Asparagus Insects in Iowa

Asparagus, brought from Europe by the early settlers, was grown as a cultivated crop in the United States for more than two centuries before it became troubled with insect pests of major importance. Eventually, however, and also from across the sea, there were introduced into America two of its enemies widely known in Europe since the earliest times as asparagus beetles. These, together with a native fly whose larva is called the asparagus miner, comprise the only insects seriously affecting the growing of asparagus in this country. It is true, however, that grasshoppers, plant bugs, cutworms and a few other insects now and then attack the asparagus plant, but these are usually not of sufficient importance to cause serious injury

Ohio Economic Insects and Related Anthropods

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Diurnal temperature variations affect development of a herbivorous arthropod pest and its predators

The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen's inequality. In the present study we evaluated the impact of temperature alternations at 4 amplitudes (DTR0, +5, +10 and + 15 degrees C) on the developmental rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) and their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). We have modelled their developmental rates as a function of temperature using both linear and nonlinear models. Diurnally alternating temperatures resulted in a faster development in the lower temperature range as compared to their corresponding mean constant temperatures, whereas the opposite was observed in the higher temperature range. Our results indicate that Jensen's inequality does not suffice to fully explain the differences in developmental rates at constant and alternating temperatures, suggesting additional physiological responses play a role. It is concluded that diurnal temperature range should not be ignored and should be incorporated in predictive models on the phenology of arthropod pests and their natural enemies and their performance in biological control programmes

The NEBLINE, April 1991

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