Bacterial disease of HNS: Chemical control

The hardy nursery stock industry is valued at over £300 million. Project HNS 71 indicated that a significant proportion of HNS subjects are affected by bacterial diseases. In susceptible crops direct losses from bacterial diseases are considerable. Additional losses can be attributed to the use of treatments that are only partly effective, or that are phytotoxic. By determining the efficacy of the chemicals currently available, ineffective, or inappropriate treatments can be avoided, and future research can be targeted at those measures which are most likely to prove effective.  

This project has clearly demonstrated that most disinfectants are effective against bacterial pathogens of HNS when used for general hygiene purposes, but Aliette, Jet 5 and Wetcol were not effective when applied as foliar sprays for control of bacterial diseases. 

Bacterial diseases cause major problems to growers of HNS. A previous HDC project (HNS 71: Bacterial diseases of HNS) identified the most important and widespread bacterial diseases of HNS. Currently the only bactericides registered as pesticides and available to growers in the UK are copper-based compounds. Bactericidal disinfectants offer potential for controlling spread of disease from infected leaf debris and other inoculum sources such as pots, surfaces, and equipment. This project examined a range of disinfectants and pesticides for use as part of a disease management strategy for bacterial diseases of HNS.