Abstract
Ferrisia gilli Gullan (Hemiptera: Pseudococcidae) is a new pest in California pistachios, Pistacea vera L. We conducted a 3-yr field study to determine the type and amount of damage caused by F. gilli. Using pesticides, we established gradients of F. gilli densities in a commercial pistachio orchard near Tipton, CA, from 2005 to 2007. Each year, mealybug densities on pistachio clusters were recorded from May through September and cumulative mealybug-days were determined. At harvest time, nut yield per tree (5% dried weight) was determined, and subsamples of nuts were evaluated for market quality. Linear regression analysis of cumulative mealybug-days against fruit yield and nut quality measurements showed no relationships in 2005 and 2006, when mealybug densities were moderate. However, in 2007, when mealybug densities were very high, there was a negative correlation with yield (for every 1,000 mealybug-days, there was a decrease in total dry weight per tree of 0.105 kg) and percentage of split unstained nuts (for every 1,000 mealybug-days, there was a decrease in the percentage of split unstained of 0.560%), and a positive correlation between the percentage of closed kernel and closed blank nuts (for every 1,000 mealybug-days, there is an increase in the percentage of closed kernel and closed blank of 0.176 and 0.283%, respectively). The data were used to determine economic injury levels, showing that for each mealybug per cluster in May there was a 4.73% reduction in crop value associated with quality and a 0.866 kg reduction in yield per tree (4.75%).
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Claims 7
Claim · model-written summary
Moderate mealybug densities were unrelated to yield and nut quality in 2005 and 2006.
- Taxon
- Pistachio
Pistacia verat0 - Interactor
- mealybuge0pest
- Outcome
- fruit yield and nut quality measurementse0
- Qualifier
- 2005 and 2006e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Linear regression analysis of cumulative mealybug-days against fruit yield and nut quality measurements showed no relationships in 2005 and 2006, when mealybug densities were moderate”
t0“Pistachio”
Claim · model-written summary
At high densities, each 1,000 mealybug-days corresponded to 0.105 kg less total dry weight per tree.
- Taxon
- PistachioPistacia verat0
- Interactor
- mealybuge0pest
- Outcome
- total dry weight per treee0
- Direction
- decreasee0
- Value
- 0.105 kge0
- Qualifier
- 1,000 mealybug-dayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for every 1,000 mealybug-days, there was a decrease in total dry weight per tree of 0.105 kg”
t0“Pistachio”
Claim · model-written summary
Each 1,000 mealybug-days corresponded to 0.560% fewer split unstained nuts.
- Taxon
- PistachioPistacia verat0
- Interactor
- mealybuge0pest
- Outcome
- percentage of split unstainede0
- Direction
- decreasee0
- Value
- 0.560%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for every 1,000 mealybug-days, there was a decrease in the percentage of split unstained of 0.560%”
t0“Pistachio”
Claim · model-written summary
Each 1,000 mealybug-days corresponded to increased closed kernel percentage by 0.176.
- Taxon
- PistachioPistacia verat0
- Interactor
- mealybuge0pest
- Outcome
- closed kernele0
- Direction
- increasee0
- Value
- 0.176e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for every 1,000 mealybug-days, there is an increase in the percentage of closed kernel and closed blank of 0.176 and 0.283%, respectively”
t0“Pistachio”
Claim · model-written summary
Each 1,000 mealybug-days corresponded to increased closed blank percentage by 0.283%.
- Taxon
- PistachioPistacia verat0
- Interactor
- mealybuge0pest
- Outcome
- closed blanke0
- Direction
- increasee0
- Value
- 0.283%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for every 1,000 mealybug-days, there is an increase in the percentage of closed kernel and closed blank of 0.176 and 0.283%, respectively”
t0“Pistachio”
Claim · model-written summary
Each May mealybug per cluster corresponded to 4.73% less quality-associated crop value.
- Taxon
- PistachioPistacia verat0
- Interactor
- mealybuge0pest
- Outcome
- crop value associated with qualitye0
- Direction
- reductione0
- Value
- 4.73%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for each mealybug per cluster in May there was a 4.73% reduction in crop value associated with quality”
t0“Pistachio”
Claim · model-written summary
Each May mealybug per cluster corresponded to 0.866 kg less yield per tree.
- Taxon
- PistachioPistacia verat0
- Interactor
- Ferrisia gilliFerrisia gillie1pest
- Outcome
- yield per treee0
- Direction
- reductione0
- Value
- 0.866 kge0
- Qualifier
- 4.75%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 0.866 kg reduction in yield per tree (4.75%)”
t0“Pistachio”
e1“Ferrisia gilli Gullan”