THE MANGOESAnthracnose, sooty mould, leaf blight, die back, powdery milddew, and a bacterial leaf spot
Anthracnose of mango On leaves, lesions start as small, angular, brown to black spots that can enlarge to form extensive dead areas. on panicles small black or dark-brown spots, which can enlarge, coalesce, and kill the flowers before fruits are produced. Ripe fruits develop sunken, prominent, dark brown to black decay spots before or after picking. sometimes “tear stain” symptom and cracking
• Spray Carbendazirn (Bavistin 0.1%) during flowering to controls blossom infection.• Spraying copper fungicides (0.3%) to control of foliar infection.• Dip treatment of fruits in Bavistin (0.1%) in hot water at 52 C for 15 minutes to control post harvest
Stem end rot of mango In fruits, the pericarp darkens near the base of the pedicel. The affected area enlarges to form a circular, black patch which under humid atmosphere extends rapidly and turns the whole fruit completely black within two or three days. The pulp becomes brown and softer • Avoid harvesting immature fruit • Careful handling to minimize mechanical injuries. • Postharvest dip of fruits in Carbendazirn (0.1%) in hot water at 52 ± 1°C for 15 minutes controls the disease in storage and transit.
Powdery Mildew White superficial powdery fungal growth on leaves, stalk of panicles, flowers and young fruits. Affected flowers and fruits drop pre-maturely
Control : Following three sprays of fungicides at 15 days interval recommended for effective control of the disease :• Wettable sulphur 0.2 % (2 g Sulfex / lit. water).• Tridemorph 0.1 %( 1 ml Calixin / lit. water).• Dinocap 0.1 % (1 ml / g Karathane / lit. water).
MalformationMisshapen shoots with short internodesand brittle leaves.Leaves are signiicantly smaller thanthose of healthy plants and re-curvetowards the stem giving a bunchy-topappearance.
• Compact and clustery appearance• Flower bud transform into vegetative
Die Back• Drying of twigs and branches followed by complete defoliation• Gives the tree an appearance of• scorching by fire.• Initially it is evident by discoloration and darkening of the bark. The dark area• advances and extends outward along the veins of leaves.• The affected leaf turns brown and its• margins roll upwards.• Exudation of yellowish brown gum 1. Pruning of the diseased twigs 2-3 inches below the affected portion and spraying Copper 2. Oxychloride (0.3%) on infected trees controls the disease. The cut ends of the pruned twigs are pasted 3. with Copper Oxychloride (0.3%).
• Black sooty mould on the leaf surface• Trees turn completely black• Mealy bug, scale insect, hoppers-honey dew-fungal growth-photosynthesis impaired Pruning of affected branches and their prompt destruction prevents the spread of the disease. Spraying of 2 per cent starch is found effective. It could also be controlled by spray of Nottasul + Metacin + gumacasea (0.2% + 0.1% + 0.3%).
• Red Rust• Rusty red spots mainly on leaves and sometimes on petioles and bark of young twigs• Spots are greenish grey in colour and velvety in texture. Later, they turn reddish brown.• Circular and slightly elevated spots sometimes coalesce to form larger and irregular spots. Control : Two to three sprays of copper oxychloride (0.3%) is effective in controlling the disease
Anthracnose of Banana• Infection appears as small, black, circular specks on the mature & immature fruits.• The specks increase, become sunken and coalesce to form large spots of black in color.• In case of severs infection, fruits may be covered with dark blemishes.• Immature or young fruits ripen prematurely and turn black. The skin shriveled and often cracked. Spraying of Chlorothanlonil (0.2%) and Bavistin (1 %) four times at 15 days interval is recommended. Minimising bruising; proper sanitation of handling and prompt cooling to 14°C are essential in minimising the disease in cold storage
Sigatoka/leaf spot of banana• First appears as small, light yellow spots parallel to the side veins of leaves.• Spindle shaped spots with grayish to ash colored sunken centers surrounded by dark brown margin and yellowish haloes.• several spots may run together to form large patches, causing the leaf blade to dry up from the edge-inwards.• Rapid drying and defoliation of mature Spray Dithane M-45 WP or Tilt leaves is the characteristic feature of 50 EC @ 0.3% at 10 days intervals. this disease.
Anthracnose of guava• Symptoms appear in both green and ripe fruits.• Small, pin-head sized spots appear on the unripe fruits.• Spots enlarge to form sunken and circular and dark brown to black• Minute black stromata appear in the centre• Spots coalesce• Infected area of the unripe fruits becomes harder and corky.• Scab or canker type symptoms can appear on young and mature fruits.• Infected fruits may be malformed and drop off.
Die-back of guavaYoung twigs are attackedFlowers shade before opening and thetwigs become dark.Gradually spreads downward resulting die-back of the young twigs and smallbranchesUltimately whole branches die.
Papaya mosaic top young leaves are much reduced in size Show blister like patches of dark green tissue alternating with yellowish green lamina and puckering Often the leaves are severely curled giving tendril like appearance. stageManagement2-3 foliar sprays of Phosphamidon (0.05%) at an interval of10 days starting from 15-20 days after sowing effectivelychecks the population of aphids
Leaf curl of papaya characterized by severe curling, crinkling, and distortion of leaves accompanied by vein-clearing and reduction in size Leaves become leathery and brittle The most prominent symptom is the rolling of leaves downward and inward in the form of an inverted cup and thickening of veins. Control Spray insecticides dimethoate @ 0.02% for vector control with 2-3 sprays at the interval of 8 days.
Papaya Ring Spot yellowing and vein-clearing of the young leaves. conspicuous yellow mottling of the leaves and sometimes severe blistering and leaf distortion. Dark-green streaks and rings also appear in the leafstalks and stems. concentric rings and spots or C-shaped markings, a darker green than the background-green fruit color. on ripe fruit darker orange-brown rings appear Control Aphids can be controlled by 2-3 foliar sprays of Phosphamidon (0.05%) at an interval of 10 days starting from 15-20 days after sowing.
Anthracnose of Papaya• Brown to black depressed spots on the fruits.• Centers of these spots later turn black and then pink when the fungus produces spores.• The flesh beneath the spots becomes soft and watery,• Small, irregular-shaped water-soaked spots on leaves.• These spots eventually turn brown. Control Spay Copper Oxychloride 0.3% or Carbendazim 0.1% at 15 days interval
Stem rot / Foot rot Water soaked spot in the stem at the ground level which enlarge and griddle the stem. The diseased area turns brown or black and rot. Terminal leaves turn yellow droop off. The entire plant topples over and dies. Control •Seed treatment with Thiram or Captan 4 g/kg or Chlorothalonil. •Drenching with Copper Oxychloride 0.25 % or Metalaxyl 0.1%
Grey leaf spot of coconut/Leaf spot of coconutDark brown to grayish white ovalspots appear scatteredly all over theleaf lamina.Margins of the spots are dark brownwith grayish centre surrounded byyellowish haloes.In severely infected trees, hundredsof spots may be found on a leafblade, causing blight and withering ofthe leaves.
Bud rot of coconutPale yellowish discoloration of the heart leaf.Basal tissues of this leaf become rotten and this leaf caneasily be pulled out from the bud.With the progress of the disease, brown lesions developat the base of all the young leaves.Dead leaves drop off till the whole crown is lost and amere stem is left standing.The soft, infected portion rots, degenerates to a slimymass and emits a foul smell.Young nuts fail to develop and fall. Brown rotten area isseen at the base of the young nuts. Apply fytolan @ 0.5% to young leaves of affected and nearby healthy plants.
Scab of citrus Irregular, corky spots on the leaves, twigs and fruits. They become warty, erupted with cracks and scabby. On the leaves, the spots are found more often on the lower surface than on the upper. On the fruits, the warty growths are surrounded by yellowish or chlorotic haloes. The color of the spot turns from yellow to orange brown and finally black. Several spots run together to form large patches of corky outgrowths. The leaves sometimes crinkle due to the occurrence of several spots on them.
Citrus canker• Lesions appear as yellowish spots on leaves, twigs, petioles, branches, fruit stalks, fruits and other parts including thorns.• The spots enlarge gradually raised, rough and corky and are surrounded by yellow halo.• The lesion on fruit looks similar to those on leaves except the yellow halo is usually absent and crater-like appearance is more noticeable.
Die back of citrusIn the early stages, symptoms are restricted to one or two limbs but ultimately thewhole tree is involved. The symptoms begin with die-back of small branches andtwigs, yellowing of leaves and heavy bearing of small fruits. Midrib and lateral veinsof old, mature leaves turn yellow with interveinal areas along the veins showingdiffuse yellowing. As the disease progresses, the symptoms intensify, resulting insevere chlorosis and mottling, reduction in leaf size and number, and wilting. Leavesmay fall with onset of summer or autumn and the die-back of twigs commences up todown. This is followed by secondary growth consisting of short, upright, small, weakshoots showing a variety of discoloration of leaves. Minute dot like structures (calledacervuli) are produced on the discolored tissues of the twigs. Often the small leaveshave green veins or green blotches. Occasionally, small, circular, green spots appearon yellow tissues in younger most leaves. The die-back of weak shoot continues.]here is extesive and premature flowering. The fruits show conspicuous sunblotching. The cropping declines, foliage reduces, die-back of twigs extends,secondary fungal wood rot advances and finally the tree is completely destroyed.When the roots of such plants are examined, the feeder roots are also observed to bedead, the bark of the larger roots, distorted and brittle, and dry rot symptoms are seen,in many lateral roots. After 7 or 8 years the plants may die, by which time, there maybe no leaf formation, the branches get dried up and the plants appears wilted almostcompletely. When the trunk root is affected most of tile altered roots are involved in asevere dry rot and the feeder roots are also dead.
Jacfruit DiseasesDiseases of importance include pink disease, Pelliculana(Corticium) salmonicolor, stem rot, fruit rot and maleinflorescence rot caused by Rhizopus artocarpi; and leafspot dueto Phomopsis artocarpina, Colletotrichum lagenarium, Septoriaartocarpi, and other fungi. Gray blight, Pestalotia elasticola,charcoal rot,Ustilana zonata, collar rot, Rosellinia arcuata, andrust, Uredo artocarpi, occur on jackfruit in some regions.