Author:
Latham L. J.,Jones R. A. C.
Abstract
Experimental plots of cool season crop legumes growing at diverse locations in
Western Australia were inspected for plants with suspect virus symptoms over 4
growing seasons (1994, 1997, 1998, 1999), and plant samples were tested for
infection with alfalfa mosaic (AMV), bean yellow mosaic (BYMV), cucumber
mosaic (CMV), and pea seed-borne mosaic (PSbMV) viruses. All 4 viruses were
detected in faba bean (Vicia faba); BYMV, CMV, and PSbMV
in field pea (Pisum sativum); AMV, CMV, and PSbMV in
lentil (Lens culinaris); and AMV and CMV in chickpea
(Cicer arietinum). Among minor crop species, AMV, BYMV,
and CMV were found in narbon bean (V. narbonensis) and
grass pea (Lathyrus sativus); BYMV and CMV in dwarf
chickling (L. cicera); BYMV in bitter vetch
(V. e r v i l i a ) and
L. clymenum; and AMV in fenugreek
(Trigonella foenum-graecum). Incidences of individual
viruses varied widely from site to site but plot infection sometimes reached
100%. Symptom severity varied widely with virus–crop combination.
In large-scale surveys of commercial crops of field pea and faba bean over 2
(1998, 1999) and 3 (1994, 1998, 1999) growing seasons, respectively, randomly
collected samples from each crop were tested for presence of AMV, BYMV, CMV,
and PSbMV. In 1999 they were also tested for beet western yellows virus
(BWYV). All 5 viruses were detected in both species. BWYV was found in
35% of faba bean and 56% of the field pea crops sampled in 1999,
with incidences of infection in individual crops up to 40% and
49%, respectively. PSbMV was found in 42% and BYMV in 18%
of field pea crops in 1999. In individual crops, highest infection incidences
of BYMV and PSbMV detected were 31% for BYMV in faba bean in 1998 and
9% for PSbMV in field pea in 1999. CMV and AMV incidences in both
species never exceeded 7% of crops or 4% of plants within
individual crops. Infection by 2 different viruses within individual crops was
common, even 3 were sometimes found. Cultivars infected with most viruses were
Fiesta and Fiord for faba bean, and Dundale, Laura, and Magnet for field pea.
BYMV was detected in the crop tested of dwarf chickling. In tests on seed
samples from Western Australia of 30 commercial seed stocks of field pea, 11
of faba bean, and 50 of chickpea, PSbMV was detected in 11, 1, and 1,
respectively; CMV in 1, 1, and 3; BYMV in 3, 1, and 0; and AMV in 0, 0, and 1.
This appears to be the first record of seed transmission of CMV in pea and
faba bean. Seed samples from Victoria were also found to contain viruses:
PSbMV in pea and AMV in lentil.
Widespread infection with viruses in evaluation plots and commercial crops of
cool season crop legumes is a cause for concern, especially where individual
crop incidences are high and 2 or more viruses are present. Sowing of infected
seed stocks leads to introduction of randomly dispersed sources of virus
infection within the crop sown, resulting in spread of infection and yield
losses. Appropriate control measures are discussed.
Subject
General Agricultural and Biological Sciences