Grape berry moth

What you see

Small caterpillars webbing flower buds together in spring, then boring into ripening berries.

Damage

Webbed flower clusters early in the season. Later, holes in individual berries, frass, and grey botrytis rot spreading from the wound.

Lifecycle on this coast

Three generations a year in Portugal: on flowers, on green berries, then on ripening fruit. Overwinters as pupa under bark.

When to act

The third generation matters most because its wounds let in botrytis. Trap from April to time it.

Months: April, May, June, July, August, September

Plants it bothers

Grape

Natural enemies

Trichogramma parasitic wasp, Bat, Spider, Earwig

Remedies

Pheromone traps, Bacillus thuringiensis (Bt), Encourage predators

The thing people get wrong

Most of the loss is not the caterpillar itself but the grey rot that follows it into the wound. Bats are a serious ally here - a single bat can take thousands of moths a night, so a bat box near the vines is a genuine control measure, not decoration.