Cyrtorhinus lividipennis Reuter

In addition to eggs and early stage nymphs of leaf and planthoppers Cyrtorhinus lividipennis feeds on eggs of other rice pests like rice hispa, gall midge and leaf-folder. As it plays an important role in preventing the flare up of natural population of brown plant hopper (BPH) and other pests, measures are often suggested for conservation of this predator. In endemic areas, timely augmentation could provide effective pest suppression.

The predator is multiplied on brown plant hopper (BPH) infested pot cultured rice plants kept in water filled trays in cages in a net house. Fifty Cyrtorhinus lividipennis adults are released in an oviposition cage containing BPH oviposited TN1 rice potted plants in zinc or enameled trays filled with water. The emerging nymphs of mirid bug feed on BPH eggs. A fresh stock of BPH oviposited plants is provided every fourth day. The developing mirid bugs are then transferred to another cage containing BPH oviposited plants for further multiplication.

The nymphs are then transferred to BPH oviposited. By continuously raising the plants, exposing them to BPH for oviposition and then exposing to mirid bug adults the supply line keeps moving. The mirid bug eggs hatch in 8.19 ± 1.17 days, four or five nymphal instars are completed in 12-13 days and about 80 percent of the nymphs survive upto adult stage with a sex ratio 1.33:1. The female adults live for 9.55± 2.19 days and males 7.33± 1.05 days. After a pre-oviposition period of 2.18±0.39 days each female lays about 26.9 ±18.43 eggs.

For multiplying Cyrtorhinus lividipennis on Corcyra cephalonica eggs a cage is fabricated from plastic petri-dishes and a piece of tri-acetate sheet. This type of cage does not get too dry or too wet avoiding water condensing on inner surface and preventing high insect mortality. The cage has two inter-connected compartments; the large upper part is meant for maintaining the insects and the small lower for storing water that keeps the muslin cloth floor of the upper part wet through a sponge piece. The three holes on the top are used for inserting food / water sachets and the insects. Although 90-95% RH is maintained in upper part yet water condensation on inner surface is avoided, the insects enjoy high moisture. The food is replenished periodically without any risk of insects getting away. Corcyra eggs are glued to a narrow piece of filter paper roll. On Corcyra eggs, 40% of the nymphs reach adult stage as compared to 53% on BPH eggs in rice seedlings. 49.4% of the adults settle on paper roll with Corcyra eggs. Each nymph consumes 7.5±1.3 Corcyra eggs per day. However, nymphal duration on Corcyra eggs is completed in 14.0± 0.4 days and on BPH eggs is 12.3±0.3 days. Emerging adults survive for 10.5±1.9 days and consume 9.84±1.2 eggs daily.

The gravid females readily deposit eggs on filter paper fold substrate though less in number (25/female) as compared to the rice seedlings (31/female). Eggs in the paper roll are incubated in closed screw cap vials. The entire life cycle of Cyrtorhinus lividipennis could be completed on Corcyra egg diet without resorting to maintenance of BPH culture on rice plants.