A wetter-than-usual spring has caused crops like tomatoes, onions and grapes to spoil because of an “explosion” of mould.

Last month was the most humid May in a decade and June has had an equally steamy start, according to the Meteorological Office. Malcolm Borg, co-ordinator of Għaqda Bdiewa Attivi, says the unseasonal rain and humidity of the last few weeks has not been welcomed by farmers.

“Mould on crops has exploded. It has been given the ideal conditions to spread,” he said.

It is also causing difficulty with the harvest of wheat crops, which use around two-thirds of Malta’s arable land and are left on the land for three days to dry before being collected in bails.

The misery of high humidity

Rain waters the crops and fills aquifers, but it is not welcome during this time of year, said Borg, who is also deputy director of MCAST’s Institute of Applied Sciences.    

“We would have preferred if the rain stopped earlier,” he said. 

May recorded an average relative humidity of 78%, which is higher than the climatic norm of 72%, according to Met Office figures.

“Considering the last 10 years, the highest humidity was recorded in May 2023 (78%), closely followed by 75% in 2018 and 72% in 2014,” it said.  

June is also on course to be the decade’s most humid, so far recording an average relative humidity of 77%, exceeding the climate norm of 67%, the Met Office added.

Onions, grapes, and tomatoes are all in a sensitive time of their life cycle, leaving them particularly vulnerable to mould and other diseases caused by humidity.

Onions, grapes, and tomatoes are all in a sensitive time of their life cycle.

Farmer Joanne Bezzina grows tomatoes, onions, strawberries, melons and watermelons in her 60 tumoli farm in Burmarrad. 

“There are a lot of diseases especially mould and black spot leaf disease,” she said, adding that rain has increased diseases among her crops at the Burmarrad farm.  

“Anything at the wrong time is harmful,” she said.   

The farm produces seven tonnes of tomatoes in a good year but she and her husband are expecting a far lower yield this time around.  

While farmers can use pesticides to control the spread, it is not enough to stop it entirely. 

“It’s like having someone shoot at you with a machine gun and defending yourself with a medieval sword,” Borg said.  

May produced a total of 18.4mm of precipitation, which is 8mm more than the month’s climatic norm, the Met Office said.  June has so far seen 3.4mm of precipitation which has not yet exceeded the monthly climate norm of 6mm. 

While June had a wet and humid start, it is due to become much hotter and drier by the weekend with Saturday forecast to be sunny and feel as hot as 30°C.