The document summarizes information about Tomato big bud disease, caused by the phytoplasma Candidatus Phytoplasma aurantifolia. It is transmitted by the leafhopper Orosius albicinctus. Symptoms include small, curled, purple leaves and swollen flower buds. The disease favors dry, moderate temperatures and low rainfall. Management includes removing weeds, using insect screens, and insecticides to control the leafhopper vector.

1. Course Teacher
Dr.PARTHASARATHY S
Asst.Prof(Pathology)
Submitted by,
PAVITHRA P
2015021094
TOMATO BIG BUD
Causal organism
Candidatus Phytoplasma aurantifolia

2. PATHOGEN
 Phytoplasmas (Mycoplasma - like organisms) are
specialised bacteria which do not have cell wall are obligate
parasites found in sieve elements of plants and some insect
vector.
 Candidatus means Unculturable, Grampositive bacteria
(Terrabacteria group) Intracellular in nature and
reproduction through budding and fission.
 It comes under the class Mollicutes

3. DISTRIBUTION
 Tomato big bud has been reported in China, India, and
other Asian countries, South Africa, and the USA, but the
strains have not been reported.
 Tomato big bud (16SrII) was first recorded in Australia. It
is reported from many Pacific Islands countries in many
different plants,but only in New Caledonia from tomato

4. SPREAD OF THE DISEASE
 Spread of the phytoplasma is by leafhoppers - Orosius
albicinctus.
 There is very little spread of the phytoplasma within crops of
tomato.
 The phytoplasma survives in weeds, and in the bodies of the
leafhoppers. Once leafhoppers become infected by feeding on a
plant with phytoplasma, they remain infected for life.

5. HOSTS
 Beach morning glory (Ipomoea pes-caprae subsp.
basiliensis), Chinese cabbage, peanut, sweetpotato,
and the weeds/ornamentals, Achyranthes, Celosia,
Crotalaria, Cyanthillium, Emilia, and Polygala.

6. FAVOURABLE CONDITIONS
 Dry weather
 Moderate temperature (25°C)
 Low relative humidity (65%)
 Low rainfall (0.6mm)

7. SYMPTOMS
 Leaves are small, curled upwards and yellowish-green or
purple Stems become erect, short, thick and purple ;
 Flower buds become swollen, with green petals - hence the
name of the disease - and normally dormant buds develop
shoots.
 Green fruits are hard, tough and woody.
 Plants infected early are bushy, because of the development
of many branches

8. SYMPTOMS ON LEAVES, STEM AND
BUDS
 www.pestnet.org www.pestnet.org

9.  www.pestnet.org  www.pestnet.org

10. MANAGEMENT
CULTURAL CONTROL
 There are few ways to control phytoplasma diseases; if the
damage is severe, it might be best to replant than suffer low
yields.
Before planting:
 Remove any "volunteer" tomato plants and weeds,
especially those in the tomato family, from around nurseries
and in and around field plots.

11.  Preferably, raise the tomato seedlings in a screenhouse or
under an insect screen cover.
 Do not plant next to other susceptible crops, such as
eggplant or capsicum.
 Preferably, raise the tomato seedlings in a screenhouse or
under an insect screen cover.
After harvest:
 Collect the plants together with weeds around the planting
and burn or bury them.

12. CHEMICAL CONTROL
The value of insecticides in the control of this disease
is not clear. Insecticides that are effective against the
leafhoppers, may not give control in the field. If plants
are infected by migrating leafhoppers, they may infect
before the insecticide kills them.

13. REFERENCE
 Thind. T.S. Diseases of Fruits and Vegetables and their
management, Second edition, 2016, Kalyani
Publishers, New Delhi.
 Saha. L.R. Handbook of plant diseases, 2015, Kalyani
publishers, New Delhi.