CVPD Disease of Citrus Plants in Bali

CVPD disease (citrus phloem degeneration) is an important disease in citrus plants. The disease is spread through citrus plant seeds that have been protected by CVPD and transmitted through D. citri insect vectors. Citrus plants infected with CVPD use yellowing or chlorosis, green leaf bone color, leaf size becomes small and leaves become stiff. As a result of chlorosis occurs because the formation of chlorophyll in the leaves is reduced. Types of citrus plants showing morphology in Kintamani District were found nine types of citrus plants, namely: Siamese oranges, Selayar, Besakih, Tejakula, Sweet, Lime, Purut, Lemo and Pamelo / Bali. Symptoms of CVPD disease in each type of orange have variations in chlorosis from mild to severe. The location of different citrus plantations shows different chlorosis, it appears in the village of citrus plantations namely: Village Katung, Belancan, Bayung Gede, Clouds, Chess, Pengotan, Evening and Pelaga. Likewise, the leaves of the same orange plant as Selayar and Siam in each location showed varying chlorosis. This discovery is a variation of the chlorosis mentioned above.
Effects of chlorosis on orange leaves Mostly describe unsaturated Zn, Fe, Mn and Mg deficiency. The effect of chlorosis on deficient orange leaves is not commonly seen on the entire first stretch of orange and on all branches of each citrus plant. However, at the onset of outbreaks of CVPD disease in oranges, chlorosis appears partially or unsuitable for orange leaves on one large expanse and per citrus plant. Then after further CVPD disease attacks further on all plants showing symptoms of chlorosis and resulting in plant death.
CVPD disease can be transmitted through grafting and vectors, due to viruses.
Subsequent discoveries showed the existence of Micoplasma-like Organisms (MLO).
In further research on phytosis symptomatic chlorosis leaf tissue cells found
an MLO cell wall structure that is thicker than mycoplasmic cell membranes in
general, so that it is questioned as mycoplasma and then called Bacterial-like
Organism (BLO). It is also known that Penicilin antibiotics can prevent the onset
of CVPD disease in oranges which further questions the notion that CVPD
pathogens are bacteria. These pathogens include gram-negative, members of the
subdivision - Proteobacteria and are referred to as' Liberibacter asiaticus for
Asian strains and 'Liberoibacter africanum' for African strains