Asian Citrus Psyllid and Huanglongbing Neil McRoberts & Carrie Teiken, UC Davis Beth GraftonCardwell, UC Riverside Tim Gottwald & Weiqi Luo, USDAARS Ft Pierce, FL Paul Mitchell, UW Madison, WI Len Coop, OSU, Corvallis, OR
Overview Introduction to pest and pathogen Indication of California situation Industry, State and federal responses to HLB threat
Asian Citrus Psyllid (Diaphorina citri) and HLB (Candidatus Liberibacter asiaticus) http://californiacitrusthreat.org/
/HLB situation in California http://www.cdfa.ca.gov/plant/acp/index.html first discovered in 2008 Now widespread in much of southern California In 2013 detections in southern San Joaquin Valley became more frequent To date only 1 confirmed case of HLB: tree in residential neighborhood of greater LA.
Incursion of into the San Joaquin Valley CA 99 CA 198 detections in 2013 CA 65 Source: CDFA CA Quarantine areas; web interface
IRCHLB III: Riskbased Residential HLB/ Survey for California, Texas, and Arizona Tim Gottwald Weiqi Luo Neil McRoberts
Purpose of a CA Residential Survey Justification: Early detection of HLB to: Maximize regulatory intervention and disease control. Minimize disease incidence, spread, and impact to commercial citrus industry. The recent finds of HLB underscore the urgency Los Angeles basin (residential) Texas (Commercial planting) Requisites and Goals: A statistically accurate and justifiable survey protocol to be used pre and postdiscovery for early detection across all citrus industries within the US that: Incorporates all HLB/ biological and epidemiological factors. Can be applied across residential areas and commercial citrus. Has high probability for early detection of both HLB and. Maximizes targeting of control/mitigation efforts. Maximizes fiscal and manpower resources.
Integration Model framework Original Census tract Filtering Elevation Water Land cover Military Indian Reservation Risk modeling Resulting residential area Weather Population & race Citrus transport (Nursery & Big box store Citrus green waste) + Final risk mapping and survey protocol
2. Risk Modeling Determining risk variables and their effects
Formula & algorithm Estimate total risk in residential area, including: Potential HLB risk Known HLB risk Output variables 1. Residential citrus population and distribution Residential citrus: 2. Residential Asian population risk 3. + location risk Residential Asian risk: R Asian 4. Citrus production related transport corridors + risk: R 5. Potential spread risk from commercial Transportation risk: R nursery, green waste facility, military Road installation, packing house and flea market Potential risk: R 6. Distance to MexicoTX border crossing LAS+ risk R LAS 7. HLB and LAS+ locations risk Border crossing risk: R 8. Proximity to commercial citrus groves Border (adjustment for sampling intensity) No prior preference for each risk factor, so equal weight is applied. The suitable weighting to be determined later from survey results. Total risk= Residential citrus *{([Asian] + [+] + [Road]+ []+[Border])/5+[LAS+]} = log( Pop citrus )* ( R Asian R R Road 5 R R Border ) R LAS Pop citrus Total risk Proximity to commercial citrus groves Sampling intensity
Formula & algorithm 4. Estimate risk from citrus fruit transport corridor (to packinghouse and juice plants) Apply HLB/ spread curve determined from Florida data Major routes with strong effects on HLB Major routes with strong effects on Full information available: Gottwald & Luo, An investigation of transport network on HLB/ spread.
Distance to commercial citrus groves Not Risk but affects sampling intensity Proposed new sampling scheme Linked with dispersal curve determined from FL data Southern California Rio Grande Valley, TX
3. Risk Mapping Integrating filtering and risk variables with GIS data to develop survey design and intensity
Total risk map (Considers all variables and filtering) Rio Grande Valley, TX Southern California
Incursion of into the San Joaquin Valley CA 99 CA 198 detections in 2013 CA 65 Source: CDFA CA Quarantine areas; web interface
Manpower and number of survey cycles/year 1 cycle/year 1 cycle/year 2 cycles/year 2 cycles/year 2 cycles/yr does not detect disease at as low an incidence
Riskbased sampling (1or 2 cycles/year) 1 cycle/year 2830 STR grids selected based on risk 2 cycles/year Cycle 1: 1393 STR grids Extra assurance = Includes random selection of a small proportion of low risk STR areas. In case we are totally wrong!!!! 2 cycles/year Cycle 2: 1464 STR grids
For more information on risk assessment A webcast by Dr Gottwald describing the process of building and deploying the risk model, mapping, and survey protocols is available at: http://www.plantmanagementnetwork.org/edcenter/seminars/outreach/citrus/hlb/
Medium to longterm solutions Organize growers into neighborhood (areawide) response groups (learn from unfortunate FL experience). Breed and release an altered Psyllid which is not competent as a vector for Clas. Subject of $15M USDA/Industry CAP grant
Where would Psyllid sit in the spectrum of opinion about GM traits? Human health benefit 0.7 0.6 0.5 0.4 0.3 0.2 Corn Papaya Mosquito Ecological risk Technology dread Genetic pollution Corporate greed/monopolies Unnatural technology Genetic pollution Unnatural technology 0.1 0 For Neutral Against Scientific merits Agricultural sustainability Editorializing Division of Google ranked pages on page 1 of searches for GM corn, GM papaya and GM mosquito.
Crossing the Rubicon Adopting a biotech solution moves the industry to a qualitatively different place in public perception Does it have to?
Simple causal model: a first look at Psyllid deployment Use of Public thinks is harmful Public thinks is dangerous Industry see as useful Industry backs Decrease insecticide use developed Political support for
Demonstrating benefit and avoiding antagonism could lead to sustainable Psyllid use 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Growers perceive nu_ as 182 404 835 2E+ beneficial 1 1 5 3 11 16 55 81 208 404 923 1 3 0 06 182 404 835 8E+ Adoption of nupsyllid 0 1 1 5 3 11 16 55 81 208 404 923 1 3 0 05 182 404 835 4E+ Decrease in pesticide use 1 0 1 1 5 3 11 16 55 81 208 404 923 1 3 0 05 Industry promotes nu_ 127 288 586 2E+ technology 0 5 2 10 11 42 54 154 279 662 1 1 1 06 168 347 750 3E+ Nu_ developed 1 2 5 6 23 34 88 165 388 758 8 1 2 06 Political support for nu_ 187 390 835 2E+ technology 1 0 0 5 9 19 40 98 190 414 873 7 6 3 06 Public perceives nu_ as 170 352 757 dangerous 1 0 0 1 0 5 8 19 35 90171379783 6 7 0 Public perceives nu_ crops 170 352 757 as harmful 1 0 0 1 0 5 8 19 35 90171379783 6 7 0 It may even be possible at low direct cost to the industry Growers perceive nu_ as 182 404 beneficial 1 5 3 11 16 55 81 208 404 923 1 3 Adoption of nupsyllid 1 1 5 3 11 16 55 81 208 404 923 Decrease in pesticide use 0 1 1 5 3 11 16 55 81 208 404 923 182 1 835 2E+ 0 06 404 835 8E+ 3 0 05 182 404 835 4E+ 1 3 0 05 Industry promotes GM technology 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 168 347 750 3E+ Industry develops GM technology 2 5 6 23 34 88 165 388 758 8 1 2 06 Political support for GM 187 390 835 2E+ technology 0 0 5 9 19 40 98 190 414 873 7 6 3 06 Public perceives GM technology 170 352 757 as dangerous 0 0 1 0 5 8 19 35 90171379783 6 7 0 Public perceives GM crops as 170 352 757 harmful 0 0 1 0 5 8 19 35 90171379783 6 7 0
What happens if public opinion is strengthened by industry promotion? Use of Public thinks is harmful Public thinks is dangerous Industry see as useful Industry backs Decrease insecticide use developed Political support for
With feedback between industry PR and public opinion things get messy Growers perceive nu_ as beneficial 1 1 5 7 7 34 9 185 140 800 725 Adoption of nupsyllid 0 1 1 5 7 7 34 9 185 140 800 725 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 281 9 196 1 281 9 694 6 Decrease in pesticide use 1 0 1 1 5 7 7 34 9 185 140 800 725 281 9 Industry promotes nu_ 133 219 technology 0 5 2 20 15 72 40 192 41 146 1 5 187 466 875 Nu_ developed 1 2 5 6 13 0 4 111 270 892 8 7 2 Political support for nu_ technology 1 0 0 5 15 49 108 268 526 Public perceives nu_ as dangerous 1 0 5 6 27 37 116 149 375 343 674 517 Public perceives nu_ crops as harmful 1 0 5 6 27 37 116 149 375 343 674 517 108 4 181 1 301 3 331 0 191 2 191 2 156 129 4 8 694 156 129 1 6 4 8 196 694 156 129 1 6 4 8 196 168 1 385 7 2E+ 06 8E+ 05 4E+ 05 3E+ 06 4E+ 06
What happens if public opinion is strengthened by industry promotion? Use of Public thinks is harmful Public thinks is dangerous Industry see as useful Industry backs Decrease insecticide use developed Political support for
With negative feedback between industry PR and skeptical public opinion there is hope Growers perceive nu_ as 107 225 458 952 7E+ beneficial 1 3 3.1 7.08 12.3 33.6 54.6 129 252 533 4 6 6 3 05 107 225 458 952 4E+ Adoption of nupsyllid 1 1 3 3.1 7.08 12.3 33.6 54.6 129 252 533 4 6 6 3 05 107 225 458 952 2E+ Decrease in pesticide use 0 1 1 3 3.1 7.08 12.3 33.6 54.6 129 252 533 4 6 6 3 05 197 397 829 1E+ Industry promotes GM technology 5 4 9.9 10.9 31.9 48.3 117 216 472 928 0 9 5 06 107 215 450 920 1E+ Industry develops GM technology 2 5 4 17.1 24.4 62.8 115 257 500 2 5 7 2 06 189 393 807 6E+ Political support for GM technology 0 2 1.1 3.28 11.6 21.1 52.2 101 220 442 930 3 7 0 05 Public perceives GM technology as 140 289 595 dangerous 1 0.95 0.91 0.81 0.7 0.38 0.1 1.27 3.42 8.14 17.4 37.1 76.9 160 329 681 2 1 6 Public perceives GM crops as 140 289 595 harmful 1 0.95 0.91 0.81 0.7 0.38 0.1 1.27 3.42 8.14 17.4 37.1 76.9 160 329 681 2 1 6
Acknowledgements USDA Citrus Research & Development Foundation (FL) Citrus Research Board (CA)