Watercress Decline in Hawaii

healthy-looking watercress field

healthy-looking watercress plants

diseased watercress field

symptomatic watercress plants

Randy Hamasaki was collecting samples from symptomatic watercress plants.

parrots feather, a potential alternative host of the phytoplasma

plantain, another potential alternative host of the phytoplasma

only symptomatic watercress plants tested positive in PCR using primers
specific for phytoplasma (used to be called MLO)

Plantain and parrots feather samples were tested
positive in PCR for phytoplasma

Watercress Decline Phytoplasma,
a Pest Emergency to Hawaii's Agriculture

(Research Needed)

1. Etiology

1) PCR

2) sequence data (Aster yellows phytoplasma?)

3) EM information

4) tetracycline treatment

2. Epidemiology

1) distribution in watercress in Hawaii

2) in other crops

3) other weeds? (plantain and parrots feather)

4) vectors (aster leafhopper)

a. distribution of the vectors

b. hosts of the vectors

3. Management

1) eradication (watercress and weeds)

2) vector control