%D 2006 %0 ARTICLE %T Mortality factors of eggs of Leptocorisa chinensis ( Hemiptera : Alydidae ) in rice fields . %J J Econ . Entomol . %V 99 ( 2 ) %P 366-72 %A Takeuchi H %A Watanabe T %M pub16686134 %X To clarify factors causing mortality of Leptocorisa chinensis Dallas ( Hemiptera : Alydidae ) eggs in rice fields , sentinel egg masses were exposed for seven days in two rice , Oryza sativa L ( Poaceae ) , fields . An insecticide was sprayed to remove natural enemies in one-half of each field before exposing egg masses to predation . An egg mass containing 14 eggs was glued to a plastic label , and 21 egg masses each were placed in the sprayed and unsprayed control plots . During exposure , the number of hatched and missing eggs was observed daily . Egg predators were sampled in the fields before and after insecticide application . After the egg masses were retrieved from the fields , mortality factors of the unhatched eggs were assessed in the laboratory . The mean number of hatched and missing eggs was not significantly different between the sprayed and control plots in field A In field B , however , the numbers were significantly different . The percentage of missing eggs in damaged egg masses ranged from 80 to 100% . In the laboratory , we observed that feeding marks caused by the grasshopper Conocephalus chinensis ( Redtenbacher ) were similar to those on the eggs exposed in the rice fields . The density of C chinensis was low in control plots of field A In contrast , the density was high in those of field B These observations suggest that the density of egg predators , eg , C chinensis , is a mortality factor of L chinensis eggs in rice fields .