• Among several bacterial diseases of tobacco, Angular leaf spot is the only one commonly prevalent in India.
• It is confined mostly to Karnataka where tobacco is grown in spring and monsoon season. Its incidence in other tracts is negligible.
• It occurs both in nusery and in the main field.
• Recently 'wildfire' caused by Pseudomonas tabaci was reported on tobacco from Coimbatore district in Tamil Nadu.

• Spots appear at any stage of seedlings or plants in field.
• In seed beds 2-3 small, angular, dark-brown to black-coloured spots appear on individual leaves. When held against light, a yellow halo is seen around the spots.
• In the field, the lesions are dark tan or black, much bigger and coalesce. Lesions are restricted between veins, irregular and on rapidly growing tobacco, leaves become puckered and torn, and the centre of the lesion fall out leaving little besides the veins.

• Cloudiness, stormy wind with rain causing water splashing are favourable factors for infection and rapid spread of the disease.
• In the absence of storm with rains, excess soil moisture accompanied with high humidity, excess nitrogen and low potassium nutrition enhance the incidence.

• Phytosanitary measures of prompt removal and destruction of diseased debris and susceptible weeds from the seedbeds and discarding affected seedlings.
• Use of Bordeaux mixture 0.4% checks the disease adequately in the nurseries. However, in the field the disease was effectively, checked by spraying antibiotics like Streptomycin or Streptocycline at 200 ppm (200 mg in 1 lit).
• Spraying Thiophanate methyl at 750 g/ha or carbendazim at 500 g/ha controls this disease.

• Anthracnose is caused by Colletotrichum tabacum
• The disease causes serious damage to the seedlings in nurseries only and it occurs rarely in the fields.
• It occurs in all the tobacco-growing tracts of India.

• Initially, infection starts on lower leaves as pale-brown circular spots of 0.5 mm diameter with papery depressed centres outlined by slightly raised brown margin.
• The leaf-spots may remain small with white areas in the centre or coalesce to form large necrotic lesions.
• Under continuous humid weather, dark brown or black, elongated, sunken necrotic lesion appears on midrib, petiole and stem resulting in petiole and stem rot. Such seedlings do not establish in the field if planted. Primary infection starts from affected bits of aerial parts left in the soil in the previous season.
• The pathogen is not seed-borne but persists in the soil on dried plant debris.

• Raised seed beds and rabbing with farm wastes help in reducing the initial infection
• Removal and destruction of all diseased debris minimises the pathogen in the soil.
• Discarding the diseased seedlings especially with necrotic lesions on stem will save gap filling in the field.
• Protective spraying with Bordeaux mixture at 1.0% (2-2-500) or 0.2% (2 g/lit) Zineb or Dithane Z 78 at 0.1% or (1 g/lit) Cuman during wet weather especially in nurseries where anthracnose appeared in previous season, is helpful.

• Apply fungicide one week after completion of germination.
• Subsequent application, depending upon weather conditions, should be given at 4 days interval if it is bright, sunny and dry and once in 2 days when it is cloudy and wet weather.
• Application should be repeated after every rain.

• It is caused by soil inhabiting fungus Phytophthora parasitica var. nicotianae and appears both in nursery as well as in the field.
• Black shank occurs sporadically in every type of tobacco and causes more damage to tobacco grown under high rainfall or irrigated conditions in light soils.
• It is caused by soil inhabiting fungus Phytophthora parasitica var. nicotianae and appears both in nursery as well as in the field.
• In nursery, the affected seedlings show blackening of roots and stem near soil. Under wet weather conditions the conidial infection spreads to leaves, which show water soaked lesions resulting in leaf blight and collapse.

• First sign of infection seen in the vigorously growing plants is yellowing of leaves, sudden wilting and ultimately death of plants under warm weather.
• The disease appears in scattered patches in the field.
• The stems of such plants when split open show brown to black dried pith.

• Discard seedlings showing blackening of roots and base of the stem.
• Spot application of Bordeaux mixture 0.4% (4g / lit) or 0.2% (2 g / lit)copper oxychloride
• Remove carefully the wilted plants and destroy them.

Alternaria longipes
Alternaria tenuis
Alternaria alternata

• Brown spot, in contrast to frog-eye spot is not normally observed in the nursery but is very much prevalent in the main field.
• In India, a decade back it was considered to be of minor importance but gradually it is gaining importance specially in tobacco grown in monsoon season.

• Initially, it appears on lower and older leaves as small brown, circular lesions, which spread, to upper leaves, petioles, stalks and seven capsules.
• In warm weather (30° C) under high humidity, the leaf spots enlarge, 1-3 cm in diameter, centres are necrotic and turn brown with characteristic marking giving target board appearance with a definite outline.
• In severe infection, spots enlarge, coalesce and damage large areas making leaf dark-brown, ragged and worthless.
• On leaves nearing maturity, leaf spots are surrounded by bright yellow halo, due to production of toxin 'alternin' by the fungus.
• Extensive toxin production can make the apparently undamaged areas of the leaf cure out dead and black.

• The fungus occurs in the soil as mycelium in the diseased plant debris such as stems of tobacco, weeds and other hosts.
• Under favourable weather in the next season conidial production starts which infect the lowermost leaves.
• As the season progresses, repeated infection cycles of the fungus attack healthy tissues of all aerial parts of tobacco of any age under high humidity.
• There is enormous spore density in the air near the end of the harvesting.
• Fungus persists as a mycelium in dead tissue for several months.

• Removal and destruction of diseased plant debris can check the primary infection promptly.
• Continuous growing of tobacco after tobacco must be avoided in the heavily infected fields.

• Weekly, spraying of fungicides such as Maneb, Dyrene (2, 4-dichloro-6-0-Chloranilenotriazine) at 450 g per acre or 0.125% (1.25 g/lit) Benomyl and Thiophanate methyl or 0.2% (2g/lit) Dithane Z 78 do give reduction in leaf spotting.

• Tobacco leaf, being the valuable endproduct of the plant is invariably invaded by several fungal and bacterial organisms during curing and storage.
• Such invasion generally reduces the quality and marketability of the cured leaf. In India, so far no work has been initiated on the barn and storage diseases of tobacco.

• This is also known as 'House burn' or 'Pole rot, which is common on air-cured tobacco.
• Flue-cured tobacco is also susceptible. There are four phases of leaf decay leading to barn rot. They are :

• It is the earliest to appear
• Lesions or spots develop on the stalks and gradually extend to the leaves.
• Cankers are formed on the stalk which girdle the stalk leading to yellowing of leaves above the girdle.
• Such type of leaves when cured, are pale or off-coloured, thin, papery and of poor quality.

• This phase is the most destructive of the house burn as the leaf affected by web-rot is worthless.
• Web rot affects the leaf during wet weather at the time of harvest. Affected leaves are brown, soft and watery but become brittle during curing. When handled, such leaves shatter and do not come to condition.

• Vein rot generally starts from the stalk rot and extends into the midrib and lateral veins.
• All the vein tissues disintegrate except the fibres.
• Affected leaves turn white or straw coloured and decay. Such leaves have no commercial value.

• Numerous small dark spots ranging from pinhead to 6 mm in diameter appear on the leaf blade. They are reddish-brown to black in colour.
• Different phases on "barn rots" mentioned above are caused by Botrytis cinerea, Rhizopus arrhizus, Aspergillus spp., Alternaria tenuis and Sclerotinia sclerotiarum.
• Prolonged moist weather during growth period is favourble for barn rot development.
• In the barn, ideal conditions for spread appear as a result of high humidity produced by over-crowding the tobacco and failure to ventilate properly.
• When the humidity reaches 85-95%, danger from barn rots is imminent.

• Barn rots can be prevented by proper manipulation of ventilators and humidity during curing.
• Increasing the temperature inside the barn by 5° – 15° C above that of the outside air and careful ventilation for 3 or 4 days will usually prevent damage.
• Curing barns should be built in the open on high ground and adequately ventilated. Usually serious barn rot damage occurs in barns, which are poorly located, tightly constructed and inadequately ventilated.

• Root-rot complex locally known in Gujarat as 'Chitri' disease is fairly widespread on bidi tobacco grown in that tract.
• Root rot and Fusarium, Rhizoctonia and nematode associated with rotten roots.

• Clear symptoms of 'Chitri' are noticed 6-8 weeks after planting though some plants show symptoms earlier also.
• Wilting of leaves is the chief symptom starting in older plants from bottom upwards.
• In younger plants all the leaves wilt simultaneously.
• Roots show brown discolouration of the cortical region.
• Root system is diminished very much compared to healthy plants. The discolouration extends to lower portion of the stem.
• The transverse section of affected roots show invasion of cortical region by septate hyphae, which are rarely noticed in vascular bundles.
• The disease appears in individual plants, or in patches of many plants.

• It is a warm weather disease. High temperature (28 – 31° C) are favourable.

• Being soil-borne pathogen, use of resistant varieties is the only solution.
• However, use of soil fumigant in nematode-infested fields is essential in addition to use of resistant variety. Tobacco after cotton is a useful rotation.

Pythium aphanidermatum, Pythium debaryanum

• Damping off is a serious problem in tobacco nurseries both in heavy clay soils and light sandy soils.
• It is caused by several soil inhabiting fungi predominant being Pythium aphanidermatum, Pythium debaryanum, Phytophthora sp. and some times Rhizoctonia solani are also involved.
• The disease may appear at any stage of the seedlings but maximum damage is observed 5-6 weeks after sowing.

Disease is noticed in two phases, viz.

• Pre-emergence damping-off
• Post-emergence damping-off

• Infected seedlings die before emergence from the soil resulting in poor and uneven stand of the seedlings.

• Post emergence damping-off is the most destructive phase.
• The tiny two leaved seedlings may disappear due to wet rotting of stems and the seedlings stand diminishes daily.
• Generally damping-off occurs in patches which spreads quickly if unchecked.
• The older seedlings show shrivelling and brown discoloration of the stems near the soils and start rotting under wet soil conditions.
• The decayed stems collapse and seedlings topple over leaving patches like brown crest over the soil.
• The wet rotting and sudden collapse of seedlings starts in circular patches and under wet weather conditions may extend over the whole seedbed causing near total loss.

• Oospores and chlamydospores in soil act as initial source of infection.
• Under favourable wet conditions oospores germinate liberating zoospores which infect the seedlings at soil level or just below.

• High humidity, high soil moisture, cloudiness and low temperature.

• Preparation of raised seed beds with adequate drainage facilities
• Use of recommended seed rate (1.0 to 1.5 g /2.5 m²)
• Regulating waterings to avoid excessive dampness.
• Pre-emergence damping off : Drench the seed bed with 1% (10g/lit) Bordeaux mixture or 2% (20g/lit) Copper-oxychloride 2 days before sowing.
• Post-emergence damping off : Drench 4% (40g/lit) Bordeaux mixture or 2% (20g/lit) copper oxychloride or 2% (20g/lit) metalaxyl compound.
• Drenching of Bordeaux mixture or any other fungicide 2 weeks after sowing and subsequently at 4 days interval under dry weather and at 2 days interval under wet cloudy weather will save the seedlings from damping off. It is better to drench immediately after each rain.

• During prolonged dry weather, tobacco leaves sometimes develop numerous large red-brown spots between the veins. Each spot is surrounded by a yellow zone.
• The spots coalesce to form large irregular patches. The margins of the leaves curve downward and dry up.

• Frog-eye leaf spot disease occurs in the seed-beds as well as in main fields. It damages the marketing quality of leaf especially of flue-cured and wrapper tobaccos.
• The disease is severe on tobacco grown under monsoon conditions.

• Frog eye spots appear mainly on the lower leaves.
• They are usually circular, brown or tan with dark-brown and pale ashy or white parchment like centre resembling frog's eye at early stages
• During wet weather they may not be typical as above, as the outline may be angular and the white centre may be absent and they may enlarge from 0.25 cm to 1.5 cm in diameter.
• During frequent rains large necrotic areas appear which destroy much of the leaf. During hot dry weather, frog eye-spot may be only pinpoint in size.
• In flue-cured tobacco the same pathogen causing infection at the harvesting time when cured results in innumerable, small, uniform, dark-brown to black spots popularly known as 'Barnspots' which affect the market value of the leaf.

• The nurseries should be located away from barns and all the diseased debris removed promptly and destroyed.
• Avoiding excess nitrogen fertilisation and picking over ripened leaves also helps in minimising leaf spotting.

• Fungicidal sprays with Bordeaux mixture 0.4% (4g/lit), Zineb 0.2% (2 g/lit) or 0.1% (1g/lit) Benomyl as per the schedule suggested under damping-off has checked leaf spotting in the seedbeds.
• In the field, removal of sand leaves immediately after the transplants have established, and weekly application of 0.4% (4g/lit) Bordeaux Mixture or 0.1% (1g/lit) Benomyl or Thiophanate methyl or 0.03% (0.3g/lit) Bavistin 5-6 weeks after planting has given adequate control of frog-eye spot.

• Stray incidence of hollow stalk has been observed on FCV tobacco in recent years

• Diseased plants were identified by the sudden wilting and rotting of the plants.
• Leaves wilt, droop and hang down. Water-soaked large lesions were generally seen on the wilted leaves.
• Symptoms on the stem consist of elongated black or dull brown patches girdling the stalk.
• Such stems when break open show browning of the pith followed by soft rotting and death of the tissue. In general, hollow stalk appears at topping and suckering time.

• The bacterium is a wound parasite and belongs to soft-rot group of bacteria. They are the natural inhabitants in soil.
• Development of the disease is favoured by damp, cloudy weather with high humidity. It was also reported that use of mineral oils as suckericides favour the reproduction of the bacterium and development of hollow stalk.

• Sanitary measures are more important than chemical spraying.
• Topping and de suckering should be avoided during damp and cloudy weather, which are ideal for the spread of the bacterium.

• Leaf curl, is fairly widespread in all tobacco tracts in India. Generally the disease appears 3-5 weeks after planting and sometimes late in the nursery.
• The virus is transmitted by an insect vector, whitefly (Bemisia tabaci). It is also graft transmissible but not by sap or seed. There are a large number of hosts of this virus as well as of its vector.
• The most characteristic symptom of toabcco leaf-curl disease is the production of leafy outgrowths known as enations from the veins on the lower surface of the leaves.
• Combined with this, is a stunting of the whole plant and twisting and curling of the leaves.
• The manifestation of the disease varies greatly according to environmental conditions and the variety of tobacco concerned.

• Whitefiles become more active in dry periods after monsoon showers. Leaf-curl is therefore, noticed more during dry period.
• Seedlings of flue-cured tobacco are easily infected and not the older plants which have plenty of epidermal hair and stick gum which perhaps prevents proper activity of whiteflies in feeding, acquiring and transmitting the virus.
• Tobacco plants become more resistant to Tobacco leaf curl virus as they grow older.
• The susceptibility of the plant was directly correlated with nitrogen supply and inversely correlated with phosphorus supply.
• Potash at increasing doses reduces susceptibility.

• Remove and destroy the diseased tobacco seedlings before and after planting whenever they are seen in the field.
• Alternate weed hosts for whitefly should be removed and destroyed.
• In endimic areas Sesbania sp. may be grown as a barrier crop around tobacco fields.
• Install 12 yellow sticky traps (castor oil coated) per hectare to monitor the whitefly population. If 100-200 whiteflies stick to the trap the following insecticide schedule has to be adopted.

II. Spraying of methyl-demeton 25 EC 20-40 ml in 10 lit.of water is also effective against leaf curl.

• This is also known as 'sun-burn' and it occurs during hot weather. Large irregular dead areas are formed on the lower surface of the leaf. Affected leaves wilt and dry up.
• Damage due to lightening, hailstorm, excessive moisture, herbicide injury and other were also reported on tobacco leaves. However, their recurrence and damage is very rare and negligible.

• Mosaic is very widely distributed and is the most common virus disease on tobacco. This is the plant virus discovered first, on which great deal of classical work has been done for basic virus and hereditary studies.
• Mosaic appears sporadically in nurseries as well as in fields. While it is easy to recognise a mosaic-affected plant in the field it is difficult to differentiate diseased seedlings in the nursery.
• In some fields 90-100% of the plants show mosaic by harvesting time, while the adjacent fields are free from it. The damage is related to age of the plants.
• The maximum loss in yield and quality of leaf occurs when crop is infected at young stage.
• It was found that if the plants are infected at the transplanting time, the loss in yield would be between 32 and 60%, 20 and 30% a month after planting and 7 and 17% at topping time.
• Crops infected near topping time may yield as much as healthy crops but the quality is usually impaired.
• Mosaic-affected leaf shows more of nicotine, total nitrogen and albumen and less of soluble sugars and carbohydrate content.

• Mosaic has very wide host range among 'herbaceous dicots, about 116 plant species belonging to 29 different families susceptible to common TMV.

• Affected plants show leaves with molting or mosaic pattern of light green and dark-green areas.
• Primary symptoms appear on newly formed young leaves as vein clearing, greenish yellow motling.
• Infection on young plants results in stunted growth, malformation, distortion and puckering of leaves. Dark-green blisters and some time enations (leafy growth) appear on the dorsal side of the leaf.
• Immature leaves show varying degree of yellow motling and chlorosis. In severe infection due to a highly virulent strain of TMV, various necrotic dark-brown spots also develop resulting into 'mosaic scorch' or 'mosaic burn' under hot sunny dry spell, damaging large areas of lamina.
• There are many strains of TMV and symptom expression depends upon the strain and the prevailing environmental factors. Mosaic-affected leaves after curing show green spots which lower the market value of the leaf.

• TMV is highly contagious and transmitted by sap. It is easily transmitted by mere contact of a diseased plant with a healthy one.
• Air-dried tobacco is a common source of new infection. Workers who chew or smoke natural leaf tobacco during nursery operations may spread the virus into the seedlings.
• Old stems and leaf trash of affected plants buried in the soil are the other sources of infection and spread.
• In the nurseries, seedlings may get affected due to the presence of susceptible weed hosts.
• The virus is not insect transmitted. The aphid (Myzus persicae Sulz) which occurs commonly on the tobacco plant is unable to transmit the virus. Occasionally chewing insects like Grasshoppers, flea beetles and caterpillars transmit TMV but this type of spread is insignificant under field conditions.
• The virus is not transmitted through tobacco seed although it is transmitted through tomato seed.
• Experimentally the virus is graft transmissible.

• TMV is highly infectious. Entry of TMV is direct through the epidermis and rarely through stomata. Entry depends upon the type of wound, toughness of epidermis, presence of inhibitors of virus and virus concentration.

• ncrease in temperature and light reduces the time required for symptom expression.
• Ultimate effect depends upon age of the plant, virus concentration and growth conditions for the host.
• Infection is inhibited above 38 – 48° C, above 27° C or below 10° C the symptoms may disappear.
• Long days and relatively high light intensity, which favour host growth generally favours initial virus synthesis.
• Young plants in general are more susceptible.

• Best effective way is to keep the crop mosaic free.
• Constant vigilance is required right from the seedling stage till harvest involving phytosanitary measures, and nothing can be done once TMV becomes systemic.
• Infected seedlings should be removed promptly and destroyed.
• Workers should disinfect their hands with soap and running water before handling seedlings, weeding or doing other cultural operations.
• Use of tobacco (smoke, snuff, or chewing) should be prohibited strictly while working in seedbeds or field.
• Weeds (Solanum nigrum) and plant (Brinjal, Tomato, Chillies) susceptible to the virus should be destroyed.
• In fields showing high incidence of mosaic, rotation for 2 years should be followed.
• Rouging of the affected plants before first interculturing considerably reduces the spread of the disease.
• However, in areas where TMV is an over-riding problem, resistant lines developed at CTRI, Rajahmundry, viz. TMVRR-2 and TMVRR-2a, TMVRR-3 can be used to overcome this problem.
• Spray leaf extracts of Basella alba, Bougainvillea (one litre of extract dissolved in 100-150 litre of water) on 30^th, 40^th and 50^th days after transplanting.

• Powdery mildew, also known as white mold or ash disease, occurs in all types of tobacco.
• Generally the damage caused is slight, but it is severe in flue-cured tobacco grown in low-lying areas of Andhra Pradesh and in tracts where tobacco is grown as rainfed crop from spring to monsoon seasons in Karnataka.
• The crop becomes unprofitable in case of severe incidence.

• Initially greyish white spots (about 0.5 – 1 cm in diameter) appear at the base of the lower leaves of the maturing plant.
• Under favourable conditions of low temperature (16 – 23° C) and high humidity these white patches spread to upper leaves, enlarge and cover the entire surface of the leaves.
• Such leaves on curing get scorched and show brown patches rendering them unfit for marketing.
• Sometimes leaves with incipient infection result in blemished on curing which reduce the commercial value of leaves.

• Excessive nitrogen fertilizer causing vigorous vegetative growth and close planting which increase the humidity around the plants and shade are predisposing factors for infection and development of the disease.
• The fungus normally attacks maturing plants in the field. The optimum temperature for infection is 16 to 23° C and relative humidity of 60-75%.

• Avoiding over fertilising, overcrowding of plants and removal of affected basal leaves will help in minimising primary infection and spread of the disease.
• Early planting to escape cool temperature prevalent at the maturing stage will also reduce the incidence.
• In black soils apply sulphur powder (200 mesh) @ 40 kg/ha to soil between plant row 6-8 weeks after planting. Mix ash or sand to sulphur for easy application. See that sulphur does not fall on tobacco leaves.
• Spray 0.2% (2 g/lit) Karathane or Thiovit or 0.05% (0.5 g/lit) Bavistin just before the disease sets in. Repeat at 10-12 days interval if necessary.
• Use resistant varieties like Swarna or Line 2359 developed at Central Tobacco Research Institute, in disease endemic area.

• In 1968, incidence of a severe type of mosaic virus was noticed in Natu tobacco (sun-cured cigarette tobacco) on a fairly wide scale in Warangal and Karimnagar districts of Andhra Pradesh.

• Affected plants show highly stunted growth, abnormal suckering and the leaf tips are modified into rat-tails.
• The leaves show typical mosaic mottling, puckering, distortion and suppression of lamina into various shapes leaving only long midrib in extreme cases.

• Screening the germplasm for Tobacco distorting virus indicated that besides TMV resistant line TMVRR-1, developed at CTRI, Rajahmundry, there are 23 genetic types (15 exotic and indigenous air-cured types) found resistant to TDV.
• D.G.3 (Desi Guntur), an improved Natu tobacco variety, is found resistant to TDV virus.

• During prolonged dry weather, tobacco leaves sometimes develop numerous large red-brown spots between the veins. Each spot is surrounded by a yellow zone.
• The spots coalesce to form large irregular patches. The margins of the leaves curve downward and dry up.

• Tobacco also suffers from non-parasitic and abiotic factors both in the nursery and field.
• In general, the damage due to abiotic factors is negligible but in certain years the loss is enormous.
• Although not much work has been done in India on the incidence of injuries due to abiotic factors, there are evidences to suspect that diseases like weather fleck, frenching, frost or cold wave injury, etc. do occur in field.

• Weather fleck is a non-parasitic leaf-spot disease.

• Symptoms are seen at first on the mature basal leaves in the form of irregular, water-soaked spots, closely aggregated, 1-3 mm in diameter.
• These spots are generally seen on the upper surface. Very soon the lesions turn brown to grey or white with necrotic centre bordered by chlorotic tissues.
• In severe cases these flecks coalesce affecting the whole leaf which in turn becomes yellow and collapses.
• Both younger and over-matured leaves were less susceptible and recently matured leaves were most susceptible.

• Sore shin is considered to be minor disease, though in certain individual plots damage caused is fairly high.
• The sore shin fungus Rhizoctonia solani attacks many plant species of economic importance and can remain as a saprophyte on decaying plants or as sclerotia in the soil.
• It appears both in tobacco nursery as well as in the field.

• In nursery, symptoms appear as a dark brown lesion on the stem near soil line, which enlarges, girdles the stem, causing decay and toppling over of the seedlings under favourable wet conditions similar to damping-off.
• In poorly drained field, the dark brown lesion on the stalk, due to infection near the soil, extends upwards as a dark-band and the roots remain unaffected.
• Under cool wet weather the infection spreads rapidly round the stem and deep in the cortical region.
• Entire stem shows black lesion, dry rot of the cortex and pith with minute black sclerotia visiable in the grey mycelium; leaves become yellow, wilt and die.
• Affected plants have weak stem which cannot withstand heavy wind.

• The disease being of minor importance and no suitable control measures have been reported.
• However, the fungus being a soil inhabitor, usual phytosanitary measures are suggested.
• In seedbeds soil disinfection with a suitable soil fumigant or dry heat (rabbing) before sowing will control primary infection.
• In the field no satisfactory control is known, neither crop rotation helps, nor any resistant types have been developed so far.

• A serious leaf spot disease on Nicotiana tabacum was reported in and around Muzaffarpur (Bihar) during 1962 onwards.
• Symptoms consisted of round or oval spots with concentric zones. The lesions enlarge, coalesce and affect the whole lamina.
• Infected leaves first become pale yellow and and then turn brown to dark brown.

• Brown,irregular, zonate spots, 1-10 mm in diameter, dark brown in the centre and light brown towards the margin were seen.
• Pycnidia were embedded in the necrotic tissue. A shot-hole disease on tobacco seedlings.
• Large white blotches upto 15 mm in diameter were seen on the leaves, the centres of which fall out to give the shot-hole effect.
• The fungus was identified as Phyllosticta nicotianae
• In India a leaf spot disease on tobacco caused by P. tabaci was reported from Maharashtra.

• Spraying with (Carbendazim 50%), Bavistin 50 W.P. @ 0.025% (2.5 gm in 10 litres of water) at 10 days interval or Dithane Z-78 @ 0.2% (20 gm in 10 litres of water) at weekly intervals. Bavistin may be sprayed at 12-15 days interval.