Sampling and Management of Bemisia tabaci (Genn.) Biotype B in Australian Cotton

Authors: SEQUEIRA, RICHARD - QLD, AUSTRALIA; Naranjo, Steven

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2007
Publication Date: 6/1/2008
Citation: Sequeira, R.V., Naranjo, S.E. 2008. Sampling and Management of Bemisia tabaci (Genn.) Biotype B in Australian Cotton. Crop Protection Journal. Vol:27 P.1262-1268.

Interpretive Summary: The silverleaf whitefly, Bemisia tabaci Biotype B is a major pest of numerous crops worldwide. The pest invaded Australia in the late 1990’s where it has had major impact on cotton production. The development of sampling methods and associated decision aids are critical elements of any IPM program. The research described here extends upon and modifies a system successfully employed in the USA. A fixed-sample size binomial (presence or absence) sampling plan based on a tally threshold of 2 adults/leaf was developed and tested using a computer resampling approach. Population growth trajectories determined from field survey data collected over four growing seasons (2002/03 – 2005/06) were used to determine action thresholds. The overall sampling plan was tested and validated using the field survey data. The Australian whitefly management strategy recommends sampling of 30 leaves per 25 ha of crop at the 5th node from the top. A decision support matrix provides threshold-based management options of suppression, control and knockdown. Management options for suppression and knockdown are appropriate at low to moderate population densities (1-1.5 adults/leaf) in relation to crop developmental stage whereas insect growth regulator type products are recommended for control at moderate to high population densities (2-2.25 adults/leaf) prior to the open boll stage. Appropriate use of chemical insecticides and tactics for successful field control of whiteflies are discussed.

Technical Abstract: A management strategy for the B biotype of Bemisia tabaci (silverleaf whitefly) in Australian cotton crops is presented. A fixed-sample size binomial (presence or absence) model based on a tally threshold of 2 adults/leaf was tested using a computer resampling approach and used to develop a sampling plan. Population growth trajectories determined from field survey data collected over four growing seasons (2002/03 – 2005/06) were used to determine action thresholds. The sampling plan was tested and validated using the field survey data. The whitefly management strategy recommends sampling of 30 leaves per 25 ha of crop at the 5th node from the top. A decision support matrix with threshold-based management options of suppression, control and knockdown is presented. The management options of suppression and knockdown are appropriate at low to moderate population densities (1-1.5 adults/leaf) in relation to crop developmental stage whereas insect growth regulator type products are recommended for control at moderate to high population densities (2-2.25 adults/leaf) prior to the open boll stage. Appropriate use of chemical insecticides and tactics for successful field control of whiteflies are discussed.