| Autor: |
Rosenheim, Jay A., Wilhoit, Lawrence R., Goodell, Peter B., Grafton‐Cardwell, Elizabeth E., Leigh, Thomas F. |
| Zdroj: |
Entomologia Experimentalis et Applicata; October 1997, Vol. 85 Issue: 1 p45-63, 19p |
| Abstrakt: |
Crop plant compensation for herbivory and the population dynamics of herbivores are two key elements in defining an herbivore's pest status. We studied the dynamics of natural, unmanipulated populations of the aphid Aphis gossypiion seedling plantings of cotton, Gossypium hirsutumand Gossypium barbadense, over a 4‐year period in California's Central Valley. Aphid populations colonized all plantings, but reached densities in excess of 0.5 aphids/leaf during only one year (1991), when outbreaks occurred. Outbreak populations were, however, ephemeral; predation and parasitism suppressed aphid populations prior to the initiation of flower bud production, when cotton plant growth may become photosynthate‐limited. Effective natural biological control was observed despite the action of hyperparasitoids and the heavy mortality of immature parasitoids that occurred when predators consumed parasitized aphids. |
| Databáze: |
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