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Impact Of Sulfur On Density Of Tetranychus Pacificus (Acari: Tetranychidae) And Galendromus Occidentalis (Acari: Phytoseiidae) In A Central California Vineyard, Michael J. Costello
Impact Of Sulfur On Density Of Tetranychus Pacificus (Acari: Tetranychidae) And Galendromus Occidentalis (Acari: Phytoseiidae) In A Central California Vineyard, Michael J. Costello
Horticulture and Crop Science
Sulfur is the oldest and most widely used fungicide in the vineyards of California, where it is used for control of powdery mildew (Uncinula necator [Schw.] Burr). For decades, sulfur use has been associated with outbreaks of Tetranychus pacificus McGregor (Acari: Tetranychidae) on cultivated grapes in the San Joaquin Valley. I undertook large-scale field studies to test this association, to evaluate the impact of sulfur on Galendromus occidentalis (Nesbit) (Acari: Phytoseiidae), a major predator of T. pacificus, and to determine if timing of sulfur applications with respect to grape bloom has an impact on T. pacificus density. The …
Spontaneous Hybridization Between Maize And Teosinte, Norman C. Ellstrand, Lauren C. Garner, Subray Hedge, Roberto Guadagnuolo, Lesley Blancas
Spontaneous Hybridization Between Maize And Teosinte, Norman C. Ellstrand, Lauren C. Garner, Subray Hedge, Roberto Guadagnuolo, Lesley Blancas
Horticulture and Crop Science
The closest wild relatives of maize, Zea mays ssp. mays are various Zea taxa known as ‘‘teosinte.’’ Hybrids between maize and the teosinte taxon, Zea mays ssp. mexicana, often occur when the 2 are sympatric in Mexico. Measuring the spontaneous hybridization rate of the 2 taxa would shed light on the mechanisms contributing to the evolution and persistence of these hybrid swarms. We conducted a series of field experiments in Riverside, CA, to measure the natural hybridization rates between maize and 2 teosinte taxa, Z. m. ssp. mexicana and Zea mays ssp. parviglumis. We planted teosinte within and …