Ecology of the Insect Vectors of Citrus Systemic Diseases and Their Control in Taiwan
This Bulletin discusses the ecology of the Asiatic citrus psyllid (Diaphorina citri) in relation to epidemics of greening disease of citrus. The citrus brown aphid (Toxoptera citricidus) is briefly mentioned, together with control measures against both vectors. The female psyllid lays eggs only on the new shoots of its host plants. It is especially active during the spring flush. The females lay eggs repeatedly whenever new shoots are available. Citrus brown aphid, a vector of tristeza, is also most common during the spring flush. In Taiwan, psyllids complete 8 to 10 generations each year. Adults and 4 - 5th instar nymphs may acquire the pathogen from diseased plants after feeding for 30 minutes or longer. Transmission is persistent throughout the adult life span (ca. 3 to 4 months or longer). However, the virulence cannot be transferred to the progeny via eggs. The Bulletin describes control technology. The importance of skilled manpower, financial support from the government and sound legislation are also emphasized in implementing control programs.