Biological studies of the cottony camellia scale , Puvinaria floccifera ( Hemiptera : Coccidae ) with updating lists of host palnts and natural enemies in Egypt

The cottony camellia scale, Pulvinaria floccifera (Westwood) (Hemiptera : Coccidae) is considered one of the most important pest infesting different crops in Egypt. The aim of this work is to study the survey of host plants and natural enemies of the cottony camellia scale P. floccifera in Egypt as well as the biological studies of the cottony camellia scale P. floccifera on citrus, fig and guava. The obtained results indicated that the list of host plant including 12 species recorded infested the cottony camellia scale, P. floccifera. Seven species recorded here for the first time in Egypt. Also, the updating lists including 14 parasitoid and 17 predator species, four and five species of parasitoids and predators recorded here for the first time in Egypt associated with the cottony camellia scale, P. floccifera, respectively. Temperatures greatly influenced the development of P. floccifera. The lowering of the temperature increased the dimension of the cottony camellia scale and prolonged the developmental period. The results on citrus, fig and guava showed that the life cycle of P. floccifera at 30C were 71.5±5.75, 80.7 ±5.00 and 58.7±0.35 days, respectively. These results indicated that the cottony camellia scale, P. floccifera prefers guava, followed by citrus and fig.


INTRODUCTION
The cottony camellia scale, Pulvinaria floccifera (Westwood) (Hemiptera: Coccidae) attacked 39 host plant species and distributed in different parts of the world (Ben-Dov,1993).They attack all parts of the plants, leaves, stem, bark, crowns and root.The severity of damage caused by this scale is graded according to the level of infestation.This followed by the appearance of honey dew on the leaves.Resulting in spread of sooty mould, then, more serious symptoms appear, such as the fall of leaves extending gradually to an almost complete defoliation and entire branch dryness on tree.Severe infestation do not result in the death of tree, but cause the reduction or even absence of yield for a number of years (Hamon and Williams, 1984).Hall, 1922, 1923and Ezzat and Hussein (1969) studied host plants of soft scale insects in Egypt including, P. floccifera.Natural enemies of P. floccifera recorded in Egypt by Abd-Rabou and Badary (2004).
The aim of this work is to study the survey of host plants and natural enemies of the cottony camellia scale P. floccifera in Egypt as well as the biological aspects of this pest on citrus, fig and guava at different temperatures.

Host plants of the cottony camellia scale, Pulvinaria floccifera:
Infested plants were examined in the field using a pocket magnification lens.Infested leaves, flowers or fruiting structures were collected from different host plants and different locations in Egypt.Identification of the cottony camellia scale, P. floccifera was done by examining adults in Canada Balsam.

Natural enemies of the cottony camellia scale, Pulvinaria floccifera:
Infested crops from different locations will be examined in the field, using a pocket lens.The parts of the plant from different locations will be collected and placed separately in paper bags for further examination in the laboratory.Materials will be kept in a well-ventilated container until the emergence of any natural enemies.Identification of natural enemies will be made by examining mounted adults in Hoyers medium.

Biological studies of the cottony camellia scale, Pulvinaria floccifera:
The cottony camellia scale P.floccifera was reared on three host plants i.e. citrus, fig and guava.For biological studies of the cottony camellia scale P. floccifera eggs and crawlers were obtained from mother P.floccifera reared on citrus, fig and guava under laboratory conditions 25-27°C, 65-75% RH and 18 hours Photoperiod.The incubation period of eggs was determined by using one day old egg of a mother soft scale.Fifty eggs from each host plant were spread on blotting paper in a small Petri dish.This Petri dish was in turn placed within a bigger dish containing some distilled water.The latter dish was covered with fine muslin so as to give maximum humidity to the eggs.The Petri dish containing the eggs was kept in a constant temperature incubator.Ten replicate Petri dish for each plant were kept at the following temperatures: 18°C, 24°C and 30°C.The procedure for determining egg viability was, similar to that of egg incubation.Fifty eggs from each host plant were kept in each Petri dish at the following temperatures: 18°C, 24°C and 30°C.Four replicate of Petri dish for host each were kept at each temperature regime.The eggs were observed daily with a stereomicroscope (X15) for the emergence of the crawlers.For studying the development of the soft scale, citrus, fig and guava washed with clean water.Newly emerged crawlers were transferred from the mother scale on to the leaves of citrus, fig and guava using a fine paint brush.Each pot was infested with 100 crawlers.The infested pot was then kept in a ventilated polystyrene box (175 mm X 115 mm X 52mm).Two boxes were kept at each of the temperatures used in the study.Twenty individual of P.floccifera exposed at each of the various constant temperatures were selected at random for studying their development.The development of the individual soft scale was observed daily using a stereomicroscope (x 15).

Natural enemies the cottony camellia scale, Pulvinaria floccifera in Egypt: 2.1. Updating list of parasitoids of the cottony camellia scale, P. floccifera in Egypt:
Abd- Rabou and Badary (2004)cies recorded infested with the cottony camellia scale, P. floccifera in Egypt.This list including 14 parasitoids species recorded associated with the cottony camellia scale, P. floccifera, four species recorded here for the first time in Egypt (astrix denote to new records).Abd-Rabou and Badary (2004) recorded ten parasitoid species recorded associated with the cottony camellia scale, P. floccifera in Egypt.This list including 17 predator species recorded associated with the cottony camellia scale, P. floccifera.Five species recorded here for the first time in Egypt.Abd- Rabou and Badary (2004)recorded 12 predator species associated with the cottony camellia scale, P. floccifera on Egypt.

Table 1 :
Average duration (in days) of the cottony camellia scale, Pulvinaria floccifera stages at three constant temperatures (18, 24 and 30°C) on citrus.

Table 2 :
Average duration (in days) of the cottony camellia scale, Pulvinaria floccifera stages at three constant temperatures (18, 24 and 30°C) on fig.