blights

Blight is a plant disease defined by rapid tissue death in parts of a plant, most often leaves, stems, or fruit. The term covers a range of pathogens that cause necrosis, including fungi, oomycetes, bacteria, and viruses, as well as severe environmental stress that produces similar symptoms. Blights typically spread quickly under warm, humid conditions and can affect a single plant or an entire crop.

Common signs include darkened lesions, wilting, and necrotic tissue that spreads across organs. Transmission occurs via spores or propagules carried by wind, rain splash, infected debris, or contaminated tools. Some blights are highly host-specific, such as potato and tomato late blight caused by Phytophthora infestans; others damage a broad range of plants.

Notable plant blights include potato late blight, early blight caused by Alternaria solani, and various leaf blights in cereals and fruit crops. The historical Irish Potato Famine is linked to Phytophthora infestans. Blights are also described in landscapes and trees, where they may manifest as branch dieback or fruit rot.

Management relies on integrated practices: using resistant varieties, crop rotation, sanitation to remove infected debris, timely pruning of infected tissue, and fungicidal or bactericidal treatments where appropriate. Cultural measures such as proper spacing, irrigation management to reduce leaf wetness, and quarantine help limit spread.

Outside agriculture, the word blight is also used to describe urban decay, economically depressed districts, or other forms of decline. In horticulture and plant pathology, however, blight refers specifically to disease-related tissue death in plants.