“Biofix” is the calendar date on which the first sustained capture of insects emerging from the overwintering generation occurs. At the Winchester research center, we establish biofix for three key moth pests of peaches and/or apples:
- oriental fruit moth;
- codling moth;
- tufted apple budmoth.
Prior to the onset of moth emergence and flight each spring, traps baited with the pheromone lure for each species are deployed in research center orchards and captures are recorded daily. When one or more moths are captured in each of at least two of three traps over at least three consecutive evenings, biofix is set as the first day on which these sustained captures occurred.
Starting on the biofix date, daily heat until accumulations (“degree-days” or “DD”) are calculated based on known developmental threshold temperatures for each species. Accumulated degree-days are used with models that predict the rate of development of eggs and the hatch of larvae for each species. Critical points in the development of each generation of each species are predicted by the model, so that tree fruit growers can time their control measures optimally.
In combination, determining the biofix date and initiating degree-day models based on biofix each year enable best management practices regardless of the potentially large annual variations in the environmental conditions that affect pest emergence and developmental rate. The accompanying table illustrates the annual variations in biofix dates for oriental fruit moth, codling moth, and tufted apple budmoth at the Winchester research center since 2000.
|Year||Oriental Fruit Moth||Codling Moth||Tufted Apple Budmoth|
|2000||April 1||April 29||April 29|
|2001||April 7||April 30||May 4|
|2002||March 30||April 27||May 5|
|2003||April 14||May 3||May 12|
|2004||April 16||April 30||May 6|
|2005||April 11||May 8||May 8|
|2006||April 7||April 23||May 1|
|2007||April 20||April 30||May 10|
|2008||April 10||April 25||May 6|
|2009||April 17||May 2||May 20|
|2010||April 5||April 29||May 13|
|2011||April 18||April 26||May 9|
|2012||March 20||April 14||April 29|
|2013||April 11||May 2||May 16|
|2014||April 12||May 8||May 12|
|2015||April 18||May 4||May 16|
|2016||April 11||April 25||May 2|
|2017||April 3||April 21||April 29|