El-Serwy, S.A., Guerrieri, E., & Evans, G.A. 2008 The parasitoid complex of the red-striped soft scale, Pulvinaria tenuivalvata (Newstead) (Hemiptera: Coccidae) and its long-term effect on the scale on sugarcane in Egypt.. Proceedings of the XI International Symposium on Scale Insect Studies, Oeiras, Portugal, 24-27 September 2007. ISA Press Lisbon, Portugal 322 pp.

Notes: Abstract. Leaves infested by the red-striped soft scale, Pulvinaria tenuivalvata (Newstead) (Hemiptera: Coccidae), were collected from untreated sugarcane, Saccharum officinarum L. in the Atfieh region Giza Govenorate, Middle Egypt) during October-November 2005 and October-December 2006. The level of parasitism, the population trend of the parasitoid complex and the role that each species plays in the regulation of the scale population was determined. Parasitoid activity in 2005 was low in late October (2%), peaked in mid November (14.7%) and began declining the following week (10.8%), with an overall mean level of 8.7%. In 2006, parasitoid activity began at a higher level in October (27.7%), peaked at 74% in early November then fell drastically to 20.7% in early December, with an overall mean of 35.5%. Nineteen species of parasitoids (Hymenoptera: Chalcidoidea), emerged from P. tenuivalvata, most of which had been previously reported from this species and some representing new distribution records for Egypt (as indicated with an asterisk *). Of these, the following nine species are primary parasitoids: Aphelinidae - Coccophagus semicircularis (Forster), Coccophagus obscurus Westwood, Coccophagus ochraceus Howard*; Encyrtidae - Metaphycus flavus (Howard), Metaphycus citricola Annecke & Mynhardt, Metaphycus sp., Microterys tricoloricornis (De Stefani), Parechthrodrynus coccidiphagus (Mercet) and Diversinervus elegans Silvestri; and the following ten species are hyperparasitoids (Hymenoptera: Chalcidoidea): Aphelinidae - Marietta leopardina Motschulsky, Ablerus chionaspidis (Howard) (= A. greatheadi Annecke & Insley); Encyrtidae - Cerapterocerus mirabilis Westwood, Cheiloneurus nr. victor Hoffer", Cheiloneurus paralia (Walker)*, Cheiloneurus latifrons Hayat, Alam & Agrawal", Mahencyrtus comara (Walker); Pteromalidae - Pachyneuron muscarum Linnaeus; Signiphoridae -, Chartocerus subaeneus (Forster) and Thysanus sp. The number of primary to secondary parasitoids was about 85:15 in 2005-6, and about 93:7 in 2006- -. The most abundant primary parasitoid species (in order of prevalence) were Coccophagus semicircularis, Metaphycus citricola and Metaphycus flavus. The first encyrtid and aphelinid individuals emerged in late October of 2005 and continued to emerge until the third week of December and m early January of 2006, respectively. During the second season, parasitoids began to emergence m October of 2006 and continued to emerge into February 2007. Cheiloneurus nr. victor was the most abundant hyperparasitoid, representing about 64% (in 2005-6) and 51 % (in 2006-7) of the total hyperparasitoids that emerged. Competition between the primary parasitoids, and the impact of Secondary parasitoids, resulted in decreased populations of Metaphycus citricola (28.3%), Parechthrodrimus coccidiphagus (6.2%), Microterys tricoloricornis (3.5%) and Diversinervus elegans (1%) from 2005-6 to 2006-7. However, their overall effect on the scale population may have been reduced by the increased numbers of Metaphycus flavus and Coccophagus ochraceus, from 0.3 to 22.3% and from 0.4 to 7.7%, respectively during the same period. The general decrease in the number of hyperparasitoids in 2006-7 could have been due to increased numbers of Coccophagus semicircularis and Coccophagus obscurus and the appearance of Coccophagus ochraceus, which had not been previously recorded as a parasitoid of P. tenuivalvata. Coccophagus semicircularis, Metaphycus citricola and Metaphycus flavus seem to be the most promising parasitoid species for use as biological control agents against the red-striped soft scale on sugarcane in Egypt.