Occurrence of in periwinkle in California
Authors Affiliations.; .; .; .; ..
Hilgardia 30(3):18-19. DOI:10.3733/ca.v030n03p18. March 1976.
Citrus stubborn disease is a serious economic problem in California, in Southwestern United States, and in other arid citrus areas of the world. Knowledge of the disease has rapidly increased since 1969 when a mycoplasma-like organism was found by electron microscopy in thin sections of diseased leaves. In 1970, a mycoplasma, now named Spiroplasma citri, was cultured from diseased citrus tissue. Further research has revealed that two leafhoppers (see California Agriculture, November 1973) can transmit the stubborn disease organism. Cultured spiroplasma have been fed or injected into these insects and they, in turn, have transmitted stubborn to healthy citrus seedlings. More recently (see California Agriculture, February 1975), one of the insects, Scaphytopius nitridus, fed on diseased citrus trees was shown to transmit a severe disease to healthy Vinca rosea L., periwinkle plants, in controlled greenhouse experiments. This information prompted our investigating the possibility of natural spread of stubborn into periwinkle plants.
Also in this issue:Hard tomatoes and hardy myths
Energy needs of pregnant heifers
Predicting meat quality
Smog hurts alfalfa
Ebbing timber supply
Improving nitrogen fixation
Iron deficiency in California crops
Devrinol and surflan: New selective weed control in young orchards and vineyards
Rose powdery mildew control in outdoor roses
Liquid protein supplement in dairy cattle rations
Maps of soil erosion potential — an aid in land-use planning in range and wildlands
Survival of the sugarbeet cyst nematode in the alimentary canal of cattle
Drip irrigation for plants grown in containers
Ocypus olens: A predator of brown garden snail
Some physiological responses in two tomato varieties associated with levels of soil bulk density