Effect of temperature on biological characteristics and life table parameters of Dicrodiplosis manihoti Harris on cotton mealybug, Phenacoccus solenopsis Tinsley

Abstract

• Dicrodiplosis manihoti Harris is one of the most common fly species in mealybugs colonies. • The average egg produced by females D. manihoti decreased as the temperature increased. • The highest (0.0374 ± 0.0206) intrinsic rate of increase (r m ) was seen at 32 °C. • Dicrodiplosis. manihoti has a good potential to control of P. solenopsis . • The temperature of around 32 °C is the best for mass rearing D. manihoti. The cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is one of the polyphagous and destructive pests in the world. It has caused a lot of damage in cotton fields and settles on other host plants, especially Chinese hibiscus shrubs Hibiscus rosa-sinensis L. and causes irrecoverable damages to these ornamental plants and urban landscape. Midge fly Dicrodiplosis manihoti Harris (Dip.: Cecidomiidae) is one of the most common fly species which was collected in mealybugs colonies. In this study, the biology and age-stage, two-sex life table parameters of Dicrodiplosis manihoti, was evaluated at four constant temperatures (22, 27, 32 and 37 ± 1 °C, 65 ± 5 % RH and a photoperiod of 16: 8 (L: D) h) in the laboratory conditions. The developmental pre-adult period was found as 36.12 ± 0.38, 24.09 ± 0.41, 14.96 ± 0.34 and 12.68 ± 0.26 days and the average egg produced by females was 23.65 ± 2.86, 11.14 ± 2.09, 12.32 ± 3.94 and 8.57 ± 0.67 at those temperatures, respectively which decreased as the temperature increased from 22 to 37 °C, respectively. The population intrinsic rate of increase (r m ) was 0.0247 ± 0.0051, 0.0291 ± 0.0099, 0.0374 ± 0.0206 and 0.0103 ± 0.0129 (d -1 ), and the population finite rate of increase (λ) for the above mentioned temperatures was 1.0249 ± 0.0052, 1.0295 ± 0.0101, 1.0384 ± 0.0212 and 1.0104 ± 0.0130 (d -1 ), respectively. Also, the net reproductive rate (R 0 ) at the above mentioned temperatures was 2.62 ± 0.5, 2.19 ± 0.53, 2.05 ± 0.73 and 1.18 ± 0.22 offspring respectively. The shortest (T = 14.88 ± 0.45 days) and the longest (T = 38.28 ± 0.65 days) mean generation time was recorded at 37 and 22 °C, respectively. According to the results of this study D. manihoti has a good potential to control of Ph. solenopsis and the temperature of around 32 °C is the best for mass rearing this predator.