The rice whorl maggot is semi-aquatic. It is common in irrigated fields and feeds on the central whorl leaf of the vegetative stage of the rice plant. It does not occur in upland rice. The insect does not prefer direct-seeded fields and seedbeds. The adult is active during the day and rests on rice leaves near the water. It floats on the water or perches on floating vegetation. It prefers thick vegetation and is attracted to open standing water around seedbeds. Neonate maggots feed on the unopened central leaves where larval development is completed in 10-12 days. The full-grown maggots pupate outside the feeding stalk.
Rice whorl maggot: Hydrellia philippina Ferino (Diptera: Ephydridae)
Kannada name: Whorl maggot
Vernacular name: Adult whorl maggot
Period of occurrence: Central whorl leaf of the vegetative stage of the rice plant.
Alternate hosts: Its alternate hosts include grasses such as Brachiaria sp., Cynodon sp., Echinochloa sp., Leersia sp., Leptochloa sp., Panicum sp., and wild rice
Damaging stage of the insect: Maggot
Factors favouring insect damage:
- Standing water in paddies during the vegetative stage
- Host plants
- Transplanted young seedlings
- Standing water and thick vegetation near fields
- Feeding damage causes yellow spots, white or transparent patches and pinholes
Life cycle :
Eggs: The egg is whitish and elongate. It is banana-shaped with a hard shell covering
Maggot: Small, white or yellowish legless maggots are approximately five to seven mm in length.
Pupa: Pupae are elongate, tapered at both ends and brown colored
Adult: Adults are small gray to dark gray colored flies of about two to three mm in length.
Symptoms of damage:
- White or transparent patches
- Damaged leaves easily break from the wind
- Somewhat distorted leaves
- Clear or yellow spots on inner margins of emerging leaves
There is no cultural control for rice whorl maggot.
Small wasps parasitized the eggs and the maggots. Dolicopodid flies prey on the eggs and ephydrid flies and spiders feed on the adults.
Submitted by naipictuasdharwad on Fri, 30/01/2009 - 15:15