VATIS UPDATE Article

Researchers at University of California, the United States, has found that Prunus Replant Disease (PRD) is a soilborne complex that suppresses growth and productivity of replanted almond and stone fruit orchards, even in the absence of plant parasitic nematodes.

Earlier in 2014 they reported that anaerobic soil disinfestation (ASD) implemented in 2013 with rice bran (20 metric tons/treated ha; in strips covering 50% plot area) was as effective as soil fumigation (Telone C35, 600 kg/treated ha; 50% plot area) for preplant control of Pythium ultimum (a PRD contributor) and early stimulation of replanted almond orchard growth, but cost of the ASD was more than double that of soil fumigation.

The researchers reported that full-season orchard responses to 2013 ASD treatments and early responses to new 2014 treatments designed to reduce ASD costs. All 2014 ASD treatments (100, 60, and 36%) were as effective as soil fumigation in reducing P. ultimum inoculum density (to 0 to 95 cfu/g soil), compared to controls (2008 to 3663 cfu/g). To date, ASD has provided tree growth stimulation equal to that of soil fumigation. Further research is needed to optimize ASD substrates and application methods for replant problems of almonds and stone fruits.