Yuanbao is the Chinese cabbage variety most resistant to green aphids
The green peach aphid, Myzus persicae, is harmful to many crops all over the world and is a vector for over 100 plant viruses. It is the main parasite of brassicas such as Chinese cabbage from northern China. Chemical control is widely used to control this aphid, but the increasing resistance to pesticides is a big obstacle for growers. 

Host plant resistance against M. persicae hasn't been reported yet and that's why entomologists from Northwest A&F University in Yangling (Shaanxi, China) studied the resistance categories of seven cultivars of Chinese cabbage. These categories included antixenosis, antibiosis and tolerance related to leaf colour and wax content.  

"The Yuanbao cultivar has shown antibiotic and aphid tolerance effects, so insect presence on this variety was lower than for the other six cultivars," explained researchers.

The aphid showed a preference for the Qingan 80 cultivar, which had the longest wavelength (green) in leaf colour. Yuanbao cabbage had a higher wax content, which in fact showed a significantly negative correlation with the preference of  M. persicae on plants. Researchers stress that the Yuanbao cultivar proved resistant to M. persicae and could therefore be used to develop integrated control programmes.