🐛✗ Tested and false“Spraying pear trees with mineral oil once you notice fruitlets blackening will stop pear midge damage that season”
The Organic Farm Knowledge/BIOFRUITNET practice abstract, drawing on its 2018-2022 UK-inclusive trial, lists mineral oil as a tested option and rates it explicitly as not very effective against this pest. RHS's own dedicated pear midge advice page doesn't mention mineral oil, or any spray, at all, favourable or not, and builds its whole management section around monitoring and physical removal instead.
Our read By the time blackening is visible, the larvae are already feeding inside the fruitlet rather than on its surface, which is consistent with why a contact spray like mineral oil would struggle to reach them and with RHS choosing not to feature spraying as a control at all.
What to do: Don't rely on mineral oil sprays for pear midge. Put the effort into the two controls both sources actually back: removing and destroying affected fruitlets before they drop, and hoeing the soil around the tree base in dry June-July weather to disrupt pupating larvae.
2 sources
“Picking up and destroying fallen or infested pear fruitlets each spring, rather than leaving them on the ground, is what actually keeps next year's pear midge numbers down”
RHS's dedicated pear midge page recommends checking fruitlets from spring and removing any that are swelling unusually fast or blackening, before the larvae finish feeding and drop into the soil. A separate 2018-2022 pheromone-trapping trial run across the UK, Netherlands, Belgium and Italy backs the same practice, recommending removal of infested fruit in May before the fruit and larvae fall to the soil. Both sources tie this directly to the life cycle: larvae that reach the soil pupate and overwinter there, so fruit removed before drop cannot contribute to the following year's emergence.
What to do: From spring, check developing fruitlets regularly and pick off any that are swelling fast or blackening at the eye end, binning them rather than composting since larvae can still reach soil from a compost heap.
2 sources
“Pear midge females lay their eggs inside the blossom before it opens, so the year's infestation is largely set before you'd ever see an open pear flower”
Both sources describe the same sequence independently: adult midges emerge from the soil in early spring and lay their eggs inside pear blossom shortly before it opens, not after. That means the whole infestation window for the year is fixed very early, by how the tree's flowering lines up with the midge's spring emergence, well before open blossom would give a gardener any visual cue.
What to do: Don't wait for open blossom as a signal to act. If monitoring closely, pheromone traps hung from early March give earlier warning than watching the flowers, and fruitlet checks should start as soon as blossom has finished rather than once it opens.
2 sources
