The UK has increased the number of fruit pickers from 10k to 30k. Professional fruit pickers follow the season across Europe so are in work all year round - which makes them cost effective and productive. The silly notion that UK citizens would just be able to take this job for 3 months and then what? Find another job for 9 months of the year or have a full time job and ask for 3 months off to go Fruit picking.
It's disingenuous and silly to suggest 'UK' workers couldn't do it because traditionally, they always have. I'm not being romantic by harking back to the days of cockneys hop picking, but there are itinerant 'do as yer likeys' workers that do follow seasons and earn good money, pick crops for 4 months, tarmac drives for four months, spend 4 months resting on the ranch back in Ireland. I'm puzzled as to why you think 'this type' of work is exclusive to poorer EU nationalities, or is this part of the workers rights ellal bangs on about?