Abstract
In 1997, several seed companies released alfalfa ( Medicago sativa L.) cultivars that were marketed as resistant to potato leafhopper, Empoasca fabae (Harris), the key pest of this crop in the Midwest and northeastern USA. Our objectives were to investigate the mechanism of insect resistance and determine if potato leafhopper‐resistant alfalfa cultivars would require revised pest management guidelines. Two field experiments were planted in Ames, IA. Four resistant cultivars (initial release) were compared with a susceptible cultivar planted in 1996. Another experiment was planted in 1998 to compare the same susceptible control with three other resistant cultivars (secondary release). Cages were used to create four levels of leafhopper stress, and nymphs were collected from inside cages when the alfalfa was harvested. Estimates of alfalfa dry weight were used to calculate linear yield‐loss models, and model coefficients were used to calculate economic injury levels and economic thresholds. Trials were run on seedling, second‐cutting seeding‐year, second‐cutting second‐year, and second‐cutting third‐year alfalfa growth. There were no measurable differences in nymph production on resistant or susceptible cultivars in any trial, indicating that an antibiotic resistance mechanism was unimportant under production conditions. The potential for resistant alfalfa to outperform susceptible alfalfa under leafhopper stress began after initial seedling growth and continued through Year 3. The mechanism was described as stand tolerance, and appeared to increase as the alfalfa stand matured. The onset of stand tolerance after the initial growth interval of the seeding year raised the economic threshold from 8 to 80 leafhoppers per 10 sweeps.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 4
Claim · model-written summary
Resistant and susceptible cultivars had no measurable difference in leafhopper nymph production.
- Taxon
- alfalfa
Medicago sativat0 - Treatment
- resistante0
- Interactor
- Potato Leafhoppert0pest
- Outcome
- nymph productione0
- Direction
- no measurable differencese0
- Comparator
- susceptible cultivarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no measurable differences in nymph production on resistant or susceptible cultivars in any trial”
t0“Alfalfa Stand Tolerance to Potato Leafhopper”
Claim · model-written summary
Resistant alfalfa could outperform susceptible alfalfa under leafhopper stress after seedling growth through Year 3.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- resistant alfalfae0
- Interactor
- leafhoppere0pest
- Outcome
- outperforme0
- Direction
- outperforme0
- Qualifier
- after initial seedling growth and continued through Year 3e0
- Comparator
- susceptible alfalfae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The potential for resistant alfalfa to outperform susceptible alfalfa under leafhopper stress began after initial seedling growth and continued through Year 3.”
Claim · model-written summary
Stand tolerance appeared to increase as the alfalfa stand matured.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- stand maturede0
- Interactor
- potato leafhoppert0pest
- Outcome
- stand tolerancee0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mechanism was described as stand tolerance, and appeared to increase as the alfalfa stand matured.”
t0“Alfalfa Stand Tolerance to Potato Leafhopper”
Claim · model-written summary
The onset of stand tolerance raised the economic threshold from 8 to 80 leafhoppers per 10 sweeps.
- Taxon
- AlfalfaMedicago sativat0
- Interactor
- leafhoppersCicadellidaee0pest
- Outcome
- economic thresholde0
- Direction
- raisede0
- Value
- 80 leafhoppers per 10 sweepse0
- Qualifier
- from 8 to 80 leafhoppers per 10 sweepse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The onset of stand tolerance after the initial growth interval of the seeding year raised the economic threshold from 8 to 80 leafhoppers per 10 sweeps.”
t0“Alfalfa Stand Tolerance to Potato Leafhopper”