Leafminer is a pest that damages vegetable crops like tomatoes. Its larvae burrow into and feed on leaf tissue, leaving winding tunnels that can cause leaves to drop prematurely and reduce crop yields. The leafminer has a 2-week lifecycle with multiple generations per year. Management strategies focus on conservation biological control using natural enemies like parasitic wasps. Cultural practices like removing old crop residues and selecting resistant varieties can also help reduce infestations. Chemicals should be avoided if possible to protect natural enemies, as the pest has developed resistance to many insecticides.

1. WEL-COME
Submitted by: Santosh pathak
IAAS, Lamjung

2. Presentation on Leafminer

3. Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Superfamily: Opomyzoidea
Family: Agromyzidae
Subfamilies
•Agromyzinae
•Phytomyzinae
•Genus and species:Liriomyza sativae Blanchard
General information

4. •A leaf miner is the larva of an insect that lives in and eat the leaf tissue of
plants. The vast majority of leaf-mining insects are moths(Lepidoptera),
sawflies (Symphyta) and flies (Diptera), though beetles and wasps also
exhibit this behavior
•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 ,India
and Nepal
• It is a polyphagous species affecting more than 78 annual plant species .
Introduction

5. •Adult leafminers typically look like small black and yellow flies,
although some insects look more silvery-gray in color.
•The larvae look like very small, yellowish-colored maggots feeding
on the undersides of the leaves.
•Check underneath the leaves for masses of tiny cream-colored, oval
eggs and crush any eggs that we find.
•Once hatched, the larvae leave a winding, white trail behind as they
feed, so keep an eye out for that symptom.
•The emergence of larvae takes place after 2-4 days.
•Then it feeds between the leaf surfaces, creating a meandering
track or "mine
Identification

6. Eggs in the mine Maggot
Pupa
Adult

7. 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.
Symptoms

8. 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.
Contd…………………..

9. 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.
Contd……………………………………………………

10. Biology
The lifecycle of leafminer is only 2 weeks in warm weather and 7-10
generation.
The developmental thresholds for eggs, larvae and pupae are estimated at 9
to 12˚c.
The combined development time required by the egg and larval stages is
about seven to nine days at warm temperature(25 to 30˚c).
Another seven to nine days is required for pupal development at these
temperatures.
Both eggs-larval and pupal development times lengthen to about 25 days at
15˚c.
At optimal temperatures(30˚c), the vegetable leaf miner completes
development from the egg to adult stage in about 15 days.

11. Life cycle of Leaf miner

12. Management
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.
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.
BiologicalControl
Several species of parasitic wasps, particularlyChrysocharis
parksi and Diglyphus begini, attack leafminer larvae; left
undisturbed, parasites often keep leafminers under control.

13. 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, we can
reduce early infestations in a new crop by removing old plantings
immediately after the last harvest.
Look for vegetable varieties that are less susceptible to leafminer
infestation, such as tomato cultivars with curled leaves.
 Don't plant any vegetables in areas where you've had previous
leafminer infestations. Always remove any remaining old plants at the
end of the growing season.

14. Chemical pesticides
It's better not to use any type of chemical controls to manage leafminer
infestations. Not only will the chemicals kill off the leafminer's natural
predators, but the insects have developed a resistance to insecticides
containing carbamates, pyrethroids and organophosphates.
Using any of those chemicals will likely make your leafminer populations
increase in size.
If we feel that you must use chemical controls, then Avermectin, a
microbially derived insecticide, seems to kill the leafminers but not their
predators.
The University of California recommends spraying Spinosad to control
leafminers on organically certified crops.

15. Mechanical control
Prune off and destroy any affected leaves on your infected vegetable
crops.
Protect small seedlings by covering them with a protective cloth or a
cold cap. Because leafminer adults are flying insects, covering your
plants should prevent the insects from landing and laying eggs.
It is particularly important to protect your leafy vegetable crops such
as lettuce and spinach because the feeding leafminers will damage the
edible part of the plant.

16. Summary and conclusion
Leaf miner is becoming major problems of vegetables especially in
tomatoes growing areas. So it s population should be remain under the
threshold level of damage by applying cultural, biological and physical
methods.

17. THANKYOU