SUMMARYUsing standard diversity indices, samples of aphids collected on a vertical net were found to be more diverse than collections from green pan traps in experiments conducted in Nanjing, China in 1981. Some species, notably Myzuspersicae, Aphis citricola, and Eriosoma (Schizoneura) japonicum, were collected in greater relative numbers in the pan traps. Several species, including the Macrosiphoniella spp., were under‐represented in the green pan traps presumably because they were not attracted to the green colour of the traps. Yellow pan traps, used concurrently to monitor landing rates of economic species, caught relatively more Aphis craccivora and M. persicae and relatively fewer Aphis gossypii than green ones.In the Nanjing area soybean mosaic virus (SMV) usually spreads in spring planted soybeans during the latter half of May, causing damage. The predominant aphid species trapped at that time were M. persicae, Lipaphis erysimi, A. gossypii, A. craccivora and E. japonicum, of which the first four are known vectors. Summer planted soybeans are usually affected during a second period of virus spread occurring in mid‐August when various Aphis spp. are abundant. The predominant vector of SMV at that time was thought to be Aphis glycines which colonises the crop; in 1981, however, A. citricola and A. gossypii, which do not colonise soybean and A. craccivora. which rarely colonises soybean, were much more abundant in mid‐August than A. glycines. A. citricola, A. gossypii and A. craccivora are all able to transmit SMV, and thus should be considered as potentially important vectors. In infectivity assays, only four of 1040 aphids transmitted SMV. These included an A. craccivora, two Toxoptera citricidus and one Aphis sp.

A viral disease of broad bean (Vicia faba) was observed in Jiangsu, Zhejiang and Sichuan Province, the People's Republic of China. Its typical symptom on infected leaves was a white mottle, and, rarely, red necrotic lesions on several broad bean cultivars. A non‐aphid‐transmissible strain of turnip mosaic virus (TuMV) was identified as the causal agent of the disease on the basis of biological properties, particle morphology, seed and aphid transmission and serological tests. The virus could not be transmitted by aphids in the non‐persistent manner.

A new strain (TN strain) of cucumber mosaic virus (CMV) was isolated from tomato plants with necrotic symptoms and proved to carry a necrogenic satellite RNA (TN-Sat RNA). Double-strand cDNA of the TN-Sat RNA was synthesized by reverse transcription and polymerase chain reaction using primers designed according to the conserved terminal sequences of known CMV satellite RNAs. Sequence analysis indicated that the TN-Sat RNA consisted of 390 nucleotides (nt). Comparison of the sequence of the TN-Sat RNA with those of other CMV satellite RNAs revealed four homologous regions (I. 1-81 nt; II. 216-261 nt; III. 278-338 nt; IV. 349-390 nt) and one hypervarible domain in the region of 82-215 nt. Moreover, the TN-Sat RNA contained a characteristic necrogenic consensus sequence at the 3' end (339-367 nt) as reported in the known necrosis-inducing CMV satellite RNAs.