Management of mango hoppers in orchards
Mango hoppers are the most serious pests of mango.
Hoppers have small sized wedge shaped body. Both nymphs and adults suck the sap from tender leaves, buds, flowers, flower stalk and fruits.
Severely infested leaves become curled and inflorescences get dried. In addition to direct damage, hoppers excrete honeydew on the infested plant parts which encourages the growth of fungal pathogen that form a sooty mould on the infested areas.
Favourable season
They are present throughout the year but are abundant only during the flowering season. The nymphs mature during June to October (feed and breed on the vegetative shoots) and January to March (breed on the flowers and inflorescence).
Egg laying
Adult female lays about 200 eggs singly by penetrating them into the midrib of the young leaves, shoots, flower stalks and unopened flowers.
Eggs are dull white in colour initially which later turn into light brown. The incubation period varies from 4 to 8 days.
After hatching from eggs, the nymphs are pinkish in colour which later turn into pale brown with prominent red bulged eyes along with long black coloured bristles on abdomen.
Nymphal period is 10-14 days. Female can be identified with the sickle shaped ovipositor. Adult longevity varies between three and four days.
Pest management
Avoid dense planting. Adopt resistant varieties and avoid susceptible varieties such as Baneshan, Chinnarasam, Bangalora, Khadar, Gaddemar, Rumani and Himayuddin ( Padiri, Neelam, Mulgoa, Peter and Sindura varieties are highly susceptible).
Orchards must be kept clean by ploughing and removal of weeds.
Remove over crowded, overlapping and infected branches.
Spray Phosalone 35 EC 1.5ml/ litre (or) Carbaryl 50WP 3gm/litre (or) Monocrotophos 36 WSC 1.25 ml/ litre.
Two rounds, first at the time of panicle emergence and the second two weeks later.
Spray 3 per cent neem oil or neem seed kernel powder extract 5 per cent.
M. KANNAN, M. KALYANASUNDARAM & P. SIVASUBRAMANIAN
TAMIL NADU AGRICULTURAL UNIVERSITY, COIMBATORE,
Friday, December 19, 2008
Thursday, December 4, 2008
Management of bacterial wilt in tomato
Management of bacterial wilt in tomato
Diseases are a major hurdle in tomato cultivation, both under controlled and field conditions.
Among them bacterial wilt is most devastating on tomato causing yield losses up to 90 per cent.
The disease is also known as southern bacterial blight or solanaceous wilt. Rapid and complete wilting of normal grownup plants is a characteristic symptom of bacterial wilt.
During warm and wet climatic conditions most conspicuous symptom of sudden drooping of leaves, without yellowing, often accompanied by rotting of the stem are seen. The roots appear healthy and well developed. Cultural management
The disease can be kept under check if crop rotations are followed with crops such as maize, ragi and okra, since they can reduce the pathogen population significantly.
Soil solarisation combined with fumigation reduces the pathogen considerably.
Destruction of weeds, collateral hosts and other off season hosts will reduce the innoculum potential. Application of sawdust
Application of sawdust, peatmoss are efficient in reducing the incidence.
Application of nitrite form of fertilizers is also capable of reducing the bacterial population.
Calcium concentration in soil should be increased to have better control of wilt disease.Chemical control
Soil treatment with chloropicrin, methyl bromide or mixture of both were found effective in retarding the wilt development.
Application of bleaching powder (15kg/ha) has also been found effective against this disease.
Seedling dip with streptocycline avoids early invasion and infection by the pathogen through wounds formed during transplanting.
Bacterinol-100 can be used as dry seed dresser, for nursery spray and field application. Streptomycin sulphate or oxytetracycline when sprayed at 200ppm at 7 days interval provides good control.
Tomato varieties such as Arka Abha, Sonali, DPT-38 and Arka Alok which are resistant to bacterial wilt can be used for cultivation.Biological management
Several biological control agents such as Pseudomonas fluorescens, Bacillus licheniformis, B. cereus, B. subtilis and mycorrihiza are very effective in delaying and reducing the wilt development.
Mallikarjun Y
, Kenganal
& Byadgi, A. S.
Department of Plant
Pathology, UAS, Dharwad
Diseases are a major hurdle in tomato cultivation, both under controlled and field conditions.
Among them bacterial wilt is most devastating on tomato causing yield losses up to 90 per cent.
The disease is also known as southern bacterial blight or solanaceous wilt. Rapid and complete wilting of normal grownup plants is a characteristic symptom of bacterial wilt.
During warm and wet climatic conditions most conspicuous symptom of sudden drooping of leaves, without yellowing, often accompanied by rotting of the stem are seen. The roots appear healthy and well developed. Cultural management
The disease can be kept under check if crop rotations are followed with crops such as maize, ragi and okra, since they can reduce the pathogen population significantly.
Soil solarisation combined with fumigation reduces the pathogen considerably.
Destruction of weeds, collateral hosts and other off season hosts will reduce the innoculum potential. Application of sawdust
Application of sawdust, peatmoss are efficient in reducing the incidence.
Application of nitrite form of fertilizers is also capable of reducing the bacterial population.
Calcium concentration in soil should be increased to have better control of wilt disease.Chemical control
Soil treatment with chloropicrin, methyl bromide or mixture of both were found effective in retarding the wilt development.
Application of bleaching powder (15kg/ha) has also been found effective against this disease.
Seedling dip with streptocycline avoids early invasion and infection by the pathogen through wounds formed during transplanting.
Bacterinol-100 can be used as dry seed dresser, for nursery spray and field application. Streptomycin sulphate or oxytetracycline when sprayed at 200ppm at 7 days interval provides good control.
Tomato varieties such as Arka Abha, Sonali, DPT-38 and Arka Alok which are resistant to bacterial wilt can be used for cultivation.Biological management
Several biological control agents such as Pseudomonas fluorescens, Bacillus licheniformis, B. cereus, B. subtilis and mycorrihiza are very effective in delaying and reducing the wilt development.
Mallikarjun Y
, Kenganal
& Byadgi, A. S.
Department of Plant
Pathology, UAS, Dharwad
Thursday, November 13, 2008
Suppression of rice leaf mite pest
Suppression of rice leaf mite pest
The rice leaf mite Oligonychus oryzae has attained pest status in the Cauvery delta regions of Tamil Nadu.
The infestation starts from the nursery till stem elongation stage. Leaf mites feed on upper and lower surface of rice leaves.
Usually they are more numerous on lower surface than upper surface.
The mites are small and microscopic and pierce the leaf tissues and suck the sap. They multiply very fast under congenial conditions and damage the entire leaf portion.Life cycle
The entire life cycle can take 8-12 days. The adults are sexually mature when they emerge and mate as soon as possible.
Egg laying begins in 1-3 days. Flattened spherical straw coloured eggs are laid singly in rows along the leaf midribs and veins. Incubation lasts 4-9 days.
This is followed by the three immature stages — larva, protonymph and deutonymph.
This mite is active and breeds throughout the year building large populations during hot weather when the life cycle lasts the shortest time.
The damage is most serious during summer months when the temperature is high and humidity is low compared to winter and rainy seasons.Management
Use chisel ploughing once in four years. Maintain the organic carbon content of the soil at optimum level.
Create a rice free period by ploughing down stubbles between crops or fallow crops with pulses and green manures in endemic areas. Maintain the bunds free from weeds.
Provide seed treatment/seedling treatment/main field application with pseudomonas flourescens at 10g/kg of seeds; 2.5 kg/ha seedlings; 2.5 kg/hectare of main field.
Top dress urea with neem cake (5:1) with LCC (leaf colour chart) based N to avoid excess nitrogen application and top dress with 50 per cent potash fertilizer.
In case of severity of mites foliar spraying of acaricides such as diafenthiuron 50WP 900 gm/ha or fenpyroximate 5SC 600ml/ha with wettable sulphur 40 WP 1.5 kg/ha if needed is recommended. .
S.M. Jalaluddin
Ravi G. & S. Jebaraj
Tamil Nadu Rice Research Institute, TNAU, Aduthurai , Tamil Nadu
The rice leaf mite Oligonychus oryzae has attained pest status in the Cauvery delta regions of Tamil Nadu.
The infestation starts from the nursery till stem elongation stage. Leaf mites feed on upper and lower surface of rice leaves.
Usually they are more numerous on lower surface than upper surface.
The mites are small and microscopic and pierce the leaf tissues and suck the sap. They multiply very fast under congenial conditions and damage the entire leaf portion.Life cycle
The entire life cycle can take 8-12 days. The adults are sexually mature when they emerge and mate as soon as possible.
Egg laying begins in 1-3 days. Flattened spherical straw coloured eggs are laid singly in rows along the leaf midribs and veins. Incubation lasts 4-9 days.
This is followed by the three immature stages — larva, protonymph and deutonymph.
This mite is active and breeds throughout the year building large populations during hot weather when the life cycle lasts the shortest time.
The damage is most serious during summer months when the temperature is high and humidity is low compared to winter and rainy seasons.Management
Use chisel ploughing once in four years. Maintain the organic carbon content of the soil at optimum level.
Create a rice free period by ploughing down stubbles between crops or fallow crops with pulses and green manures in endemic areas. Maintain the bunds free from weeds.
Provide seed treatment/seedling treatment/main field application with pseudomonas flourescens at 10g/kg of seeds; 2.5 kg/ha seedlings; 2.5 kg/hectare of main field.
Top dress urea with neem cake (5:1) with LCC (leaf colour chart) based N to avoid excess nitrogen application and top dress with 50 per cent potash fertilizer.
In case of severity of mites foliar spraying of acaricides such as diafenthiuron 50WP 900 gm/ha or fenpyroximate 5SC 600ml/ha with wettable sulphur 40 WP 1.5 kg/ha if needed is recommended. .
S.M. Jalaluddin
Ravi G. & S. Jebaraj
Tamil Nadu Rice Research Institute, TNAU, Aduthurai , Tamil Nadu
Thursday, November 6, 2008
Managing fruit borer menace in pomegranate
Managing fruit borer menace in pomegranate
Pest incidence is more during rains
Pomegranate faces a serious set back due to infestation by insect pests. The most obnoxious is Anar butterfly(Deodorex isocrates.)
The larvae of this insect directly bore into the pomegranate fruit. There are no satisfactory control measures for the pest after it enters into the fruits. Peak infestation
The incidence of the pest is at its peak during the month of August during monsoon season, while in winter crop it is more during November/December.
The female butterfly lays eggs on flowers-buds and the calyx of developing fruits; in a few days the caterpillars enters the fruit and feed on the pulp.
The conspicuous symptoms of damage are offensive smell and the excreta from holes. The fruits rot and drop off.
The fruit borers may cause loss of an entire crop unless the flowers are sprayed two times 30 days apart.
All the pomegranate varieties are susceptible to the pomegranate butterfly infestation.Management
— Bagging of fruits with butter paper before maturity should be done in isolated and smaller scale.
— Remove and destroy all the affected fruits (fruits with exit holes).
— Removal of flowering weeds, should be carried out on a regular basis.
— Frequent release of egg parasitoid Trichogramma species was found effective in controlling the pest.
— Spray Deltamethrin at 0.002 per cent at the time when more than 50 per cent of fruits are set. Repeat after two weeks with Carbaryl at 0.2 per cent or Fenvalerate at 0.005 per cent in non-rainy season. Quinalphos at 0.06 per cent is also effective.
— Malathion (0.1 per cent) spray and covering the fruits with butter paper bags recorded the highest fruit yield per tree.
D. N. Kambrekar S. B. Kalaghatagi & S. B. Jagginavar Regional Agricultural Research Station, Bijapur Karnataka
Pest incidence is more during rains
Pomegranate faces a serious set back due to infestation by insect pests. The most obnoxious is Anar butterfly(Deodorex isocrates.)
The larvae of this insect directly bore into the pomegranate fruit. There are no satisfactory control measures for the pest after it enters into the fruits. Peak infestation
The incidence of the pest is at its peak during the month of August during monsoon season, while in winter crop it is more during November/December.
The female butterfly lays eggs on flowers-buds and the calyx of developing fruits; in a few days the caterpillars enters the fruit and feed on the pulp.
The conspicuous symptoms of damage are offensive smell and the excreta from holes. The fruits rot and drop off.
The fruit borers may cause loss of an entire crop unless the flowers are sprayed two times 30 days apart.
All the pomegranate varieties are susceptible to the pomegranate butterfly infestation.Management
— Bagging of fruits with butter paper before maturity should be done in isolated and smaller scale.
— Remove and destroy all the affected fruits (fruits with exit holes).
— Removal of flowering weeds, should be carried out on a regular basis.
— Frequent release of egg parasitoid Trichogramma species was found effective in controlling the pest.
— Spray Deltamethrin at 0.002 per cent at the time when more than 50 per cent of fruits are set. Repeat after two weeks with Carbaryl at 0.2 per cent or Fenvalerate at 0.005 per cent in non-rainy season. Quinalphos at 0.06 per cent is also effective.
— Malathion (0.1 per cent) spray and covering the fruits with butter paper bags recorded the highest fruit yield per tree.
D. N. Kambrekar S. B. Kalaghatagi & S. B. Jagginavar Regional Agricultural Research Station, Bijapur Karnataka
Management of false smut infestation in paddy
Management of false smut infestation in paddy
False smut of rice, once considered as a minor disease, has now become a serious disease in Tamil Nadu and also other rice growing states of India.
For the past three years, the disease incidence has been reported in many places in an alarming proportion.
The disease is caused by a fungus also known as Lakshmi disease of rice. Yield loss is not only due to the occurrence of the smut balls but also due to increased sterility of kernels adjacent to the smut balls. Affects grain quality
Usually, only a few grains in a panicle get infected. At severe infection, most of the grains in the panicles are affected by the disease. The disease not only reduces the yield but also affects the quality of grains or seeds.
Prominent high yielding rice varieties such as CO:43, CR:1009, ADT:38, ADT:39 and BPT:5204 are also found to be affected by the this infestation.
Due to fungal infection, individual grains of the panicles transform into greenish spore balls of velvety appearance.
Spore balls are small at first growing gradually to reach one cm or more in diameter and enclosing the floral parts. High moisture or rainfall accompanied by cloudy days during the period between flowering and maturity of grains favour the development of false smut. Management
Healthy seeds or seeds free from sclerotia should alone be used.
Early planted crop has less smut balls than the late planted crop.
At the time of harvesting, diseased plants should be removed and destroyed so that sclerotia do not fall in the field.
This will reduce primary inoculum for the next crop. Field bunds and irrigation channels should be kept clean to eliminate alternate hosts.
Excess application of nitrogenous fertilizer should be avoided.
Regular monitoring of disease incidence during rabi season is very essential.
Spraying of copper oxychloride at 2.5 g/litre or Propiconazole at 1.0 ml/litre at boot leaf and milky stages will be more useful to prevent the fungal infection.
A. Karthikeyan
& S. Jebaraj
Tamil Nadu Rice Research Institute, Aduthurai
Thanjavur , Tamil Nadu
False smut of rice, once considered as a minor disease, has now become a serious disease in Tamil Nadu and also other rice growing states of India.
For the past three years, the disease incidence has been reported in many places in an alarming proportion.
The disease is caused by a fungus also known as Lakshmi disease of rice. Yield loss is not only due to the occurrence of the smut balls but also due to increased sterility of kernels adjacent to the smut balls. Affects grain quality
Usually, only a few grains in a panicle get infected. At severe infection, most of the grains in the panicles are affected by the disease. The disease not only reduces the yield but also affects the quality of grains or seeds.
Prominent high yielding rice varieties such as CO:43, CR:1009, ADT:38, ADT:39 and BPT:5204 are also found to be affected by the this infestation.
Due to fungal infection, individual grains of the panicles transform into greenish spore balls of velvety appearance.
Spore balls are small at first growing gradually to reach one cm or more in diameter and enclosing the floral parts. High moisture or rainfall accompanied by cloudy days during the period between flowering and maturity of grains favour the development of false smut. Management
Healthy seeds or seeds free from sclerotia should alone be used.
Early planted crop has less smut balls than the late planted crop.
At the time of harvesting, diseased plants should be removed and destroyed so that sclerotia do not fall in the field.
This will reduce primary inoculum for the next crop. Field bunds and irrigation channels should be kept clean to eliminate alternate hosts.
Excess application of nitrogenous fertilizer should be avoided.
Regular monitoring of disease incidence during rabi season is very essential.
Spraying of copper oxychloride at 2.5 g/litre or Propiconazole at 1.0 ml/litre at boot leaf and milky stages will be more useful to prevent the fungal infection.
A. Karthikeyan
& S. Jebaraj
Tamil Nadu Rice Research Institute, Aduthurai
Thanjavur , Tamil Nadu
Management of bacterial wilt in tomato
Management of bacterial wilt in tomato
Though several diseases are major hurdles in its cultivation, bacterial wilt is most devastating causing severe tomato yield losses up to 90 percent. The disease is also known as southern bacterial blight or solanaceous wilt.Common symtoms
Rapid and complete wilting of normal grownup plants is a characteristic symptom of bacterial wilt.
During warm and wet climatic conditions the most common symptom of sudden drooping of leaves, without yellowing, often accompanied by rotting of the stem are seen.
The disease is caused by a bacterium Ralstonia solanacearum, that infects more than 200 plant species. The pathogen is soil borne and survives for 2 years in absence of any host. How it spreads
It is found in soil up to 45cms depth and spreads through irrigation water, soil movement, implements and infected plant material.
It is more severe in sandy loam soil and is favoured by high temperature (30-35{+o}C) and high soil moisture.
The bacterium enters through wounds created during transplanting, cultivation, by insects or nematodes invasion.
Wilt occurs within 2-5 days after infection depending upon host susceptibility, temperature and virulence of the pathogen.Management
— The disease can be kept under check if crop rotations are followed with crops such as maize, ragi and okra, since they can reduce the pathogen population significantly.
— Several biological control agents such as Pseudomonas fluorescens, Bacillus licheniformis, B. cereus, B. subtilis and mycorrihiza are effective in delaying and reducing the wilt development.
—Tomato seedlings can be treated with root dipped in Pseudomonas fluorescens before planting. .
—Application of bleaching powder (15kg/ha) has also been found effective against this disease.
—Bacterinol – 100 can be used as dry seed dresser for nursery spray and filed application.
— Varieties such as Arka Abha, Sonali, DPT-38 and Arka Alok which are resistant to bacterial wilt can be used for cultivation.
Mallikarjun Y Kenganal
& Byadgi, A.S.
Department of Plant Pathology
University of Agricultural Sciences, Dharwad
Though several diseases are major hurdles in its cultivation, bacterial wilt is most devastating causing severe tomato yield losses up to 90 percent. The disease is also known as southern bacterial blight or solanaceous wilt.Common symtoms
Rapid and complete wilting of normal grownup plants is a characteristic symptom of bacterial wilt.
During warm and wet climatic conditions the most common symptom of sudden drooping of leaves, without yellowing, often accompanied by rotting of the stem are seen.
The disease is caused by a bacterium Ralstonia solanacearum, that infects more than 200 plant species. The pathogen is soil borne and survives for 2 years in absence of any host. How it spreads
It is found in soil up to 45cms depth and spreads through irrigation water, soil movement, implements and infected plant material.
It is more severe in sandy loam soil and is favoured by high temperature (30-35{+o}C) and high soil moisture.
The bacterium enters through wounds created during transplanting, cultivation, by insects or nematodes invasion.
Wilt occurs within 2-5 days after infection depending upon host susceptibility, temperature and virulence of the pathogen.Management
— The disease can be kept under check if crop rotations are followed with crops such as maize, ragi and okra, since they can reduce the pathogen population significantly.
— Several biological control agents such as Pseudomonas fluorescens, Bacillus licheniformis, B. cereus, B. subtilis and mycorrihiza are effective in delaying and reducing the wilt development.
—Tomato seedlings can be treated with root dipped in Pseudomonas fluorescens before planting. .
—Application of bleaching powder (15kg/ha) has also been found effective against this disease.
—Bacterinol – 100 can be used as dry seed dresser for nursery spray and filed application.
— Varieties such as Arka Abha, Sonali, DPT-38 and Arka Alok which are resistant to bacterial wilt can be used for cultivation.
Mallikarjun Y Kenganal
& Byadgi, A.S.
Department of Plant Pathology
University of Agricultural Sciences, Dharwad
Controlling cocoa mealy bug
Controlling cocoa mealy bug
Pest attack is more in July-October
Cocoa is now becoming popular as a mixed crop in coconut plantations.
The cocoa mealy bug, Planococcus lilacinus is the most important insect attacking cocoa trees.
The nymphs and adults of mealy bug occur in colonies and infest growing shoots, terminal buds, flower stalks, foliage and pods and start sucking the sap.
Growth of followers is suppressed, young pods dry up, tender leaves are deformed into hair like structures.
Sunken patches in the developing pods result in the formation of scabs. Brown patches, irregular cracks and pits can be seen on mature pods.
The adults excrete honey dew on the leaves over which a sooty mould develops which in turn inhibits photosynthetic activities of the plant.Life history
Mealy bugs are small, oval and light yellow. Nymphs are usually disseminated by wind. A female can lay around 200 eggs which hatch into nymphs within six hours. Nymphal period lasts for 20-25 days.
Their incidence is maximum during July-October. Ants are attracted to the sugary substance excreted by the mealy bugs and thus ants serve as protective and carrying agents for them.Control methods
Neem oil suspension of 3 per cent may be sprayed on pods and foliage at the early state of nfestation.
Spray 0.05 per cent fenthion, dimethoate or phosalone.
Spot application of insecticide is to be undertaken when the population reaches above 15 per cent in the field.
The insecticide must be applied only after collecting the pods which are ready for harvesting.
Give a second round of spray after 30 days if the incidence persists.
Soil drenching of monocrotophos or dimethoate is also found to be effective.
Larvae of certain blue butterflies and coccinellid beetles are predaceous on the mealy bug in nature.
Release predatory lady bird beetles at 5-10 adults/tree.
Destroy ant nests to minimise the spread of the pest.
J. JAYARAJ & M. ANANTHAN
Horticultural Research Station, Thadiyankudisai Perumparai Dindigul, Tamil Nadu
Pest attack is more in July-October
Cocoa is now becoming popular as a mixed crop in coconut plantations.
The cocoa mealy bug, Planococcus lilacinus is the most important insect attacking cocoa trees.
The nymphs and adults of mealy bug occur in colonies and infest growing shoots, terminal buds, flower stalks, foliage and pods and start sucking the sap.
Growth of followers is suppressed, young pods dry up, tender leaves are deformed into hair like structures.
Sunken patches in the developing pods result in the formation of scabs. Brown patches, irregular cracks and pits can be seen on mature pods.
The adults excrete honey dew on the leaves over which a sooty mould develops which in turn inhibits photosynthetic activities of the plant.Life history
Mealy bugs are small, oval and light yellow. Nymphs are usually disseminated by wind. A female can lay around 200 eggs which hatch into nymphs within six hours. Nymphal period lasts for 20-25 days.
Their incidence is maximum during July-October. Ants are attracted to the sugary substance excreted by the mealy bugs and thus ants serve as protective and carrying agents for them.Control methods
Neem oil suspension of 3 per cent may be sprayed on pods and foliage at the early state of nfestation.
Spray 0.05 per cent fenthion, dimethoate or phosalone.
Spot application of insecticide is to be undertaken when the population reaches above 15 per cent in the field.
The insecticide must be applied only after collecting the pods which are ready for harvesting.
Give a second round of spray after 30 days if the incidence persists.
Soil drenching of monocrotophos or dimethoate is also found to be effective.
Larvae of certain blue butterflies and coccinellid beetles are predaceous on the mealy bug in nature.
Release predatory lady bird beetles at 5-10 adults/tree.
Destroy ant nests to minimise the spread of the pest.
J. JAYARAJ & M. ANANTHAN
Horticultural Research Station, Thadiyankudisai Perumparai Dindigul, Tamil Nadu
Management of downy mildew in grape
Management of downy mildew in grape
Downy mildew is a highly destructive fungal disease of grapevines in all grape-growing areas of the world. Economic losses are associated with cluster destruction and loss of vine foliage resulting in the loss of photosynthetic area. Disease symptoms
Initial symptoms are light greenish yellow oily spots on the upper surface of the leaves.
These spots enlarge and coalesce to cover the entire leaf surface. On the corresponding lower surface glistening white downy growth of the fungus is seen which is more prominent in the humid weather.
In severe infection, the entire lower surface of the leaf would be covered with the dirty white downy growth of the fungus.
Severely affected leaves fall prematurely. Young shoots and tendrils turn brown and become stunted and distorted.
They become soft, emit fishy odour and are often swollen and may curl. Older shoots and nodes are more susceptible than internodes.
Flower clusters are highly susceptible. Infected inflorescences turn oily yellow to brown and may become whitish during periods of high humidity at night.
Sometimes only a part of the bunch is affected. When infection occurs early, clusters are covered with a grey mat of fungal material, which leads to rotting of berries.
The fungus grows internally on these berries causing a condition referred to as brown rot.
Infected fruit on white varieties turns dull green and black fruited varieties turn red. Berries eventually turn brown, fail to soften and become slightly wrinkled. Disease management
Grapevine orchards should be established in well-drained sites with good air movement.
Planting in rows makes natural patterns of air movement minimize leaf wetness.
Use of overhead irrigation should be avoided. Reducing leaf litter and pruning may reduce the amount of over wintering inoculum.
Five sprays of Bordeaux mixture, Blitox-50 (0.3 per cent), Zineb, Maneb and Mancozeb (0.2 per cent) and captan (0.2-0.5 per cnt) can be applied. Mallikarjun
Y Kenganal
Hemavati Ranebennur
& Byadgi, A. S.
Department of Plant
Pathology, UAS, Dharwad
Downy mildew is a highly destructive fungal disease of grapevines in all grape-growing areas of the world. Economic losses are associated with cluster destruction and loss of vine foliage resulting in the loss of photosynthetic area. Disease symptoms
Initial symptoms are light greenish yellow oily spots on the upper surface of the leaves.
These spots enlarge and coalesce to cover the entire leaf surface. On the corresponding lower surface glistening white downy growth of the fungus is seen which is more prominent in the humid weather.
In severe infection, the entire lower surface of the leaf would be covered with the dirty white downy growth of the fungus.
Severely affected leaves fall prematurely. Young shoots and tendrils turn brown and become stunted and distorted.
They become soft, emit fishy odour and are often swollen and may curl. Older shoots and nodes are more susceptible than internodes.
Flower clusters are highly susceptible. Infected inflorescences turn oily yellow to brown and may become whitish during periods of high humidity at night.
Sometimes only a part of the bunch is affected. When infection occurs early, clusters are covered with a grey mat of fungal material, which leads to rotting of berries.
The fungus grows internally on these berries causing a condition referred to as brown rot.
Infected fruit on white varieties turns dull green and black fruited varieties turn red. Berries eventually turn brown, fail to soften and become slightly wrinkled. Disease management
Grapevine orchards should be established in well-drained sites with good air movement.
Planting in rows makes natural patterns of air movement minimize leaf wetness.
Use of overhead irrigation should be avoided. Reducing leaf litter and pruning may reduce the amount of over wintering inoculum.
Five sprays of Bordeaux mixture, Blitox-50 (0.3 per cent), Zineb, Maneb and Mancozeb (0.2 per cent) and captan (0.2-0.5 per cnt) can be applied. Mallikarjun
Y Kenganal
Hemavati Ranebennur
& Byadgi, A. S.
Department of Plant
Pathology, UAS, Dharwad
Sugarcane early shoot borer management
Sugarcane early shoot borer management
Sugarcane is grown mainly during December - May in Tamil Nadu.
The main sugarcane planting seasons are categorized as early planting (Dec -Jan), mid planting (Feb - March) late planting (April - May) and special season (June - Sep) grown in parts of Tiruchirapalli, Perambalur, Karur, Salem, Namakkal and Coimbatore districts.
The crop grown in the special season is mostly damaged by early shoot borer and other insect pests. The pest damages mostly 1-3 months old crop.Symptoms
The caterpillars of the shoot borer cause dead hearts in young plants. The dead hearts in young plants formed at shoot stage can be pulled out easily. They emit foul odour and the canes are also damaged.
Small pale greyish brown moth lays white flat eggs in clusters of 8-60 eggs in 3 to 5 rows on the under surface of the leaf sheaths.
The larvae that hatch from the eggs in 1-6 days get scattered and enter the stem by making a hole just above the ground level. The larva may migrate and attack a number of shoots similarly. It becomes full grown in 25-30 days and pupates inside the stem. Adult moth emerges in 6-8 days. The total life cycle is completed in 35-40 days.Management
—Early season planting is ideal to evade the pest damage.
—Intercropping with green gram, black gram, daincha effectively checks shoot borer.
—Spray granulosis virus twice on 35 and 50 days after planting or release 125 gravid females of Sturmiopsis inferens/ha on 30 and 45 DAP
The virus should be applied with teepol (0.05 per cent) during evening hours immediately followed by irrigation.
A sticker like ‘teepol’ (250 ml for 500 I) can also be added to make the solution stick on to the surface of the crop.
N. Raju
D. Packiaraj
& S. Paneerselvam
TNAU, Sugarcane Research Station, Sirugamani
Tamil Nadu
Sugarcane is grown mainly during December - May in Tamil Nadu.
The main sugarcane planting seasons are categorized as early planting (Dec -Jan), mid planting (Feb - March) late planting (April - May) and special season (June - Sep) grown in parts of Tiruchirapalli, Perambalur, Karur, Salem, Namakkal and Coimbatore districts.
The crop grown in the special season is mostly damaged by early shoot borer and other insect pests. The pest damages mostly 1-3 months old crop.Symptoms
The caterpillars of the shoot borer cause dead hearts in young plants. The dead hearts in young plants formed at shoot stage can be pulled out easily. They emit foul odour and the canes are also damaged.
Small pale greyish brown moth lays white flat eggs in clusters of 8-60 eggs in 3 to 5 rows on the under surface of the leaf sheaths.
The larvae that hatch from the eggs in 1-6 days get scattered and enter the stem by making a hole just above the ground level. The larva may migrate and attack a number of shoots similarly. It becomes full grown in 25-30 days and pupates inside the stem. Adult moth emerges in 6-8 days. The total life cycle is completed in 35-40 days.Management
—Early season planting is ideal to evade the pest damage.
—Intercropping with green gram, black gram, daincha effectively checks shoot borer.
—Spray granulosis virus twice on 35 and 50 days after planting or release 125 gravid females of Sturmiopsis inferens/ha on 30 and 45 DAP
The virus should be applied with teepol (0.05 per cent) during evening hours immediately followed by irrigation.
A sticker like ‘teepol’ (250 ml for 500 I) can also be added to make the solution stick on to the surface of the crop.
N. Raju
D. Packiaraj
& S. Paneerselvam
TNAU, Sugarcane Research Station, Sirugamani
Tamil Nadu
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