Botrytis

摘要

Mainly important on stored onion crops, also affecting other alliums such as garlic, shallot, multiplier onion and leek. Separately, B. bysoidea causes grey neck rot while B. squamosa causes small sclerotial neck rot.The causal pathogen is B. allii, which produces copious asexual conidia and rapidly spreads the disease. Affected bulbs become covered with large black resting bodies (sclerotia).Principally, this is a seed-borne disease and is also spread via infected onion sets and on shallots. Even where infected seed is stored at low temperatures the pathogen can survive for up to three years in a dormant state.