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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Biological Control of Marmara gulosa Guillén and Davis in the San Joaquin Valley

Kirkland, Crystal A 01 February 2009 (has links) (PDF)
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.
2

Taxonomy, Biogeography and Pest Status of Marmara sp. in Northern Mexico and California Citrus Production

Semet, Paul 01 June 2010 (has links)
A novel lepidopteran sex pheromone lure which was thought to be species-specific to the citrus pest Marmara gulosa (Lepidoptera: Gracillariidae) Guillén (McElfresh et al. 2009) has attracted male moths exhibiting two distinct morphologies. The morphological features examined were the sclerotized parts that make up the male genitalia; which include the valvular lobes, costal lobes, cucullar lobes, and the aedeagus. The sclerotized parts were methodically dissected and mounted on microscope slides. Digital images captured of the slide-mounted specimens proved to be inconsistent with the illustrations provided in the original Marmara gulosa species description (Guillén et al. 2001). The morphologies of all specimens from both the San Joaquin and Coachella valley show remarkable consistency; regardless of host plant origin, collection method, and collection date. Two specimen groups (one from an orchard in Northern Mexico and the other from backyard citrus in Riverside, California) exhibited entirely different morphological features in which the three lobes mentioned above are fused together. This difference in morphology can only be noticed when examining the sclerotized parts of the male genitalia under a microscope; it is otherwise indistinguishable from M. gulosa via macroscopic features such as antennae shape and wing pattern. These two specimen groups with fused lobes are considered a new species belonging to the genus Marmara and currently remain undescribed. A genetic study conducted at UC Riverside, which concentrated on the CO1 region of mitochondrial DNA, reported significant differences in genetics based on the geographic origins of specimens (Vickerman and Stouthammer 2006). Geographically, the genetic distribution described in the 2006 study does not coincide with the distribution of morphologies described in this paper. The species description of Marmara gulosa is in need of revision. In addition, further collection and research is required in order to describe and name the newly discovered Marmara species.

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