Pumpkins and other squashes are susceptible to several viruses, which are transmitted to the plants by aphids. The aphids that fly in to the planting are the ones that bring the virus from reservoir weeds, and other plants that harbor viruses in the area around your garden. There is no cure for viruses in plants. Usually, the younger the plant at the time of infection, the more severe the effect of the virus on its host. Flower abortion may occur. Fruit production will be slowed or may stop, and the fruit and leaves may be deformed. Plants that stop bearing should be destroyed. The fruit that does develop, even though it is deformed, is still safe to eat. In pumpkins, some kids get a kick out of deformed fruit – the uglier, the better. So deformed and blistered pumpkins may be worth more than virus-free jack-o-lanterns.
