CATT as a non-chemical pest and nematode control method in strawberry mother planting stock¹

Abstract

Until 2008 methyl bromide (MeBr) was used in The Netherlands for fumigation of strawberry runners, intended as mother planting stock, to make them free of contamination by strawberry tarsonemid mites (Phytonemus pallidus). As an alternative of MeBr fumigation a 48 h CATT method was developed and scaled up by Wageningen UR in cooperation with the plant propagating association Plantum. This results in an excellent disinfection and a mortality of 99.8% of the strawberry tarsonemid mite. This method provides a healthy production of highly qualified strawberry runners in the field. From 2009 CATT is up scaled to a commercial level and widely applied by Dutch nurseries. In 2011 this CATT method was successfully modified to eradicate also root knot nematodes Meloidogyne hapla (>99.7% mortality), which was not effectively controlled by MeBr fumigation. For an effective killing of the root knot nematodes, temperature must be raised to 40°C. In several experiments the optimum for a high mortality of both tarsonemids and nematodes was studied. This leads into an adapted CATT of 20 hours at a temperature of 35°C and 50% CO₂ followed by 20 hours at a temperature of 40°C. In 2012 this adapted CATT was successfully upgraded and tested under field conditions.