Scientific name: Atherigona oryzae (= samoaensis) Malloch

Common name: Rice seedling maggot, corn seedling maggot

Deadheart caused by the rice seedling maggot Atherigona oryzae Malloch A field with missing plants attacked by rice seedling maggot Yellowish gray adult of rice seedling maggot with distinct two to three pairs of dorsal black spots on lower half of yellow abdomen Elongated white egg of rice seedling maggot  Shiny yellow larva of rice seedling maggot Brown pupa of rice seedling maggot

Taxonomy:

Economic importance

Seedling maggots are restricted to upland rice environments. They are important during the seedling growth stage of the crop. The larvae cause deadhearts and a severe infestation may cause many missing hills in the field.

Geographical distribution

Australia, Bangladesh, Caroline Islands, China, India, Indonesia, Japan, Malaysia, Myanmar, Nepal, New Caledonia, Pakistan, Papua New Guinea, Philippines, Samoa, Singapore, Sri Lanka, Thailand, and Tonga.

Morphology

Egg
The eggs are white and 1.5 mm long. They are elongate and are laid singly or in small clusters on the leaf blades of the rice seedlings.

Larva
The larva is maggot-like. It is very shiny and yellow.

Pupa
The pupa is small and brown.

Adult
The adult fly is yellowish gray and about 3 to 3.5 mm long. It has an angular head with deep-set antennae and two to three pairs of dorsal black spots located on the lower half of the yellow abdomen.

Symptoms

Larval feeding causes the central tiller to dry, a condition known as deadhearts, which is similar to that caused by stem borers. Unlike the damage by stem borers, the dried tiller is rotten at the base when pulled.

The infested leaves are ragged in appearance. They are also discolored with transparent patches of damaged leaf tissue along the margins.

Biology and ecology

The seedling maggot is a serious pest of upland rice and corn seedlings. It is a strong flier and is active in daytime. It damages rice seedlings less than one month old.

The female can lay as many as 100 individual eggs in her life span of 3 to 7 days. The eggs are laid singly or in small clusters, which are glued to the leaf blades by a sticky substance secreted by the female. Egg incubation is 3 days and hatching occurs in the morning. The morning dew allows the maggot- like larva to move up and down the leaf blade, enter into a tiller, and feed on the internal tissue.

After passing through three larval instars in 6 to 10 days, the maggot pupates in the soil or within the base of the tillers or stem. Pupation is 8 days. The adult can live for 10 to 12 days.

Host range

Apart from the rice plant, the insect prefers maize, sorghum, wheat, sugarcane, Brachiaria distachya (L.) Stapf, B. ramosa (L.) Stapf, B. reptans (L.) Gard. & C.E. Hubb., Cymbopogon sp., Cynodon dactylon (L.) Pers., Digitaria ciliaris (Retz.) Koel., D. longiflora (Retz.) Pers., D. decumbens, Echinochloa colona (L.) Link, Eragrostis japonica (Thunb.) Trin., Eriochloa procera (Retz.) C.E. Hubb., Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult., Panicum psilopodium Trin., Paspalum sp., Pennisetum glaucum (L.) R. Br., Setaria intermedia Roem. & Schult., S. pumila (Poir.) Roem. & Schult., and Themeda quadrivalvis (L.) O.K.

Detection and inspection

Rice seedlings can be thoroughly inspected for the presence of white and elongated eggs, which are glued to the leaf blades by a sticky substance. The larvae are maggot-like and the adult is a yellowish gray fly with two to three pairs of black spots on the abdomen.

Management

Biological control
The eggs are parasitized by Trichogramma sp. and the larvae by Opius sp. and Tetrastichus sp. Spiders such as Araneus inustus (L. Koch), Argiope catenulata (Doleschall), Clubiona japonicola (Boes. & Strand), Lycosa pseudoannulata (Boes. & Strand), Neoscona theisi (Walckenaer), Oxyopes javanus (Thorell), Tetragnatha javana (Thorell), and T. nitens (Audouin) prey on the adults.

Selected references

Barrion AT, Litsinger JA. 1994. Taxonomy of rice insect pests and their arthropod parasites and predators. In: Biology and management of rice insects. Manila (Philippines): International Rice Research Institute. p 13-362.

Dale D. 1994. Insect pests of the rice plant: their biology and ecology. In: Heinrichs EA, editor. Biology and management of rice insects. Manila (Philippines): International Rice Research Institute. p 363-486.

Pont AC, Magpayo FR. 1995. Muscid shoot-flies of the Philippine Islands (Diptera: Muscidae, genus Atherigona Rondani). Bull. Entomol. Res. Suppl. No. 3:1-123.

Pont AC. 1986. Studies on the Australian Muscidae (Diptera) VII. The genus Atherigona Rondani. Aust. J. Zool. Suppl. No 120:1-90.

Reissig WH, Heinrichs EA, Litsinger JA, Moody K, Fiedler L, Mew TW, Barrion AT. 1986. Illustrated guide to integrated pest management in rice in tropical Asia. Manila (Philippines): International Rice Research Institute. 411 p.

Shepard BM, Barrion AT, Litsinger JA. 1995. Rice-feeding insects of tropical Asia. Manila (Philippines): International Rice Research Institute. 228 p.