The seasonal of the parasite complex of the red-striped soft scale, Pulvinaria tenuivalvata (Newstead), in Egypt was studied. Sugarcane (Saccharum officinarum L.) leaves infested by the soft scale were collected weekly from untreated fields in Atfieh region at Giza govenorate, Middle Egypt, from September 1999 to February 2000 and from September to December in 2001 and 2002. The highest rate of parasitism was recorded in 2001 (55.8%) whilst during 1999-2000 and 2002 those values were 43.5% and 37%, respectively. Eight species of primary parasitoids (Hymenoptera), i.e. Coccophagus semicircularis (Forster) and Coccophagus obscurus (Forster) (new record) (Aphelinidae), Metaphycus flavus (Howard), Metaphycus citricola Annecke & Mynhardt (new record) Microterys nietneri (Motschulsky), 'Parechthrodryinus coccidiphagus (Mercet) (new record), Comperia alfieri (Mercet) (new record) and Diversinervus elegans Silvestri (Encyrtidae) and six hyperparasitoids (Hymenoptera), i. e. Pachyneuron muscarum L. (Pteromalidae) , Marietta leopardina Motschulsky (new record) and Ablerus chionaspidis (Howard) (= A. greatheadi Annecke & Insley) (new record) (Aphelindae), Mahencyrtus comara (Walker) (new record), Cerapterocerus mirabilis Westwood (new record) and Cheiloneurus sp. (Encyrtidae) were identified. Ratios between primary and secondary parasitoids collected were 99: 1 (1999-2000), 94: 6 (2001-2002) and 96: 4 (2002-2003). M. flavus and M. citricola seem to be the most promising parasitoids to be used as biocontrol agents against the red-striped soft scale on sugarcane in Egypt. The former species was more abundant between late October and early March in 1999- 2000 and during mid and late September till mid- February in 2001-2002 and 2002-2003; in the same period, the most abundant hyperparasitoid was P. muscarum. Competition between primary parasitoids species resulted in a decrease of M. flavus and C. semicircularis collected during 1999-2000 to 2002-2003; probably their activity was replaced by that of M. citricola whose rate of parasitism increased from 12.5% to 31.9% in the same period. However, the general increase of hyperparasitism recorded during 1999-2000 to 2002-2003 could have played a role in the decrease of M. flavus and C. semicircularis. In 2001-2002 and 2002-2003, P. coccidiphagus represented 4% of the prirnary parasitoids emerged. The parasitic activity of M. nietneri had a peak (9%) in 2001-2002, opposed to 2% recorded in the two other seasons. D. elegans and C. alfieri as well as C. obscurus emerged only in a few numbers in different seasons. Competition between secondary parasitoids species resulted in a general decrease of M. leopardina (about 15%) and in an increase of P. muscarum (10%) during the second season. Their activity was somewhat replaced by that of Cheiloneurus sp., who dominated in 2002- 2003.
Seasonal fluctuation of the parasite complex of Pulvinaria tenuivalvata (Newstead) (Hemiptera: Coccidae) on sugar cane in Giza Egypt.
Guerrieri E
2005
Abstract
The seasonal of the parasite complex of the red-striped soft scale, Pulvinaria tenuivalvata (Newstead), in Egypt was studied. Sugarcane (Saccharum officinarum L.) leaves infested by the soft scale were collected weekly from untreated fields in Atfieh region at Giza govenorate, Middle Egypt, from September 1999 to February 2000 and from September to December in 2001 and 2002. The highest rate of parasitism was recorded in 2001 (55.8%) whilst during 1999-2000 and 2002 those values were 43.5% and 37%, respectively. Eight species of primary parasitoids (Hymenoptera), i.e. Coccophagus semicircularis (Forster) and Coccophagus obscurus (Forster) (new record) (Aphelinidae), Metaphycus flavus (Howard), Metaphycus citricola Annecke & Mynhardt (new record) Microterys nietneri (Motschulsky), 'Parechthrodryinus coccidiphagus (Mercet) (new record), Comperia alfieri (Mercet) (new record) and Diversinervus elegans Silvestri (Encyrtidae) and six hyperparasitoids (Hymenoptera), i. e. Pachyneuron muscarum L. (Pteromalidae) , Marietta leopardina Motschulsky (new record) and Ablerus chionaspidis (Howard) (= A. greatheadi Annecke & Insley) (new record) (Aphelindae), Mahencyrtus comara (Walker) (new record), Cerapterocerus mirabilis Westwood (new record) and Cheiloneurus sp. (Encyrtidae) were identified. Ratios between primary and secondary parasitoids collected were 99: 1 (1999-2000), 94: 6 (2001-2002) and 96: 4 (2002-2003). M. flavus and M. citricola seem to be the most promising parasitoids to be used as biocontrol agents against the red-striped soft scale on sugarcane in Egypt. The former species was more abundant between late October and early March in 1999- 2000 and during mid and late September till mid- February in 2001-2002 and 2002-2003; in the same period, the most abundant hyperparasitoid was P. muscarum. Competition between primary parasitoids species resulted in a decrease of M. flavus and C. semicircularis collected during 1999-2000 to 2002-2003; probably their activity was replaced by that of M. citricola whose rate of parasitism increased from 12.5% to 31.9% in the same period. However, the general increase of hyperparasitism recorded during 1999-2000 to 2002-2003 could have played a role in the decrease of M. flavus and C. semicircularis. In 2001-2002 and 2002-2003, P. coccidiphagus represented 4% of the prirnary parasitoids emerged. The parasitic activity of M. nietneri had a peak (9%) in 2001-2002, opposed to 2% recorded in the two other seasons. D. elegans and C. alfieri as well as C. obscurus emerged only in a few numbers in different seasons. Competition between secondary parasitoids species resulted in a general decrease of M. leopardina (about 15%) and in an increase of P. muscarum (10%) during the second season. Their activity was somewhat replaced by that of Cheiloneurus sp., who dominated in 2002- 2003.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
