Assessment of three strategies for the management of Meloidogyne arenaria on carrot in Mexico using Pochonia chlamydosporia var. mexicana under greenhouse conditions

Three control strategies for management of Meloidogyne arenaria were evaluated on carrot under greenhouse conditions. The control strategies tested were: i) incorporation of fresh broccoli; ii) carbofuran (Furadan®); and iii) Pochonia chlamydosporia var.mexicana, isolate Pcp21. Each strategy was evaluated separately and in combination (16 treatment combinations), each with three replicates. The experiment was done between February and April 2014 and repeated over the same time period in 2015. Each replicate experimental unit consisted of a 1 kg pot filled with tyndallised soil, to which broccoli, fungus and carbofuran were added according to treatment. Carrot seeds were sown into each pot and inoculated with M. arenaria eggs according to treatment. Pots were then maintained in the glasshouse for 12 weeks at 25 ± 5°C. After this time the fresh root weight, root length, percent reduction in root galling, P. chlamydosporia var. mexicana colony forming units (CFU)/g of soil, and CFU/g root were all measured. Results showed that isolate Pcp21 of P. chlamydosporia var. mexicana significantly reduced root galling percentage by 50 and 78% in 2014 and 2015, respectively. Application of the fungus in combination with broccoli or carbofuran also reduced root galling. The number of CFU/ g of soil or root remained the same over the 12 weeks of the experiment. This isolate of P. chlamydosporia significantly reduced damage caused by M. arenaria on carrot and is a promising agent for management of this nematode.