A status yellow potato blight warning was issued at 8:00pm last night, July 11, by Met Eireann for later this week.
This follows on from a similar warning issued earlier this week for both Monday and Tuesday.
Weather conditions conducive to the spread of potato blight is expected late on Friday and right through on Saturday, according to Met Eireann.
This warning is set to apply to mostly coastal areas in the west and north-west, it added.
Conditions today, Wednesday, are expected to be mainly dry and bright, with good sunny spells and light variable breezes.
There is a risk of one or two light showers, as temperatures reach as high as 22º. On Wednesday night, cloud is set to increase in the west, with rain and drizzle developing overnight.
It will be cloudier overall tomorrow, Thursday, in western and northern areas, with scattered outbreaks of rain. It will turn brighter in the evening, with just a few showers.
Mostly dry and fairly bright for a time in the morning in the southern and eastern areas, but a little showery rain will develop in places in the afternoon and evening.
Highest temperatures of 16º to 21º are forecast in moderate south-west breezes.
Both Leinster and Munster are expected to enjoy some dry, bright or sunny spells on Friday. Connacht and Ulster will start off dry, but rain and drizzle will move in from the west in the afternoon and early evening.
This is set to extend to much of the country on Friday night. Temperatures are likely to range from 15º in the north-west to 20º in the south-east.