Daniel A. Herms, Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, Ohio.
During 1997, the author monitored the phenology of 56 plant species and/or cultivars and 22 species of insects. From 1998 to 2002, this list was expanded to 91 plant and 43 insect and mite taxa. Four individuals of each plant species or cultivar were monitored. To control for microenvironmental variation, all individuals of a particular taxon were located either in uniform sun or shade, depending on the environment to which the species is best adapted. Plants in microenvironments obviously altered by buildings, parking lots, bodies of water, and other such factors were not included.
Plants were monitored at least three times each week, with the dates of first bloom and full bloom recorded. First bloom is defined as the date on which the first flower bud on the plant opens, revealing pistils and/or stamens, and full bloom as the date on which 95% of the flower buds have opened (i.e., one bud out of 20 has yet to open). These phenological events can be identified and recorded with precision.
The insect and mite species monitored in this study represent diverse life histories and include defoliators, wood borers, scales and other sucking insects, gall formers, leafminers, and spider mites. In contrast to methods used to monitor plant phenology, which were designed to minimize variation in order to increase predictive power, sampling protocols for insects were designed to characterize the phenology of the entire population.
Degree-days were calculated using the double sine wave method (Allen, 1976) from daily maximum and minimum temperature data for Wooster (OARDC Weather System, Wooster Station), using a base temperature of 50°F (DD50) and a starting date of January 1. For more detail regarding the calculation and use of degree-days, see Herms, 1999 and 2001.