Planting of wild Saccharum spontaneum in
paddy field for controlling leaf-folder

Wild sugarcane (Saccharum spontaneum) twigs of height 4 to 5 feet and 4 to 5 cm diameter are planted after 15 days of transplanting in rice field for control of leaf-roller. These erected branches harbour the predators at the time of occurrence of leaf-roller, thereby suppressing the incidence of pest. About 90% farmers in the Benakunda village of Ganjam district in Odisha adopt this practice. Wild sugarcane, Saccharum spontaneum grows near river banks on marshy lands. The plant is used by the farmers of Bhanjanagar area (Ganjam district) to control case worm in rice.

Results and discussion

Field experiments were carried out during the rainy (kharif) season of 2002, 2003 and 2004 at two locations, i.e. at (i) CRRI, Cuttack and (ii) farmers’ fields in the villages. At CRRI, Cuttack the treatments taken were: planting Saccharum spontaneum at 7 days after transplanting (DAT), 14 DAT, and after infestation, foliar spray of insecticide (imidacloprid) @ 0.05 kg ai/ha and untreated control. In farmers’ fields three treatments were used: planting of S. spontaneum at insect infestation, insecticide treatment, and untreated control.

Field experiments were carried out during the rainy (kharif) season of 2002, 2003 and 2004 at two locations, i.e. at (i) CRRI, Cuttack and (ii) farmers’ fields in the villages. At CRRI, Cuttack the treatments taken were: planting Saccharum spontaneum at 7 days after transplanting (DAT), 14 DAT, and after infestation, foliar spray of insecticide (imidacloprid) @ 0.05 kg ai/ha and untreated control. In farmers’ fields three treatments were used: planting of S. spontaneum at insect infestation, insecticide treatment, and untreated control.

Mode of action of S. spontaneum

Observations taken on the micro-ecosystem after planting of Saccharam spontaneum revealed the following facts

1. Almost all the leaves of S. spontaneum provided habitation for spiders.
2. Spider eggs were available in 65% of S. spontaneum implanted in both leaf surfaces and at the leafsheath portion.
3. Spider population was 2-3/m2 after 5 days of planting of S. spontaneum, which gradually increased to 6-8 after 15 days, with small spider nymphs all over the field.
4. Two types of spiders Araneus sp. and Oxyopes sp. were observed to kill and devour the larvae of leaf-folder.
5. Web formation was perhaps another mode of action for controlling the caseworm by trapping it at moth stage.
6. High rate of egg laying of some of the spiders