I ssue number: 17
Date: 05/09/2014
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).
Native budworm
Spot type net blotch on barley
Root lesion nematodes
Fusarium Crown Rot in Wheat
Cereal aphids
Canola aphids
Lupin aphids
Diamondback moths
Green peach aphids
Flag smut in wheat
Mice
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.
Alana Hartley (Landmark) reports that lupin and canola crops in the region covering Calingiri , west Ballidu , Ballidu , Cadoux and Wongan Hills have been checked for pests using a sweepnet. Native budworm caterpillar numbers in the crops sampled range from 6 to over 30 per
10 sweeps, with the majority of caterpillars greater than 10mm long. Sweep netting of crops in the
Konnongorring area revealed much lower levels of caterpillars with three budworm caterpillars per 10 sweeps the largest count recorded.

Alana commented that it is likely that warm north easterly weather patterns last month produced winds that assisted native budworm flights in a south westerly direction. Many of the crops are now in the pod filling to late flowering growth stages and will be closely monitored to check on population changes in numbers of caterpillars and their size.
Matt Willis (Elders) reports that widespread spraying of lupin and canola crops to control native budworm caterpillars is occurring in the areas north of the Dowerin , Wyalkatchem and Trayning road. Matt also commented that budworm caterpillar numbers are approaching threshold levels in the areas up to 10 kilometres south of this region.
A grower reported to DAFWA Northern Agricultural Region staff that canola crops near Dalwallinu have been sprayed to control exceptionally high levels of native budworm caterpillars. One crop had 60 caterpillars per 10 sweeps.
Ashton Gray (ConsultAg) reports) that he found an average of 3.5 budworm caterpillars per 10 sweeps whilst checking a canola crop north of Lake Grace this week. The caterpillars are very small and easily confused with small DBM larvae. The crop is in the pod fill to late flowering growth stage (last 10-20% flower) and will continue to be monitored.
A farmer near Varley reports finding 2 budworm caterpillars (2 –5mm) per ten sweeps in a canola crop.
A budworm moth trapper east of Maya reports finding two budworm caterpillars per 10 sweeps
(30mm) in a field pea crop, the crop will be sprayed to reduce caterpillar numbers.
Although some farmers in northern and eastern cropping zones have sprayed crops to control the native budworm, others will continue monitoring and only spray if caterpillar numbers remain above threshold levels as canola and lupin crops mature and reach the growth stage when pods commence to become attractive to the caterpillars. Demand on aerial spray contractors may prompt some growers to spray early.
Moth flights into some areas have declined in the last week, however budworm moth trappers are still reporting significant moths numbers flying into areas such as Cowcowing (88 moths),
Doodlakine (457 in two weeks) Kellerberrin (55) and Wyalkatchem (47).
For the locations of budworm moth numbers caught in pheromone traps in recent weeks refer to:
Native Budworm Moth Trap Numbers 2014.
For previous reports of high numbers of native budworm see PestFax 29/08/14 and 22/08/14
For further information on native budworm see the webpage: Management and economic thresholds for native budworm and the Winter/Spring Insecticide Spray Chart 2014.
Pesticide options for the control of native budworm can be found in the Winter/Spring Insecticide
Spray Chart 2014.
Clinton Mullan (AgVivo) reports lots of spot type net blotch in the Tincurrin area. Previously the problem was worst in paddocks which had barley sown on barley, and this was dealt with over the last few weeks with a second fungicide spray. It’s now being seen on barley crops that were sown into pasture or canola stubble. The varieties involved are mainly Buloke and Hindmarsh with crop stages at flag leaf emergence through to finishing flowering. Disease is seen on flag leaf and flag-
1 at 5%, flag-2 at 10% and lower leaves no worse than 15%.
DAFWA plant pathologist Kith Jayasena says that he is not surprised by the movement of the disease into barley that has been sown on crops other than barley as the conidia of spot type net blotch can be blown long distances in a down wind direction. Both the affected varieties are susceptible to the disease and further spread in the upper canopy will depend on warm weather and intermittent rainfall over the coming weeks. Kith suggests it might be worth spraying with a
Propiconazole (such as Tilt or Cogito), Prothioconazole, Pyraclostrobin or Expoxiconazole base at a high rate with large water volume and medium droplet size for good canopy penetration.

Further information could be obtained from following DAFWA webpage: Managing net-type net blotch and spot-type net blotch in barley in Western Australia .
DAFWA plant pathologist Alison Mackie reports the continued incidence of root lesion nematodes
(RLN) at high levels in crops diagnosed by Agwest Plant Laboratories.
High populations of Western Australia
’s most common RLN species
Pratylenchus neglectus have been identified in wheat from the northern agricultural region. P.neglectus and P. teres both continue to be identified as the cause of crop issues in barley and oats from the central and southern agricultural region. Continued incidences of the less common species P. penetrans have also been reported.
DAFWA nematologist Sarah Collins says that the correct identification of nematodes is important because the choice of suitable break crops to mitigate future crop damage is dependent on knowing which plant parasitic nematode species are present. Sarah speculates that consecutive seasons favourable to RLN and burrowing nematode and the increasing inclusion of canola to crop rotations may be contributing to the build-up of nematode numbers.
Suspected root disease or nematode problems in-crop can be confirmed by a chargeable laboratory analysis of soil and/or roots by AgWest Plant Labs. Send fresh samples of roots in an undisturbed soil ball (not washed roots) using sampling guidelines available at the DAFWA ’s
AgWest Plant Labs . The cost is $308 per sample.
For further detailed information see PestFax No. 13 Aug 8 , How to diagnose Root Lesion
Nematode , and Root disease under intensive cereal production systems.
Ciara Beard (DAFWA Plant Pathologist) reports that she has recently observed Crown Rot in a couple of wheat trials in the Mingenew area, both being the variety Mace. Crown rot is a fungal disease that affects roots and lower stems and is usually not detected until after heading when white heads, prematurely ripened, are seen scattered throughout a crop (not in distinct patches as with take-all). When the leaf sheaths are pulled back at the tiller base, the typical honey-brown colour can be seen on the stem. This helps distinguish Crown Rot from other causes of white heads such as take-all, frost, copper, molybdenum deficiency and physiological response to moisture stress. Pink discolouration can form around or in the crown or under leaf sheaths infected with Crown Rot - with pink colour becoming very evident on infected plants left in a damp plastic bag for several days.
Most wheat varieties grown in WA are susceptible to Crown Rot and it is most common in continuous cereal crops, or after long-term grass pastures. The fungus blocks water movement from root to stem so affected heads have shrivelled or no grain. Significant yield losses can occur when high disease levels coincide with moisture stress during grain fill – crown rot causes greater yield losses in seasons with a wet start followed by a dry finish. Crown rot can persist in infected crop residues for up to two years and be carried over in infected grass weeds. Use Predicta B to monitor soil disease levels. For confirmation of diagnosis during the season plant samples can be sent to AGWEST Plant laboratories , this is a chargeable service.
Where fusarium crown rot is yield limiting, a combination of management practices is recommended:
 rotations with non-susceptible crops or fallow e.g. a two-year break with grass-free crops, grass-free legume pastures or fallow
 cultivation that buries crowns helps break down infected stubble thereby reducing subsequent inoculum levels
 control grass weeds early in season prior to sowing cereals
 use inter-row sowing – sowing between the rows of the previous cereal crop can decrease the severity and incidence of crown rot in the current cereal crop.

For further information and photos of the symptoms visit the webpage: Crown rot of cereals .
Entomologist Dusty Severtson (DAFWA/UWA) reports finding mostly low levels of oat aphids in wheat crops west of Quairading and north of Mingenew . At W. Quairading he noticed very high numbers of oat aphids on ryegrass within pasture and roadsides indicating potential for populations to fly into nearby crops.
An agronomist reported to DAFWA Northern Agricultural Region staff that cereal aphids have increased to damaging levels on some crops around Moora and east of Walebing.
For further information on control of cereal aphids visit the webpages: PestFax 15 Aug 14 , GRDC cereal aphid factsheet , Aphid feeding damage to cereal crops and the Winter/Spring Insecticide
Spray Chart 2014.
Dusty Severtson (DAFWA/UWA) reports finding low levels of turnip and cabbage aphids at the edges of flowering/podding canola crops from west York to Quairading . Green peach aphids were also found in the canola crop inspected. Dusty noted that the GPA were mostly, as expected, on the underside of lower leaves. But most importantly some swollen orange/pink dead aphids, were starting to appear indicating an insect-specific fungus is infecting the aphid populations. Further rainfall will increase moisture levels within the canopy and will promote the fungus and kill more aphids. He also noted green lacewings, whose larvae feed on aphids, were found in the sweep net samples, indicating the predators are probably now laying their eggs within the crops. Other predators such as parasitic wasps, hover flies and ladybirds will also increase with warming weather. These predators can keep aphid populations below threshold levels.
Dusty is currently conducting his PhD research into cabbage aphid distribution in canola crops and would like to hear from anyone who has seen further infestation starting and is willing for him to inspect their crops. Contact Dusty on dustin.severtson@research.uwa.edu.au
or
+61 (0)427 196 656.
For more information visit the webpage: Aphid management in canola crops .
Alana Hartley (Landmark) reports that aphids have been in particularly large numbers on some lupin crops in the Wongan Hills/Ballidu district. Many of the lupin crops are at the pod filling growth stage with only late flowers on tertiary stems and the effect of the aphids is likely to be minimal, with more concern about the presence of native budworm caterpillars (see above).
For further information visit the webpages: Identification of aphids in lupin crops and Aphid control in WA lupin crops .
Entomologist Dusty Severtson (DAFWA/UWA) has found low numbers of diamondback moth
(DBM) caterpillars in two canola crops at west Quairading . They ranged in numbers of 10
–30
DBM per 10 sweeps and minor ‘windowing’ of leaves was evident.
Ashton Gray (ConsultAg) reports that he found an average of 10 DBM caterpillars per 10 sweeps while checking a canola crop north of Lake Grace this week. The crop was in the pod fill to late flowering growth stage (last 10-20% flower) and although the current level of DBM do not pose any threat to crop yield the presence of small native budworm caterpillars (see above) maybe of greater concern. The crop will continue to be monitored.
Alana Hartley (Landmark) reports that DBM caterpillar numbers are generally at very low levels in the Wongan/Ballidu area such as five small DBM grubs per 10 sweeps found north of Ballidu this week.

These reports confirm previous reports this season of low numbers of DBM caterpillars. Given population trends from previous seasons it seems most unlikely that canola growers will need to spray for the pest this season apart from perhaps a few isolated locations.
For further information on sampling and control of diamondback moths visit the webpages:
Diagnosing diamondback moth and the GRDC diamondback moth factsheet.
David Tooke (DAFWA) reports that seed potato inspectors are finding an early increase in the prevalence of winged, green peach aphids (GPA) in seed potato crops in the Dandaragan area and SW horticultural areas. The inspectors say that in previous year’s aphid populations on potato crops have been known to increase toward October, however this year the aphids have been noticed in late August and early September. Potato growers are remaining vigilant against the presence of GPA as they are known vectors of potato virus diseases that can affect tuber quality.
Green peach aphids are also known to be difficult to control resulting from their resistance to insecticides, especially for broadacre canola growers that have limited registered chemical options. In 2013 a number of canola growers in high rainfall areas sustained damage to their seedling canola crops by unusually high numbers of GPA that persisted into winter and even some populations that continued into spring on mature plants.
For further information visit the webpages: Resistance management for green peach aphids and
Aphid management in canola crops.
Ciara Beard (DAFWA Plant Pathologist) has received a report of flag smut being found this week on a couple of tillers in a Mace crop near Mingenew . Flag smut usually only occurs sporadically as it is well managed by fungicide seed dressings. It is usually seen following successive plantings of susceptible varieties not treated with a fungicide seed dressing. Spores of the flag smut fungus are carried on seed and in soil, the spores can survive in soil up to seven years.
Ciara Beard said that if flag smut is found, it is important to use clean fungicide-treated seed of resistant varieties to reduce future disease risk. Mace is rated as susceptible-moderately susceptible to flag smut. See the 2014 Wheat variety guide for varieties that have resistance to flag smut. Seed dressings are always recommended for susceptible varieties. Where soil-borne infection is known to occur, it is recommended to sow resistant (R) or moderately resistant (MR) varieties with a fungicide seed dressing. Barley, oats and broad leaf crops are not affected by flag smut.
For further information on smuts and bunts see Flag smut of wheat and Smut and bunt diseases of cereal, and fungicide seed dressing information can be found at here .
Andrew Heinrich (Farm and General) reports that a canola crop near Gibson has patches in the crop where 10% of pods have been chewed by mice. Damage has also been seen in a wheat crop near Grass Patch where up to 5% damage in patches is occurring. The mice are chewing some of the wheat stems just below the head.
Mice will preferentially feed on the developing pods of canola as they are an attractive food source. Baiting maturing crops is effective but kill rates may be substantially lower (around 40 –
50%) than when applied at the seedling growth stage as there is less food competition. Mice researchers have found that one to two poison baited grains are sufficient to kill a mouse, however, mice will continue to eat palatable bait after a lethal dose has been consumed (5
–15 grains per mouse). Therefore, increasing bait rates will not improve efficacy, nor will it reduce the levels of reinvasion.
For further information visit the GRDC webpage: Mouse management

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
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.
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
Other regional DAFWA news updates are available on DAFWA website.
Seasonal climate outlooks are available on DAFWA website.
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
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