Midseason pest status of the cotton aphid (Homoptera : Aphididae) in California cotton : Is nitrogen a key factor?

Field experiments were conducted from 1996 to 1998 to assess the effects of nitrogen fertilization rates and planting dates on the population dynamics of the cotton aphid, Aphis gossypii Glover, during the midgrowing season of California cotton. Cotton aphids reached higher densities in high nitroge...

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Bibliographic Details
Published in:Environmental entomology 2001-06, Vol.30 (3), p.501-510
Main Authors: CISNEROS, Jorge J, GODFREY, Larry D
Format: Article
Language:English
Subjects:
Animal and plant ecology
Animal, plant and microbial ecology
Animals
Aphididae
Biological and medical sciences
Demecology
Fundamental and applied biological sciences. Psychology
Gossypium hirsutum
nitrogen
Phytopathology. Animal pests. Plant and forest protection
Protozoa. Invertebrata
Protozoa. Invertebrates
Records, symptoms, damages, economic importance, population surveys
USA, California
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Summary:Field experiments were conducted from 1996 to 1998 to assess the effects of nitrogen fertilization rates and planting dates on the population dynamics of the cotton aphid, Aphis gossypii Glover, during the midgrowing season of California cotton. Cotton aphids reached higher densities in high nitrogen fertilized plants (227 kg N/ha, rate currently used by cotton growers) than in low nitrogen fertilized plants (57 kg N/ha). In addition, late-planted cotton (May-June), which had more nitrogen content, also harbored higher aphid populations than early plantings (April). Overall, aphid abundance was positively correlated with plant nitrogen content. In a moderate aphid pressure year (1996), planting the cotton early (April) was effective in keeping the aphid population below the midseason economic threshold. However, in a high aphid pressure year (1997), it was necessary to drastically reduce the nitrogen fertilization to 57 kg N/ha to maintain the aphid density under this threshold. Recent cultural practices in California cotton include higher rates of nitrogen fertilization, which increases nitrogen content of plants. The current data suggest that this practice (i.e., high fertilization) is an important factor contributing to the increased severity of the cotton aphid as a pest of California cotton during the midseason.
ISSN:0046-225X
1938-2936
DOI:10.1603/0046-225x-30.3.501