Heat Accumulation for Timing Lygus Control Measures in a Safflower-Cotton Complex13

Degree-day accumulation related to the phenology of Douglas-fir tussock moth and white fir during five seasons of monitoring in southern Oregon.

“…The use of degree-days for predicting insect development is becoming a common integrated pest management practice for several agricultural pests (Toscano et al 1979, Sevacherian et al 1977 Where temperature instru mentation can be readily established in outbreak areas, it is a practical way to forecast development In most forest situations where instrumentation of the many varied sites is difficult, however, foliage development can be used to predict Douglas-fir tussock moth egg eclosion and dispersal to new foliage (Wickman 1978b) It would also be helpful to know if the heat unit development at a given site varied much from year to year during the late spring season This knowledge would help determine starting dates for foliage examinations In fact, the temperature measurements taken at Mare's Egg Spring from 1976 to 1980 indicate that annual degree-day variation was very low during the critical period from bud burst through dispersal off the egg masses and these phenological events occurred at about the same dates each of the 5 yrs This is even more surprising when considering that threshold temperature dates in April varied as much as 30 days between some years The close synchrony of degree-days and phenological events and the small amount of annual variation, during the 5-yr period monitored, enhanced larval survival…”

Day-Degree Methods for Pest Management1

“…Actual day-degrees were computed from hourly temperatures, using the triangulation method of Sevacherian et al (1977). Temperatures recorded at Mead, Nebraska, at 5-min intervals to the nearest 0.01°C were used to determine the accuracy of the triangulation approximation.…”

Distribución Optimizada De Volúmenes Limitados De Agua De Riego Y Su Efecto Sobre El Rendimiento Y La Calidad De La Cebada Cervecera

“…Para la simulación de la cebada también se necesita la duración de las etapas de Kc y Ky en grados día acumulados (GDD). MOPECO utiliza el método de doble triangulación, que requiere dos parámetros para el cálculo GDD (Sevacherian et al, 1977): TL (temperatura umbral mínima para el desarrollo) y TU (temperatura umbral máxima a la que la tasa de desarrollo comienza a disminuir). Para establecer los valores de TL y TU en el área de estudio, se han analizado y comparado con los valores propuestos por otros autores en áreas similares (Canadá; Etiopia, Italia, Siria, EE.UU.).…”