Tuesday, June 23, 2009
Wednesday, April 8, 2009
Monday, April 6, 2009
Role of seed treatment in insect pest management
Role of seed treatment in insect pest management
Seed treatment is an application of chemicals to the seeds either at
the time of sowing or before sowing which is an alternative to
traditional foliar or soil treatment.
Efficient function
Application of insecticides to seeds before or at the time of sowing
offers the most effective means of protecting the germinating seed or
seedling.
The chemical insecticide is absorbed by the plant tissue and
transported in the sap through the entire plant through the vascular
system, right up to the top leaf.
Natural enemies
The pest ingests the chemical compounds along with the plant juice
that is lethal for them.
Natural enemy population such as coccinellids, spiders and chrysoperla
remain unharmed.
The efficacy of seed treatment depends upon a mulltitude of
interacting factors such as seed type, chemical formulation,
compatibility of materials, adjuvants and species of insects etc. Seed
treatment with lower doses of imidacloprid, at 5g/kg seed was found
effective in controlling jassids up to 60 days after emergence of crop
and higher seed cotton yield.
Treatment method
Treatment with marshal 25 DS at 80g/kg of seeds has recorded least
population of sucking pests and resulted in higher yield of sunflower.
Acetamiprid 20 SP at dosage of 25g a i/kg of seed protects cotton crop
up to 35 days against pests.
Seed treatment of sorghum with imidacloprid 70 WS at 15g/kg seeds or
thiamethoxam 70 WS at 10g/kg followed by foliar sprays after 30 days
with imidacloprid 17.8 SL at 0.01 per cent or thiamethoxam 25 WG at
0.01 per cent were found highly effective for the management of shoot
fly and stem borer.
Sharanabasappa
D. Satish
& Satyanarayan
Regional Agricultural Research Station, Raichur
& Department of Genetics and Plant breeding
College of Agriculture
UAS Dharwad
Seed treatment is an application of chemicals to the seeds either at
the time of sowing or before sowing which is an alternative to
traditional foliar or soil treatment.
Efficient function
Application of insecticides to seeds before or at the time of sowing
offers the most effective means of protecting the germinating seed or
seedling.
The chemical insecticide is absorbed by the plant tissue and
transported in the sap through the entire plant through the vascular
system, right up to the top leaf.
Natural enemies
The pest ingests the chemical compounds along with the plant juice
that is lethal for them.
Natural enemy population such as coccinellids, spiders and chrysoperla
remain unharmed.
The efficacy of seed treatment depends upon a mulltitude of
interacting factors such as seed type, chemical formulation,
compatibility of materials, adjuvants and species of insects etc. Seed
treatment with lower doses of imidacloprid, at 5g/kg seed was found
effective in controlling jassids up to 60 days after emergence of crop
and higher seed cotton yield.
Treatment method
Treatment with marshal 25 DS at 80g/kg of seeds has recorded least
population of sucking pests and resulted in higher yield of sunflower.
Acetamiprid 20 SP at dosage of 25g a i/kg of seed protects cotton crop
up to 35 days against pests.
Seed treatment of sorghum with imidacloprid 70 WS at 15g/kg seeds or
thiamethoxam 70 WS at 10g/kg followed by foliar sprays after 30 days
with imidacloprid 17.8 SL at 0.01 per cent or thiamethoxam 25 WG at
0.01 per cent were found highly effective for the management of shoot
fly and stem borer.
Sharanabasappa
D. Satish
& Satyanarayan
Regional Agricultural Research Station, Raichur
& Department of Genetics and Plant breeding
College of Agriculture
UAS Dharwad
Saturday, February 14, 2009
Control of late blight disease in tomato
Control of late blight disease in tomato
Late blight, caused by a fungus Phytophthora infestans, is one of the most devastating diseases of potato and tomato worldwide.
It first appears on the leaves and stems, and later on the fruits. Symptoms appear on leaves as pale green, water-soaked spots, often beginning at leaf tips or edges. The circular or irregular leaf lesions are often surrounded by a pale yellowish-gree n border that merges with healthy tissue. White mould growth
Lesions enlarge rapidly and turn dark brown to purplish-black. During periods of high humidity and leaf wetness, a cottony, white mould growth is usually visible on the lower leaf surface at the edges of lesions. In dry weather, infected leaf tissues quickly dry up and the white mould growth disappears.
Infected areas on stems appear brown to black and entire stem may be killed in a short time when moist weather persists.Fruit lesions
The fungus produces grey-green water-soaked spots which enlarge, coalesce, and darken, resulting in large, firm, brown, leathery-appearing lesions on fruits.
Cool nights and warm days with moist weather, which prevail during October-November, are the best conditions for development of the disease. Rain, fog or heavy dew are also ideal.Some management tips
— The disease is soil borne and can be managed by using integrated approaches to crop production and protection.
— Plant only healthy tomato transplants. Check to make sure plants are free of dark lesions on leaves or stems.
— Planting at recommended space (100 x 60cm), raising the crop in raised beds, removing infected fruits and staking of plants to avoid contact of fruits with soil for good air circulation is advisable.
— Spray at regular intervals. Begin chemical control programs before symptoms appear.
Copper hydroxoide(2g/lit) chlorothalonil (2g/liter) and mancozeb (2.5 g/liter) fungicides are the standard protectants used for control. They are usually applied every seven to ten days for best protection.
P.Chowdappa
Girija Ganeshan
& N.Ramachandran
Division of Plant Pathology
Indian Institute of
Horticultural Research
Bangalore
Late blight, caused by a fungus Phytophthora infestans, is one of the most devastating diseases of potato and tomato worldwide.
It first appears on the leaves and stems, and later on the fruits. Symptoms appear on leaves as pale green, water-soaked spots, often beginning at leaf tips or edges. The circular or irregular leaf lesions are often surrounded by a pale yellowish-gree n border that merges with healthy tissue. White mould growth
Lesions enlarge rapidly and turn dark brown to purplish-black. During periods of high humidity and leaf wetness, a cottony, white mould growth is usually visible on the lower leaf surface at the edges of lesions. In dry weather, infected leaf tissues quickly dry up and the white mould growth disappears.
Infected areas on stems appear brown to black and entire stem may be killed in a short time when moist weather persists.Fruit lesions
The fungus produces grey-green water-soaked spots which enlarge, coalesce, and darken, resulting in large, firm, brown, leathery-appearing lesions on fruits.
Cool nights and warm days with moist weather, which prevail during October-November, are the best conditions for development of the disease. Rain, fog or heavy dew are also ideal.Some management tips
— The disease is soil borne and can be managed by using integrated approaches to crop production and protection.
— Plant only healthy tomato transplants. Check to make sure plants are free of dark lesions on leaves or stems.
— Planting at recommended space (100 x 60cm), raising the crop in raised beds, removing infected fruits and staking of plants to avoid contact of fruits with soil for good air circulation is advisable.
— Spray at regular intervals. Begin chemical control programs before symptoms appear.
Copper hydroxoide(2g/lit) chlorothalonil (2g/liter) and mancozeb (2.5 g/liter) fungicides are the standard protectants used for control. They are usually applied every seven to ten days for best protection.
P.Chowdappa
Girija Ganeshan
& N.Ramachandran
Division of Plant Pathology
Indian Institute of
Horticultural Research
Bangalore
Thursday, January 29, 2009
Management of downy mildew in sunflower
Management of downy mildew in sunflower
Sunflower crop is among the top five commercial oilseed crops grown all over India.
Its cultivation is mainly hindered by diseases and pests. Among the diseases downy mildew is a serious obstacle in sunflower cultivation due to its systemic nature of infection.
Typical symptoms occur in seedling stage. Infested seedlings die, but those that survive produce stunted plants with erect, platform heads with no flowers. Drought stress
If any flowers are produced they remain sterile and bear no seeds. The infested plants serve to perpetuate the fungus in the soil and are more prone to drought stress and lodging.
The disease is initiated by soil borne dormant structures called oospores or infected seeds.
Oospores germinate during spring in wet soils. They can survive in the soil for five to 10 years.
Cool, water-saturated soil during this period greatly favours the infection spread.
Plants become increasingly resistant to infection with age, so systemic infections occurs over a short period (two to three weeks) after germination.
Irrigation water running through an infested field also may carry mildew spores into a previously disease-free field. Management
— Plant high quality certified seeds free from downy mildew pathogen.
— Practise a five-year or longer crop rotation between sunflower crops with non-hosts such as corn and small grains.
— Eliminate weeds that can serve as alternate hosts of downy mildew.
— Avoid reuse of irrigation water from sunflower fields and provide adequate but not excessive irrigation, especially early in the season.
— Seed treatment with metalaxyl 6gm/kg seed will reduce the infection during the seedling stage. Spraying of rydomil MZ 3gm/lit or metalaxyl 3gm/lit water helps in controlling foliar infection.
— Using resistant varieties. is a good practice.
Mallikarjun Y, Kenganal, Hemavati, Ranebennur & Byadgi, A. S.
Department of Plant Pathology
University of Agricultural Sciences,
Dharwad, Karnataka
Sunflower crop is among the top five commercial oilseed crops grown all over India.
Its cultivation is mainly hindered by diseases and pests. Among the diseases downy mildew is a serious obstacle in sunflower cultivation due to its systemic nature of infection.
Typical symptoms occur in seedling stage. Infested seedlings die, but those that survive produce stunted plants with erect, platform heads with no flowers. Drought stress
If any flowers are produced they remain sterile and bear no seeds. The infested plants serve to perpetuate the fungus in the soil and are more prone to drought stress and lodging.
The disease is initiated by soil borne dormant structures called oospores or infected seeds.
Oospores germinate during spring in wet soils. They can survive in the soil for five to 10 years.
Cool, water-saturated soil during this period greatly favours the infection spread.
Plants become increasingly resistant to infection with age, so systemic infections occurs over a short period (two to three weeks) after germination.
Irrigation water running through an infested field also may carry mildew spores into a previously disease-free field. Management
— Plant high quality certified seeds free from downy mildew pathogen.
— Practise a five-year or longer crop rotation between sunflower crops with non-hosts such as corn and small grains.
— Eliminate weeds that can serve as alternate hosts of downy mildew.
— Avoid reuse of irrigation water from sunflower fields and provide adequate but not excessive irrigation, especially early in the season.
— Seed treatment with metalaxyl 6gm/kg seed will reduce the infection during the seedling stage. Spraying of rydomil MZ 3gm/lit or metalaxyl 3gm/lit water helps in controlling foliar infection.
— Using resistant varieties. is a good practice.
Mallikarjun Y, Kenganal, Hemavati, Ranebennur & Byadgi, A. S.
Department of Plant Pathology
University of Agricultural Sciences,
Dharwad, Karnataka
Wednesday, January 7, 2009
Mealy bug — a new threat to cotton cultivation
Mealy bug — a new threat to cotton cultivation
Cotton crops in Punjab, Rajasthan, Maharashtra, Andhra Pradesh, Gujarat and Tamil Nadu are being seriously infested with mealy bugs during the last 2-3 cropping seasons.
In Tamil Nadu the pest has been observed in Salem, Coimbatore, Perambalur, Erode, and Virudhunagar districts.
Mealy bugs are small, soft bodied sucking insects which suck the sap from the stem, twigs, leaves, flower buds and young bolls. Sooty mould
A sugary liquid secreted by these insects falls on the leaves and serves as a medium for the growth of sooty mould, a fungus that reduces photosynthetic ability of the plant.
Adult female lays 400-600 eggs in a thin bag called ovisac and within 3-9 days young mealy bugs called crawlers emerge from the ovisac.
The crawlers actively spread through various means and settle down in 25-30 days.
The pest causes premature leaf drop, dieback and death of plants if unchecked.
Serious attack of the pest results in bunchy growth, plants remain stunted and produce fewer bolls. Heavy clustering of mealy bugs can be seen on lower surface of leaves giving the appearance of a thick mat with waxy secretion.
The honeydew excreted by the mealy bugs attracts ants which help in spreading of the pest and provide protection from predators and parasites.Management
—Field borders should be free from weeds.
—Crop residues with infestation should be removed and burnt.
—Plough the infested fields to expose the immature stages in the soil to the biotic and abiotic factors.
—Discourage growing alternate host plants such as hibiscus, okra, custard apple, guava in nearby cotton fields.
— Encourage cowpea as border crop on bunds and irrigation channels to enhance the multiplication of predatory insects.
— Ant fences should be treated with chlorpyriphos 20 EC at 2.5 ml/lit through drenching (or) by application of malathion dust 5 per cent at 25 Kg/ha .
B. Dhara Jothi &
N. Gopalakrishnan
Central Institute for Cotton Research
Regional Station
Coimbatore, Tamil Nadu Mealy bug — a new threat to cotton cultivation
Cotton crops in Punjab, Rajasthan, Maharashtra, Andhra Pradesh, Gujarat and Tamil Nadu are being seriously infested with mealy bugs during the last 2-3 cropping seasons.
In Tamil Nadu the pest has been observed in Salem, Coimbatore, Perambalur, Erode, and Virudhunagar districts.
Mealy bugs are small, soft bodied sucking insects which suck the sap from the stem, twigs, leaves, flower buds and young bolls. Sooty mould
A sugary liquid secreted by these insects falls on the leaves and serves as a medium for the growth of sooty mould, a fungus that reduces photosynthetic ability of the plant.
Adult female lays 400-600 eggs in a thin bag called ovisac and within 3-9 days young mealy bugs called crawlers emerge from the ovisac.
The crawlers actively spread through various means and settle down in 25-30 days.
The pest causes premature leaf drop, dieback and death of plants if unchecked.
Serious attack of the pest results in bunchy growth, plants remain stunted and produce fewer bolls. Heavy clustering of mealy bugs can be seen on lower surface of leaves giving the appearance of a thick mat with waxy secretion.
The honeydew excreted by the mealy bugs attracts ants which help in spreading of the pest and provide protection from predators and parasites.Management
—Field borders should be free from weeds.
—Crop residues with infestation should be removed and burnt.
—Plough the infested fields to expose the immature stages in the soil to the biotic and abiotic factors.
—Discourage growing alternate host plants such as hibiscus, okra, custard apple, guava in nearby cotton fields.
— Encourage cowpea as border crop on bunds and irrigation channels to enhance the multiplication of predatory insects.
— Ant fences should be treated with chlorpyriphos 20 EC at 2.5 ml/lit through drenching (or) by application of malathion dust 5 per cent at 25 Kg/ha .
B. Dhara Jothi &
N. Gopalakrishnan
Central Institute for Cotton Research
Regional Station
Coimbatore, Tamil Nadu
Cotton crops in Punjab, Rajasthan, Maharashtra, Andhra Pradesh, Gujarat and Tamil Nadu are being seriously infested with mealy bugs during the last 2-3 cropping seasons.
In Tamil Nadu the pest has been observed in Salem, Coimbatore, Perambalur, Erode, and Virudhunagar districts.
Mealy bugs are small, soft bodied sucking insects which suck the sap from the stem, twigs, leaves, flower buds and young bolls. Sooty mould
A sugary liquid secreted by these insects falls on the leaves and serves as a medium for the growth of sooty mould, a fungus that reduces photosynthetic ability of the plant.
Adult female lays 400-600 eggs in a thin bag called ovisac and within 3-9 days young mealy bugs called crawlers emerge from the ovisac.
The crawlers actively spread through various means and settle down in 25-30 days.
The pest causes premature leaf drop, dieback and death of plants if unchecked.
Serious attack of the pest results in bunchy growth, plants remain stunted and produce fewer bolls. Heavy clustering of mealy bugs can be seen on lower surface of leaves giving the appearance of a thick mat with waxy secretion.
The honeydew excreted by the mealy bugs attracts ants which help in spreading of the pest and provide protection from predators and parasites.Management
—Field borders should be free from weeds.
—Crop residues with infestation should be removed and burnt.
—Plough the infested fields to expose the immature stages in the soil to the biotic and abiotic factors.
—Discourage growing alternate host plants such as hibiscus, okra, custard apple, guava in nearby cotton fields.
— Encourage cowpea as border crop on bunds and irrigation channels to enhance the multiplication of predatory insects.
— Ant fences should be treated with chlorpyriphos 20 EC at 2.5 ml/lit through drenching (or) by application of malathion dust 5 per cent at 25 Kg/ha .
B. Dhara Jothi &
N. Gopalakrishnan
Central Institute for Cotton Research
Regional Station
Coimbatore, Tamil Nadu Mealy bug — a new threat to cotton cultivation
Cotton crops in Punjab, Rajasthan, Maharashtra, Andhra Pradesh, Gujarat and Tamil Nadu are being seriously infested with mealy bugs during the last 2-3 cropping seasons.
In Tamil Nadu the pest has been observed in Salem, Coimbatore, Perambalur, Erode, and Virudhunagar districts.
Mealy bugs are small, soft bodied sucking insects which suck the sap from the stem, twigs, leaves, flower buds and young bolls. Sooty mould
A sugary liquid secreted by these insects falls on the leaves and serves as a medium for the growth of sooty mould, a fungus that reduces photosynthetic ability of the plant.
Adult female lays 400-600 eggs in a thin bag called ovisac and within 3-9 days young mealy bugs called crawlers emerge from the ovisac.
The crawlers actively spread through various means and settle down in 25-30 days.
The pest causes premature leaf drop, dieback and death of plants if unchecked.
Serious attack of the pest results in bunchy growth, plants remain stunted and produce fewer bolls. Heavy clustering of mealy bugs can be seen on lower surface of leaves giving the appearance of a thick mat with waxy secretion.
The honeydew excreted by the mealy bugs attracts ants which help in spreading of the pest and provide protection from predators and parasites.Management
—Field borders should be free from weeds.
—Crop residues with infestation should be removed and burnt.
—Plough the infested fields to expose the immature stages in the soil to the biotic and abiotic factors.
—Discourage growing alternate host plants such as hibiscus, okra, custard apple, guava in nearby cotton fields.
— Encourage cowpea as border crop on bunds and irrigation channels to enhance the multiplication of predatory insects.
— Ant fences should be treated with chlorpyriphos 20 EC at 2.5 ml/lit through drenching (or) by application of malathion dust 5 per cent at 25 Kg/ha .
B. Dhara Jothi &
N. Gopalakrishnan
Central Institute for Cotton Research
Regional Station
Coimbatore, Tamil Nadu
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