Effects of temperature, host plants, rainfall, and photoperiod on the population dynamics of the cotton fleahopper, Pseudatomoscelis seriatus (Reuter)

Abstract

Early nymphal mortality in the cotton fleahopper, Pseudatomoscelis seriatus (Reuter), was increased in constant temperatures below 23.6°C or above 29.4°C. Nymphal to adult stage survival in 40.6, 12.8 and 15.0°C regimens was low. No significant differences were found in preoviposition or oviposition periods or numbers of eggs deposited at different constant temperatures. However, fewer females deposited eggs in temperatures below 23.9°C or above 29.4°C. There was close agreement between theoretical thermal constants and observed thermal constants calculated for insects reared in constant, fluctuating and insectary conditions where temperatures were not extreme. Predictions of developmental rates at high or low temperatures were less accurate. During the time most fleahoppers are present in the field, the egg to egg thermal constant for fleahoppers reared on hosts as suitable as beans and potatoes is probably between 570 and 600°C-days above a developmental threshold of 7.0°C. Mortality and developmental rates of the cotton fleahopper were affected by the species and maturity of host plants. Survival was higher and development was faster on Croton sp. plants than on other hosts such as spotted beebalm, cutleaf primrose, and cotton. Also, survival and development rates were higher on flowering plants than on plants in a pre-flowering growth stage. Predictions of fleahopper development based on temperature data were affected by the host plant. Heat units required for total nymphal development varied from 98.2°C-days on flowering croton to l63.2°C-days on pre-flowering cutleaf primrose. ...