South Perth, Australia
August 26, 2005
Western
Australian growers may soon be able to predict the timing of pea
weevil infestations in field pea crops using a temperature-based
model developed in South Australia.
The
Department of Agriculture is encouraging local growers and
crop consultants to help trial the model in Western Australia to
optimise the timing of sweep-net monitoring and spraying of
crops for pea weevil.
Department pulse extension officer Ian Pritchard
said many growers who failed to monitor crops, ended up spraying
too early to control the pest.
“The South Australian model has yet to be
validated for Western Australia's conditions and will require
the input of field pea producers throughout the State’s
grainbelt,” Mr Pritchard said.
“The model was developed by
the South Australian
Agricultural Research and Development Institute and is
available to trial from
http://www.sardi.sa.gov.au
in the entomology section.”
Mr Pritchard said Western Australian growers
would need to monitor their field pea crops with a sweep net to
determine when the pea weevil invasions commenced and then
compare the field results with the model. The results should be
forwarded to Mark Seymour on 9083 1143 or Ian Pritchard on 9690
2158.
“As a general
guide, growers should begin monitoring the crop with a sweep net
just before the first pods begin to form (5 – 7 days after
flowering). Monitoring is best on warm days above 18°C, firstly
along the edges of paddocks near trees and last year’s field pea
stubble,” he said.
“If more than
one pea weevil in 100 sweeps is present then spraying a
synthetic pyrethroid immediately is recommended.
“In large,
tree-cleared paddocks, it is only necessary to spray a 60 metre
border around the paddock because pea weevils work their way in
from the edges of the paddock. Eggs on pods and larvae in pods
will not be killed by insecticide so it is important to kill
adults before they lay eggs.”
Mr Pritchard
said monitoring should recommence about 14 days after spraying,
and if more pea weevils were found then the entire crop would
need to be sprayed. |