Ecological aspects of Sassetia spp. ( Coccidae: Coccoidae: Hemiptera) and thier natural enemies in Egypt

In Egypt, Saissetia spp. (Coccidae: Coccoidae: Hemiptera) are the most dangerous soft scale insects infesting fruit trees. The aim of this work is to study the ecological aspects of Saissetia spp. and its natural enemies in Egypt. The result indicated that Genus Saissetia Deplanche comprises here by two species These are the soft brown scale, Saissetia coffeae (Walker) and the Mediterranean black scale, Saissetia oleae (Olvier). Genus Saissetia recorded here associated with 14 parasitoid species and 16 predator species. The seasonal abundance of S. coffeae was studied for two successive years from 2009-2010 on olive trees in Northern Coast .The obtained results showed that, the insect population reached maximum during mid September (7728 and 8368/ 60 leaves/30 twigs) in first year and second year, respectively. Numbers by parasitoids Metaphycus lounsburyi (Howard), Microterys flavus (Howard) and Scutellista cyanea Motschulsky and a predator Scymnus syriacus Mars., reached maximum (31,9,3, and19 /60 leaves/30 twigs) during September, July, September and August, in the first year, respectively and 20,8,2 and 15 during September in the second year, respectively. The seasonal abundance of S. oleae was studied for two successive years from 2009-2010 on olive trees in El-Arish. The obtained results showed that, the insect population reached maximum during mid of August (9729/ 60 leaves/30 twigs) in first year and mid of September (6899/ 60 leaves/30 twigs) in the second year. Numbers by the parasitoids, Metaphycus helvolus (Compere), Microterys flavus (Howard) and the predators, Coccinella undecimpunctata L. and Exochomus flavipes Thunb., reached maximum (22,5,8 and 28 /60 leaves/30 twigs) during August, August ,September and August, in the first year, respectively and 24,19,4 and 22 during September in the second year, respectively.

The damage of Saissetia spp., feed on plant juices, cause a loss of vigor, spots on the foliage due to toxins in the scale saliva, deformation of infested plant parts, loss of leaves, retarded plant growth, even death of the plant and causing premature death of pointed gourd vines (Valand et al., 1989 andCarvalho et al., 2003).Saissetia spp.are the most serious soft scale insects infesting fruit trees in Egypt (El-Minshawy et al., 1971,1974and Abd El-Razak, 2000).
The present work dealt with the ecological aspects of Saissetia spp.and its natural enemies in Egypt.

Infested leaves and twigs
of olive were examined in the field using a pocket magnification lens.Infested leaves and twigs were collected from different host plants and different locations in Egypt during 2009-2010.Identification of Saissetia spp. was done by examining adults in Canada Balsam.Also Infested leaves and twigs will be examined in the field, using a pocket lens.The leaves and twigs will be collected and placed separately in paper bags for further examination in the laboratory.Materials will be kept in a wellventilated container until the emergence of any natural enemies.Identification of natural enemies will be made by examining mounted adults in Hoyer's medium.Abundance of the populations of Saissetia sp. and their natural enemies were carried out on olive trees during 2009 and 2010 in El-Arish and Northern Coast.The plant areas selected for these investigations received no chemical control measures for several years.Twenty trees of olive almost similar in age, size, shape and growth condition were randomly chosen for sampling at twice a week intervals for each location.
On each biweekly sampling, 60 leaves and 15 twigs of olive were chosen at random.Thereafter, the leaves and twigs were kept in a closed paper bags and transferred to the laboratory for further examination and counting.For natural enemies each monthly sampling, 60 leaves and 15 twigs of olive trees were chosen randomly.Each leaf and twig were stored in a well-ventilated emergence glass tube and monitored daily for parasitoid emergence.Rate of parasitism was determined by dividing the number of emerging parasitoid from each by the number of hosts existing.Predators was counted in filed and transferred to the laboratory for further examination.Simple correlation and regression values were calculated to obtain information about the relationships between the three tested weather factors and the population of the pest and its natural enemies.

Abundance of Saissetia coffeae in Egypt:
The seasonal abundance of S. coffeae was studied for two successive years from 2009-2010 on olive trees in Northern Coast .The obtained results in Fig.

Metaphycus lounsburyi Microterys flavus Scutellista cyanea Scymnus syriacus
Data in Table ( 1), show that the simple correlation between the population of Metaphycus lounsburyi, Scymnus syriacus, maximum, minimum temperature, relative humidity% and the mean number of the soft brown scale, Saissetia coffeae were significant (r = 0.63, 0.60, 0.84, 0.79 and 0.81), respectively and non-significant (r = 0.41 and 0.38) between Microterys flavus (Howard) and Scutellista cyanea Motschulsky and the mean number of the soft brown scale during the 2009 .Also, results in Table (1), show that the simple regression for changing the population of Metaphycus lounsburyi, Scymnus syriacus, maximum, minimum temperature, relative humidity% and the mean number of S. coffeae were significant (b = 0.62, 0.66, 0.81, 0.80 and 0.78), respectively and non-significant (b = 0.37 and 0.32) between the Microterys flavus (Howard) and Scutellista cyanea Motschulsky and the mean number of the soft brown scale during the 2009.Data in Table (2), show that the simple correlation between the population of Metaphycus lounsburyi, Scymnus syriacus, maximum, minimum temperature, relative humidity % and the mean number of the soft brown scale, Saissetia coffeae were significant (r = 0.71, 0.68, 0.87, 0.82 and 0.85), respectively and non-significant (r = 0.36 and 0.29) between Microterys flavus (Howard) and Scutellista cyanea Motschulsky and the mean number of the soft brown scale during the 2010 .Also, results in Table (2), show that the simple regression for changing the population of Metaphycus lounsburyi, Scymnus syriacus, maximum, minimum temperature, relative humidity% and the mean number of S. coffeae were significant (b = 0.70, 0.69, 0.85, 0.84 and 0.73), respectively and non-significant (b = 0.31 and 0.30) between the Microterys flavus (Howard) and Scutellista cyanea and the mean number of the soft brown scale during the 2010.
S. coffeae had three generations, during April-May, June-July and August-September.The third generation overwinters as second nymphal instar from November till February (El-Minshawy and Saad, 1977).While Hanafi in the same year recorded 3-4 peaks for this soft scale.El-Agamy et al. (1994) recorded three generations of S. coffeae on guava trees in Kafr El-Sheikh governorate in May, August and October.Hendawy (1999) stated that S. coffeae had two duration's of activity, the first from October to November, while the second from May up to Hoda Badary 168 August, it is note worthy that the adults (usually females) are absent from December to February; Moursi (2010) found S. coffeae had three and two periods of activity during the first and second seasons, respectively.(1977) mentioned that Scutellista cyanea Motsch, was the most important enemy attacking S. coffeae.This parasitoid was prevent on S. coffeae and S. oleae from August to November and on C. floridensis in March and September (El-Minshawi et al., 1978).Abd-Rabou (2001b) studied the dynamic of the hemispherical scale, Saissetia coffeae (Walker) in Alexandria.He recorded the total rate of parasitism reached 27.0%, out of which M. helvolus was responsible for 13 %.In the Northern Coast region, the total rate of parasitism reached 31.9% out of which C. lycimnia was resposible for 10.6%.M. helvolus was collected from all investgated locations.Moursi. (2010) C. bipustulatus, S. syriacus, Pharaoscymnus Varius Kirsch and R. cardinalis were found feeding on some soft scale insects and Chrysop sp.larvae are very common and polyphagous predators feeding on many soft scale insects (Hamed and Hassanein, 1991).C. bipustulatus, S. syriacus, C. carnea, C. septempunctata and Orius laevigatus Fab.Recorded associated with different species of soft scale insects in Kafr El-Sheikh (El-Agamy et al., 1994).

The Mediterranean black scale, Saissetia oleae (Olvier) 4.2.1. Host Plants:
During the present work, Olea europaea was recorded as a host plant of S. oleae.The Meditterranean soft black scale S. oleae is a cosmopolitan and polyphagous soft scale pest of more than 60 plant species in the Mediterranean region, including citrus and olives (Carvalho et al. 2003).Abd El-Razak (2000) reported S. oleae (Oliver) from 6 host plant species.

4.2.3.2.Predators:
Twelve species of predators were recorded and collected from concerned specimen under investigation here found in Egypt.These are Coleoptera:
Data in Table (3), show that the simple correlation between the population of Metaphycus helvolus, Exochomus flavipes, maximum, minimum temperature, relative humidity% and the mean number of the soft brown scale, Saissetia coffeae were significant (r = 0.66, 0.71, 0.86, 0.77 and 0.74), respectively and non-significant (r = 0.27 and 0.31) between Microterys flavus, Coccinella undecimpunctata and the mean number of the soft brown scale during the 2009.Also, results in Table (3), show that the simple regression for changing the population of Metaphycus helvolus, Exochomus flavipes, maximum, minimum temperature, relative humidity% and the mean number of S. coffeae were significant (b = 0.71, 0.70, 0.84, 0.74 and 0.73), respectively and non-significant (b = 0.25 and 0.29) between the Microterys flavus, Coccinella undecimpunctata and the mean number of the soft brown scale during the 2009.4), show that the simple correlation between the population of Metaphycus helvolus, Exochomus flavipes, maximum, minimum temperature, relative humidity% and the mean number of the soft brown scale, Saissetia coffeae were significant (r = 0.73, 0.71, 0.89, 0.70 and 0.72), respectively and non-significant (r = 0.28 and 0.22) between Microterys flavus, Coccinella undecimpunctata and the mean number of the soft brown scale during the 2010 .Also, results in Table ( 4), show that the simple regression for changing the population of Metaphycus helvolus, Exochomus flavipes, maximum, minimum temperature, relative humidity % and the mean number of S. coffeae were significant (b = 0.72, 0.62, 0.88, 0.77 and 0.75), respectively and non-significant (b = 0.27 and 0.21) between the Microterys flavus, Coccinella undecimpunctata and the mean number of the soft brown scale during the 2010 .Abd-Rabou (2001a) conducted a survey of the parasitoids of S. oleae was carried out monthly between April 1995 and March 1997 in three different locations in Egypt.Five species of Encyrtidae, a species of Pteromalidae and an aphelinid hyperparasite were found.Three of these records were new for Egypt.The parasitoid, S. caerulea was recorded for the first time associated with S. oleae by Abd-Rabou (2004a).The parasitoid, S. caerulea which associated with S. oleae infested olive in Northern Coast.The maximum parasitism rate reached 38.2 and 40.9 % during the first and second years, respectively.While average parasitism rates was 21.3 and 23.5 % during the first and second years, respectively.Later, Abd-Rabou ( 2004) mass reared and released the parasitoid at monthly intervals in olive groves infested with S. oleae at three localities in Egypt and percentages of parasitism increased after releasing from 14 to35%.Abd-Rabou (2004b) studied the Indigenous parasitoid Metaphycus lounsburyi from different localities in Egypt, were manipulated, reared and mass-produced for classical biological control in Egypt, more than 193,130 parasitoids were released.Several releases were made between May 1999 and April 2001.Increases of the parasitism from 17.4 to 42.0 and from 6.4 to 19.2 during the first year (1999)(2000) and the second year (2000-01), respectively, in the Northern Coast.This parasitoid became established in some of the release sites in El-Arish and Matruh Governorates.Tena et al. (2008) Overall, the results show that the most abundant and widely distributed parasitoids of black scale in citrus and olive crops in eastern Spain are S. caerulea, M. flavus and M. lounsburyi.These parasitoids should be considered when determining the side effects of pesticides on beneficials, as an important component of Integrated Pest Management strategies.

Fig ( 1 )
Fig (1): Population dynamics of the soft brown scale, Saissetia coffeae on olive trees in Northern Coast region during 2009 and 2010.

Fig ( 4 )
Fig (4): Population dynamics of the Mediterranean black scale, Saissetia oleae on olive trees in Al-Arish region during 2009 and 2010.

Table 1 :
Simple correlation and regression values of the population dynamics of the soft brown scale, Saissetia coffeae and its parasitoid and predator on olive trees in Northern Coast Governorate during 2009.

Table 2 :
Simple correlation and regression values of the population dynamics of the soft brown scale, Saissetia coffeae and its parasitoid and predator on trees in Northern Coast Governorate during 2010.

Table 3 :
Simple correlation and regression values of the population dynamics of The Mediterranean black scale, Saissetia oleae and its parasitoid and predator on olive trees in Al-Arish region during 2009.

Table 4 :
Simple correlation and regression values of the population dynamics of The Mediterranean black scale, Saissetia oleae and its parasitoid and predator on olive trees in Al-Arish region during 2010.