Issue Number: 08 Date: 04/07/2014



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department of agriculture and food, western australia logo on the left. graphic element of leaves on the right.

Issue Number: 08

Date: 04/07/2014

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 National Invertebrate Pest Initiative (NIPI) a Grains Research and Development Corporation (GRDC) project that promotes national pest management information and Integrated Pest Management (IPM) principals.nipi_logo_col

Newsletter of the Department of Agriculture and Food, Western Australia

Contents


Mites and lucerne flea

Sclerotinia in canola

Aphids

Caterpillars



Slugs

Earwigs in canola


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.

Mites and lucerne flea


Courtney Piesse (Elders) reports that a four to five leaf canola crop near Cranbrook, has been damaged by redlegged earth mite (RLEM) at a stage when the crop would normally have been expected to be safe from mite damage. The damage is especially evident in areas of the paddock where the canola has been damaged by herbicide. The canola was sown into last year’s pasture and did not receive any pre-emergent miticide control. Last year’s pasture paddocks are most likely to have the highest populations of RLEM especially those that were not heavily grazed and did not have a spring insecticide spray. If RLEM numbers are high following a pasture rotation they are capable of damaging the more advanced four to six leaf canola plants.

A farmer at South Stirling reports that a canola crop at the three leaf stage was damaged by RLEM, despite the paddock receiving a spray of bifenthrin pre-seeding. A few years ago a paddock about one kilometre away tested positive for synthetic pyrethroid (SP) resistant RLEM. It is highly probable that this current paddock also has RLEM that are resistant to SP’s.

Courtney Piesse (Elders) reports that lucerne flea are damaging a four leaf wheat crop near Frankland. A recent dry spell has slowed crop growth which is struggling to outgrow the feeding damage and a spray is likely to be required. Lucerne flea has also been reported damaging cereal crops in the Ravensthorpe area. The pests have now been controlled by using registered rates of organophosphate sprays.

Courtney also has observed what appears to be brown wheat mite on cereals in the Cranbrook area. The brown wheat mite (Petrobia latens) has a very similar appearance to bryobia mites with long forelegs and a lighter coloured, brownish body. They are often mistaken in identity for bryobia or other mites, however they rarely cause economic damage to cereals at this time of year. Cooler winter temperatures and more frequent rainfall will see these mites decrease in numbers and they are unlikely to cause further damage to crops unless extended dry and sunny periods prevail.



Redlegged earth mite control failure

The Department of Agriculture and Food, Western Australia (DAFWA) provides a free RLEM resistance testing service. Growers and agronomists who observe surviving RLEM following applications of insecticides such as bifenthrin or alphacypermethrin should take advantage of this service to determine the resistance status of their mites. To use this free service contact –

Svet Micic, DAFWA Albany

Email: svetlana.micic@agric.wa.gov.au

Phone: +61 (0)8 98928591 or +61 (0) 427 772 051

Peter Mangano DAFWA Perth

Email: pmangano@agric.wa.gov.au

Phone: +61 (0)8 9368 9753 or +61 (0) 404 819 534

For further information see the following links – Diagnosing redlegged earth mites and Prevent redlegged earth mite resistance

Sclerotinia in canola



Figure Sclerotinia apothecia
DAFWA Plant Pathologist Ciara Beard visited a property near Northampton yesterday where a grower found apothecia in his canola paddock. These are the small cream coloured mushrooms that spread sclerotinia spores. The apothecia found this week were tiny so it is likely they are newly germinated following recent rain. They were found in a canola crop that is at 20%-30% flowering, and the grower is intending to apply fungicide to the crop this week. Crop flowering stage, along with weather conditions are the main determinants of when to spray for sclerotinia. DAFWA research has shown the optimal time for a single fungicide application in most years is 20 - 30% flowering (when 15 - 20 flowers are open on the main stem). sclerotinia apothecia found in a canola crop at 20-30% flowering, near northampton
DAFWA Plant Pathologist Kith Jayasena also reports seeing apothecia of sclerotinia near the DAFWA office in Albany. This indicates that conditions may be right for emergence of apothecia more broadly across the high rainfall grain belt.
For more information on the sclerotinia lifecycle, disease symptoms and management strategies with fungicide see Pest Fax No.7 27 June 14 and the DAFWA webpage Managing sclerotinia stem rot in canola.

Aphids


Daniel Bell (Landmark) has observed high numbers of turnip aphids on wild radish in pasture paddocks east of Esperance. The feeding damage from the aphids is killing the plants.

DAFWA Entomologist Svet Micic says that cool wet conditions during winter often keep aphid numbers below damaging levels. Mild and warmer weather patterns through winter are likely to favour aphid survival and increase through winter. Turnip and cabbage aphids are nearly always present on canola crops each spring. Rising spring temperatures will see a build-up in aphid populations, but in many years they never reach economically damaging levels. Early monitoring of crops will give advance warning of aphid increase. Use of preventative sprays is often unnecessary and only lead to death of beneficial insects and increase in the likelihood of selection pressure to select for aphids that are resistant to insecticides


For further information see the Diagnosing canola aphid and Aphid management in canola crops webpages

Caterpillars


Woolly bear caterpillars

A grower in the Dongara area reported to PestFax that some of their paddocks are “crawling” with high numbers of woolly bear caterpillars. The caterpillars are being seen in hundreds per square metre on pasture/weedy paddocks and in some cases even climbing the walls of nearby houses.

The presence of woolly bear caterpillars has been reported to PestFax over the past two weeks mainly from areas north of Geraldton, although the caterpillars are also being found over widespread areas including the Perth metro area. Some crop damage has occurred from the movement of caterpillar into crops from adjoining weedy edges or pastures.

For further information see the caterpillar section in PestFax No.6, 20 June 2014.



Pasture day moths

DAFWA Entomologist David Cousins has observed pasture day moth caterpillars in moderate numbers in pasture paddocks near Badgingarra and lesser numbers near Dongara and further south at Williams. The colourful day flying moths with brown and yellow patterns on their wings can be seen flying on some paddocks. Courtney Piesse (Elders) reports that pasture day moth caterpillars have caused chewing damage to a three leaf wheat crop in the Williams area. These caterpillars usually feed on broadleaved weeds, however when these weeds are removed by herbicide sprays the caterpillars are known to move onto cereal crops.

Pasture day moth caterpillars (Crop insects: the ute guide page 33) are dark brown with yellow and reddish orange markings. They have two prominent yellow spots near the end of the body and an orange-black head. The moths have brown and yellow patterns on their wings and may be seen flying by day (as the name implies).

Pasture day moth larvae rarely cause economic damage to pastures or crops. They have a preference to feed on broad-leafed weeds such as capeweed, in some paddock situations this feeding preference is considered beneficial. The caterpillars grow to about 60 mm long before commencing to burrow into the ground where they pupate. The insect has only one generation per year.

For further information and images see the pasture day moth info sheet

Slugs


Daniel Bell (Landmark) has found black keeled slugs in a cereal paddock near Ravensthorpe. The cereal crop which is at the two to five leaf stage is out growing any damage. A farmer in the Katanning region reports that his crop is now outgrowing slug damage from black keeled slugs as well as reticulated slugs. However, the slugs were present in paddocks that had no previous known history of the pests. Black keeled slugs can survive a hot dry summer and one to two slugs per square metre can cause significant damage to a germinating canola crop.

Further reports of slugs damaging crops have been received from Mt Barker, Katanning, Kojonup and Boyup Brook.

For further information on slug control refer to Identification and control of pest slugs and snails for broadacre crops in WA and the GRDC publication Slug control: Slug identification and management. Visit the South Australian Research and Development Institute (SARDI) website to view information on slug baiting.

Earwigs in canola


Courtney Piesse (Elders) reports that a farmer near Kendenup has seen chewing damage to a four to five leaf canola crop. The farmer had inspected the crop but could find no insect pests in the area of the damage.  Courtney advised the farmer to place a pitfall trap on the edge of the damage and to check it the next day. Earwigs and weevils were found. Native earwigs do not cause crop damage whereas european earwigs can cause significant crop damage and can be difficult to control. The farmer intends to get the earwigs correctly identified before implementing any control measures.

Correctly identifying the pest responsible for crop damage is important in choosing the right control measure as it avoids the application of unnecessary or incorrect insecticide sprays.

For more information on identifying European earwig refer to the DAFWA webpages - Management of European earwig and Diagnosing European earwig

Also available:


List of registered insecticides

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 Departmental 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? Send in your digital pictures (in focus) or send live specimens in a non-crushable plastic jar for free identification. Mail 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 98928591 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 9753 or +61 (0) 404 819 534


Integrated Pest Management Guidelines for grains

AgTactic and AgMemo

Other regional DAFWA news updates are available on DAFWA website.



Growing Season Outlook

Seasonal climate outlooks are available on DAFWA website.



AGWEST Plant Labs

Plant disease diagnostic service 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 webpage.




Next issue of PestFax – 11 July 2014

Copyright © Western Australian Agriculture Authority, 2014



The Chief Executive Officer of the Department of Agriculture and Food and the State of Western Australia accept no liabilitywhatsoever by reason of negligence or otherwise arising from the use or release of this information or any part of it.


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