Our current, still limited, understanding of the comparative biology and evolution of polydnaviruses (PDVs) is reviewed, especially in the context of the possible origins of these parasitoid viruses and of their coevolution with carrier wasps. A hypothetical scenario of evolution of PDVs from ascovirus (or ascovirus-like) ancestors is presented, with examples of apparent extant transitional for...

Virus-infected host plants can have positive, neutral or negative effects on vector aphids. Even though the proportion of non-vector aphids associated with a plant far exceeds that of vector species, little is known about the effect of virus-infected plants on non-vector aphids. In the present study, the English grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae), a non-vector of Whe...

Since 1987, morbillivirus infections have caused serious disease outbreaks with high mortality among aquatic mammals. Baikal seals (Phoca sibirica) in Siberia were involved in an outbreak caused by a virus closely related to canine distemper virus (CDV) in 1987. Harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) in north-western Europe were struck by a newly recognised morbilliv...

Citrus species grown in Japan are affected by several viruses and viroids, including satsuma dwarf virus, citrus vein enation exocortis viroid, other viroids. Recently, a comprehensive review was made on the occurrence, history, research of following three major Japan: tatter leaf virus (apple stem grooving virus), tristeza (Iwanami 2022). As sequel, this study reviews development viroids as we...