Environmental Entomology (1990) 19, 803-807

Bruce A. Barrett and Jay F. Brunner (1990)
Types of parasitoid-induced mortality, host stage preferences, and sex ratios exhibited by Pnigalio flavipes (Hymenoptera: Eulophidae) using Phyllonorycter elmaella (Lepidoptera: Gracillariidae) as a host
Environmental Entomology 19 (3), 803-807
Abstract: The different types of parasitoid-induced mortality, host stage preferences, and sex ratio exhibited by Pnigalio flavipes (Ashmead) to its host, Phyllonorycter elmaella Doganlar and Mutuura, was investigated in commercial apple orchards in central Washington. The parasitoid-induced mortality of Phyllonorycter elmaella consisted on average of 57.2% host stinging with oviposition, 32.7% host feeding, and 10.1% host stinging without oviposition. Pnigalio flavipes laid eggs on Phyllonorycter elmaella tissue feeders (fourth and fifth instars) an average of 5.4 times more than it did on sap feeders (first-third instars), but host-fed on sap feeders an average of 12.1 times more than on tissue feeders. When healthy tissue feeders became scarce late in the season, Pnigalio flavipes began to lay eggs on previously attacked tissue feeders (superparasitize) and then switched to laying eggs on sap feeders. The sex ratio (M:F) of Pnigalio flavipes reared from tissue feeders was almost 1 to 1. Only male Pnigalio flavipes were reared from sap feeders.
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Database assignments for author(s): Bruce A. Barrett, Jay F. Brunner

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phyllonorycter elmaella	Apple (Malus)	U.S.A. (NW)
Pnigalio minio (parasitoid)	Phyllonorycter elmaella	Apple (Malus)	U.S.A. (NW)