Date of Award


Degree Name

MS in Agriculture - Crop Science


Horticulture and Crop Science


David Headrick


Peelminer, Marmara gulosa Davis and Guillén, has been reported as a sporadic pest in California and Arizona since 1998. Marmara gulosa has been a persistent pest in the San Joaquin Valley of California (USA) since 1998. Prior to 2000 the only reports of high populations of citrus peelminer were in the Coachella Valley. The larval stages of M. gulosa create serpentine mines scarring the upper epidermal layers of citrus rind, rendering it unacceptable for fresh market sale. Chemicals have failed to provide adequate control of M. gulosa; thus, the use of natural enemies is considered the best long-term option. Cirrospilus coachellae Gates (Eulophidae: Eulophinae) is an effective gregarious parasite of peelminer in the Coachella Valley; however, attempts to establish this species in the San Joaquin Valley have so far been unsuccessful. Other natural enemies may be necessary to control peelminer in this region. The discovery of populations of the tetrastichine eulophid Hadrotrichodes waukheon LaSalle parasitizing M. gulosa in the San Joaquin Valley indicates a possible option for biological control of this pest. Hadrotrichodes waukheon (Hymenoptera: Eulophidae: Tetrastichinae) is a parasite of M. gulosa. Newly discovered morphological variations within the species are reported, including the first description of the male. New biological information including preferred life stage of host for parasitism, clutch sizes, male to female ratios and meconial positioning are included. Field studies demonstrated that one to four adult H. waukheon could emerge from a single M. gulosa larva, and later instar M. gulosa larvae were preferred. Hadrotrichodes waukheon is a gregarious, primary parasitoid and may be a candidate agent for biological control of M. gulosa.

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Entomology Commons