Effects of sprinkle irrigation on the occurrence and abundance of Psorophora columbiae eggs in ricelands.

Low-pressure sprinkler irrigation was investigated as to its potential influence on the frequency of occurrence and relative abundance of Psorophora columbiae eggs in Texas ricelands. Analysis of egg sampling data collected from soybean, rice and sorghum field sites subjected to either sprinkle or flood irrigation practices during 1982-83 indicated no significant differences in either the frequency of occurrence or relative abundance of Ps. columbiae eggs in the various sites. Data collected during 1984 indicate that the amount of water applied to a field by a sprinkler system will have some influence on the numbers of Ps. columbiae eggs occurring in the field. The frequency of occurrence and relative abundance of Ps. columbiae eggs occurring in field sites sprinkle-irrigated at full-pan evaporation rates (i.e., all moisture in the soil lost to evaporation was replenished via irrigation) were significantly higher than was the case in the sites irrigated at half-pan and quarter-pan rates.