CITRUS

Name of the diesease	Symptoms	Control Measures
LEAF FALL AND FRUIT ROT	Shedding of leaves from the lower branches of the affected trees. Affected leaves show dark water soaked patches. Water soaked patches on the rind of fruits. Affected fruits drop off and rot. Fallen fruits are covered by whitish cottony growth. Complete defoliation and drying of the twigs is very common. P. palmivora also cause bark-rot, crown-rot and girdling of the stem.	Spray 1% Bordeaux mixture, one spray before the onset of the monsoon in June and second at the end of monsoon in August or September.
PHYTOPHTHORA ROOT ROT	Elliptical to irregular brownish lesions on tap roots and feeder roots. Disintegration of cortical cell layers. Girdling of plant at the base. Leaves of infected plants become yellow and drop off.	: 1. Select light soils with good drainage. 2. Use resistant rootstocks like trifoliate and citranges. 3. Drench soil around plant base with 1% Bordeaux mixture. 4. Avoid injuries to roots.
POWDERY MILDEW	Whitish powdery growth on young leaves and twigs. Affected leaves are distorted, and they ultimately fall off. Young fruits drop off prematurely	1. Spray Sulfex (0.3%) or Calixin (0.1%) at 20-30 days interval. 2. Use sulphur dust when the dew is present on leaf surface.
GUMMOSIS	: Profuse oozing of gum on the affected bark is the main symptom. Conspicuous brown staining alongwith hardened masses of gum are also found on the surface of bark. Affected bark gradually turn dark brown and develops longitudinal cracks. When scrapped, the affected portions of the bark appear brown. Infected trees die due to girdling on account of complete rotting of bark.	1. Select proper place with good drainage. 2. Use resistant root-stocks, high buding and high planting. 3. Every year apply Bordeaux paste on the stem upto 60 cm.
SCAB	Lesions on leaves are pustular elevations, flat or depressed at centre. Infected leaves are distorted, wrinkled, stunted and mis-shapen. Lesions on fruits are corky which often break into scabs.	1. Remove infected leaves, twigs and fruits and destroy. 2. Spray Blitox (0.3%) or lime sulphur at monthly intervals beginning with new flush or Difolatan (0.2%) at 15 day intervals.
CITRUS CANKER	The disease affects leaves, twigs, young branches and fruits. Disease is characterised with small, watery translucent spots with raised convex surface. The spots are surrounded by chlorotic halo. As disease advances, the surface of spots become white or greyish and rupture. Fruit lesions are also raised but not surrounded with halo. In severe cases, fruit may crack and drop off.	1. Pruning and destruction of infected plant parts. 2. Spraying of neem cake @ 20 kg/ha. 3. Spraying with Streptomycin sulphate (0.05%). Four Sprayings with Copper oxychloride (0.5%) or Bordeaux mixture (1%).
CITRUS TRISTEZA VIRUS	The Symptoms in acid lime are; vein flecking, vein clearing, stem and root pitting, stunting and yellowing of plants. Leaves may be erect, twisted and brittle. Bark becomes abnormally thick and wood remains thin. Plants may flower heavily and bear large number of small fruits before showing decline symptoms. The first symptoms in mandarins/sweet oranges on susceptible root stocks are the partial or complete supression of new flush of growth and appearance of various types of deficiency symptoms.	1. Use of certified planting material. 2. Sweet orange and mandarins should not be budded on tristeza susceptible root stocks like sour orange. Periodic sprays of insecticides would reduce the secondary spread of tristeza within the orchards.
CITRUS GREENING Click on Image for larger photo.	Leaves show various types of deficiency symptoms resembling those caused by zinc or magnesium. Interveinal chlorosis or complete chlorosis of leaf lamina, reduced size of leaves, early defoliation, green islands in chlorotic leaves, excessive branching, shortening of internodes upright and sparse foliage and die-back of twigs, are the other symptoms.	1. Use of certified planting material. 2. Rigorous control of citrus psylla by spraying systematic insecticides. 3. Application of antibiotics like penicillin and Oxytetracycline hydrochloride.