In our latest edition of Topics in Subtropics - we printed an article by Tim Spann outlining some of the tactics being employed to deal with huanglongbing – “An Outline of Management Options for HLB in Florida”. Much of the presentation was on the use of nutritional sprays to mitigate the effects of the disease on fruit yield and quality. In the past, anecdotal evidence was used to evaluate the nutritional spray programs. Recently an article by Grottwald et. al., 2012 looked at nutritional sprays and found that even with the very expensive practice it was not possible to improve fruit size and tree yield with the sprays, even at a cost of approximately $750 per acre. This is the first trial to actually look at the impact of the sprays on yield. Tree canopies might look better, but effect on yield had never been fully evaluated. Further, by not following a rouging program of removing symptomatic trees, the spray program could promote area-wide buildup of inoculum and increase the spread of disease both within and between citrus orchards.
Gottwald, T.R., J.H. Graham, M.S. Irey, T.G. McCollum and B.W. Wood. 2012. Inconsequential effect of nutritional treatments on huanglongbing control, fruit quality, bacterial titer and disease progress. Crop Protection 36 (2012): 73-82