CPHST Support: Bringing Pests, Surveys, Plants, and Science Together Melinda SullivanLisa Jackson Daniel MackesyTalitha Molet

Vectored Pathogens

The Issue… How should CAPS handle insects or pathogens that vector damaging pathogens but may not be damaging on their own? How should CAPS handle insects or pathogens that vector damaging pathogens but may not be damaging on their own? Most common vectors: aphids, thrips, leafhoppers, planthoppers, psyllids, some beetles, some fungi, some nematodes, etc. Most common vectors: aphids, thrips, leafhoppers, planthoppers, psyllids, some beetles, some fungi, some nematodes, etc. In general, the insects are small, fairly non- descript and do not have specific traps and lures. In general, the insects are small, fairly non- descript and do not have specific traps and lures. Fungal/nematode vectors are also non- descript and usually employ visual survey or generalized soil sampling (nothing specific). Fungal/nematode vectors are also non- descript and usually employ visual survey or generalized soil sampling (nothing specific).

Example – Tropical Pest List Hypocryphalus mangiferae (mango bark beetle) vectors Ceratocystis manginecans (mango sudden decline fungus) Hypocryphalus mangiferae (mango bark beetle) vectors Ceratocystis manginecans (mango sudden decline fungus) Vector failed; Pathogen passed Vector failed; Pathogen passed Can’t have disease development without the vector, but the pathogen is the damaging part of the complex. Can’t have disease development without the vector, but the pathogen is the damaging part of the complex.

Choices 1)Ignore the vectors? 2)Run the vectors and pathogen separately? 3)Do a combination analysis where both the insect and vector receive the same rank?

1. Ignore the vectors This is currently the default. This is currently the default. The vectors are generally small, fairly non- descript, do not have specific survey methods, and do not cause appreciable damage on their own. The vectors are generally small, fairly non- descript, do not have specific survey methods, and do not cause appreciable damage on their own.

2. Run the vectors separately Many of these vectors do not cause appreciable damage on their own. Many of these vectors do not cause appreciable damage on their own. Don‘t often rank high in ranking model Don‘t often rank high in ranking model Most will fail the post-assessment. Most will fail the post-assessment. Most vectors that were included on our prioritized pest list in the past occurred prior to the post-assessment being used Most vectors that were included on our prioritized pest list in the past occurred prior to the post-assessment being used Example: Diaphorina citri (Asian citrus psyllid)– vector of HLB/ citrus greening Example: Diaphorina citri (Asian citrus psyllid)– vector of HLB/ citrus greening

3. Combination analysis Both pathogen and vector get same rank (analyzed as a complex) Both pathogen and vector get same rank (analyzed as a complex) Issue: Some vectors could potentially vector multiple pathogens; some pathogens are vectored by multiple species of vectors Issue: Some vectors could potentially vector multiple pathogens; some pathogens are vectored by multiple species of vectors Example: PPV vectored by 20 different aphid species Example: PPV vectored by 20 different aphid species

Aphis arbuti A. craccivora* A. fabae A. gossypii* A. hederae A. spiraecola* Brachycaudus cardui B. helichrysi** B. persicae* Dysaphis plantaginea D. pyri Hyalopterus pruni* Macrosiphum rosae Megoura rosae Myzus persicae** M. varians Phorodon humuli** Rhopalosiphum padi Sitobion fragariae Ureleucon sonchi *Recognized aphid vectors in United States, ** Most important vectors. Data from Levy et al. (2000b). Aphid Vectors of Plum pox virus

What if the vector is already in the United States? Insects present in the United States would likely be non-reportable at the port of entry. Insects present in the United States would likely be non-reportable at the port of entry. CAPS wouldn’t necessarily support survey for the vector but there may be an open pathway for the pathogen. CAPS wouldn’t necessarily support survey for the vector but there may be an open pathway for the pathogen. Vector could harbor an exotic pathogen of interest or new strains/ virulent isolates of an endemic pathogen. Vector could harbor an exotic pathogen of interest or new strains/ virulent isolates of an endemic pathogen. Most of the pest suggestions that fall into this category are still pending (pre-assessments completed but only running highly damaging pathogens through the model). Most of the pest suggestions that fall into this category are still pending (pre-assessments completed but only running highly damaging pathogens through the model).

10 of 11 suggestions still pending Andean potato latent virus (APLV) Andean potato mottle virus (APMoV) Begomovirus potato deforming mosaic virus (PDMV) Potato virus V (PVV) Potato yellow vein virus (PYVV) Potyvirus Moroccan watermelon mosaic virus (MWMV) Rice hoja blanca virus (RHBV) Tomato blackring virus (TBRV) Tomato leaf curl New Delhi virus (ToLCNDV) Tomato torrado virus (ToTV) Tomato Yellow Leaf Curl Virus (TYLCV) (exotic strains)

Questions /Discussion