Page 42 - SV 3 2024

The dreaded midge
ADRIAN BAGGALEY
When it comes to fruit pests, most people have heard of codling moth
(a serious pest of apples and a lesser one of pears) and that is about it. Anyone with the odd pear tree would, highly likely not even notice the large orb shaped fruitlets among the other fruitlets. These orb shaped fruitlets
and indeed others not conforming to a typical pear shape will, in around couple of weeks turn black and drop off, by that time the occupants of these fruitlets will have dropped to the ground, these are the next generation and will re-emerge the following April as adult midges, Contarinia pyrivora.
I once read that pear midge was a minor pest of pears, if that was true at the time
of writing it certainly is not true now. I read of people, euphemistically describing this pest as doing you a favour by thinning the fruit for you. I would much rather thin my own fruit. The amount of infestation you get depends on when the tree is in blossom, around here (Nottinghamshire) any pear blossom in March generally escapes, so this Spring I had mixed feelings about
most of the pear blossom coming out in March, (this has never happened before), it would mostly miss the midge, but may be hit by frost. I was wrong; some of the one hundred and twenty-three pear trees in the orchard were annihilated by the little beggars. Instead of pyriform shaped fruitlets whole trees had orb and urn shaped fruitlets (see the
Infected fruitlets
mulch to stop them re-emerging, this didn’t work, so it is not going to work with one hundred and twenty three trees. Of those two original trees it was noticeable that
the midge had their favourite, they always went for the William bon Chretien ( Bartlet or Christ’s Pear) and left the Conference, the William bon Chretien generally
an infected fruitlet. Where this gets a bit difficult is when the mature pear variety
is round. Don’t skip the top of the tree as I did for years, most are generally infected. The first few pickings were examined and there was no visible damage inside so these were buried in the wormery, not sure what the brandlings would make of them. Further pickings showed signs of damage; the larvae tend to eat the seeds and the surrounding area. These fruitlets are put into a container of water – the tenants don’t swim too well, under no circumstances throw them on the ground. Leave the infected fruitlets in the water until they are black and the occupants are dead – make sure they have not just pupated. Don’t do as I did in 2022 I left a Rhino Tub with a serious amount of infected fruitlets in it for several days, when I got back to it there was a Great Escape underway.
I find that the following can have minimal damage, Conference, Concorde and Onward, this may be that they are prolific croppers and are slightly later blossoming. I think there will always be sacrificial lambs. One of this seasons sacrificial lambs is certainly Doyenne’ d E’te’ with lots of blossom resulting in lots of infected fruitlets and barely any healthy fruitlets. ATB Proof read by MCB.
pics), little normal fruit
set. Considering I have been picking them off for years, ever since Bifenthrin was withdrawn, it now amounts to devastation.
Perhaps I should be introducing a few hens into the orchard to scratch about and bring the larvae up to the surface
flowered first, so that was the one they ‘pounced’
on, depositing their eggs on the anthers, if the blossom on this variety was frosted they attacked the Conference. This should
be telling me something – perhaps the anthers
are severely damaged by the frost leaving them no alternative. The arrival of pear midge pheromone traps cannot arrive too soon for me, but they may be years away. Picking
off must be done before
It would be reasonable
to assume that picking
off the infected fruitlets
year on year; they would
gradually die out – not the
case, at least up to now,
they are on the increase.
The most larvae I have
found in an infected fruitlet
is around twenty-two, so
what is the mortality rate
of these larvae preserved in the ground for around eleven months? Perhaps I should be introducing a few hens into the orchard to scratch about and bring the larvae up to the surface. When I had a mere two trees, I covered up the ground with a plastic
the fruitlets turn black. This season I started picking the infected
ones off a little earlier; you have to find an uninfected typical baby pear, these are not unlike a very, very miniature Conference, longish tapering neck to a rounded base, a thin neck to a bulbous base is generally
42 Simply Vegetables