Invasive Species Compendium

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Abstract

Survey for natural enemies of Drosicha sp. (Homoptera: Margarodidae) in Skardu, Pakistan.

Abstract

This paper reports the results of surveys for natural enemies of Drosicha sp. conducted in 2017 in Skardu (Olding, Khargrong, Chumik, Tangus, Sundus and Sumbul Town) and adjoining areas such as Baghicha, Pakistan, at lower elevations and approximately 40 km from Skardu. Two natural enemies were identified attacking the pest. These were Cryptochaetum sp. nr. grandicornis (Diptera: Cryptochetidae) and Tetrastichus sp. (Hymenoptera: Eulophidae). Releases of the predator Sumnius renardi (Coleoptera: Coccinellidae), which occurs naturally in some areas of Pakistan but not where Drosicha sp. has reached pest status, were also initiated. This represents the first report of Cryptochaetum sp. nr. grandicornis associated with Drosicha sp. in Pakistan. This cryptochetid is found primarily in the Mediterranean basin, but similar cryptochetids have been reported from India. Adult flies were reared from aggregations of Drosicha sp. on Salix spp. in Olding, Khargong, Sundus and Chumik in Skardu and Baghicha. The phenology and biology of this natural enemy on Drosicha sp. is not clear. It appears that adult flies deposit their eggs on surfaces on surfaces near aggregations of Drosicha sp. Larvae hatching from the eggs were observed feeding on various immature stages in the aggregations. Larvae pupated within these aggregations, and adults emerged singly from puparia. Tetrastichus sp. wasps were reared from Drosicha sp. nymphs and adult females from May to September. Parasitism was highest in August, approaching 70% of Drosicha sp. in the aggregations. Sumnius renardi has been reported from India and Pakistan, but its only known host is Drosicha stebbingi.