scientific name: Anomala sp.
Common names: Green beetle and Toy beetle
Alternate hosts: Santol, avocado, coconut, cashew etc.
Destructive stage: Adults
Parts affected: Mainly leaves and sometimes flowers and fruits
Description: Adults are metallic green. They feed mainly on the leaves and occasionally on the flowers of mango. these insects also attack young fruits by chewing bits and pieces of the peel or skin, particularly near the fruit stalk.
Prevention/control
- Remove the adults from the tree by shaking the branches and spray insecticide.
- Adults are attracted to light; hence, light trapping is an effective control measure.
- Avoid piling compost or other organic matter near mango trees since these are preferred sites for egg-laying.
Mango cecid fly
Scientific name: Procantarinia sp.
Common names: Leaf gall midge, Gall fly and Mango leaf gall
Parts affected: Leaves and fruits
Destructive stage: larvae, adult
Description: Adults which are mosquito-like in appearance prefer to lay eggs on new flushes (young leaves). The larvae, which develop from eggs, mine the leaves producing galls or swelling tissues. Under heavy infestations, the leaves wrinkle and remain yellow. Close examination of the leaves shows dark green, circular galls randomly distributed on the leaves blade. When open, each gall contains yellow larvae of the cecid fly. When the adults emerged from this galls, the leaves produce circular spots or holes which are sometimes mistaken as fungal infections (anthrac nose). The latter, is however, irregular in shape.
While the damage of cecid fly is usually associated with galling of young leaves, infested fruits produce circular, brown to black, scab-like spots randomly distributed on the fruit surface. This damage is commonly called “buti”, armalite, and kurikong ’and‘saksak walis’ by growers the water –soaked spots with contains small, yellow larvae. Infested fruits retain the scabby lesions at harvest affecting their quality.
Prevention/control
- Orchard sanitation is important. Clear weedy areas since adults prefer to stay on these plants.
- Young leaves are very attractive for egg laying. Spraying Sevin, Decis, Karate, and Stingray (3 to 4 tbsp per 16 L of water) will minimize damage. Spray insecticides in the afternoon, preferably 5:00 to 6:00 pm.
- Prune crowded branches (particularly irregular branches) to allow light penetration.
- Bag the fruits 55 to 60 days after flower induction.
Mango thrips
Scientific name: Scitothrips dorsalis (Giard)
Selenothrips rubocinctus (Giard)
Common names: Mango thrips, Red-banded thrips
Destructive stage: Nymphs and adults
Parts affected: leaves and flowers
Description: Mango thrips are small insects with “fringe” wings. These are occasional insect pests of mango but maybe destructive in some areas. Adults and nymphs destroy the leaves by scrapping the surface and feeding on the plant sap. Affected leaves develop brown areas, and later dry up and fall to the ground. Burning effect on flowers is a common damage of thrip injury.
Prevention/control
Both young and adults insects are sensitive to light. Prune crowded branches to allow light penetration, which create an environment less favorable for their development. Many insecticides are effective in the control of thrips, provided these are sprayed in fine mist and sprayed underneath the leaves where they hide.
Mealybugs
Scientific name: Ferrisia virgata (Cockerell)
Planococcus lilacinus (Cockerell)
Common names: Grey mealy bug and Cottony cushion mealybug
Alternate hosts: Many ornamental plants and fruit trees.
Destructive stage: Nymphs and adults
Parts affected: leaves, flowers and fruits
Description: Mealybugs (white, cottony insects) feed on leaves, especially on the flushes by sucking the plant sap. Affected parts turn yellow, dry up, and eventually fall. Mealybugs also excrete a sticky fluid known as “honey dew” where the sooty molds grow. The latter covers the leaf area producing black papery film on the surface. Sooty molds affect the photosynthetic activity of the leaves.
Both adults and nymphs attack the flowers by feeding on the base, gradually moving up to cover the entire flower. The flowers dry up and drop off prematurely. The “honey dew” produced by mealy bugs attracts red ants and serves as medium for the growth of sooty molds.
Both adults and immature insects congregate on the stalk before moving to the lower portions of the fruit. Excessive feeding of the sap damages the stalk and result to fruit drop. On the fruit surface, the insect secretes “honey dew” from which sooty molds develop. This spoils the appearance of the fruit. At harvest, mealy bugs can persist on the fruit affecting quality. It can attract ants that are cumbersome during harvest.
Prevention/control
- Pruning creates an environment that is not favorable for the growth of mealy bugs.
- Like scale insects, mealy bugs have symbiotic relationship with red ants. Mealy bugs and scale insects provide food for the red ants through their excreta (honey dew). In return, ants offer protection and distribute to insect to the different part of the tree. Spray the red ants with Malathion (1 ½ to 3 tbsp per 16 L water), decis (1 to 5 tbsp per 16 L water), and karate (3/4 to 1 ½ tbsp per 16 L water) to prevent the spread of mealy bugs.
- Bag the fruits at 55 to 60 days after induction to prevent damage from mealy bugs. The paper bag should be closed properly at all sides and should remain intact up to harvest.
June beetle
Scientific name: Leucopholis irrorata (chevrolat)
Common names: toy beetle, June beetle
Alternate hosts: Santol, avocado, Cashew, Coconut, and many other fruit trees
Destructive stage: Larva and adult
Parts affected: Roots, leaves and sometimes flowers
Description: The adults are brown ans are easily dropped down when foliage are shaken. They feed extensively on the leaves, leaving only the midrib. The larvae (grubs) feed on the roots. The insect gets into the root system from infested organic matter, affected plant wilts and if uprooted, small, curved larvae can be seen feeding on the roots.
Prevention/control
- Before applying the organic matter as fertilizer for mango, dry it thoroughly to kill the eggs of the beetle.
- Granular insecticide like Furadon can be applied in the soil to kill the larvae.
- Adults can be controlled by spray application of insecticide.
Scale insect
Important species recorded on mangoes:
Oriental scale: Aonidiella orientalis (Newstead)
Tropical scale: Hemiberlesia palmae (Cockerell)
Alternate hosts: Several fruit trees
Destructive stage: Adults, nymphs (crawlers)
Parts affected: Almost all parts of mango particularly twigs, branches, leaves and fruits
Description: Scale insects are usually circular in form with scale-like appearance. In the nursery, leaves of grafted mangoes are readily infested with scale insects, causing them to dry and fall. On bearing trees, high population of scale insects cause blackening of the canopy due to growth of fungus “sooty mold” which develops from their excreta (honey dew). Affected leaves are covered with a thin, black, papery film which produces unsightly appearance. Moreover, the photosynthetic activity (food production) of the leaves is reduced considerably. The branches and twigs of mango are susceptible to attack of scale insects. While feeding, they inject toxic substances into the tissues which result in the production of galls (bulging of twigs) and distortions of affected parts. Damaged portions fail to heal or recover.
Prevention/control
- Young scale insects are carried and distributed by red ants to different parts of the tree. To prevent spread, ants should be destroyed by spray application (Please see Annex for suggested control measures.)
- Prune regularly to remove unhealthy and crowded branches.
- Bag the fruits at 55 to 60 days after induction to prevent damage from scale insects. Seal the paper bag properly at all sides and let it remain intact up to harvest.
- Use clean planting materials free from any infestation.
- Trees which are sickly and crowded are susceptible to scale insect attack.
- Under severe attack, prune affected parts, spray insecticide with sticker, fertilize and irrigate.
Termite
Scientific name: Macrotermes gilvus (Hagen)
Common names: White ants, termite
Alternate hosts: Several fruit trees
Destructive stage: Adults and immature
Parts affected: Roots, trunks and branches
Description: Similar to ants but have soft bodies and are whitish in color. Termites construct earthen tunnels visible near damaged plant parts. The barks may be partly or fully eaten. Termites multiply very fast and are capable of destroying the entire tree. After damaging the roots, termites go up the trunk through earthen tunnels. The workers feed on the bark and underlying tissues. Parts affected are partially or totally destroyed.
Prevention/control
- Paint or brush the trunk with used diesel oil to discourage the movement of termites from soil to the upper parts of the tree.
- Prune crowded branches to allow light penetration. This will provide unfavorable environment for the multiplication of the insect. Termites have soft bodies and die upon exposure to sunlight.
- Insecticides can be sprayed to control termites. Be sure to destroy the earthen tunnels before applying insecticides.
- For termite mounds, make a hole on one side, deep enough to reach the nest and pour kerosene.
Mango leafhopper
Scientific name: Idioscopus clypealis (Lethierry)
Common names: Blossom leafhopper, Mango leafhopper
Parts affected: Leaves, flowers and young fruits
Destructive stage: Nymphs and adults
Description: Adults are brown to gray with wedge-shaped body. Head is distinct with protruding eyes on the side. Nymphs are smaller, light brown and have no wings.
Nymphs and adults damage the flowers by piercing the tissues and sucking the plant sap which causes withering, drying and falling of individual flowers. Under severe infestation, no fruit develops. The insects excretes fluid called “honey dew”, an excellent medium for development of the fungus, “sooty mold”, which interferes with the photosynthetic activity of the leaves. It also disturbs flower fertilization and spoils the appearance of fruits. Under high insect population, the entire canopy is covered with sooty mold with the leaves and flowers turning black.
Prevention/control
- Since hopper population is expected to be high in summer, early induction of mango trees (September, October and November) will minimize hopper problems in the field.
- Use light traps during early stages of flower development to attract and kill adults which are ready to lay eggs. To install a light trap, hang the source of light (electric bulb or kerosene operated lamp) on the tree. Place a basin containing a mixture of soap and water (1:10) underneath the light. Hoppers which are attracted to the light are drowned in the solution. One light trap is required per hectare of mango plantation.
- Prune crowded branches to discourage hoppers from staying in the tree. Pruning allows good light penetration and makes the habitat unfavorable for hopper development.
- Spray insecticide directed to the nymphal stages rather than the adults, hence, detection of this stage is important. (Please see Annex for suggested control measures)
Mango tipborer
Scientific name: Chlumetia transversa (Walker)
Common names: Tipborer, shoot borer
Alternate hosts: Cashew, Guava
Destructive stage: Larva
Parts affected: Young shoots and flowers
Description: While mango tipborer is a common problem on young shoots, the insect is also observed to destroy early flowers. Newly-developed flowers are damaged entirely while mature flowers are cut into half, with the upper portion being destroyed. The insect is becoming a serious problem of mango flowers, especially during early induction.
Prevention/control
The adult destroys flowers from bud emergence to elongation. Hence, early spraying of insecticides is necessary to protect these stages especially during summer. Insecticides recommended for hopper control will also protect the flowers of mango from tip borer infestation. If infestation is minimal, cut affected portion. (Please see Annex for suggested control measures)
Tent caterpillar
Scientific name: Orthaga melanoperalis (Hampson)
Common names: Web worm
Alternate hosts: Cashew
Destructive stage of the pest: Larvae
Parts affected: Leaves and flowers
Description: The insect is destructive to mango leaves. However, when flowers are present, these are also destroyed by the larvae which secrete a web-like structure and feed on individual flowers.
Prevention/control
- Prune crowded branches and damaged leaves.
- Control infestation on the foliage by insecticidal spray to prevent transfer of the insect to the flowers during the productive stage.
Mango fruit fly
Scientific name: Bactrocera philippinensis sp. n. And
Bactrocera accipitalis (Bezzi)
Common names: Mango fruit fly
Alternate hosts: Guava, Santol, Sineguelas, Starfruit, Guyabano, Chico, Papaya, Passion fruit, Macopa
Parts affected: Fruits
Destructive stage: Adults and larvae
Description: Damage on fruits starts during egg-laying of adult that resembles colorful housefly. Fresh punctures may not be readily recognized until after 3 to 5 days when soft brownish spots appear on the skin and the underlying tissues start to spoil. The larvae cause the major problem since continuous feeding destroys large portions of the flesh. Breakdown of tissues makes the mango fruits unsuitable for consumption. In the field, infested fruits drop to the ground and decay. Under severe infestation, as much as 70 percent of the crop is damaged.
Prevention/control
- Collect and bury fruit droppings at least half a meter below the ground to prevent the development of the insect.
- Avoid bruising of fruits during spraying since damaged fruits are susceptible to fruit fly attack.
- Bag the fruits using newsprint at 55 to 60 days after induction (chicken egg size) to minimize damage from fruit fly. (Please see Annex for suggested control measures)
- Avoid planting papaya, guava, sineguelas or santol as intercrops for mango since these fruits are preferred hosts of the insect. On the other hand, cashew and calamansi are less preferred.
- Spray the insecticides at 90 to 105 days after induction since fruits at these stages are attractive for egg laying. Recommended insecticides to prevent fruit fly infestation are Baythroid (1 to 1 ½ tbsp per 16 L water), Karate (3/4 to 1 ½ tbsp per 16 L water) and Decis (1 to 5 tbsp per 16 L water). Last spraying should at least be 15 days from harvest. (See annex for recommended control measures)
Mango seedborer
Scientific name: Noorda albizonalis (Hampson)
Common names: Red-ringed mango caterpillar,
Red boring caterpillar, Fruit boring caterpillar, Mango fruit borer and Mango seed borer
Parts affected: Fruits and seeds of mango
Destructive stage of the pest: larvae
Description: Unlike the fruit fly which feeds mainly on the flesh, the mango seed borer consumes both the flesh and seed. Damage starts when the newly-hatched larvae enter the fruit by boring holes through the apex or the narrow tip of the fruit. As the larvae develop, they feed on the tissues beneath the skin. The damaged area later collapses causing the apex to burst and the fruits eventually fall to the ground.
Serious damage is brought about by the destruction of the seed, since a single larva is capable of consuming the entire mango seed in a short period of time.
Prevention/control
- Pick the fruits showing damage. Otherwise, larvae will transfer and destroy adjacent healthy fruits.
- Collect and dispose infested fruits on the ground by burying them to prevent the insect from completing its life cycle.
- Bag the fruits with newsprints a 55 to 60 days after the induction will also minimize damage of the borer.
- Adults can be controlled by spray application of insecticide in the afternoon. (Please see Annex for suggested control measure)
Mango pulp weevil
Scientific name: Sternochetus frigidus (Fabricius)
Common names: Pulp weevil
Parts affected: Flesh or pulp of the fruit
Destructive stage: Adult andlarvae
Description: adults lay their eggs on young fruits while the larvae feed on the flesh. Affected fruits fall to the ground. Damage is not visible externally. However, inner tissues are destroyed by the feeding larvae. The pest is found in Palawan which resulted to the quarantine of the province.
Prevention/control
- Adults stay away from light. Pruning is a practical means to discourage movement of insect to mango trees.
- Collect and properly dispose dropped fruit by burying them half a meter below the ground to prevent the insect from completing its life cycle.
- Bag the fruits at 55 to 60 days after induction.
- Several pyrethroids can be sprayed to control pests.
- Do not allow other mango varieties to flower since they serve as alternate host of the pest.
Twig cutter/borer
Scientific name: Niphonoclea albata (Newman) and N.capito (Pascoe)
Common names: Twig borer (old); Twig cutter (new)
Parts affected: Branches and twigs
Destructive stage: Adult andlarvae
Description: Before laying eggs, the adult cuts or girdles the branch/twig. This is done by nipping the branch halfway, then turning around to make another cut just as deep as, but slightly lower, than the first cut. Affected parts fail to transport nutrients and water causing the terminal leaves to dry up. Dried leaves on the tress canopy are a common sign of twig borer infestation.
Prevention/control
- Avoid planting corn as intercrop for mango.
- Under brushing of surrounding areas (grasses, creeping vines, etc.) is recommended since these plants serve as habitat for the adult insect.
- The insect can be controlled by spraying insecticide.
Mango trunk borer
Scientific name: Plocaederus sp (Guerin)
Common names: Mango bark borer
Parts affected: Cashew
Destructive stage: Larva and adult
Description: The insect belongs to the family of the long-horned beetle. Damage is done by adults who bore holes into the trunk during egg laying. Larvae which develop, feed on inner wood. Water and nutrients are prevented from going up the tree, depriving the leaves and twigs of nourishment. Affected parts dry up and eventually die. Damage is pronounced on neglected and abandoned trees.
Prevention/control
- Trees with poor growth are easily attacked and damaged by the mango trunk borer. Hence, application of fertilizer and proper pruning are necessary. Yearly application of 3 to 5kg complete fertilizer is recommended to improve vigor.
- Crowded branches should be pruned to provide good light penetration and air circulation within the canopy.
- Infected parts should be removed and burned.
Helopeltis/capsid bug
Scientific name: Helopeltis sp.
Common names: Capsid bug
Tea mosquito
Parts affected: Cacao, guava and Cashew
Destructive stage: Leaves and fruits
Description: the adult is a medium-sized bug, black in color with orange marking in the thorax. It is a sucking insect and feeds on young leaves and fruits.
Affected leaves shows dark brown, irregular spots that result in the wrinkling of leaf and blade. On fruits, corky raised irregular brown spots resembling scab-like damage is prominent. Unlike damage of cecid fly, the damage from capsid bug is characterized by spots which are irregular and dry.
This is a result of a substance in the saliva, introduced in the tissue during feeding. The damage is also known as ‘kurikong’, or ‘armalite’.
Prevention/control
- Spray insecticide on young flushes.
- Prune for field sanitation purposes
- Bag fruits
- If insecticides are to be sprayed, apply these in the afternoon.
DISEASES
Anthracnose
Causal organism: Colletotrichum gloeosporioides Penz
Parts affected: Leaves, flowers and Fruits
Description: Considered as the most seriousfungal disease of mango in the Philippines, anthracnose occurs in all mango growing areas. It attacks the different parts of the tree, but major damage occurs at flowering and after harvest. It is serious during the wet seasons and usually occurs as a post harvest disease of mango fruits.
The disease is characterized by the appearance of tiny spots on the leaves. These later enlarge to form discrete, rounded or angular spots which come together to form large, irregular shaped-patches with light brown to black spots. However, during advance stage of the disease, the spots give way and produce “shot hole” appearing in various shapes and sizes. This must be differentiated from the “shot holes” produced by the cecid fly which are small and circular.
Anthracnose is the most devastating disease of mango flowers, especially when induction is done early in season (August to October). The presence of rain and high humidity favors the development of disease, thus, the flowers are easily infected. Common signs of the disease are black streaks on the main stalks and branches of the flower, which later become large, black patches. Under severe infection, entire flowers turn black and fail to develop.
Young fruits are also affected and fall prematurely. Symptoms are, however, not visible since the fungus does not have proper condition for development (hard and acidic fruits). After harvest, when fruits start to ripen, the fungus is reactivated and spread over the surface (latent infection)
Early symptoms of the disease are black, pin-pricked lesions. Later, the lesions form bigger black spots, until the whole fruit is covered. The disease is most serious during wet seasons and usually occurs as important post-harvest disease of mango fruits.
Prevention/control for leaves
As a fungal disease, the development and spread of anthracnose are facilitated by high relative humidity within the tree canopy. Young leaves are susceptible to the disease.
- Prune crowded branches to allow light penetration and good air circulation that will create an environment unfavorable for disease development.
- Remove dead and diseased branches to reduce the source/reservoir of fungal spores.
- Ring cultivation can lessen humidity underneath the trees, which discourage germination of spores.
Prevention/control for flowers
- Prune after harvest to increase ventilation and reduce humidity inside the canopy.
- Collect and burn trashes to reduce sources of disease inocula.
- Some farmers practice shaking of branches after blooming to remove morning dew deposited on the flowers. By doing so, the relative humidity is reduced and male flowers are eliminated, providing enough space for development of hermaphrodite flowers which produce fruits after pollination.
- Several chemicals such as Benlate (1 to 2 tbsp per 16 L water). Maneb (4 to 6 tbsp per 16 L water), Dithane (4 to 7 ½ tbsp per 16 L water), and Manzate (½ tbsp per 20 L water) have given varying degree of protection for flowers against anthracnose. These are applied singly or in combination in a sequential spray program. It is also suggested to incorporate any of these fungicides in the flower inducers, especially when flower induction is done early in season. (Please also see Annex for other suggested control measures)
Prevention/control for fruits
- Apply protectant fungicides such as Daconil (1/2 tbsp per 16 L water), Manzate (1/2 tbsp per 16 L water), Dithane (4 to 7 ½ tbsp per 16 L water), a week after bud break, at fruit set and 20 days before harvest. (Please also see Annex for other suggested control measures)
- Bagging of fruits at 60 days after flower induction can minimize the problem.
- Hot water treatment (HWT) by dipping newly harvested fruits in heated water (52 to 55°C) for 10 minutes, followed by hydro-cooling and air drying.
Die-back
Causal organism: Colletotrichum
Gloeosporioidez (Penz)
Parts affected: Terminal shoots
Description: The symptoms are discoloration and darkening of the twig at some distance from the tip. As the disease advances, the twig withers, dropping it leaves. Dead twigs are often seen protruding from the tree canopy like “sticks” devoid of leaves. When split often, the twigs show internal discoloration with gummy sap. Blackening of the twigs is associated with the presence of the fungus.
Prevention/control
The fungus multiplies in crowded and shady canopies. To minimize fungal infection, prune to make the environment less favorable for their growth and spray fungicide.
Gummosis
Causal organism: Phytophthora palmivora Butl
Common names: Crown rot, Root rots
Parts affected: Trunk, branches
Description: The disease occurs during both wet and dry seasons causing slow death of mangoes. In seedling stage, infection starts from the roots while in the nursery. In bigger trees, infections extend from the trunk upward and laterally to the branches, where early symptoms are manifested. In seedlings, infection results in root rot, while on big trees, infection is largely confined to the bark with profuse gumming/bleeding. When scraped, the affected part is brown in contrast to green healthy tissues.
Water soaked lesions first appear, followed by ruptures. Latex or gummy sap comes out and hardens to form short colored strips along trunk and branches of the affected area. Affected parts become watery and rot. The whole tree sheds leaves and later dies.
Prevention/control
· Since the fungus is soil inhabiting, sterilize the potting media by pouring boiling water to reduce the source of infection before bagging the seedlings.
· Field planning is recommended in well drained soil (avoid water logged areas)
· Tree spacing of less than 10x10 m apart should be discouraged.
· Avoid root and trunk injuries during cultivation.
· Fungicide can be applied as ‘slurry’ over the affected parts. This is done by mixing the fungicide in water to form a ‘paste’. The later is applied to affected areas.
Seedling wilt
Causal organism: Pythium sp and other soil-borne fungi
Common names: Seedling wilt
Parts affected: Roots and young stem
Description: Considered a serious disease of seedlings grown in plastic bags. The disease is caused by overcrowding, too much shading, and excessive watering. Leaves become dull. Light green with brownish spots near the base. Within a few days, the leaves bend downward, curl, and die. Infected seedlings shoe excessive decay of roots.
Prevention/control
- Use sterile soil media. This is prepared by cooking the soil in a half-drum container for 1 to 2 hours or by pouring boiling water on it before bagging the seedlings.
- Avoid arranging grafts too closely in the nursery. Early sunlight should reach the plants through partial shading.
- Water only when necessary
- Remove infected plants from healthy ones to prevent further spread of the sisease.
Scab
Causal organism: Elsinoe mangiferae (Brit and Jenkins)
Common names: Scab
Parts affected: Flowers and Fruits
Description: The disease is more prominent on fruits as compared to leaves and flowers. Young fruits are susceptible to scab and fall to the ground. When examined, irregular, raised corky structures are present on the surface. During rainy days, the scab becomes dark brown but remain light brown during the dry months. On mature fruits, the scabby lesions remain very distinct and persist after harvest affecting quality.
Prevention/control
· Like anthracnose, scab produces spores which remain dormant on dead twigs/branches and trashes below the tree. Prune and collect dead leaves and branches and burn them.
· Apply protectant fungicides a week after bed break, fruit setting and during fruit enlargement. (Please see Annex for suggested control measures)
· Avoid mechanical injuries during harvesting
· Bagging of fruits at 55 to 60 days after induction is a practical way of preventing damage and reduce incidence of scab in the field. Seal the paper bag properly at all sides and let it remain intact up to harvest.
Sooty molds
Causal organism: genus-tripospermum, Limaculina, Trichopelteca, Chaetothyrium,Capnodendron and Polychaeton
Parts affected: Flowers and Fruits
Description: Sooty mold is caused by a fungus which grows andobtains its nourishment from ‘honey dew’ excreted by sucking insects like leafhoppers, scales, and mealy bugs. Although no direct damage is done to the plant, the photosynthetic activity of the leaves is adversely affected. Thus, the trees bear fruits poorly and show a general reduction in vigor. The fungus grows as a thin, black papery film on the surface of the leaves.
The disease develops on the leaf surface as black, papery film especially in areas where honey dew deposits are present. Unlike anthracnose which covers the entire flowers, sooty mold development is randomly distributed on the different parts of the flowers. Affected fruits have a dirty appearance.
Prevention/control
- The disease develops from excreta (honey dew) deposited on the leaves by sucking insects like mango leaf hoppers, scales, and mealy bugs. A practical approach to prevent the occurrence of sooty mold is to destroy the sucking insects by spray application of recommended insecticides such as Malathion (1 ½ to 3 tbsp per 16 L water), Decis (1 to 5 tbsp per 16 L water), or Karate (3/4 to 1 ½ tbsp per 16 L water)
- Prune infected branches
- Bag the fruits to minimize infection of sooty mold
- Hot water treatment has been found to facilitate cleaning of fruits affected by the disease, provided it is treated immediately after harvest.
Stem end rot
Causal organism: Dothiorella dominicana (Dd)
Common names: Stem end rot, DSER
Parts affected: Fruits
Description: The disease is considered next to anthracnose in importance and is responsible for about 2-6 percent of storage and transit rots of mango.
The disease is characterized by appearance of dark discoloration near the fruit stalk (pedicel). Under warm and moist conditions, the infected area extends towards the end of the fruit. Later, the symptom turns from dark brown to purplish-black and the tissues become soft and watery. The disease produces soft rot in contrast to the hard rot produced by anthracnose.
Prevention/control
- Remove and burn primary sources of the disease such as dead twigs, barks and other trashes.
- Since high incidence of stem-end rot occurs on fruits without stalks, harvest the fruits with about 1.0 to 2.0 cm of the stalk attached.
- The pre-harvest sprays of fungicides recommended for anthracnose can also be used to prevent stem-end rot.
- Avoid the use of organic materials as liners for mango during packaging
OTHER PESTS
Parasitic flowering plants
Scientific name: Family: Loranthaceae
Common names: Parasitic plants
Phanerogamic parasites
Alternate hosts: Many shade trees and fruit trees
Parts affected: Branches and twigs
Destructive stage: All stages of development
Description: Parasitic plants grow on branches of mango trees to obtain nutrient and water. Affected parts are starved, decay, and eventually die
Prevention/control
- Prune crowded branches for good light penetration to discourage the growth of parasitic plants
- Avoid planting the trees too close (less than 10x10 m) to prevent in the later years.
- One percent herbicide has shown to control these parasitic plants. Direct spray on the parasitic plant is recommended to prevent herbicide injury to mango
Mango gallmite
Scientific name: Unidentified
Common names: Mango galls, gall mite
Parts affected: Leaves
Description: The pest is not an insect, but a small mite related to spiders. Mites feed on both young and old leaves which result in the production of galls. The damage is similarly observed in the leaves of ‘Bangkok’ santol. Affected leaves produce galls, curl and photosynthetic activity is reduced. During heavy infestation, growth is stunted. The problem is confined to Mindanao, particularly in Davao and Cotabato.
Prevention/control
- Avoid planting ‘Bangkok’ santol as intercrop for mango since the leaves are very susceptible to mite infestation
- Prune affected parts
- Acaricides are sprayed to control mites
Rat
Scientific name: Rattus argentiventer, R. mindanensis (Mearns)
Common names: field rat, rice land rats
Alternate hosts: Rice, corn, grains and fruit trees
Destructive stage: Both young and adult stages
Parts affected: Stems of newly planted trees and occasionally, fruits
Description: Newly planted trees are attractive to rats, especially when rice or corn fields are vacant. Rats prefer to eat or chew stems of mango resulting to cutting of young plants. As high as 12 percent damage have been reported in the field. In some instances, fruits about to be harvested are also destroyed by rats.
Prevention/control
- Cut down and remove weeds in surrounding areas. This will reduce shelter and burrowing sites
- Avoid planting rice and corn as intercrops for mango, especially in rat infested areas
- Rats can be controlled by baits made of rice bran and rodenticide
FRUIT ABNORMALITIES
BIOKO
Description: a common complaint among growers is the abnormal development of fruits despite good management. Those affected remain small, round and green at harvest. In the Visayas, this abnormality is called ‘Bioko’, in Luzon, ‘ Paninglon’. Bioko can affect 2 to 10 percent of the total fruit production. The cause(s) of this problem is not known although there are speculations that is associated with lack of micro-elements, lack of water during fruit development and side effects of chemicals particularly insecticides. Some growers value the fruits because they command high price in the market and are believed to have aphdisiac properties.
Prevention/control
- Apply foliar fertilizers containing micro-elements like zinc, boron, magnesium, and copper. Spray at 42 to 45 days induction and 3 to 4 weeks later. The following foliar sprays are recommended for mango: Albatros (1 ½ to 2 tbsp per 4 L water), Nutraphos (4 tbsp per 16 L water), Wokozin (1 to 2 ml per L), Crop giant (4 tbsp per L) and Agrowel (2 to 3 tbsp per gallon).
- Apply water during fruit development at 15 day intervals and stop irrigation one month before harvest.
KASOY-KASOY
Description: ‘Bioko’ fruits are round and green. However, sometimes fruits are malformed and curved, resembling a cashew seed. These symptoms are referred to as ‘Kasoy-kasoy’. Commonly, the fruits split on the curved side and the tips are usually yellow in color. Fruits produced on the tips of the flowers usually exhibit the symptom. Kasoy-kasoy fruits do not grow big and fall to the ground prematurely.
There are indications to show that this problem is associated with parthenocarpy, a process of fruit development without fertilization. This happens when pollination does not occur because of the absence of flies, bees, ants etc. however, other factors such as lack of water and nutrients have to be considered.
Prevention/control
- Avoid spraying insecticides during full bloom to protect insect pollinators (flies, wasp, bees, ants etc.)
- Maintain flowering plants in the orchard as source of food for pollinators.
- Encourage pollinators to visit the trees by spray application of 10 percent honey or sugar solution. Apply the solution at full bloom as spot treatment.