Vectors of Plant Viruses of Crop Plants in Southeast Asia 167
250 species are serious pests for agriculture and
forestry as well as an annoyance for gardeners.
Virus Transmission and Virus–Vector Rela-
tionship Aphids constitute the largest vector
group transmitting plant viruses. Cardamom
mosaic (Katte) is an important virus affecting the
production of cardamom in Karnataka. The virus
was transmitted by aphid, Pentalonia nigroner-
vosa. There was a negative correlation between
aphid population and the disease spread. The
highest spread of disease occurred when aphid
population was low. The spread of the disease
was more associated with aphid activities rather
than aphid population (Deshapande et.al. 1972 ).
The seed borne nature of common bean mo-
saic virus and its transmission by Aphis crac-
civora Koch, A. fabae sub-sp solanella, A. gos-
sypii Glov. Liphaphis erysimi, and M. persicae
Sulz. were reported by Muniyappa ( 1976 ). Citrus
tristeza virus (CTV) and a virus disease resem-
bling Hassaku dwarf in acid lime ( Citrus auran-
tifolia) were transmitted efficiently by aphid,
Toxoptera citricida Kirkaldy (Balaraman and
Ramakrishnan1977a, 1977b).
Marrow mosaic virus, a strain of watermel-
on mosaic virus, is transmitted by M. persicae
(Sulz.) to marrow plants in a typical stylet-borne
manner. Preacquisition starving of vectors was
not essential for transmission, but did increase
the transmission rate. Single aphid could trans-
mit the virus, more than 5/plant were required
for 100 % transmission. A feeding period of only
30 s was needed for acquisition of the virus, but
one of 2 min resulted in maximum percentage
transmission (Raychaudhuri and Varma 1977 ).
Pepper vein banding virus on bell pepper was
reported to be transmitted by two aphid species,
A. gossypii and M. persicae with the transmis-
sion efficiency of 62.0 % and 75.0 %, respective-
ly (Nagaraju and Reddy 1981 ). Similarly, pepper
veinal mottle virus and cucumber mosaic virus
also reported on bell pepper and were transmitted
by the same aphids (Nagaraju and Reddy 1980 ).
In the absence of reliable virus-free garlic
plants, Chenopodium album local lesion host of
garlic mosaic virus–D isolate was successfully
transmitted nonpersistently through M. persicae
and A. craccivora (Noda and Inouye 1989 ). Ba-
nana bunchy top virus transmission is through its
insect vector, the banana aphid ( Pentalonia ni-
gronervosa Coq) with minimum feeding period
of 1.5–2 h on susceptible plants. An average of
about 25 days incubation is necessary for the
development of banana bunchy top symptoms.
Nymphs are more effective vectors than mature
aphids (Magnaye and Valmayor 1995 ).
Cucumber mosaic virus (CMV), pepper vein
banding, pepper veinal mottle, potato virus Y, and
tobacco etch viruses infected chilli crop through
aphids namely A. craccivora, A. gossypii, and M.
persicae in a nonpersistent manner as reported by
Bidari and Reddy ( 1990 ). Likewise, mosaic dis-
ease was reported in sunflower crop for the first
time from Karnataka (India) and they were trans-
mitted successfully by three aphid species viz., A.
gossypii, A. craccivora and M. persicae. A. crac-
civora and M. persicae transmitted the mosaic
virus in garlic nonpersistently to Chenopodium
album (Ghosh and Ahlawat 1997 ).
The efficient transmitter M. persicae was able
to transmit three cucumber mosaic virus (CMV)
isolates in a nonpersistent manner to solanaceous
crops. The efficiency of transmission was rang-
ing from 67 to 70 % for CMV in brinjal, 81–85 %
for CMV in chilli, and from 77–81 % for CMV in
tomato (Kiranmai et al. 1997 ). Transmission of
CMV infecting cowpea was through A. cracciv-
ora, A. gossypii, and M. persicae in a nonpersis-
tent manner (Nagaraju and Keshavamurthy 1994 ;
Mahalakshmi et al. 2008 ). Single aphid M. per-
sicae was able to transmit the CMV with 3 min
AAP and 5 min IAP. The transmission efficiency
of vector increased with 1 h preacquisition star-
vation (Nagaraju and Keshavamurthy 1997 ).
PRSV was reported to be transmitted by sev-
eral aphid species tested with transmission ef-
ficiency of more than 90 % (Lakshminarayana
Reddy et al. 2007 ). A strain of PRSV was report-
ed infecting several cucurbitaceous crops around
Bangalore through M. persicae, A. gossypii, and
A. craccivora (Sreenivasa Rao Gude et al. 2008 ).
Gherkin ( Cucumis anguria) crop was found
infected with two viral diseases namely, PRSV
strain P (PRSV-P) and cucumber green mottle
virus (CGMV) (Rashmi et al. 2005a, 2005b).