Thermal Requirments And Life Tables Of Dicrodiplosis manihoti (Diptera, cecidomyiidae) As A predator Of Phenacoccus parvus (hemiptera, pseudococcidae)

Document Type : Original Article

Authors

Plant Protection Research Institute, Agric. Res. Center, Giza, 12618, Egypt

Abstract

The effect of three degrees of temperature (20, 25 and 30oC) and 55-60% RH, on biological aspects of Dicrodiplosis manihoti Harris as a predator of Phenacoccus parvus Morrison was studied. Temperature of 30oC was the most suitable one for either development or reproduction.
Developmental times over tested temperatures revealed negative relation with temperature increase while developmental rates were positive. Female total developmental time was 43.3, 27.42 and 22.22 days at 20, 25 and 30oC, respectively. Corresponding rates were 0.02, 0.04 and 0.05 per day at same temperatures. These rates were fitted to linear equation with R2 = 0.98. Total thermal developmental requirement was 456.5 degree days over thermal threshold of 9.09oC. Male developmental times, rates and thermal requirement for development were very similar. Adults longevity was relatively short (i.e. less than 5 days). Oviposition duration was two days regardless tested temperature. Total female life cycle was 47.90, 30.68 and 24.44 days for females at tested temperatures. Corresponding values for male were 48.44, 30.5 and 24.54 days, respectively.  Fecundity per female was 32.10, 35.15 and 49.50 eggs/female over tested temperatures during its longevity of 4.80, 3.26 and 2.22 days, respectively.
Life table parameters showed highest values of net reproductive rate (Ro = 17.80), intrinsic rate of increase (rm = 0.12), finite rate of increase (exp. rm = 1.13) and the shortest mean generation time (23.92 days) at 30oC.

Keywords

Egyptian Academic Journal of Biological Sciences, F. Toxicology & Pest Control
Volume 7, Issue 1
December 2015
Pages 99-103

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