Laboratory studies were carried out in the lnsectary of Economic Entomology
Department, Faculty of Agriculture, Mansoura University, from the beginning of
September, 2004 till the end of December 2005 to evaluate the effect of mealybug
species as preys on the developmental time; feeding capacity and fecundity of
vedalia beetle Rodolfo cardinafis (Mulsant). The obtained results showed that, the
averages of the duration period of the predator larvae were 13.34 : 1.26; 15.23
1.73 and 12.23:1.95 days when reared on Pianococcus citn' (Risso): lcerya
seycheliarum (Westwood) and lcerya purchasr' Mask, ell respectively. The averages of
the total consumption during the larval stage were 76.93: 5.93: 53.22: 3.35 and
91.14: 5.91,of third nymphal instar individuals from the three tested mealybugs
respectively. The longevity period of the predator adult female, averages 40.45: 2.93
45.62: 2.40 and 36.53: 2.65 days when fed on P. cftri ; f. seychellarum and l
Purchasi, consecutively . The predator female consumed during its life span an
average of 413.32: 6.39; 305.54: 3.79 and 311.92: 6.75 of third nymphal instar
individuals when reared on the three tested mealybug species successively . The
average total number of eggs laid by female of R. cardinalr's through its life span was
significantly affected by the prey consumed by these female. The number of eggs
deposited per female reached an average of 350.76: 7.53; 296.47 : 22.35 and
420.35: 3.5 by rearing on the three previously mealybug species. During the
longevity period of the predator male, averages 25.73: 1.57; 30.56: 2.75 and 27.35
respectively 1.92 days, when this predator male fed on P. citri; l. seycheilarum and i
purchasi. The predator male consumed during its longevity period an average of
202.22: 5.94; 162.73: 2.56 and 175.35: 3.37 of third nymphal instar individuals of the
three previously mealybug species.
The statistical analysis showed that, there were highly significant differences
in the biological characteristics of R. cardinaiis larvae and adult when reared on P
citrr'; i. seycheliarum and l. Purchasi consecutively.
In conclusion, the results obtained assured R. cardinalis preferred as prey f
purchasi than P. citri and l. seychellarum, because this predator has a short
developmental time, a high predation efficiency and reproductive capacity when fed
on l. purchasr' and this predator can be used as biological control agent against the
three previously mentioned mealybug species.