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ABSTRACT
A biological study on Dicrodiplosis manihoti Harris (Diptera: Cecidomyiidae), the common predator of the mealy bug, Phenacoccus solenopsis Tinsley (Homoptera: Pseudococcidae) was carried out under the laboratory conditions of 32±2°C (in summer months) and 25±2°C (in autumn months). Results indicated that the incubation period of the predator's eggs averaged 2.15±0.06 and 3.28±0.06 days, respectively. Durations of larval stage were 8.78±0.19 and 13.78±0.23 days, while those of the pupal stage were 7.25±0.09 and 11.10±0.11 days at the two tested temperatures, respectively. Longevity of adult female was 2.23±0.05 and 3.9±0.12 days and the total number of eggs deposited/ female recorded 41.5±2.9 and 40.2±2.9 eggs at the two tested temperatures, respectively.
Key words: Dicrodiplosis manihoti, Phenacoccus solenopsis, Biological parameters.
INTRODUCTION
The cotton mealy bug, Phenacoccus solenopsis Tinsley was recorded recently for the first time in Egypt infesting Hibiscus sp. in September, 2009 (Abd-Rabou et al., 2010). P. solenopsis is a polyphagous pest and was recorded on 154 host plant species including, field crops, vegetables, ornamental, weeds, bushes and trees. Economic damage was observed on cotton, brinjal, okra, tomato, sesame, sunflower and China rose and reached plant death in severe conditions (Arif et al., 2009).
In Egypt, the cecidomyiid predator, Dicrodiplosis manihoti Harris was recorded for the first time in August 2013 at Alexandria, associated with the mealy bug, Phenacoccus gossypii Hall that infested Hibiscus rosasinensis L. (Rosaceae) (Skuhrava et al., 2014a). Geographical distribution of D. manihoti includes Afro-Asian, Senegal, Democratic Republic of Congo (Harris, 1981), Oman (Abbas, 1999), Iraq (Al-Rubeae et al., 2011) , Egypt (Skuhrava et al., 2014a) and Iran (Skuhrava et al., 2014b).
D. manihoti was recorded preying on cassava mealy bug, Phenacoccus manihoti Matile-Ferrero on cassava plant (Manihot esculenta Crantz) (Harris, 1981). Also, it was reared on the long tailed mealy bug, Pseudococcus longispinus (Targioni Tozzetti) that infested custard apple, citrus, copper leaf and Indian peach (Abbas, 1999). Moreover, D. manihoti was reared on the spherical mealy bug, Nipaecoccus vastator (Maskell) (Al-Rubeae et al., 2011), the Mexican mealybug, P. gossypii that infested H. rosa-sinensis L. (Skuhrava et al., 2014a), and the striped mealybug, Ferrisia virgata (Cockerell) and the citrus mealy bug, Planococcus citri (Risso) (Gagne and Jaschhof, 2014).
According...