Issue number: 19
Date: 19/09/2014
PestFax
PestFax is a weekly informative and interactive reporting service, providing risk alerts, current
information and advice on pests and diseases threatening crops and pastures throughout the grain
belt of Western Australia (WA).
PestFax is supported by the Grains Research and Development Corporation (GRDC) and
promotes national pest management information and Integrated Pest Management (IPM)
principals.
Newsletter of the Department of Agriculture and Food, Western Australia (DAFWA).
Contents
Native budworm
Cereal aphids
Armyworm
Barley leaf rust
Physiological leaf damage
Locusts
To view a map of pest and disease reports, see PestFax Map and PestFax newsletters for back
copies of PestFax. If you have recently observed or heard news of insect or disease pests in crops
and pastures contact PestFax@agric.wa.gov.au or use the online ‘make an on-line report’ link.
Native budworm
Ashton Gray (ConsultAg) reports that native budworm numbers are being closely monitored in
eastern grainbelt areas including near Lake Grace, Kulin and Corrigin. A few crops have been
found with native budworm caterpillars numbers at damaging levels however sweep net checks to
date have found that many other crops have low numbers. Many canola and lupin crops checked
this week have an average of 1–2 caterpillars per 10 sweeps. Most caterpillars are currently less
than 15 milimetres (mm) long and some advanced lupin crops that are commencing to mature and
start leaf drop seem likely to escape the need for spray control.
Ben Whisson (ConsultAg) reports that canola and lupin crops checked in the Pingaring,
Newdegate and Lake King areas have been found with increasing numbers of native budworm
caterpillars. Levels of five or more caterpillars per 10 sweeps are being found in some of the
Supporting your success
crops. These are currently mostly small caterpillars (less than 15mm) and close monitoring will
continue in the coming week (after the anticipated rain front) so that decisions on control can be
made.
Chloe Bairstow (Landmark) reports finding between 8-15 caterpillars per 10 sweeps (10–20mm) in
a lupin crop south of Lake Grace, the crop will be sprayed to control the caterpillar numbers later
this week.
Consultants reported to DAFWA central and northern agricultural region staff that native budworm
caterpillars in crops from Meckering, Cunderdin to Wongan Hills are above threshold levels and
crops have been sprayed to control caterpillar numbers. There are also some crops near Moora
that have caterpillar numbers that are likely to require control.
Native budworm moths are continuing their south - westward flights into crops, generally in low
numbers, however high numbers of moths have been reported this week from budworm moth
trappers in N. Badgingarra (265 moths) N.E Badgingarra (116) and W. Binnu (355).
Many crops in northern and eastern areas are drying rapidly and some will soon reach a point
where they are becoming too dry for the native budworm caterpillars to chew into the hard pods.
The budworm moth flights recorded in places like west Binnu are unlikely to find these advanced
crops attractive for egg laying. Any eggs laid by these late moth flights onto these crops are
unlikely to cause a problem as the small caterpillars will be unable to damage the hard pods.
However it is important to continue monitoring late maturing pulse, canola and lupin crops as eggs
laid by moths which arrived several weeks ago will have now developed into small to medium
sized caterpillars.
Lupin crops do not become vulnerable to damage from native budworm unless caterpillars are
larger than 15mm long whilst canola crops are vulnerable to damage from any sized grubs. Both
canola and lupin crops are vulnerable to damage to their pods by native budworm from time of
commencement of leaf drop and colour change of pods. Late maturing crops should be rechecked to confirm the absence of the pest. Growers need to be mindful to adhere to chemical
label spray withholding periods prior to harvest/swathing.
Results of moth trapping can be found in the webpage: Native Budworm Moth Trap Numbers
2014. For further information on native budworm see the webpage: Management and economic
thresholds for native budworm. Pesticide options for the control of native budworm can be found in
the Winter/Spring Insecticide Spray Chart 2014.
Cereal aphids
Ashton Gray (ConsultAg) reports that cereal aphids in some wheat and barley crops in the
Narrogin, Pingelly and Cuballing areas are near or above the economic spray threshold level of
15 or more aphids on 50% of tillers. Crops east of these areas generally have much lower levels.
Whilst inspecting crops Ashton observed hoverfly adults and larvae (see page 116 of the crop
Insects: Ute guide) predating on the aphids. He also noticed the pupal stage of the hover fly (see
figure 1) attached to wheat heads. Hoverfly larvae feed on aphids and when fully grown and
mature turn into the pupal stage. Some stick themselves onto the awns and heads of cereal crops.
Figure 1 Pupal stage of hoverfly
Regular monitoring of aphid levels over a number of weeks will provide a level of confidence in the
rate of increase in aphid numbers and the levels of beneficial insects such as adult and larval
hoverflies, lacewings and ladybird beetles. Parasitoid wasps (1-3mm long) are now also active in
some crops along with the swollen, bronze-brown coloured dying/dead aphids (aphid mummies)
that result from the internal feeding of the wasp larvae.
For further information PestFax 12 Sept 14 and visit the webpages: Diagnosing cereal aphids,
Aphid feeding damage to cereal crops and the Winter/Spring Insecticide Spray Chart 2014. For
some of the beneficial insects likely to be encountered in broadacre crops and pastures, view the
GRDC Back Pocket Guide Beneficial Insects.
Armyworm
A consultant also reported to DAFWA regional staff that a few armyworm caterpillars are being
found in some barley and wheat crops near Moora. They are currently small caterpillars and are
only doing minor leaf damage at present, but their levels will be closely monitored.
Grant Thompson (Crop Circle Consulting/Landmark) reports that armyworm caterpillars are
continuing to be found (see PestFax 12 Sept 14) in cereal crops in the Moonyoonooka area.
Most crops have caterpillar numbers that are below economically damaging levels and patchy
throughout individual paddocks. Grant found numbers ranging from 2-3 caterpillars in 10 sweeps
to over 12 caterpillars per 10 sweeps. Frustratingly, when crops are re-checked after a few days
sweep net caterpillar numbers can be very different for the same paddock location. This is
because their movements will vary with weather conditions and feeding preference. Sometimes
caterpillars are found sheltering on the ground and under leaf litter whilst on other days they will be
high up on the plants or on the heads and easily picked up using sweep nets. A useful visible sign
of armyworm caterpillars (when at damaging levels) is to look for their green to straw-coloured
droppings (excreta), about the size of a match head, found on the ground between the cereal
rows.
For further information see PestFax 12 Sept 14 and the webpages Diagnosing armyworm and
Management of armyworm in cereal crops.
Barley leaf rust
Barley leaf rust is on the move in the Esperance area. Plant pathology research officer, Andrea
Hills, reports that levels of leaf rust in a crop of Bass barley at Gibson has increased noticeably
over the past week as the weather has warmed up. While rust levels in the south east have been
relatively low this season, late sown crops of susceptible varieties should be monitored and may
benefit from a fungicide application if the crop yield potential is good and leaf rust is present on the
upper leaves.
For further information see the webpages Managing barley leaf diseases and Registered foliar
fungicides for cereals.
Physiological leaf damage
Doug Sawkins (DAFWA) reports that he has observed physiological leaf damage on at least three
separate Mace wheat crops in the central grainbelt area.
Physiological leaf symptom (sometimes referred to as pathogenic leaf blotch or ‘flame yellows’) is
a condition associated with rust resistant genes in some wheat varieties that causes leaf damage.
The impact of this leaf damage on yield is unknown.
Doug says that the symptoms appear as light yellow flecking through to large dead elongated
patches on leaves. Symptoms will vary according to seasonal weather conditions, time of year,
plant vigour and/or nutrition.
He commented that leaves in poorer conditions, particularly low in nitrogen, die back from the tip
and may have larger irregular dead lesions and or dead areas extending down the leaf or midrib.
Doug suspects that this symptom will be more prevalent this year because many crops are
nitrogen deficient. He also cautioned that physiological leaf symptoms are easily confused with
some leaf diseases and zinc or potassium deficiency. Most importantly there is no treatment and it
does not respond to fungicide applications.
For further information and pictures of symptoms see the physiological leaf damage in wheat
webpage.
Locusts
Entomologist Svet Micic reports that Australian plague locusts are being observed in some eastern
grainbelt areas including near Warralakin. Cameron Wild (DAFWA) has observed patches of
locust (up to 70 per square metre) on some paddocks. He first observed newly hatched locusts
about two weeks ago and is now seeing some immature locusts that are commencing to form wing
buds (4th instar).
Svet commented that the small immature locusts now being found in eastern areas have hatched
from eggs laid by adult locusts in the same area during the autumn/early winter period this year.
These locusts will continue to develop to the winged adult growth stage and are expected to cause
minor localised damage to green patches of late maturing crops and pastures. However the
majority of crops are likely to mature, dry off or be harvested before the adult locusts reach their
fully grown mobile damaging growth stage.
For more information see the DAFWA Australian plague locust webpage.
Also available:
List of registered insecticides
A list of registered insecticides to control winter/spring pests on canola, lupins, cereals, field peas
and pastures is available on the PestFax webpage: Winter/Spring Insecticide Spray Chart 2014
A list of registered insecticides to control autumn/winter pests on canola, lupins and cereals is
available on the PestFax webpage: Autumn Winter Insecticide Guide 2014
Crop insects: the ute guide
This book covers crop pests, beneficial insects, biological control, grain storage pests and
biosecurity pest threats specific to WA. Copies are available from some DAFWA offices for a cost
of $10.00 or by mail order by phoning the DAFWA South Perth office on +61 (0)8 9368 3710.
Free insect identification
Having troubles identifying mites or other pests? For free identification, send your digital pictures
(in focus) or live specimens (in a non-crushable plastic jar) to Peter Mangano or Svetlana Micic at
the postal details below.
Svet Micic, DAFWA Albany
444 Albany Highway,
Albany WA 6330
Email: svetlana.micic@agric.wa.gov.au
Phone: +61 (0)8 9892 8591 or +61 (0)427 772 051
Peter Mangano, DAFWA South Perth
3 Baron-Hay Court,
South Perth WA 6151
Email: pmangano@agric.wa.gov.au
Phone: +61 (0)8 9368 3753 or +61 (0)404 819 534
Integrated Pest Management Guidelines for grains
AgTactics and AgMemo
Other regional DAFWA news updates are available on DAFWA website.
Seasonal climate outlook
Seasonal climate outlooks are available on DAFWA website.
AGWEST Plant Labs
Plant disease diagnostic services are located at the DAFWA South Perth office. For information on
sending samples and charges contact +61 (0)8 9368 3721 or Fax +61 (0)8 9474 2658 or visit the
DAFWA website or the AGWEST Plant Laboratories
Next issue of PestFax – 26 September 2014
Important disclaimer
The Chief Executive Officer of the Department of Agriculture and Food and the State of Western
Australia accept no liability whatsoever by reason of negligence or otherwise arising from the use
or release of this information or any part of it.
Copyright © Western Australian Agriculture Authority, 2014