Nisaga simplex caterpillar on rice in western Orissa.
Observations were carried out on the biology of the eupterotid Nisaga simplex, which regularly causes damage in upland and medium rice fields in western Orissa, India. Adults emerged in June at the onset of the monsoon and oviposited on weedy growth in scrubby jungles and adjoining rice fields. The incubation period lasted 7-9 days. In the laboratory, 8 larval instars were completed in 68-76 days. Pupation took place in the soil. Larvae fed voraciously on the rib lamina, leaving only the midrib. In the field, the pest pupated in loose lateritic soil, often as deep as 30 cm, in October and overwintered until the following June. Weedy fields attracted larger populations than weed-free ones. The larvae also attacked maize, sorghum, finger millet, sugarcane and 15 weed species including Cynodon dactylon, Echinochloa sp., Leersia hexandra and Panicum repens.