Huanglongbing (HLB) is a devastating citrus disease worldwide. A three-pronged approach to controlling HLB has been suggested, namely, removal of HLB-symptomatic trees, psyllid control, and replacement with HLB-free trees. However, such a strategy did not lead to successful HLB control in many citrus producing regions. We hypothesize this is because of the small-scale or incomprehensive implementation of the program, conversely, a comprehensive implementation of such a strategy at regional level can successfully control HLB. Here we investigated the effects of region-wide comprehensive implementation of this scheme to control HLB in Gannan region, China, with a total planted citrus acreage of over 110,000 ha from 2013–2019. With the region-wide implementation of comprehensive HLB management, overall HLB incidence in Gannan decreased from 19.71% in 2014 to 3.86% in 2019. A partial implementation of such a program (without a comprehensive inoculum removal) at the regional level in Brazil resulted in HLB incidence increasing from 1.89% in 2010 to 19.02% in 2019. A dynamic regression model analyses predicated that in a region-wide comprehensive implementation of such a program, HLB incidence would be controlled to a level of less than 1%. Economic feasibility analyses showed that average net profits were positive for groves that implemented the comprehensive strategy, but negative for groves without such a program over a ten-year period. Overall, the key for the three-pronged program to successfully control HLB control is the large scale (region-wide) and comprehensiveness in implementation. This study provides valuable information to control HLB and other endemic diseases worldwide.

Comparisons between petroleum spray oil (PSO)-based pest management (pest management based on petroleum spray oil) and conventional pest management were made in a navel orange orchard from 2004 to 2005 in Ganzhou, Jiangxi province, South China. PSO-based management reduced chemical pesticide use and increased the species richness of natural enemies. To control the key pests below the economic threshold, PSO use, compared with chemical pesticide, reduced the cost of pest management. PSO had no negative effects on fruit yield and quality, and could form the basis of a practical and sustainable pest management program in navel orange.

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