Transcript Identification, Symptoms and nature of damage Leaf miner

Identification, Symptoms and nature
of damage: Leaf miner
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Identification, Symptoms and nature of damage: Leafminer
Introduction
•The scare was caused by a tiny but beautiful species of agromyzid fly,
Liriomyza trifolii (Burgess) that entered India accidentally probably,
during 1990-91.
•The native country of this pest is USA (Florida). It was introduced
probably along with cut chrysanthemum flowers during early 1970s to
California, USA .
•The fly was accidentally introduced into Kenya around the same period.
•It is now very widely spread in most countries including Pakistan and
India and has now spread to most of the states in India.
• It is a polyphagous species affecting more than 78 annual plant species
being especially serious on greens, cucurbits, tomato, castor and
ornamental plants
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Identification
•Adults look pale yellow in colour.
•Female thrust eggs into the epidermal layer of leaves.
•The emergence of larvae takes place after 2-4 days.
•Then it feeds between the leaf surfaces, creating a meandering track or "mine.“
• At high population levels, entire leaves may be covered with mines.
•Minute orange yellowish apodous maggots mature after 7-10 days then it
leaves the mines, dropping to the ground to pupate.
•The life cycle takes only 2 weeks in warm weather; there are seven to ten
generations a year.
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Maggot
Eggs in the mine
Adult
Pupa
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Symptoms
The severely affected leaves may drop.
Liriomyza leaf miner may act as vector of disease, kill seedlings, cause
reduction in crop yields, accelerate leaf drop thus exposing fruits like
tomato for sunburn and reduce aesthetic value of ornamental plants.
Maggots mines into leaves and causes serpentine mines drying and
drooping of leaves.
Life cycle of Leaf miner
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Nature of damage
The adult female makes punctures in the leaf tissue with
its ovipositor for both feeding and oviposition.
The ratio of oviposition punctures to feeding punctures
varies from 1:6 to 1:14.
The male also uses the feeding punctures made by
females for feeding.
The larvae that hatch out from the eggs mine the leaf
feeding on the mesophyll region leaving a serpentine
structure and thus the common name.
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Leafminer feeding results in serpentine mines (slender, white,
winding trails); heavily mined leaflets have large whitish blotches.
Leaves injured by leafminers drop prematurely; heavily infested
plants may lose most of their leaves.
If it occurs early in the fruiting period, defoliation can reduce yield
and fruit size and expose fruit to sunburn.
Pole tomatoes, which have a long fruiting period, are more
vulnerable than other tomato crops.
Leafminers are normally a pest of late summer tomatoes and can
reach high numbers.
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Management
The most important aspect of leafminer management is
conserving their natural enemies, which are often killed by broadspectrum insecticides applied for other tomato pests.
Reduce the risk of leafminer outbreaks by applying insecticides
for fruit pests only when monitoring shows treatment is needed
and by choosing insecticides that will not destroy the leafminer
parasites.
Biological
Control
Several species of parasitic wasps, particularlyChrysocharis
parksi and Diglyphus begini, attack leafminer larvae; left
undisturbed, parasites often keep leafminers under control.
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Cultural Control
Check transplants before planting and destroy any that are
infested; leafminers reach damaging levels earlier when
infestations begin on seedlings.
Where a series of tomato crops is planted in the same area,
you can reduce early infestations in a new crop by removing old
plantings immediately after the last harvest.
Organically Acceptable Methods
Biological and cultural controls as well as spray of formulation
of spinosad are acceptable for use on an organically certified
crop.
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Lets sum up
•Liriomyza trifolii (Burgess) that entered India accidentally probably, during
1990-91.
•The native country of this pest is USA (Florida). It was introduced
probably along with cut chrysanthemum flowers during early 1970s to
California, USA .
• It is a polyphagous species affecting more than 78 annual plant species
being especially serious on greens, cucurbits, tomato, castor and ornamental
plants
•The life cycle takes only 2 weeks in warm weather; there are seven to ten
generations a year.
The larvae that hatch out from the eggs mine the leaf feeding on the
mesophyll region leaving a serpentine structure and thus the common name.
Maggots mines into leaves and causes serpentine mines drying and
drooping of leaves.
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The most important aspect of leafminer management
is conserving their natural enemies, which are often
killed by broad-spectrum insecticides applied for other
tomato pests.
Several
species
of
parasitic
wasps,
particularlyChrysocharis parksi and Diglyphus begini,
attack leafminer larvae; left undisturbed, parasites often
keep leafminers under control.
Biological and cultural controls as well as spray of
formulation of spinosad are acceptable for use on an
organically certified crop.
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