Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Brian K. Hamilton x
Clear All Modify Search

A simple and fast method for measuring low boiling point (LBP) volatile terpenoids in carrots (Daucus carota L.) was developed by using a direct headspace sampling technique. Seven LBP terpenoid compounds were separated with high sensitivity and consistency via gas chromatography. High boiling point terpenoids above terpinolene were not well characterizable. Standard compounds showed highly linear responses up to 10 μg.g-1, with a detection limit of 0.01 μg.g-1. We confirmed that high α- and β-pinene and/or total terpenoids contributed to harsh or oily flavors. Up to 40 samples can be analyzed in an 8-h day using this method, compared to 10 samples using previous methods.

Free access

Thrips are the major insect pest of onions grown in South Texas. Four cultivars, `IPA-3', `TG1015Y', `1664' (glossy control), and `1900B' (waxy control), were grown in a split-plot design with insecticide sprayed or nonsprayed treatments as the main plots and cultivar as the subplots. The experiment was conducted at the Texas Agricultural Experiment Station, Weslaco, Texas, in the 1995-96 season. The objectives of the study were to compare `IPA-3' and `TG1015Y' for thrips resistance and evaluate possible resistance mechanisms that may be present in `IPA-3'. The average number of thrips per plant and leaf damage rating were significantly higher for `TG1015Y', indicating that some resistance is present in `IPA-3'. However, there were no significant differences in yield between the two cultivars. A comparison of leaf wax characteristics indicated no significant difference between `TG1015Y' and `IPA-3' using gravimetric or gas chromatography techniques. However, scanning electron micrographs of `TG1015Y' leaves appeared more similar to `1900B' and `IPA-3' appeared more similar to `1664'. The insecticide spray treatment had significantly fewer thrips, less damage, and higher yield than the nonsprayed treatment.

Free access