And three in four teachers say their teacher training course failed to help them recognise and take action to help a child with dyslexia, the survey of 1,577 members of the Professional Association of Teachers shows.
Released to coincide with the national dyslexia campaign week, the survey reveals that fewer than a third of schools employ dyslexia specialists, even though 4 per cent of pupils suffer from "word blindness".
Paul Cann, director of the BDA, said the findings prove that teachers are failing to pick up warning signs early, starting a cycle of failure which can lead to serious social problems.
"There is a link between bad behaviour in the classroom and failure to learn. If learning difficulties aren't identified at an early age, we are setting up a dangerous spiral where children don't like going to school and feel out of place there. That can cause all sorts of problems later on," he said. "Teachers need to be given the support and resources so that every teacher feels equipped to deal with dyslexia."
The warning signs, said Mr Cann, include a "jagged" learning profile and chronic difficulties with spelling, reading or another part of the curriculum.
The association is pressing the Government to ensure that an understanding of dyslexia is compulsory in the new national teacher training curriculum. It wants pupils to be screened for dyslexia in their first two terms as part of baseline assessment.