MANGO CULTURE - FAR NORTH QUEENSLAND

SCIENTIFIC NAME: Mangifera indica
FAMILY: Anacardiaceae

INTRODUCTION
The mango industry in Far North Queensland is still small but there has been a dramatic increase in mango plantings in the Mareeba district over the last few years. The number of trees has quadrupled to approximately 14,000 trees of which 3,000 are currently bearing. Production during 1980 was 14,000 trays (6.5 kg/tray), with a total value of $140,000.

The main increase has taken place in the traditional tobacco-growing areas. Limits on expansion and the movement of small growers out of the tobacco industry, has prompted diversification into mangoes and other crops.

The climate and soils of the Mareeba tobacco area are well-suited to mango production. In addition, the Mareeba-Dimbulah irrigation scheme, provides adequate water for irrigation of the trees.

Present production is based entirely on the Kensington variety. Variety diversification should be considered. The time of harvest in this area (late December - early January) means that supplies from Mareeba do not coincide with the major Queensland mango-producing region near Bowen. Therefore, growers can minimise the problem of market 'gluts' and consequent low prices.

Mangoes are an economic proposition at average yield levels and prices about $7.00 per tray. A six-hectare orchard is considered a one-man operation. This area requires an initial total capital investment of $65,550 or around $11,000 per hectare, where the orchard is started from 'scratch'.

The present industry is based almost entirely on the Kensington variety.

Growers should be looking for a spread of the harvest period to avoid both a peak work-load and also glut condition on the market.

For the Mareeba area, growers should trial small plantings of the later-maturing varieties. There is little point in looking for earlier varieties as these will clash with production from other parts of coastal Queensland.


OPERATIONRECOMMENDATION
Climatic RequirementThe area must be frost-free.
  
 Preferably with no rain, dews or heavy fogs from bud break to early fruit development. No heavy rain when fruit is ripening.
  
 Strong winds can cause fruit drop.
  
 A growth-check period of 2 to 4 months before flowering is necessary to give regular heavy flowering. This check period is obtained by cool dry weather conditions from mid April to mid June.
SOIL 
Soil Type Light to medium-textured soils are most suitable.
  
Preparation Deep ripping of the area is recommended.
  
Ground CoverEstablish a sward by slashing existing vegetation and if desired, plant a low-growing legume such as stylo.
  
Tree SpacingPlant with 12 metres between rows and 6 metres between trees within the row. Every 2nd tree is then removed at approximately 15 years of age, when canopies touch.
12 x 6 140 trees per hectare
12 x 12 = 70 trees per hectare
  
Weed ControlApply a mulch around young trees to control weed growth and conserve moisture.
  
 Do not apply a mulch after year 2.
  
 Careful use of paraquat (Cramoxone (R) Shirquat (R) around trees will control most weeds. If problem weeds resistant to paraquat are present use Glyphosate (Round Up (R). Care must be taken with the above sprays to avoid spraying the stems of young trees.
  
IrrigationThe use of small under-tree jet sprays is suitable for young trees. These can be changed to larger sprinkler type sprays after year 3.
 The irrigation system must be designed to be capable of delivering a minimum of 1 800 litres per tree every 2 weeks when trees are 15 years of age and older (1½ acre inches every 2 weeks).
  
Management of Bearing TreesDo not apply any water to the trees during the period from the end of the wet season until the first sign of flowering. This is necessary to check the growth of the trees to promote flowering.
 At the first sign of flower spikes, apply water. Regular application of water is important from flowering till harvest to obtain maximum fruit size and number and also to prevent fruit splitting.
  
VARIETIESThe flowering and harvest times given for the following varieties were recorded at Walkamin Research Station. The harvest period in the Walkamin area is 1 to 2 weeks later than the Mareeba Dimbulah area (See Appendix No.1).
  
Kensington Pride
(Bowen Special)
This is the main commercial variety and has.been used as a standard to judge the performance of newer varieties.
 There can be variations in the Kensington types because the existing industry has been established by the use of seedling trees. Therefore both the nurseryman and the grower should take care when selecting Kensington trees for planting or propagation. A guide to a good Kensington type is:
 The fruit should be approximately 115 mm x 90 mm (measurements of fruit given are from stem end to apex and across the broadest part of the shoulders) with an average weight of 480 grams. The skin when mature should have an attractive red blush on the shoulders. The flesh should be mid orange in colour, with little fibre and good flavour.
 The flowering period is between late July to mid-October with a peak in mid-September. Harvesting commences in late December and continues to early February with a peak during mid to late January.
 A common fault with the Kensington types is that they can suffer from a breakdown of flesh at the stem end. There is evidence from trials in the U.S.A. that this could be caused by a calcium deficiency. Further investigations under Queensland conditions would be necessary before recommendations for control can be given.
  
N.B.The desired levels of calcium in the leaf tissue should be 2.5% to 3.5% on acid soils for the Kensington variety. Levels around 2% may be adequate for other varieties.
  
N.B.The fruit is of medium size and the average weight is 360 grams. The skin is red when the fruit is mature making the fruit very attractive. The flesh is orange in colour, free from fibre and fair in flavour.
  
ZillZill flowers from early July to late August with peak flowering in mid-August.
 The harvest period is close to Kensington and is from mid January to mid February with a peak late January/early February.
 The fruit is susceptible to anthracnose infection. but the infection could be controlled. (See disease and pest control and post harvest treatment).
 Zill gives medium to heavy production of fruit.
  
KentKent is a medium to large size fruit. the average weight is 400 grams. The skin has a red blush and the flesh is orange-yellow in colour, firm, good flavour and has little fibre. Kent has a good appearance and is moderately resistant to anthracnose.
 The flowering period is from late July to early October and harvest period is from late January to early March, with a peak harvest in mid-February, being four weeks later than the Kensington variety.
 Kent shows a heavy bearing habit.
  
Banana I
(Banana Callo)
The fruit is long and oblong in shape with a medium-size seed. The average weight of the fruit is 260 grams. The skin is smooth, thin and is an attractive pale yellow when mature. The flesh is firm, sweet, acid, yellow in colour and has little fibre. Banana I is subject to anthracnose attack and a spray programme would be necessary.
 The harvest period is from mid December to mid January. Banana Callo has a regular, medium to heavy bearing habit.
  
GlennIs an attractive fruit with good flavour. The skin is yellow with a red blush and the flesh is yellow and firm, The fruit is subject to light Anthracnose fungal infection.
 Glenn shows a good fruit-bearing habit.
  
Tommy Atkins A large and extremely attractive fruit with a turpentine flavour and must be picked early as the flesh quickly breaks down to a jelly as the fruit matures. The fruit is also subject to anthracnose damage.
 The skin is dark red (plum) in colour while the flesh is yellow and stringy. Average weight of fruit is 515 grams. The harvest period for Tommy Atkins is from mid-January to early February.
 Market problems could occur with this variety because of the internal (jelly) breakdown and reaction to turpentine flavour.
  
HadenA large fruit weighing up to 470 grams. When ripe the skin is yellow with red blush and the flesh is firm, sweet and yellow in colour with a slight turpentine flavour,
 Flowering occurs in late July to early September with a peak in mid-August. The fruit are harvested from early January to mid-February with a peak at late January.
 Haden is very susceptible to anthracnose attack and is not recommended as a commercial variety.
  
CarrieHas a medium-size fruit with an average weight of 225 grams. The skin colour is yellow when ripe while the flesh is yellow, sweet and moderately firm and free of fibre.
 Flowering occurs between late July and mid-September with a short harvest period from mid-January to late January.
 Carrie is not a very productive variety. The varieties Glenn and/or Kent have shown to be more attractive and more productive.
  
Irwin The fruit is a medium to large size with average weight of 350 grams. The skin has a red blush when mature. The flesh is sweet, firm, yellow in colour and has little fibre.
 The flowering period for Irwin is from early August to early September with a peak in late August. The harvest period is from late January to early February. The variety is not as productive as Kent, Zill and Glenn, but is more dwarfed in habit.
 Some Recently Introduced Varieties - (But will not be readily available from nurseries until at least 1983).
 Fruiting lines at Walkamin are only for young trees and for one year - variation may occur in following years. (See appendix on flowering and fruiting trees).
  
EdwardAverage size of fruit 120 mm x 80 mm, average weight 475 grams. The skin is orange when ripe, firm with light orange flesh and good flavour. Shows good resistance to anthracnose.
 Edward flowers late July to early September with a peak in late August. The harvest period is from early February to mid-March.
  
HoodA small fruit; average size 85 mm x 85 mm with average weight of 275 grams. The skin is an attractive dark red and the flesh is orange with a reasonable flavour. The fruit shows good resistance to anthracnose fungal attack.
 This variety flowers from mid-August to mid-September and the harvest period is mid-February to mid-March.
 A medium size fruit, average size 104 mm x 89 mm with average weight of 375 grams. The skin is an attractive orange-red when ripe and the flesh is yellow. The fruit shows good anthracnose resistance.
  
FascellA medium size fruit, average size 104 mm x 89 mm with average weight of 375 grams. The skin is an attractive orange-red when ripe and the flesh is yellow. The fruit shows good anthracnose resistance.
 The flowering period is from late August to mid-October with a peak mid-September. The harvest period is early March to early April.
 Fascell could turn out to be a good late producing variety.
  
Nam Dok Mai A long plump fruit; average size being 160 mm x 80 mm with average weight of 435 grams. The skin ripens to yellow starting from the base. The flesh is orange, firm and has a reasonable flavour.
  
 The fruit is moderately resistant to Anthracnose attack. Nam Dok Mai flowers from early August to mid-October with a peak in mid-September. The harvest period is from mid=January to mid-February.
  
Early GoldThe fruit has an average size of 100 mm x 75 mm and an average weight of 325 grams. The skin is yellow and the flesh is orange when the fruit is mature. The fruit has a slight turpentine flavour.
 Flowering occurs between mid-August to mid-October with a peak in mid-September. The harvest period is between mid-December and mid-January, clashing with the harvest of the Kensington variety.
  
FlorigonMedium size fruit 90 mm x 85 mm with an average weight of 320 grams. The skin colour is an attractive pale orange colour and the flesh is yellow. It appears to have good resistance to fruit rots and the flavour is good.
  
PROPAGATION 
SeedFor polyembryonic varieties (Kensington and Common) propagation by seed is satisfactory. It is most important that seed is selected from good fruit and not the rejected fruit. Do not select seed from malformed fruit or fruit with spongy end problems.
  
SeedbedSeed should be planted 3 to 5 cm deep in light soil, damp sand or sawdust in a shaded seedbed. Most seeds will germinate in 3 to 6 weeks. One to eight seedlings may be obtained from each seed planted of polyembryonic varieties. Straight-stemmed seedlings are selected and transplanted 4 to 8 weeks after germination, when the first leaves have hardened, and shaded until growing well. Seedlings are placed in nursery rows or potted into planter bags for further growth until ready for eventual field planting.
  
GraftingGrafting is used for varieties which do not breed true from seed (monoembryonic varieties). Scions of the required varieties are grafted on to Kensington and common rootstocks. A 60% take can readily be obtained with a suitable grafting technique. The remaining seedling can be regrafted.
  
Planting of TreesDig a hole slightly larger and deeper than the size of the container. Broadcast ½ kg of dolomite and 250 gms of superphosphate in the hole and over the excavated soil. All fertilizer should be weighed to give accurate application rates. Extra superphosphate at planting time could 'burn' the plant.
 Fill enough soil into the hole to bring to correct planting level. Remove the plant from the container and place in the hole. To prevent damage to root system, do not pull the plants out of the containers they are potted in. Cut the container away from the roots. Place the plant in the hole and half fill with soil and compress. Now fill the remainder of the hole and again compress soil around the plant. Water adequately. When the tree has settled in, the top of the potting medium should be at ground level.
 Do not fertilize the young tree till it has made two growth flushes and has obviously commenced active root growth.
 Young trees should be mulched with peanut shells or coarse grass, etc. Keep trees mulched till 2 years of age.
  
PRUNING 
Non-bearing treesPrune early to allow development of a strong open frame. Remove top to force 2 to 3 side branches about a metre above the ground. Remove tops of side branches to force further branches.
  
Bearing Trees Prune immediately after harvest. A further light pruning to remove sucker growth is usually necessary in May. Prune to maintain open frame, to remove dead or diseased wood, to allow light penetration and to keep the top at a height to facilitate management, i.e. spraying and harvesting. Prune by thinning as the mango is essentially an external bearer. Prune low branches which interfere with cultivation.

Recommended Fertilizer Programme


 YearFertilizer/TreeTime of Application
Young trees1100 gms UreaApply Urea late December
 500 gms 10:2:17Apply 10:2:17 mid-January
   
2150 gms Urea 
 600 gms 10:2:17 
   
3200 gms Urea 
 700 gms 10:2:17 
 300 gms DolomiteApply dolomite at end of wet season
(late March - early April)
Fruiting trees4275 gms UreaApply Urea 2 weeks before harvest and 10:2:17 immediately after harvest.
 850 gms 10:2:17
  
5400 gms Urea
 1 kg 10:2:17
  
6600 gms Urea
 1.5 kg 10:2:17
  
7800 gms Urea
 2 kg 10:2:17
  
81 kg Urea
 3 kg 10:2:17
  
91.5 kg Urea
 4 kg 10:2:17
  
101 kg Urea
 5 kg 10:2:17
  
111.5 kg Urea
 6 kg 10:2:17
  
122.5 kg Urea
 7 kg 10:2:17
  
133 kg Urea
 8 kg 10:2:17
  
143.5 kg Urea
 9 kg 10:2:17
  
154 kg Urea
 10 kg 10:2:17

  The fertilizer rate per tree now continues at the same level as for year 15.

N.B.In areas deficient in Boron a yearly application of Borax at the rate of 10 gms per tree per year of age with a maximum of 100 gms per tree at 10 years of age should be applied to the drip zone of the tree and watered in.
  
 All applications of fertilizer should be followed by 25 mm of water within 48 hours.

POST HARVEST 
Hot Water DippingPurpose is to control post-harvest anthracnose infection. Requirements (for full details, see later section on mango diseases) - immerse fruit for 5 minutes in hot water (52 °C) to which 1 gram of Benlate/litre has been added.
 
Packing and ContainersUse tray pack (7 kg). Use paper-wool to reduce bruising. Mark containers to indicate 'Mangoes', 'Number of Fruit', and if named, Variety. Tray should be full without spaces.
Cold StorageMangoes will only store for a short period at low temperatures. The optimum storage temperature for both green and ripening fruit is about 12.5 °C. Storage life will be from 2 to 3 weeks. Lower temperatures cause chilling injuries. Green fruit stored at this temperature will ripen during storage, but may develop a tart flavour. The flavour will generally improve if such fruit are held at 21 to 24 °C for 2 to 3 days after removal from the cool store.
 If mangoes are to be stored for subsequent processing, only fully-ripe fruit should be chosen, and these can be held at 0 to 1 ° for up to 6 weeks. At such temperatures, the skin will blacken, but the ripe flesh will remain in good condition for processing.
  
RipeningMangoes will ripen rapidly under the influence of ethylene. However, ripening with ethylene is not recommended as it can result in fruit of poor quality. Fully mature fruit will ripen to a good quality, but immature fruit will not.
  
MarketsQueensland and New South Wales - no restrictions.
  
 Victoria and South Australia - Fruit Fly restrictions apply.
 All fresh mango fruit must be disinfested under supervision using E.D.B. fumigation at 20 grams per cubic metre for 2 hours at 20 °C in an approved facility. Fumigation chambers or tents loaded with packed produce must be filled to not less than 23% and not more than 45% of their internal volume.
  
Market RegulationsFruit of Kensington must have a minimum dry matter content of 13% and Commons a minimum of 11%.
  
MANGO DISEASES 
Anthracnose (Colletotrichum gloeosporiodes)Symptoms This disease affects leaves, twigs, flowers and fruit. Leaves show rusty brown irregularly shaped spots. Twigs die back and develop cankers. Flowers become blackened and fail to set, or small fruit are infected and shed. In fruit, the disease can be latent until the commencement of ripening when black, slightly sunken spots develop. Spots vary in size from small dots to large blotches covering most of the surface.
 Control : The disease is favoured by wet, humid weather and heavy dews. Both field sprays and post-harvest dipping treatment are needed to control anthracnose.
  
Field SpraysRegularity of spraying depends somewhat on weather conditions. Mancozeb (880 g/kg) at 2 grams/litre weekly during flowering and then monthly until harvesting.
  
Post-Harvest DipDip fruit for 5 minutes in hot water (52 °C) to which Benomyl at 1 gram/litre has been added. Caution - do not add wetting agent to dip mixture. Cool with water - open air allow to dry before packing.
  
Bacterial Black SpotSymptoms: A recently recognised disease of importance in Mangoes. Leaf lesions darken with age and develop into black, angular, raised areas, frequently with a narrow yellow margin and restricted by the veins. Fruit lesions are oval with star-shaped cracks. A gummy exudate may be present on the fruit.
 Control: No chemical is presently registered for the control of the disease. However, it has been found that copper sprays give some control of most bacterial diseases. Farm and nursery hygiene is most important for the control of this disease.
  
Powdery Mildew (Oidium sp.)Symptoms: A white powdery growth on young shoots, flowers and small fruit. Affected fruit fall prematurely. Older fruit show purplish brown blotchy areas on the skin.
 Control: Mancozeb as used for anthracnose control will give control of this disease.
  
MANGO PESTS 
Fruit FlySymptoms: Surface stings and presence of maggots. Small active wasp-like fly seen on fruit - may also be found resting under leaves.
 Control: Apply Fenthion at 14 day intervals while fly is active. Destroy fallen fruit. Withholding period 7 days.
 A post-harvest disinfestation treatment involving a fumigation procedure has recently been developed.
  
Mango ScaleSymptoms: Sites of infestation in light attacks are normally on under surface of older leaves and are generally spotted yellow. In more severe attacks, both sides of leaves and twigs may be covered by massive colonies of the white scales, resulting in leaf and twig dieback.
 Control:
  • 1) Prune out excessive foliage;
  • 2) Maintain a high nutritional status of tree;
  • 3) Repeated white oil applications used at 1:40 should prove effective, but should be avoided in warm weather and when the fruit are maturing. Carbaryl (125 grams/100 litres) mixed with white oil (1:100) gives good control of this type of scale, but is currently not registered.
  
Pink Wax ScaleSymptoms: Infestation on mature leaves, usually associated with sooty mould.
 Control: Spray in early October when the young scales have hatched and dispersed, with methidathion 0.05% a.i. plus 1:100 white oil.
 Repeat in March to coincide with the growth flush which occurs at this time. If methidathion is used, this spray will assist in the control of mango tip borer as well as controlling pink wax scale. If the weather is very hot, reduce the white oil to 1:120 to avoid burn.
  
Flattid Plant-HopperSymptoms: Jumping insect with tent-like wings, commonly found on the underside of leaves.
 Control: Apply carbaryl 0.07% a.i. when large populations occur on fruit stalks, usually in October-November.
  
Seed WeevilSymptoms: Weevil in seed of mature fruit.
 Control: Destroy fallen fruit, ensure disinfestation of seed - burn. Other insects found on mango in various localities are mango tip borer, fruit spotting bug, and fruit sucking moth.
 The use of a spray schedule on the mango is most unsound. The application of the above sprays at minimal levels is the only treatment advisable.
  
Withholding PeriodsDo not harvest fruit within 21 days after an application of methidathion.
 Do not harvest fruit within 7 days after an application of fenthion.
 Do not harvest fruit within 3 days after an application of carbaryl.
 Do not harvest fruit within 1 day after an application of white oil.
F.O. HAMS,
A.J. WAIT,
Courtesy D. P. I. Kamerunga

DATE: January 1984

* * * * * * * * * * * * *