Cyrtobagous salviniae Calder & Sands

Adults of Cyrtobagous salviniae vary in length from 1.88 to 3.1 mm and in width from 1.2 to 16 mm. Females being larger than males. Newly emerged adults are light brown but darken to black within five days after elusion.

Mating occurs more than once, between 5 and 26 days after emergence and the female starts laying eggs within 6-14 days. Egg period lasts about 10 days. Newly emerged larvae are white and crescentric in, shape. They first feed on the leaves for two or three days then bore into the stem or unopened leaves. The three instars of the larval period are completed in 22-25 days. Pupation takes place within a cocoon (about 2.0 x 2.6 mm) spun by the larvae beneath surface of water in loose contact with living plant tissue. Pre-pupal and pupal periods are completed in 3 and 8-10 days respectively. Adults live for about 60 days.

Adults damage the leaf buds and young terminal leaves by extensive feeding. First instar larvae feed on the buds or roots while second and third instar tunnel within the apical rhizomes, causing the leaves first to darken in colour then to turn brown and finally drop off.

Fresh and healthy plants are placed in 5 liters plastic basin with fresh water. Each such basin can accommodate about 100 plants. Thereafter 20 pairs of adults are released (after pre-oviposition period is over) for three days and basins are covered with ventilated lids. After exposure adults are collected back. Generally adults hide inside buds or in rhizomes. While collecting adults back, care should be taken that the plants are not damaged. Exposed plants can be transferred in 61 x 40 x 30 cm opaque plastic troughs filled with water or in plastic fishing pools or cemented tanks. Exposure with same set of adults can be repeated for 15 times. Each through which can accommodate about 400 plants can yield 100-150 adults

Alternatively, Salvinia are released at the rate of about 5 per square meter. Fresh adults can be collected for field releases after 45 days. Collections can be made by placing fresh Salvinia plants among the browning weed-mat, on which the insects congregate.