TY - JOUR
T1 - A degree-day model for predicting adult emergence of the citrus gall wasp, Bruchophagus fellis (Hymenoptera Eurytomidae), in southern Australia
AU - Mo, Jianhua
AU - Stevens, Mark M.
N1 - Funding Information:
The study was part of a research project funded by Hort Innovation Australia with a levy from the Australian Citrus Industry. Andrew Creek and Steven Falivene helped with the selection of monitoring sites. Scott Munro, Peter Simmons, and Stephen Hegedus helped with data collection. Bernie Dominiak is thanked for providing constructive comments on an early version of the manuscript.
Publisher Copyright:
© 2021 Elsevier Ltd
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/5
Y1 - 2021/5
N2 - The citrus gall wasp, Bruchophagus fellis,
is a serious pest of citrus in southeast Australia and the ability to
accurately predict its highly synchronised adult emergence periods is
critical for its effective management. We monitored emergence of the
citrus gall wasp for six years during 2010–2017 in southern Australia,
yielding a total of 22 site-by-year datasets from two citrus production
regions and multiple citrus varieties. For each dataset, the proportions
of emerged wasps on different monitoring dates were related to the
corresponding degree-days using a 2-parameter Weibull function. The two
degree-day parameters, the lower development threshold temperature and
biofix date, were estimated at 8 °C and August 1 respectively by
cross-validation of a series of candidate values using the sum of
squared differences between the predicted and observed median emergence
dates as the performance indicator. According to the final fitted
Weibull function, 5, 50, and 95% emergence occur when 560, 723 and 835
degree-days above 8 °C have accumulated after August 1. The predicted
median emergence dates differed from the corresponding observed median
emergence dates by an average of 2.8 days across the 22 datasets. The
average deviations for 5 and 95% emergence were slightly larger, at five
and four days, respectively. Observed degree-days for median emergence
did not differ significantly between the two citrus production regions,
indicating there is no need for separate degree-day models for different
regions. Based on the degree-day model, an interactive, online timing
tool has been developed, allowing growers to use local weather station
data to predict when the gall wasp is likely to emerge in average, warm,
and cool years.
AB - The citrus gall wasp, Bruchophagus fellis,
is a serious pest of citrus in southeast Australia and the ability to
accurately predict its highly synchronised adult emergence periods is
critical for its effective management. We monitored emergence of the
citrus gall wasp for six years during 2010–2017 in southern Australia,
yielding a total of 22 site-by-year datasets from two citrus production
regions and multiple citrus varieties. For each dataset, the proportions
of emerged wasps on different monitoring dates were related to the
corresponding degree-days using a 2-parameter Weibull function. The two
degree-day parameters, the lower development threshold temperature and
biofix date, were estimated at 8 °C and August 1 respectively by
cross-validation of a series of candidate values using the sum of
squared differences between the predicted and observed median emergence
dates as the performance indicator. According to the final fitted
Weibull function, 5, 50, and 95% emergence occur when 560, 723 and 835
degree-days above 8 °C have accumulated after August 1. The predicted
median emergence dates differed from the corresponding observed median
emergence dates by an average of 2.8 days across the 22 datasets. The
average deviations for 5 and 95% emergence were slightly larger, at five
and four days, respectively. Observed degree-days for median emergence
did not differ significantly between the two citrus production regions,
indicating there is no need for separate degree-day models for different
regions. Based on the degree-day model, an interactive, online timing
tool has been developed, allowing growers to use local weather station
data to predict when the gall wasp is likely to emerge in average, warm,
and cool years.
KW - Adult emergence
KW - Bruchophagus fellis
KW - Citrus gall wasp
KW - Degree-day model
KW - Online timing tool
KW - Phenology
UR - http://www.scopus.com/inward/record.url?scp=85100068099&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85100068099&partnerID=8YFLogxK
U2 - 10.1016/j.cropro.2021.105553
DO - 10.1016/j.cropro.2021.105553
M3 - Article
AN - SCOPUS:85100068099
SN - 0261-2194
VL - 143
SP - 1
EP - 7
JO - Crop Protection
JF - Crop Protection
M1 - 105553
ER -