Abstract
Thirteen indigenous and exotic
Acacia
species grown in Saudi Arabia were evaluated for their host status for
Meloidogyne javanica
in pot tests both in the growth chamber and under outdoor conditions. In both experiments, 21-day-old seedlings were transplanted individually into 15-cm-diam. plastic pots containing a steam-sterilized mixture of equal parts loam and sandy loam. Seedlings were inoculated with 5,000
M. javanica
eggs/plant 30 days later. After 120 days, fresh root weight, disease index (1-9 scale), the number of eggs/pot (Pf), eggs/g fresh root, and a reproductive factor (Rf) were determined. Results of both the growth chamber and the outdoor tests were similar. Species were grouped into host suitability categories according to Rf, and they were also grouped into resistance categories based on the sum of gall index, gall size, and percentage of the root system that was galled. Only
A. salicina
was a poor host and was resistant to
M. javanica
.
Acacia farnisiana
,
A. gerrardii
subsp.
negevensis
var.
najdensis
, and
A. saligna
were excellent hosts and highly susceptible. Both
A. nilotica
and
A. stenophylla
were classified as good hosts and highly susceptible, while
A. ampliceps
,
A. ehrenbergiana
,
A. gerrardii
subsp.
negevensis
var
negevensis
,
A. sclerosperma
,
A. seyal
,
A. tortilis
, and
A. tortilis
subsp.
spirocarpa
were also good hosts but were classified as susceptible rather than highly susceptible. This is the first report on the susceptibility of
Acacia
species to
M. javanica
in Saudi Arabia, including some new hosts worldwide.