Phytophthora ramorum
Trials of silvicultural methods for treating "P. ramorum" began in Humboldt County in northwest coastal California in 2006. The trials have taken place on a variety of infested properties both private and public and have generally focused on varying levels and kinds of host removal. The largest () and most replicated trials have involved removal of tanoak and bay laurel by chainsaw throughout the infested stand, both with and without subsequent underburning designed to eliminate small seedlings and infested leaf litter. Other treatments included host removal in a modified “shaded fuelbreak” design in which all bay laurel is removed, but not all tanoaks; bay and tanoak removal using herbicides; and removal of bay laurel alone. The results of these treatments are still being monitored, but repeated sampling has so far detected only very small amounts of "P. ramorum" in the soil or on vegetation in the treated sites.
Moniliophthora perniciosa
Generally, there are four major strategies that can be used for disease control of Witches’ Broom. One strategy is phytosanitation, which is the removal and destruction of diseased plant parts. This can only be conducted during dry periods, or one risks spreading the disease further. Other strategies for control are chemical control, genetic resistance and biological control. Genetic resistance is currently being researched. In order to achieve durable resistance to a specific pathogen, extensive knowledge of the genetics of specific host-pathogen interaction is required. Host-pathogen interaction for "M. perniciosa" is not fully known. Some of these strategies can be tedious and expensive, for example, 95% phytosanitation is required to achieve 50% reduction in pod loss. Among the endophytic fungi associated with cacao are many species of "Trichoderma". Several species of "Trichoderma" have been isolated from cacao and is one of the most often used biofungicides. One of the isolates, "T. stromaticum" parasitizes the saprotrophic mycelium and basidiocarps of M. perniciosa, which reduces the formation of basidiocarps by 99% when brooms are in contact with soil and 56% in brooms remaining on trees. It can reduce pod infection by 31%. This biofungicide has shown variable performance due to environmental conditions of high humidity and moisture from rainfall, which is ideal for disease development, but not necessarily ideal for optimizing biocontrol efficacy.