Supporting your success

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 WA.Newsletter of the Department of Agriculture and Food, Western Australia

Issue Number: 25 25 Oct. 2013

ContentsNew wheat leaf rust pathotypeCanola sclerotiniaNative budwormLocustsLoose smut in barleyVagrant insectsStored grain insectsPassing on the baton

To view pest and disease reports, see the http://www.agric.wa.gov.au/pestfaxback copies of PestFax

If you have recently observed or heard news of insect or disease pests in crops and pastures contact the editor:

Peter ManganoDAFWABaron-Hay Crt.South Perth 6151p: (08) 9368 3753 or 0404819534 e: use the online report

PestFax is supported by the National Invertebrate Pest Initiative (NIPI) a GRDC project that promotes national pest management information and Integrated Pest Management (IPM) principals.

PestFax

are asked to continue to collect any further discoveries of cereal rusts on any available late maturing crops.

Rust infected leaves should be mailed in paper envelopes (no plastic lined packages) to the Australian Cereal Rust Survey, Plant Breeding Institute, Private Bag 4011, Narellan NSW 2567, Ph (02) 93518800 for pathotype analysis. Include location, date, variety and sender’s contact information. For further details see Uni Sydney Cereal Rust website

Further and more comprehensive details on the pathotype discovery and implication can be found in the Sydney Uni. PBI Cereal Rust Report 2013 Volume 11 Issue 6 , 22 Oct 13:  http://sydney.edu.au/agriculture/plant_breeding_institute/cereal_rust/reports_forms.shtml

Canola Sclerotinia Andrea Hills (DAFWA) reports that CBH are monitoring canola deliveries for canola scerotinia sclerotes i.e. the hard black irregular shaped fruiting structures of the fungus. Delivery levels set by CBH are 2.5 g of sclerotes in a 500g sample. Early harvested canola delivered to CBH Esperance commenced approximately two weeks ago and inspections of grain samples to date have found scerlotinia sclerotes ‘fairly regularly’ with some loads understood to near the accepted limit.

The incidence of canola sclerotinia reported this season has been much higher than previous seasons as can be seen in the PestFax Map link here.

For more details and images of disease see the 2012 crop updates proceedings page 145 “Canola Diseases Foliar fungicides for managing Sclerotinia stem rot and blackleg in canola” and Managing the risk of Sclerotinia stem rot in canola farmnote 546

Native budwormAn agronomist reported to DAFWA Northern Agricultural region staff that native budworm caterpillars are still being found in some late maturing canola crops in eastern wheatbelt areas. Many crops have low levels of the caterpillars that are below economic spray thresholds (e.g. 2-3 grubs/10 sweeps). However each paddock needs to be inspected as numbers can vary greatly. About two weeks ago crops in the east Dalwallinu – Goodlands area were found with damaging numbers of budworm (10-12 / 10) sweeps prompting farmers to spray.

For further information on native budworm see the Management of Native Budworm Farmnote; also see PestFax No. 21, 27/09/13 for withholding periods for registered chemicals. 

LocustsThe sightings of locusts and increases in their size have been continuing in eastern grainbelt localities.  The Department has been actively monitoring spring locust populations. To date the only activity has been in the central agricultural region and locust distributions have been patchy although high in some localities. This week a DAFWA officer estimated numbers of 400 second instar (approx 8 mm long) locusts per M² within localised patches on two separate properties in the Westonia shire. 

Gary McDonald (DAFWA) reports that along with the immature nymphs of Australian plague locust he is also finding pockets of other adult winged locusts that are probably the species Urnisa guttulosa. This week he found small swarms of the specked coloured, ‘solid’ locusts NE of Mukinbudin feeding on the ‘greener’ Paterson’s curse weed along a roadside.

Many crops in eastern areas are rapidly approaching harvest and will soon be too advanced / dry to be attractive to the locusts.  Experience from previous years suggests that late maturing green crops or areas of pasture remaining green will be most at risk of potential damage and aggregation by the locusts.  Extensive spray control of locusts in some eastern wheatbelt areas is unlikely to be economically justified where there are low crop yield potential and tight margins.

Entomologist Svet Micic says that locust nymphs will develop through 5 growth stages, increasing in size with each stage.  They often aggregate together and in some seasons can be seen as distinct ‘bands’ which move slowly across paddocks.  The final moult to the winged adult usually takes around 6-8 weeks

2

from their initial hatching date.  The adult locusts (winged with body length ~ 20mm) will need to feed on green plant material to accumulate fat and become sexually mature.

Late rainfall through parts of the eastern grainbelt has prolonged green feed and favoured some locust survival. If further rainfall occurs during summer and green feed is present in paddocks then this current generation of locusts may have  sufficient body fat to lay up to 3 egg pods each (i.e. ~ 200 eggs). Fortunately most summers are dry enough not to allow that level of breeding.

It is the survival, density and location of the subsequent locust populations that will indicate where and at what density any locust problems will carry-over into 2014.

For previous reports to PestFax of locust hatching in recent weeks, see PestFax map link here.   Specific information on some of the insecticide withholding periods is available in the ‘Locust spraying and withholding periods information sheet’ also see the registered or permitted chemical guide for APL

More information on identification, monitoring and control is available from www.agric.wa.gov.au/locusts

Loose smut in barleyAndrea Hills (DAFWA) reports on the results of two barley loose smut trials conducted at Wongan Hills and Gibson. Plots were sown with infected Hindmarsh seed that had various seed dressings. Results demonstrated that seed dressings can reduce loose smut from a high of 4.7% to near zero levels.

Loose smut infection was observed in a number of barley crops this season and it is likely that harvested seed will have some level of infection. Seed carried over for next year’s sowing will need to be seed treated as infected plants produce no grain on their tillers, resulting in lost yield. The percentage yield loss is similar to the percentage seed infection.  Some of our markets also have a zero tolerance for this disease.

The seed dressings that best controlled loose smut in the DAFWA trials this year were EverGol® Prime and Jockey® + Raxil® (Jockey® Stayer™). However, all seven seed treatments trialled in 2013 were effective at significantly reducing loose smut to some degree.

Andrea advised that a critical step to ensure good control of disease, regardless of the seed dressing, is even coverage so that every seed is treated. The barley loose smut fungus is carried within the seed (that looks normal) which is why good application is vital – the fungicide in the seed dressing needs to reach the germinating embryo where the smut fungus is located, to stop its development in the seedling.

For more information see the Southern AgMemo October issue or contact Andrea Hills, at DAFWA Esperance on 9083 1144 or Geoff Thomas, Plant Pathologist, South Perth on 9368 3262. For summary pages on registered seed treatments see Seed Dressings for use on Wheat, 2013 and Seed Dressings for use on Barley, Oats and Triticale, 2013. For further reading refer to Leaf diseases of barley, Farmnote.  

Vagrant insects – grain contaminationInsect contamination of grain that occurs during the harvesting process is of increasing concern for some growers and importers of Australian grain. Generally these include non grain-damaging field insects (vagrant insects) which can become grain contaminants and result in dockages or even downgrading of price or cost of cleaning the grain to acceptable levels.

The important point is to assess levels of vagrant insects in grain and calculate if the cost of grain cleaning is economical. The difference in price between segregations may not warrant cleaning. Harvest trials in cereals conducted in 2003/04 by Entomologist Svet Micic and Tony Dore (DAFWA) looked at the types and number of insects that contaminate grain in south coastal areas on swathed and standing crops.

The most common insects found in their trials were adult bronzed field beetles, vegetable beetles and European earwigs. Bronzed field beetle and vegetable beetle adults are flightless, will move into the swath to seek shelter and protection away from the exposed stubble areas. The ground under the swath is a perfect shelter for them.

Swath versus standing crop: The longer a swath lays down the more insects that accumulate under it and the more that can contaminate the grain. A lot less insect contaminants are found in grain

3

harvested from standing crops. However Svet’s trails showed that, there was no difference in numbers of snails between swathed or standing crops.

Crop lifters versus belt pick up front: Provided that the swath height was well above the soil (recommended height for cereal is 125 mm), it didn’t matter what header front was used in the trials as the number of insect contaminants in the grain did not differ. However, if the swath is on or close to the ground, harvesters fitted with crop lifters are better able to pick up the low swaths (as well as the insects sheltering there) than harvesters fitted with belt pick-up fronts.

Night versus day harvest: The time of harvest (i.e. night or day) affects the number of insects contaminating grain. Sampling of swaths during the hottest part of the day (i.e. mid-day on a hot day) showed that very low insect numbers were found within the swath and nearly all of them had moved to the ground, under the swath. At night, however, the insects were present within the swath. More insect contaminants were found in grain harvested from swaths at night, than during the day.

Canola Vagrant Insects: Canola crops sometimes have high numbers of Rutherglen bugs that can be caught up in the harvester front resulting in unacceptably high levels within grain samples. Rutherglen bugs are usually actively flying in the warmer parts of the day. Attaching different screens to headers and harvesting standing crops at night or in cool weather will often minimise the levels picked up in the grain sample. Another suggested solution if there are Rutherglen bugs in recently harvested canola is to leave the seed in an uncovered field bin overnight and they should make their way to the top and escape.

No registered insecticides: There are no insecticides registered for use under swaths. Trials have shown that insecticides sprayed under swaths do not decrease the number of vagrant insects in harvested grain. However, sprays under swaths increase the risk of residues on grain.

 How to know what  pests may be in your paddock next yearIdentifying the species of vagrant invertebrates harvested with grain can be an early warning system that pests in paddocks are increasing or indicate what may cause damage to susceptible crops (like canola) next year. One of the first signs that pests such as snails, European earwigs, weevils and vegetable beetle are building up is their presence in harvested grain. These pests are known as resident pests as they do not fly or are weak fliers. They also do not easily move from paddocks and can be found year in year out in the same paddocks.

The appearance of resident pests in grain does not necessarily mean that control is needed. Summer conditions will affect pest numbers especially if it is a hot dry summer.

If European earwigs and/or snails is found in harvested grain growers should take note of the paddocks they were found in. These pests are often introduced into paddocks and farms  on vehicles and machinery. Consider cleaning your machinery before moving from one paddock to the next, and particularly between properties, to minimise the risk of introducing these resident pest to new areas.

For further reading refer to: Identification and control of slugs and snails for broad acre crops in Western Ausutralia, European earwigs - pest of crops, Farmnote Weevils - Indentification and cultural control on insect pests in canola, Bulletin Vegetable beetle: An occasional pest of canola, Farmnote

For more information contact Svetlana Micic, Entomologist, Albany on 9892 8591.

Stored grain insectsGrowers are reminded that they should check and maintain grain silos before storing this year's harvest to guard against grain insect activity.  Regulations prohibit the sale and handling of insect infested grain and the application of contact insecticides other than malathion to stored grain. Sealed silos are preferred  but rubber seals should be checked; augers, field bins and silos should be thoroughly cleaned of grain residues and treated with a hygiene spray or dust; and the ground around storages cleared of weeds and rubbish to prevent harbouring insects.  For details on sealed silos see the Farmnote: Sealed silos make $ense and other Departmental stored grain protection publications.

Entomologist Rob Emery says that phosphine is a very effective fumigant gas but must be held under gas-tight conditions at a lethal concentration for 7-10 days to kill all insect growth stages.  Poor fumigation can result in only adult and larval insects being killed giving the mistaken impression that the

4

Copyright © Western Australian Agriculture Authority, 2013Important 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.

This is the last issue of PestFax for the 2013 growing season.

Next issue of PestFax – 18 October 2013

fumigation was successful. However, the immature eggs and pupae will not be killed so infestations will likely build up again quickly, selecting for resistant populations.

Farmers keeping grain on farm for their own use, with silos that are not sealed can use aeration or Dryacide or a combination of both as alternative methods to keep insects in low number.  Aeration is a tool for creating a low temperature in the silo so that insects breed very slowly.  Insects rely on the environmental temperature for body warmth and breed faster in warm conditions.  If the temperature is kept below 20°C they will produce less progeny in the storage period.  However to stop reproduction, grain temperatures must be kept below 14°C ; temperatures below 10°C (difficult in WA) will eventually kill the insects.  Failure to follow these strategies may result in the grain having a low number of insects and cannot be sold off-farm without fumigation by transferring it to a fully sealed and tested silo.

Dryacide is an insecticide and will provide good control for at least 12 months.  It is a non-toxic, diatomaceous earth product that must be applied when loading the silo at a rate of 1 kg / tonne.  This grain can only be used on your own farm since most central grain buyers will not accept it because it changes the flow characteristic of the grain.  However you can store grain even in an open shed very safely using Dryacide.

For more information on stored grain management techniques visit the GRDC supported website storedgrain.com.au

Passing on the batonThis is the last issue of PestFax for the 2013 season. It is also the last issue with me (Peter Mangano) as the lead editor. I have been editor of PestFax for 18 years, since I commenced the service in 1996 and it is time that I “passed the baton on” to a younger person.

I would like to thank the many readers of PestFax who have contributed reports and comments to the last 461 issues which covered over 14,000 of your reports. I consider that I have been in a privileged position in being able to represent your reports and other people’s research/insights so that we all could be better informed about abundance and spread of pests, diseases and beneficials; and allow for better crop management decisions. I have felt a huge weight of responsibility as I have struggled with what to include (or not) in each article and tried to distill and edit information into what I thought was timely and relevant content. I thank God for the energy and passion he has given me through some difficult situations. Many of you have commented how you have benefited from the information in the past and this has given me a great deal of job satisfaction to continue for as long and I have. Thank you.

THIS IS THE LAST ISSUE OF PESTFAX FOR THE 2013 GROWING SEASON. EXTRA EDITIONS MAY BE CIRCULATED IF EXTRAORDINARY CIRCUMSTANCES OCCUR. PESTFAX WILL RESUME WEEKLY ISSUES IN AUTUMN 2014.

Also available on the PestFax page on the DAFWA website: Registered insecticides for autumn/winter 2013 : canola, lupins and cereals Winter/Spring Insecticide Spray Chart 2013

Available at www.agric.wa.gov.au and search on “PestFax 2013”.

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 Departmental Offices for a cost of $10.00 or by mail order by phoning the Dept of Agriculture and Food, South Perth on 9368 3710.

Free Insect Identification - having troubles identifying mites or other pests? Send in your digital pictures (in focus) or send live specimens in a non-crushable plastic jar for free identification. Send to Peter Mangano 0404819534, pmangano@agric.wa.gov.au, DAFWA 3 Baron-Hay Crt South Perth 6151. or Svetlana Micic (042777205) at DAFWA 444 Albany Hwy Albany 6330. svetlana.micic@agric.wa.gov.au

AGWEST Plant Labs. - Plant disease diagnostic service. Department of Agriculture and Food, 3 Baron-Hay Crt. South Perth, 6151 For information on sending samples and charges contact 9368 3721, Fax 9474 2658 or website

5