Abstract
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 (MayJune), 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.
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Claims 6
Claim · model-written summary
High nitrogen fertilization increased cotton aphid densities relative to low nitrogen.
- Taxon
- Cotton
Gossypium hirsutume0 - Treatment
- 227 kg N/hae0
- Interactor
- Cotton aphids
Aphis gossypiie0pest - Outcome
- Cotton aphids reached higher densitiese0
- Direction
- highere0
- Comparator
- 57 kg N/hae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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)”
Claim · model-written summary
Late planted cotton harbored more aphids than early planted cotton.
- Taxon
- cottonGossypium hirsutume0
- Treatment
- late-planted cotton (MayJune)e0
- Interactor
- aphide0pest
- Outcome
- aphid populationse0
- Direction
- highere0
- Comparator
- early plantings (April)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“late-planted cotton (MayJune), which had more nitrogen content, also harbored higher aphid populations than early plantings (April)”
Claim · model-written summary
Aphid abundance correlated positively with plant nitrogen content.
- Taxon
- CottonGossypium hirsutumt0
- Interactor
- aphide0pest
- Compound
- nitrogene0
- Outcome
- aphid abundancee0
- Direction
- positively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“aphid abundance was positively correlated with plant nitrogen content”
t0“California Cotton”
Claim · model-written summary
Early planting kept aphids below the economic threshold in 1996.
- Taxon
- cottonGossypium hirsutume0
- Treatment
- planting the cotton early (April)e0
- Interactor
- aphide0pest
- Outcome
- aphid populatione0
- Direction
- belowe0
- Comparator
- midseason economic thresholde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a moderate aphid pressure year (1996), planting the cotton early (April) was effective in keeping the aphid population below the midseason economic threshold”
Claim · model-written summary
In 1997 nitrogen reduction to 57 kg N/ha kept aphids under the threshold.
- Taxon
- CottonGossypium hirsutumt0
- Treatment
- 57 kg N/hae0
- Interactor
- aphide0pest
- Outcome
- aphid densitye0
- Direction
- undere0
- Comparator
- this thresholde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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”
t0“California Cotton”
Claim · model-written summary
High nitrogen fertilization contributed to more severe cotton aphid pest pressure.
- Taxon
- cottonGossypium hirsutume0
- Treatment
- high fertilizatione0
- Interactor
- cotton aphidAphis gossypiie0pest
- Outcome
- severity of the cotton aphide0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high fertilization) is an important factor contributing to the increased severity of the cotton aphid as a pest of California cotton during the midseason”
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.