an infectious disease of plants of the family Solana-ceae (tomatoes, potatoes, peppers, eggplants) and of certain weeds (bindweed). The causative agent of big bud is generally believed to be Lycopersicum virus-5; some authorities believe the source of the disease to be mycoplasma. Characteristic symptoms of big bud are yellowing, inhibited growth, severe dwarfing of leaf lobules, loss of coloration in the center of leaves and reddening of leaf margins, and deformation and sterility of flowers. Tomato flesh becomes woody and inedible, and potato tubers become spindle-shaped and during sprouting produce threadlike shoots. The reservoir hosts of the disease’s causative agent in nature include the European glorybind (Convolvulus arvensis) and certain other plants in whose roots the agent winters. The carrier of the virus is the cicada Hyalesthes obsoletus (mainly adult individuals), whose larvae winter on weed roots.

Big bud may lead to large crop losses. Control measures include the cultivation and deep autumn plowing of fields to destroy weeds and cicada larvae and the growing of crop varieties resistant to the disease.