Economic injury level, action threshold, and a yield-loss model for the pea aphid, Acyrthosiphon pisum (Homoptera: Aphididae), on green peas, Pisum sativum
Economic injury level, action threshold, and population development studies with the pea aphid (PA), Acyrthosiphon pisum (Harris), were conducted during 1983-85. Pea aphid densities, simulating those in commercial pea fields, were established using insecticides to manipulate infestations levels. Three experiments, incorporating 12 treatments and six replications, were analyzed. A generalized, nonlinear equation relating pea yield to accumulated aphid feeding days (AFD) is described. The model approximates two phases of a sigmoid infestation-yield curve. An upper maximum plateau and a region of rapidly decreasing yield are approximated. Beyond 1800 AFD, a lower minimum yield plateau is hypothesized. Economic injury levels calculated for the 3 years' experiments using the generalized model were 22.2, 18.2, and 12.2 AFD, respectively. Action threshold estimates were determined from linear regression estimates of yield versus aphids per plant at bloom. Action thresholds were 3.6, 0.3, and 0.3 aphids per plant for the years 1983, and 1985, respectively. The pea quality components, tenderometer (TD) and sieve size, were altered by maximum PA densities. High AFD levels increased TD and decreased sieve size significantly when compared with aphid-free controls. Protein content of green peas was not significantly altered by PA feeding
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| Format: | biblioteca |
| Published: |
1986
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| Subjects: | GRANOS, PISUM SATIVUM, PERDIDAS, RENDIMIENTO, ACYRTHOSIPHON PISUM, HOMOPTERA, DENSIDAD DE LA POBLACION, MODELOS, |
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