Coffee Leaf Rust Confirmed on the Islands
Kaua’i and Moloka’i in Hawaii
July 21 - 2021
Coffee Geography Magazine
The Hawai`i Department of Agriculture (HDOA) in the U.S. has
confirmed the detection of coffee leaf rust (CLR) on Kaua’i and Moloka`i. The
serious coffee plant pathogen has now been found on all major Hawaiian Islands.
On June 28, 2021, a commercial coffee grower in Kilauea, Kaua`i,
reported a possible CLR infection. HDOA collected samples and CLR was confirmed
on July 9, 2021. Preliminary assessments indicate that CLR had been on Kaua`i
for at least six months.
On June 14, 2021, HDOA staff conducted a survey of feral coffee
plants on Moloka`i . A low-level infestation was detected on two coffee plants
in a field of 50 wild coffee plants in Kaunakakai and CLR was confirmed on June
23, 2021. Subsequent surveys detected more infestations on the east side of the
island. It is estimated that the infestation on the east side had been there
for at least three months.
CLR was first detected in the state in October 2020 on Hawai`i Island
and Maui and subsequently detected on O`ahu and Lana`i in January 2021.
Since the first detection, the Hawai`i Board of Agriculture
(Board) approved an interim administrative rule which restricted the movement
of coffee plants, plant parts and other CLR hosts from infected islands to try
to stop the spread of the disease. With the detection of CLR statewide, HDOA is
reassessing these restrictions; however, they will remain in place until
further action is taken by the Board or the interim rule lapses in November
2021.
CLR is a devastating coffee pathogen and was first discovered in
Sri Lanka in 1869 and can cause severe defoliation of coffee plants resulting
in greatly reduced photosynthetic capacity. Depending on CLR prevalence in a
given year, both vegetative and berry growth are greatly reduced. There
are multiple long-term impacts of CLR, including dieback, resulting in an
impact to the following year’s crop, with estimated losses ranging from 30
percent to 80 percent.