Monitoring is a key component of IPM programs, but is complicated in ornamental landscapes and nurseries by the tremendous diversity of plants and pests. Because the development of both plants and insects is temperature-dependent, the blooming sequence of ornamental plants accurately tracks degree-day accumulation, and thus can be used to predict pest activity.
A Biological Calendar had been established for Wooster, Ohio from 1997-2001 consisting of phenological events for a 43 key arthropod pests of nurseries and landscapes, and the blooming sequence of 94 ornamental plants. Despite substantial year-to-year variation in weather, the order in which phenological events occurred remained highly consistent. This demonstrated that the easily-monitored sequence of flowering plants can be used accurately as a Biological Calendar to track degree-days and predict the emergence of insect pests, and that phenological indicators for a particular site can be based on just one year of data.
However, there is substantial variation in degree-day accumulation across Ohio, and degree to which the Biological Calendar developed in Wooster can be applied accurately elsewhere has previously been an open question. Documenting the phenological wave across Ohio would dramatically improve the ability to predict the development of key pests, time pest management decisions, and facilitate extension recommendations on a state-wide basis. Therefore, our objective in this project was to evaluate the state-wide significance of the Biological Calendar by monitoring plant and pest phenology at key locations across Ohio (including northeast in Lake and Geauga Counties, central in Franklin and Clark Counties, southwest in Hamilton County, and in northwest Ohio)..
In 2002, the phenology of the 43 pests and 94 plants were monitored in Secrest Arboretum, and the 32 pests and 74 plants were monitored in nurseries in Lake County, Ohio. Daily maximum and minimum temperatures were used to calculate growing degree-days for each phenological event at both sites. Despite unusually warm winter, there was an extremely high degree of correspondence in the sequence of phenological events as they occurred in Secrest Arboretum in 2002, and the previous five years (Spearman's r = 0.99). This confirms that at a particular location, the phenological sequence remains quite constant from year-to-year, despite unusual fluctuations in weather patterns.
Furthermore, the sequence of plant and insect events in Lake County, Ohio corresponded almost exactly with the sequence of the same events as they occurred in Secrest Arboretum (Spearman's r = 0.98), providing support for the hypothesis that the Biological Calendar has state-wide significance. This hypothesis is being evaluated further as an ongoing project by comparing the Wooster sequence with phenological events monitored in other regions of Ohio. Calibrating with these other locations is continuing as a multi-year project which will continue in the 2004 growing season and beyond.
The state-wide significance of the Biological Calendar has been enhanced by the development of a phenology web site by Dave Lohnes (OARDC Communications and Technology), where degree-day data for the state of Ohio is accessible in real-time, and is linked directly to this Biological Calendar (http://www.oardc.ohio-state.edu/gdd). Daily temperature data from the 12 OARDC stations around Ohio are used to calculate current degree-day values for any location in the state. Upon entering any Ohio zip code, current degree-day accumulation for that location is calculated, and the user is directed to the appropriate spot on the BioCalendar. Users can scroll up or down to see what pest events have already occurred, as well as what has yet to occur. In this way, the BioCalendar can be used to predict accurately the emergence of insect pests and time pest management activities for any location in Ohio. Accurately timed management tactics result in more effective pest management and increased crop quality, while decreasing pesticide use and production costs.
In summary, this research demonstrates that the BioCalendar can be used accurately to track degree-day accumulation and predict pest activity, because the phenological sequence of insect emergence and plant flowering remains remarkably consistent from year-to-year, even in different locations where weather varies considerably. Using the BioCalendar to accurately predict pest emergence and timing management activities will result in more effective pest management and increased crop quality, while decreasing pesticide use and production costs in Ohio nurseries.
Funding of this project in 2002 with this special IPM grant, including the purchase of traps and equipment for pest monitoring and travel reimbursements has helped develop a core of cooperators covering the regions of Ohio (except southeast) that will solidify the Biological Calendar with observations made of the phenological wave statewide in subsequent years.
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