Abstract
Insect herbivory can affect morphology and physiological functions of plants. Defoliation caused by herbivores may alter photosynthetic rates of remaining plant tissues or reduce the leaf area and limit the photosynthate needed to fulfill the energy and nutritional requirements of the plants. The reduction in plant leaf area may reduce the quality and quantity of biomass, which is critical for bioenergy crops. Plants may also compensate for herbivory losses utilizing their energy and resulting in less vigorous plants. Two switchgrass (Panicum virgatum L.) cultivars, Shawnee (upland) and Kanlow (lowland), were evaluated for yield response to simulated leaf-mass consumption. The data showed no significant effect of up to 80% simulated insect defoliation on the yield of switchgrass under suitable weather conditions. During the first year of the study with abundant rainfall, a significant reduction in leaf area index (LAI) did not result in a significant effect on switchgrass yield. However, the following year, drought occurred and resulted in significant yield reduction, along with reductions in LAI and percent light interception. Switchgrass cultivars (Shawnee and Kanlow) were tested for their photosynthetic response to simulated leaf injury. Mechanical defoliation with different insect feeding patterns was applied to individual leaves to determine the effect on photosynthetic rates. No significant differences among various patterns of tissue removal were recorded in Kanlow. However, during 2011, double edge cutting treatment significantly reduced the photosynthetic rates in Shawnee. Significant reductions in photosynthetic rates were recorded over time in Kanlow for both years. Photosynthetic rates differed significantly between the years even prior to treatment, likely as a result of water stress in the second year. The actual feeding rates of nymphs and adults of red-legged grasshopper, Melanoplus femurrubrum (DeGeer) (Orthoptera: Acrididae) were quantified. The average leaf area consumed and the weight gained by each stage of grasshopper were measured after three days of feeding. The results of the study indicated that the third instar of M. femurrubrum consumed the maximum amount per unit of body weight per day while the maximum weight gain was observed in adults and the fifth instars. These results may explain the higher metabolic rates and digestive efficiencies of early instar grasshoppers. The study results suggest control of grasshoppers at early stages is needed to avoid potential economic losses.
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Claims 13
Claim · model-written summary
Up to 80% simulated insect defoliation had no significant effect on switchgrass yield under suitable weather.
- Taxon
- switchgrass
Panicum virgatume0 - Treatment
- up to 80% simulated insect defoliatione0
- Outcome
- yielde0
- Direction
- no significant effecte0
- Qualifier
- under suitable weather conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no significant effect of up to 80% simulated insect defoliation on the yield of switchgrass under suitable weather conditions”
Claim · model-written summary
In the rainy first year, leaf area index was significantly reduced.
- Taxon
- SwitchgrassPanicum virgatumt0
- Outcome
- leaf area index (LAI)e0
- Direction
- reductione0
- Qualifier
- first year of the study with abundant rainfalle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During the first year of the study with abundant rainfall, a significant reduction in leaf area index (LAI)”
t0“Switchgrass (Panicum virgatum L.)”
Claim · model-written summary
In the rainy first year, the reduced leaf area index did not significantly affect switchgrass yield.
- Taxon
- switchgrassPanicum virgatume0
- Organ / stage
- leaf area index (LAI)e0
- Outcome
- yielde0
- Direction
- did not result in a significant effecte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a significant reduction in leaf area index (LAI) did not result in a significant effect on switchgrass yield”
Claim · model-written summary
Drought in the following year significantly reduced switchgrass yield.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- droughte0
- Outcome
- yielde0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the following year, drought occurred and resulted in significant yield reduction”
t0“Switchgrass”
Claim · model-written summary
Drought in the following year reduced leaf area index and percent light interception.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- droughte0
- Outcome
- LAI and percent light interceptione0
- Direction
- reductionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“drought occurred and resulted in significant yield reduction, along with reductions in LAI and percent light interception”
t0“Switchgrass”
Claim · model-written summary
Patterns of tissue removal did not significantly differ in photosynthetic response in Kanlow.
- Taxon
- SwitchgrassPanicum virgatumt0
- Material
- Kanlowe0
- Treatment
- various patterns of tissue removale0
- Outcome
- photosynthetic ratese1
- Direction
- No significant differencese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No significant differences among various patterns of tissue removal were recorded in Kanlow.”
e1“effect on photosynthetic rates”
t0“Switchgrass”
Claim · model-written summary
Double edge cutting significantly reduced photosynthetic rates in Shawnee in 2011.
- Taxon
- SwitchgrassPanicum virgatumt0
- Material
- Shawneee0
- Treatment
- double edge cutting treatmente0
- Outcome
- photosynthetic ratese0
- Direction
- reducede0
- Qualifier
- during 2011e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“during 2011, double edge cutting treatment significantly reduced the photosynthetic rates in Shawnee”
t0“Switchgrass”
Claim · model-written summary
Photosynthetic rates in Kanlow significantly decreased over time in both years.
- Taxon
- SwitchgrassPanicum virgatumt0
- Material
- Kanlowe0
- Outcome
- photosynthetic ratese0
- Direction
- reductionse0
- Qualifier
- over timee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significant reductions in photosynthetic rates were recorded over time in Kanlow for both years.”
t0“Switchgrass”
Claim · model-written summary
Photosynthetic rates differed significantly between years before treatment.
- Taxon
- SwitchgrassPanicum virgatumt0
- Outcome
- Photosynthetic ratese0
- Direction
- differede0
- Qualifier
- prior to treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthetic rates differed significantly between the years even prior to treatment”
t0“Switchgrass”
Claim · model-written summary
Water stress in the second year was proposed as the reason for the pretreatment photosynthetic difference.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- water stresse0
- Outcome
- Photosynthetic rates differed significantly between the yearse0
- Qualifier
- likelye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthetic rates differed significantly between the years even prior to treatment, likely as a result of water stress in the second year.”
t0“Switchgrass”
Claim · model-written summary
Third-instar M. femurrubrum consumed the most switchgrass leaf area per body weight per day.
- Taxon
- SwitchgrassPanicum virgatumt0
- Organ / stage
- third instare0
- Interactor
- M. femurrubrum
.jpg?width=60)
Melanoplus femurrubrume0pest - Outcome
- leaf area consumede1
- Direction
- maximume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“the third instar of M. femurrubrum consumed the maximum amount per unit of body weight per day”
e1“average leaf area consumed”
t0“Switchgrass”
Claim · model-written summary
Adult and fifth-instar grasshoppers had the maximum weight gain after feeding.
- Taxon
- SwitchgrassPanicum virgatumt0
- Organ / stage
- adults and the fifth instarse0
- Interactor
- M. femurrubrumMelanoplus femurrubrume1pest
- Outcome
- weight gaine0
- Direction
- maximume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the maximum weight gain was observed in adults and the fifth instars”
e1“M. femurrubrum”
t0“Switchgrass”
Claim · model-written summary
The authors recommend controlling grasshoppers at early stages to avoid potential economic losses.
- Taxon
- SwitchgrassPanicum virgatumt0
- Interactor
- grasshoppersAcridomorphae0pest
- Outcome
- control of grasshoppers at early stagese0
- Qualifier
- to avoid potential economic lossese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“control of grasshoppers at early stages is needed to avoid potential economic losses”
t0“Switchgrass”
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See all 5 papers →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.