Abstract
From 1998 to 2001, the relationship between the proportion of tillers with >0 mummified aphids (Ptm) and the proportion of cereal aphids parasitized (Pp) was estimated on 57 occasions in fields of hard red winter wheat located in central and western Oklahoma. Both original (57 fields) and validation data (34 fields; 2001-2002) revealed weak relationships between Ptm and Pp, however, when Ptm > 0.1, Pp always exceeded the recommended parasitism natural enemy threshold of 0.2. Based on the relationship between Ptm and Pp, upper (Ptm1) and lower (Ptm0) decision threshold proportions were set at 0.1 and 0.02, respectively. We monitored cereal aphid populations in 16-25 winter wheat fields over time, and based on the upper and lower decision threshold proportions (Ptm1 = 0.1, Ptm0 = 0.02), predicted whether aphid intensities (# per tiller) would increase above or be maintained below selected economic thresholds (3, 9, and 15 aphids per tiller). Results of this validation study revealed that aphid intensity exceeded an economic threshold in only one field when predicted to remain below Ptm > 0.1, but aphid intensity reached a maximum of only four aphids per tiller. The sampling plan developed during this study allowed us to quickly classify Ptm, and independent of initial cereal aphid intensities, very accurately predict suppression of populations by parasitoids. Sequential sampling stop lines based on sequential probability ratio tests for classifying proportions were calculated for Ptm1 = 0.1 and Ptm0 = 0.02. A minimum of 26 tiller samples are required to classify Ptm as above 0.1 or below 0.02. Based on the results of this study, we believe that simultaneous use of aphid and parasitoid sampling plans will be efficient and useful tools for consultants and producers in the southern plains and decrease the number of unnecessary insecticide applications.
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Claims 6
Claim · model-written summary
The relation between tillers with mummified aphids and aphid parasitism was weak in original and validation field data.
- Taxon
- Winter Wheat
Triticum aestivumt0 - Interactor
- cereal aphidse1pest
- Outcome
- weak relationships between Ptm and Ppe0
- Setting
- 57 fieldse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both original (57 fields) and validation data (34 fields; 2001-2002) revealed weak relationships between Ptm and Pp”
t0“Winter Wheat”
e1“cereal aphids parasitized”
Claim · model-written summary
When Ptm exceeded 0.1, aphid parasitism always exceeded the 0.2 natural enemy threshold.
- Taxon
- Winter WheatTriticum aestivumt0
- Interactor
- cereal aphidse1pest
- Outcome
- Ppe0
- Direction
- exceedede0
- Value
- 0.2e0
- Qualifier
- Ptm > 0.1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when Ptm > 0.1, Pp always exceeded the recommended parasitism natural enemy threshold of 0.2”
e1“cereal aphids parasitized”
t0“Winter Wheat”
Claim · model-written summary
The developed Ptm sampling plan classified tiller parasitism quickly and accurately predicted aphid suppression independent of initial aphid intensity.
- Taxon
- Winter WheatTriticum aestivumt0
- Interactor
- cereal aphide0pest
- Outcome
- predict suppression of populations by parasitoidse0
- Comparator
- initial cereal aphid intensitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The sampling plan developed during this study allowed us to quickly classify Ptm, and independent of initial cereal aphid intensities, very accurately predict suppression of populations by parasitoids”
t0“Winter Wheat”
Claim · model-written summary
Only one field exceeded an economic aphid threshold when suppression was predicted, and it reached only four aphids per tiller.
- Taxon
- Winter WheatTriticum aestivumt0
- Interactor
- aphide0pest
- Outcome
- aphid intensitye0
- Direction
- exceedede0
- Value
- four aphids per tillere0
- Comparator
- economic thresholde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“aphid intensity exceeded an economic threshold in only one field when predicted to remain below Ptm > 0.1, but aphid intensity reached a maximum of only four aphids per tiller”
t0“Winter Wheat”
Claim · model-written summary
The sampling plan required at least 26 tiller samples to classify Ptm above 0.1 or below 0.02.
- Taxon
- Winter WheatTriticum aestivumt0
- Outcome
- tiller samplese0
- Value
- 26 tiller samplese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A minimum of 26 tiller samples are required to classify Ptm as above 0.1 or below 0.02”
t0“Winter Wheat”
Claim · model-written summary
The authors recommended simultaneous aphid and parasitoid sampling to reduce unnecessary insecticide applications.
- Taxon
- Winter WheatTriticum aestivumt0
- Outcome
- simultaneous use of aphid and parasitoid sampling planse0
- Setting
- southern plainse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“simultaneous use of aphid and parasitoid sampling plans will be efficient and useful tools for consultants and producers in the southern plains and decrease the number of unnecessary insecticide applications”
t0“Winter Wheat”