Insect Pests of Vegetable, Tuber and Spice Crops

Serpentine leaf miner

2. Serpentine leaf miner, Liriomyza trifolii (Agromyzidae: Diptera)

Distribution: All over the world.

Host plants: Large number of host plants including tomato, capsicum, potato, black gram, cowpea, peas, beans, cruciferous crops, cucurbits, okra, cotton, many ornamental plants and weeds

Damage:

• Damage is caused by the larvae
• Feed on the palisade mesophyll tissue in between the two epidermis of the leaf.
• Infested leaves become transparent papery in the mined areas
• Photosynthesis is reduced.
• The attack appears during April and is more pronounced from June onwards.

Identification:

• Eggs: Newly laid eggs are white, translucent and turn opaque as the development advances.
• Larvae: The larvae are orange yellow, apodous. They move through peristaltic action between the two epidermis. Full-grown maggots are1.88 x 0.70 mm.
• Pupae: Orange yellow initially which turn dark-brown on maturity. They measure1.84 X 0.68 mm
• Adults: The adults are minute grayish black flies with plum red eyes and a yellow spot on the scutellum. The females are bigger (2.01x0.61mm) in size than males (1.79x0.52 mm).

Life cycle:

• Eggs hatch in 2-3 days
• First, second and third larval stages develop in 2-3, 1-3 and 5-7 days
• Pupal period lasts for 8-10 days.
• Preoviposition period 1-3 days
• Oviposition period is 8-15 days.
• Post-oviposition period is for 1-3 days.
• Male longevity is 8-12 days
• Fmales live up to13-17 days

Salient features

• The eggs are deposited singly in close proximity by embedding them in to the leaf tissue.
• Larvae feed through peristaltic action between the two epidermis
• Fecundity is 22-186 eggs
• Many generations in a year

Management:

• Judicious use of nitrogenous fertilizer reduces the build up of the pest in endemic areas.
• Severely infested leaves should be removed and destroyed.
• NSKE @ 4.0 per cent along with sticker is effective.
• The pest can be controlled by spraying the crop with triazophos (0.15%) or deltamethrin (0.0028%) or imidacloprid (0.0075%).
• Natural enemies especially larval and pupal parasitoids are active during July-August