Victorian guide to exotic pests and diseases of grain crops Exotic Plant Pest Hotline (1800 084 881)

Edited by Jemma Pearl and Luise Fanning (Agriculture Victoria)

With acknowledgments to Kurt Lindbeck (NSW DPI), Kat Fuhrmann (FAR Australia) and the Agriculture Victoria Chief Plant Health Officer’s team for their contribution of content and expertise.

@The State of Victoria Department of Jobs, Precincts and Regions 2020

This work is licensed under a Creative Commons Attribution 3.0 Australia licence. You are free to re-use the work under that licence, on the condition that you credit the State of Victoria as author. The licence does not apply to any images, photographs or branding, including the Victorian Coat of Arms, the Victorian Government logo, the Department of Jobs Precincts and Regions and the Agriculture Victoria logo. To view a copy of this licence, visit http://creativecommons.org/licences/by/3.0/a/deed.en

ISBN 978-1-76090-280-3 (Print) ISBN 978-1-76090-281-0 (pdf/online/MS word)

Cover photo Faba bean rust by: Luise Fanning, Agriculture Victoria

Accessibility If you would like to receive this publication in an alternative format, please telephone the DJPR Customer Service Centre on 136 186, email [email protected] or via the National Relay Service on 133 677 www.relayservice.com.au. For Translating and Interpreting Service, phone 131 450 and ask them to phone the Exotic Plant Pest Hotline on 1800 084 881. This document is able available on the internet at www.agriculture.vic.gov.au.

Disclaimer This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. Exotic Plant Pest Hotline (1800 084 881)

Contents

Area of Freedom - what do we mean? 4 Exotic viruses • Red vein mosaic virus 26 CropSafe program • spindle streak mosaic 27 INTRO 5 Reporting suspect pests and disease Exotic pests 6 • Barley stem gall midge 29 Exotic diseases • Cabbage seedpod weevil 30 DISEASES Soil-borne diseases • European wheat stem sawfly & 31 BORNE SOIL • Fusarium wilt of canola 8 Wheat stem sawfly • Fusarium wilt of chickpea 9 • Hessian 32 FOLIAR • Cyst nematode (exotic strains) 10 • Khapra beetle 33 DISEASE • Canola verticillium wilt 11 Case study - Khapra beetle 34 Foliar diseases • Leaf miner as a group 35 • Leaf blight of wheat 12 • Sunn pest 36 RUST • Lentil anthracnose 13 • Turnip 37 • Lupin anthracnose 14 • Wheat aphid 38 Case study - Lupin anthracnose 15 • Wheat stem maggot 39

Rust HEAD • Ramularia 16 Exotic weeds • Barley stripe rust 17 • Asiatic witchweed 41 • Barley stem rust (exotic strains) 18 EXOTIC EXOTIC

• and Lentil rust 19 Glossary 42 VIRUSES • Leaf rust (exotic strains) 20 Useful resources 43 • Wheat stem rust, pathotype Ug99 21 • Wheat stripe rust (exotic strains) 22 PESTS Head EXOTIC • Karnal bunt 23 Case study - Karnal bunt 24 WEEDS EXOTIC EXOTIC Exotic Plant Pest Hotline (1800 084 881)

Area of freedom - why is it important?

The term ‘area of freedom’ is frequently used with It is important to not accidentally introduce exotic regards to biosecurity and surveillance for exotic pests or diseases into Australia after travelling pests and diseases, but what does the term mean? overseas. The risk of intoducing exotic diseases or new mutations of a pathogen into Australia can be Area of freedom is the understanding that a region minimised by having a biosecurity hygiene plan is free of a disease or pest, which can be proven following overseas travel. statistically through sample/data collection in a region over time. The requirements have changed in Basic biosecurity hygiene includes washing clothes the last 20 years so that it is no longer enough to not and cleaning footwear before returning to have detected these pests or diseases. Countries Australia or immediately on return. If high risk areas now need evidence to show that they have looked have been visited, consider leaving clothing and for these pests and diseases and not found them in footwear behind. Remind family members, order to be able to declare an area of freedom. employees or others travelling to also take these precautions. Hence surveillance is necessary to demonstrate area of freedom in order to meet trading partner The importance of surveillance requirements, as well as to demonstrate successful As you can imagine proving an area of freedom, and pest eradication at the end of a nationally approved the surveillance required, can be a very expensive eradication campaign. process.

While the process of collecting and analysing In the Karnal Bunt case study (see page 24), the samples may sound simple, all the processes need number of samples that were collected in order to to be linked to a set of protocols that meet a set prove an area of freedom required significant time standard for collection of surveillance data. This and investment, but were necessary to maintain surveillance data provides the evidence that certain trade access. pests and diseases have not been detected in Australia. This can then be used by our businesses This demonstrates targeted surveillance, which is to trade with countries that require evidence of important in establishing area of freedom (or area absence of a pest or disease. The surveillance data of spread) due to a suspected incursion. Other types collected also increases the early detection (and of surveillance include long term, general therefore ability to eradicate) any exotic pests and surveillance programs which provide evidence of diseases. area of freedom for a wide range of pests and diseases. Examples of these include the Sentinel A successful biosecurity system is a shared Silo Surveillance program (see page 33) and the responsibility, requiring scientists, government, CropSafe program. industry, and the community to cooperate.

Fewer pest and disease problems mean lower production costs. Areas where rigorous biosecurity can deliver ‘area of freedom’ gives Australian producers an enormous advantage in international markets and allows us to have safer and cheaper locally produced food.

4 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

CropSafe program

CropSafe Program The CropSafe program maintains rigour through CropSafe is a critical tool in identifying potential contained communication and a range of extension exotic pests and disease threats to Victoria’s grains products. This ensures that the agronomists in the

industry. Agriculture Victoria delivers the CropSafe network and the wider industry understand the key INTRO program in collaboration with a number of major pests and diseases that are of greatest risk to agribusiness companies. Together, this cluster Victorian grain growers. Growers and agronomists incorporates approximately 80 per cent of Victoria’s can find the key 34 pests, diseases and parasitic agronomists. CropSafe has a network of over 200 weeds that are threats to the Victorian grains experienced agronomists continually looking for industry in this booklet. A link to the electronic new pests and diseases. This means Victorian version of the booklet can be found in the useful farmers can be far more confident that their grain resources section. DISEASES crops are free of exotic pests. The CropSafe BORNE SOIL program has streamlined sample receipt, analysis, For sampling material and instructions (including reporting and record keeping. plastic specimen bags and plastic vials) or information on joining CropSafe, contact Luise The 2018 CropSafe general surveillance survey Fanning on (03) 4344 3111 or resulted in CropSafe agronomists reporting on just [email protected]. FOLIAR over 1.9 million hectares which is approximately half DISEASE of the estimated 3.2 million hectares of grain crops The success of CropSafe was acknowledged with a in Victoria. Crops were inspected three to ten times National Biosecurity Award in March 2017. (average five times) during the growing season, depending on the crop type and scouting program required for crop pest and disease management.

Table 2. Probability of area of freedom* for RUST 2018 based on the area surveyed by CropSafe agronomists for Victoria’s top exotic pests and diseases in broadacre agriculture. Exotic pest/disease 2018 Table 1. 2018 passive crop surveillance inspection reported to CropSafe American Serpentine Leaf Miner 0.91600

Crop Number of paddocks Hectares Leafhopper 0.99999 HEAD inspected Turnip Moth 0.85538 Wheat 9,004 620,628 Barley Stem Gall Midge 0.99437 Barley 5,309 470,322 European Wheat Stem Sawfly 1.00000 Oats 1,416 67,232 Cabbage Seedpod Weevil 0.90201

Triticale 93 4,679 Fursarium Wilt of Canola 0.94531 EXOTIC VIRUSES Canola 4,659 270,935 Fursarium Wilt of Chickpea 0.50917 Lentils 1,881 236,631 Barley Stripe Rust 0.99995 Vetch 1,219 121,163 Lentil Rust 0.95467 Field pea 417 52,109 Lupin Anthracnose 0.68911 PESTS Faba beans 646 43,555 Lentil Anthracnose 0.85283 EXOTIC

Lupins 468 33,768 Karnal Bunt 0.99878

Chickpeas 164 20,570 *Given design prevalence of 1:1000 plants and 1:1000 crops affected, and a 1:20 year chance TOTAL 25,276 1,941,591 of incursion WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 5 Exotic Plant Pest Hotline (1800 084 881)

Reporting suspect pests and diseases

IF YOU SEE ANYTHING UNUSUAL, CALL THE EXOTIC PLANT PEST HOTLINE 1800 084 881

Any unusual plant pest should be reported The caller will then be connected to the relevant immediately to the relevant state or territory authority for that jurisdiction where calls will be agriculture agency through the Exotic Plant Pest answered by an experienced person, who will ask Hotline (1800 084 881). Early reporting increases the some questions to help understand the situation, chance of effective control and eradication. such as:

Careless use of information, particularly if a pest • What was seen (describe the pest or send a has not been confirmed, can result in extreme stress photo) and when was it first noticed? for individuals and communities, and possibly • Where was it found and what was it on? damaging and unwarranted trade restrictions. • How many pests are present/how infected is the crop? Calls to the Exotic Plant Pest Hotline will connect • How widely distributed is it? to an automated system that allows the caller to choose the state or territory that the call relates to.

6 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Exotic diseases

Source: Agriculture Victoria CropSafe I Guide to exotic pests and diseases of grain I 7 Exotic Plant Pest Hotline (1800 084 881)

Fusarium wilt of canola

Symptoms Where? Seedlings are attacked at ground level and in severe USA, Argentina and Canada. cases, rot though the stem. Australia - Queensland and the Northern Territory.

Symptoms are similar to drought stress. Infected plants may be stunted, discoloured and have poor seed set. Fusarium wilt causes a discolouration of the stem, often seen as purple, grey or brown streaks starting from the foot region and moving up the plant. These symptoms are visible in stems cut lengthwise. Only one side of the plant or only a few branches may show symptoms.

One of the ways to determine if the disease is Fusarium wilt is to scrape or cut away the outer layer of the stem (epidermis). The presence of dark streaks inside the stem (in the vascular tissue) is characteristic of the disease. Infected plants often die prematurely and crop yield can be greatly reduced.

Organism Furasium oxysporum f. sp. conglutinans

Host range Cruciferous crops e.g. canola, cabbage and broccoli.

Method of spread This pathogen can be spread with infected plants and seed, soil, equipment contaminated with soil, by water flow, and by wind. It can survive in the soil for many years in the absence of a host. In rare cases, seeds can become infected and possibly transmit the fungus. Many cruciferous crops and weeds may be symptomless, alternate hosts and have potential to transmit the pathogen as well.

Conditions favouring disease Fusarium oxysporum f. sp. conglutinans can survive Image 1. Fusarium wilt of canola seed head. for many years in soil. Warm dry conditions may Source: Canola Council of Canada. increase disease severity and yield loss.

Confused with? Root rot, blackleg, and sclerotinia stem rot. Fusarium wilt can be differentiated from root rot because the roots of affected plants remain intact. Similarly, it differs from blackleg in that there is an absence of lodging and cankers on the stem base. Fusarium wilt differs from sclerotinia rot by the absence of bleaching and shredding of stems.

8 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Fusarium wilt of chickpea

Symptoms The disease can appear approximately three weeks after planting. Symptoms consist of wilting, paler coloured leaves, shrunken stems above and below ground, followed by plants collapsing flat onto the INTRO ground. Infection of adult plants shows wilting progressing from the petioles and the youngest leaflets to the whole plant in two to three days. Leaves turn greyish green then a dull yellow colour, especially the lowest ones, followed by plant death. In both seedling and adult plant infections, inspection of roots split longitudinally shows a brown to black discolouration of internal vascular DISEASES SOIL BORNE SOIL tissue (pith and xylem).

Chickpeas are infected via roots and the pathogen moves through the vascular system, produces Image 2. Vascular discolouration (left stem). enzymes that break down the host cells to form gels. Source: M.P. Haware, Y.L. Nene & S.B. Mathur

These gels block the vascular system thus causing a (ICRISAT) FOLIAR DISEASE yellowing and wilting of leaves and eventually plant death. Confused with? Organism Fusarium wilt of chickpea can be confused with Fusarium oxysporum f.sp. ciceris phoma blight, damping off, rhizoctonia and phytophthora root rot, but may be distinguished RUST Host range from them by the discolouration of the internal root Chickpea (Cicer arietinum). tissue.

Method of spread Where? This pathogen can be spread with infected seed, India, Bangladesh, Myanmar, Nepal, North Africa, soil, in plant debris, by water flow and by rain splash. Spain and Mediterranean countries, America, It can survive in the soil for many years in the

Mexico and Brazil. HEAD absence of a host.

Conditions favouring disease Conditions favouring disease are early planting. Disease development can be enhanced by failure to remove host debris from infected fields, shallow ploughing and crop rotations of less than three EXOTIC EXOTIC years. VIRUSES PESTS EXOTIC

Thank you to Kurt Lindbeck (NSW DPI) for assistance with his contribution of content. WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 9 Exotic Plant Pest Hotline (1800 084 881)

Cyst nematode (exotic strains)

Symptoms Method of spread Above ground symptoms of Heterodera latipons, Cereal cyst nematodes would be most likely to enter H. avenae and H. filipjevi are similar, and include in soil contaminants in containers, machinery, plant yellowing, poor tillering, stunting of plants and bulbs, grain, etc. Once present in Australia, cysts patchy growth. Leaves may be thin with could potentially be dispersed in high winds, in reddish-yellow colouring. water or especially on machinery with infected soil.

Root symptoms of wheat and barley plants infested Conditions favouring disease with H. avenae include elongation of the main root, The biology of H. latipons and H. filipjevi appear bunched tips of rootlets and a knotted appearance similar to H. avenae. A late break is likely to delay due to cysts. Infected oat roots appear ‘ropey’ hatching and only one cycle is completed per year. and swollen. White cysts (which turn brown as the season progresses) may be visible to the naked eye. Confused with? H. avenae is characterised by the lemon shaped Cereals - Cereal cyst nematode strains currently cysts: however, this is true of both endemic and present in Australia and nutritional disorders, exotic strains. drought stress or herbicide injury.

Root symptoms of H. latipons appear to be different Pulses - nutritional disorders, drought stress or to that seen with H. avenae with no characteristic herbicide injury. “knotting” caused by excessive production of lateral roots at the site of infection. Where? Africa, Asia, Europe, North America and New Organism Zealand. Heterodera latipons, Heterodera avenae (exotic strains), Heterodera filipjevi and Heterodera glycines.

Host range Heterodera latipons = wheat, barley and oats Heterodera avenae = wheat, barley and oats Heterodera filipjevi= wheat, barley and oats Heterodera glycines = lentils, and faba beans

Image 3. Heterodera glycines cyst nematode. Source: Jonathan D. Eisenback, Virginia Polytechnic Institute and State University, Budwood.org.

10 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Canola verticillium wilt

Symptoms Initial symptoms of the wilt are yellowing (chlorosis) of lateral branches and leaves. Verticillium longisporum colonises the upper stem and leaves, while V. dahliae colonises the roots and lower stem. INTRO Both fungi have similar symptoms.

Chlorosis and stunting of the entire plant develops later. A dark brown circle in the vascular system is visible when the stem is cut, but is hard to detect in oilseed crops and can sometimes be confused with blackleg. Stems finally develop a bronze colour that DISEASES coincides with the fungal development of BORNE SOIL microsclerotia. Premature senescence and ripening occur, and reduced yields of 50 per cent have been reported. Image 4. Canola verticilium wilt on infected plants Wilting causes the fungus to form microsclerotia in on left. FOLIAR the senescing and necrotic plant tissue, which are Source: A McTaggart (2007) DISEASE incorporated into the soil with host death to renew the cycle. Conditions favouring disease Infection is likely under moist conditions with an air Organism temperature of about 23°C and cooler soil Verticillium longisporum temperatures of 15 to 19°C. RUST Host range Confused with? Canola and charlock (wild mustard) can be infected Other wilt inducing microbes, for example blackleg, with V. longisporum. Oats and wheat can be infected and expert diagnosis is often required. but do not show symptoms. Can be confused with symptoms of V. dahliae which Method of spread is present in Australia but only colonises the basal

V. longisporum microsclerotia are abundant in soil region of plants. HEAD and infected plant tissue where the disease occurs, so the movement of soil and infected plants can Where? spread the disease. Canada, Europe, Japan, Russia and USA.

Microsclerotia can remain viable in soils for many years. Spread via microsclerotia contaminants in EXOTIC EXOTIC

seed is also possible. VIRUSES PESTS EXOTIC WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 11 Exotic Plant Pest Hotline (1800 084 881) Leaf blight of wheat

Symptoms The disease symptoms appear when wheat plants are seven to eight weeks old. Symptoms gradually spread to the upper leaves and by the time the crop matures symptoms are severe. Infection is first evident as small, oval, tan-coloured lesions, scattered on the leaves. Lesions enlarge and turn dark-brown to grey and are irregular in shape. Some lesions are surround by bright-yellow margins. The lesions vary in size, reaching a diameter of one centimetre or more.

As the disease progresses, several lesions coalesce to cover large areas, resulting in the death of the entire leaf. In some cases the leaf starts drying up from the tip, prematurely, when lesions appear. Black, powdery spores (conidia) may cover the lesions at this stage under moist conditions. The lowermost leaves are the first to show the signs of infection; the fungus gradually spreads to the upper leaves. In severe cases, similar symptoms are produced on the leaf sheath and stem, as well as the awns and glumes if spikes are infected before flowering (pre-anthesis stage). If the spike is infected this early, seeds do not form. Infection at the dough stage of seed development results in glume infection, ear infection, and seed infection. Image 5. Field symptoms of leaf blight of wheat. Heavily infected fields appear ‘burnt’ and can be Source: Jihad Orabi. identified from a distance.

Organism Conditions favouring disease Alternaria triticina Susceptibility to the pathogen increases with plant age. Host range Wheat (Tritcum aestivum). Infection requires at least 48 hours of 100 per cent relative humidity. Maximum disease development Method of spread occurs on ten week old plants under high relative The fungus is considered to be seed-borne. It can humidity and temperatures up to 25°C. survive for two months on infected wheat debris on the soil surface and for four months on infected Confused with? debris buried in the soil. The fungus multiplies in Other fungal diseases or damage. the soil and infects leaves either by rain splash of spores onto leaves or by leaves contacting the Where? ground. Asia, Europe, Africa, Mexico and Argentina.

12 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Lentil anthracnose

Symptoms First seen as green-white lesions on leaves, which become tan-coloured lesions of variable size as the plant matures, followed by premature leaf drop. Lesions on stems develop soon after the appearance of leaf lesions. Stem lesions may be either small, brownish with a black border, or

larger, stretching along the stem. As lesions age, INTRO small, black microsclerotia (small, pinhead-sized structures) are formed within the lesions. As the crop grows, more and more lesions develop at the base of the plant, as well as on the upper part of the stems, and many stems can become completely girdled. As a result, large areas of brown and dying plants can be found in the field. DISEASES SOIL BORNE SOIL Organism Colletotrichum truncatum (lentil infecting strains). Image 6. Stem lesions on lentils in the field. Host range Source: Kurt Lindbeck, NSW Department of Primary The lentil infecting form of Colletotrichum Industries. FOLIAR truncatum only attacks plant species belonging to DISEASE Confused with? the Lens and Vicia families. In Australia the Symptoms of the disease are very similar to pathogen has been found on peanut and , Ascochyta blight and may require trained but the lentil infecting form is considered exotic. pathologists to distinguish the diseases. Colletotrichum truncatum has a very broad host Microsclerotia are very distinct compared to the range including peanut, soybean, lentil, field pea, pycidia (small, black fruiting bodies) produced by subterranean clover, vetches, faba bean and ascochyta. The microsclerotia tend to be larger and RUST Stylosanthes spp. But this pathogen is known to raised within the lesion. have ‘pathotypes’ that only attack some species. Where? Method of spread North America, Europe, Middle East and Pakistan. Anthracnose-infected debris from previous lentil The disease is known to be most destructive in crops is the main source of inoculum, however it can North America on lentil. The lentil-infecting form of

be seed-borne at low levels. In addition, the fungus HEAD C. truncatum is exotic to Australia. survives as microsclerotia, which continue to survive in the soil for some time, at least five years or more, even in the absence of the host and initiate new infections.

The pathogen will survive over summer in infected seed, infected trash, and as microsclerotia in the EXOTIC EXOTIC soil. Spores are spread via rain splash onto VIRUSES surrounding seedlings. Spores are produced in large numbers on infected seedlings that spread the disease further onto surrounding plants.

Conditions favouring disease PESTS Anthracnose spores infect lentil readily at 20-24°C EXOTIC and require 18-24 hours of leaf wetness. Image 7. Leaf lesions on lentils. Source: Kurt Lindbeck, NSW Department of Primary Industries. Thank you to Kurt Lindbeck (NSW DPI) for assistance with his contribution of content. WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 13 Exotic Plant Pest Hotline (1800 084 881) Lupin anthracnose

Symptoms Seedlings can develop lesions on the hypocotyl or cotyledons. Stem lesions are very distinctive and (Image 9) are oval shaped, up to two centimetre long and contain spore masses which are pink to orange. These lesions cause the stem to collapse on one side and bend to produce a ‘shepherds crook’ symptom. Lupin branches die back as the lesions mature, eventually causing the death of the whole plant. Further rainfall will allow infection progress to infect pods and seeds. Pods can develop lesions which also result in twisting and distortion of pods. Pod infection can result in nil seed set or infected seed. Lesions on pods also develop brightly coloured spore masses which vary in colour from pink to white. Symptoms are most noticeable during flowering. Image 8. Stem infection on albus lupins. Source: Kurt Lindbeck, NSW Department of Primary Infected lupin seeds can be discoloured, however, Industries infected seed may not have symptoms.

Organism Colletotrichum lupini (formerly known as Colletotrichum gloeosporioides).

Host range Lupinus spp.

Method of spread Infested seed and trash carry the pathogen to new areas, water splash will spread spores short distances within crops. Lesions on infected plants produce an abundance of spores that are spread through the crop by rain splash, but movement by machinery, , birds and seed also occur. Image 9. Early stem infection. Conditions favouring disease Source: Kurt Lindbeck, NSW Department of Primary Colletotrichum lupini can survive over summer on Industries infected trash and seed. Wet conditions in winter favour germination of infected seed and disease Phytophthora root rot of lupin can also result in establishment. Frequent rainfall during flowering sudden wilting and death of plants which can favours spread of the disease within crops and sometimes produce a collapsed stem. Plants with development of shepherds crook symptom. this disease will have a badly-rotted root system.

Confused with? Discolouration of seed can also be caused by The disease can be confused with frost injury, which another fungal disease, brown leaf spot, caused by can also cause collapse and premature death of the the fungal pathogen Pleiochaeta setosa. main stem. However, only anthracnose produces bright pink to orange spores masses within stem Where? lesions. The disease is widespread throughout Western Australia and South Australia.

Thank you to Kurt Lindbeck (NSW DPI) for assistance with his contribution of content.

14 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Case study - Lupin anthracnose

early 1850s Lupins introduced into Australia

1960s Standard breeding lines developed 5 September 1996 Lupin anthracnose was detected in Western Australia, with major outbreaks occuring in the Geraldton and Mingnew areas. The initial survey identified that 40 properties were infected, this grew to 133 properties for the outbreak. Ultimately this affected approximately 40,000 hectares of crop and 5,000 INTRO hectares of pasture lupins by the end of the 1996 growing season.

The Western Australian state government tried to reduce the spread of the disease by placing a moratorium on lupin production until 1998. While initally the aim was to elimate the disease through a process of destruction of standing crops, it became clear that this was not economically viable and

therefore a disease management phase was implemented. DISEASES SOIL BORNE SOIL

1997-1998 While Lupin anthracnose spread throughout Western Australia, all available lupin germplasm was sent to New Zealand for resistance testing. Through this testing it was shown that the Albus lupins were highly susceptible to Lupin anthracnose, but there were varieties that did show some resistance. FOLIAR DISEASE Because the life cycle of Lupin anthracnose requires the disease to inhabit the lupin seed, the movement and germination of infected seed is a major contibution to its spread. Therefore, research was undertaken to determine what percentage of infected seed would result in a major outbreak. For Albus lupins, French researchers determined that only one infected seed per 10,000 seeds can result in a major outbreak. Research also showed that a yield penalty of between 0.2 to 1.0 t/ha could result from seed that was only RUST 0.5 per cent infected.

Given the issue with lupin seeds infected with Lupin anthracnose, there are resistrictions on the movement of lupin seeds. Agriculture Victoria reminds growers that the following restrictions for lupin seed entering Victoria must be complied with to avoid a Lupin anthracnose outbreak. Lupin seed for HEAD planting must originate from a state with a current area freedom certificate for Lupin anthracnose or be certified as being tested free from the disease. Growers wanting to import packages used with lupins, seed or plants or lupin diagnostic samples (including seed etc) must first obtain a permit from an Agriculture Victoria Plant Standards Officer by telephoning 136 186. Businesses receiving stock feed containing lupins from states affected by Lupin anthracnose should immediately implement best practice biosecurity EXOTIC EXOTIC measures to reduce the risk of inadvertently spreading the disease in VIRUSES Victoria. Best practice biosecurity measures include not planting lupin crops in paddocks where the material containing lupins was fed to stock in the previous season and managing volunteer plants in subsequent seasons. October 2016 Lupin anthracnose detected in Southern New South Wales, eastern Riverina district. A collaboration between NSW DPI and Local Land Services PESTS successfully eradicated the disease, thus protecting the $65 million lupin EXOTIC industry in NSW. References: ‘Resistance screening in New Zealand and breeding activity’ by W.A. Cowling, B.J. Buirchell, D. Luckett, H. Yang and M.W. Sweetingham. Journal of Agriculture, vol.40, no.1, 1998/1999. ‘Case study: industry response to the lupin anthracnose incursion in Western Australia’ by G. Shea, G. Thomas, B. Buirchell, M. Salam, S. McKirdy and M. Sweetingham, 2008 WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 15 Exotic Plant Pest Hotline (1800 084 881) Ramularia

Symptoms Ramularia leaf spot is caused by an endophytic fungal pathogen, which develops within the plant from the seedling stage without disease symptoms being manifest. The disease, which is primarily seed-borne, typically develops leaf spot lesions during flowering or grain fill as a result of an environmental stress.

Lesions are a red-brown colour and rectangular in nature within the margins of leaf veins with a yellow halo around the lesion. Once lesions are fully formed they can be seen on both sides of the leaf and cause early senescence of the leaf typically from the leaf tip working back to the base. Once fully senesced Image 10. Ramularia leaf infection. translucent/white spores are produced on the Source: Luise Fanning, Agriculture Victoria. underside of the leaf, these are visible with a hand lens and occasionally with the naked eye. Confused with? Seed infection does not cause physical defects Ramularia is commonly confused with both spot on the seed and cannot be detected by visual form net blotch and net form net blotch. Lesions of Ramularia can look like a combination of both of inspection. the net blotches with the chlorotic halo similar to spot form net blotch and the rectangular nature of Organism ramularia can be confused with net form net blotch. Ramularia collo-cygni (formly known as Ophiocladium hordei, Ovularia hordei and Where? Ramularia hordeicola). The pathogen was first detected in Tasmania in 2016 and again in 2018. It was first detected on the Host range mainland in the South Stirling region of Western A disease of Barley, its host range also includes oats, Australia in 2017. Internationally Ramularia collo- wheat, , maize and grasses (Poaceae spp.). cygni has been reported in New Zealand, North and South America and Europe. Method of spread Primarily a seed borne pathogen causing spread of disease through sowing infected seed. The pathogen can also spread through infected trash and once symptoms have expressed airborne spores can further promote the spread of the pathogen locally.

Conditions favouring disease Primarily a disease of the high rainfall zone, mild and wet conditions favour the disease with a stress event needed to produce plant symptoms for example a wet period during flowering.

Image 11. Ramularia leaf infection. Source: Nick Poole, FAR Australia.

Thank you to Kat Fuhrmann (FAR Australia) for assistance with her contribution of content.

16 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Barley stripe rust

Symptoms There are no known Barley stripe rust pathogens currently in Australia. Therefore any barley plants with symptoms of stripe rust should be sent for testing.

Closely related to the Wheat stripe rust fungus, symptoms of the two diseases are very similar. The INTRO fungus produces stripes of rust pustules between the veins of the leaves. Pustules may also form on the heads. In susceptible cultivars the entire leaf blade may become covered with the rust. In barley, the pustules may be more yellow than orange.

Organism DISEASES

Puccinia striiformis f.sp. hordei Image 12. Tiny pustules between leaf veins. BORNE SOIL Source: Cheryl Reynolds, University of California. Host range Hordeum spp. and Triticum spp.

The primary host of Barley stripe rust is spring FOLIAR barley with certain races of rust surviving on wild DISEASE barley species such as Hordeum jubatum (foxtail barley) and H. leporinum, H. glaucum, H. murinum (barley grass complex).

Method of spread

Wind, contaminated machinery, plant debris and RUST clothing. The major commercial spring barley varieties are susceptible to this disease.

Conditions favouring disease Barley stripe rust development is most rapid at temperatures between 10°C and 15°C. It requires a minimum of three hours of leaf wetness HEAD (intermittent rain or dew) for new infections to occur.

Confused with? Barley grass stripe rust and Wheat stripe rust. While no Barley stripe rust is present in Australia, Barley grass stripe rust and Wheat stripe rust can

both cause similar symptoms on commercial barley EXOTIC VIRUSES cultivars. Hence any commerical barley cultivars with stripe rust symptoms should be sent in for testing.

Puccinia hordei (Barley leaf rust) This species is cosmopolitan and found in Australia. PESTS Image 13. Stripe rust forms yellow orange stripes EXOTIC Where? along leaf veins. Asia, Europe, Central Africa, North, Central and Source: Agriculture Victoria. South America. WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 17 Exotic Plant Pest Hotline (1800 084 881) Barley stem rust (exotic strains)

Symptoms Where? Large pustules can occur on stems, leaf surfaces, There are strains that exist in Australia, but there leaf sheaths and heads. They are oval to elongated are a number that are still exotic to the region. If and are often surrounded by a characteristic torn you find a previously resistant barley plant with margin. Pustules are full of reddish-brown spores symptom of stem rust a sample should be sent for which are easily dislodged. As the plant matures, testing. black spores, which do not dislodge, are produced in the pustules.

Organism Puccinia graminis f.sp. hordei (exotic strains). In Australia, Barley stem rust can be caused by exotic strains of Puccinia graminis f.sp. hordei or the endemic P. graminis f.sp. tritici, and P. graminis f.sp. secalis and hybrids between the two, which are referred to as f.sp. hordei because of their virulence to commerical barley.

Host range Barley

Method of spread The fungus survives the summer mainly on volunteer wheat, barley, triticale and some grasses including common wheat grass and barley grass. Wind spreads spores from these hosts to the new crop. Heavily infected volunteer plants in the autumn can be a source of rust for the new season’s barley crop. If these conditions are followed by a mild winter and a warm wet spring, the chances of a stem rust epidemic are high.

Confused with? Leaf and stem rust may be confused, but they are distinguised by their colour and size. Leaf rust being lighter in colour, smaller and rounder than stem rust.

Conditions favouring disease Image 14. Barley stem rust is similar in appearance Disease development is favoured by high humidity to Wheat stem rust pictured here. and heavy dews. It is most rapid at temperatures Source: Grant Hollaway, Agriculture Victoria. between 15-30°C and markedly reduced by temperatures below 15°C and above 40°C. A mild winter and a warm wet spring heighten the chances of a stem rust epidemic. Stem rust can cause complete crop loss but suitable conditions for a severe outbreak are rare.

18 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Pea and Lentil rust

Symptoms The first symptoms are minute, whitish, slightly raised spots. These spots enlarge and change to form an orange-brown (rust coloured) pustules (typical of rust diseases of other crops) often surrounded by a light coloured halo. Leaves, stems and pods can all be infected. INTRO

Lentil and field pea rust can be confused with other rust diseases. However, neither rust has been recorded on field pea in Australia.

Organism Uromyces pisi DISEASES

Uromyces viciae-faba (exotic strains) BORNE SOIL Image 15. Uromyces viciae-faba. Host range Source: Tadesse Negussie and Zacharias Pretorius. Field pea rust and Lentil rust are major fungal diseases affecting spp. (field pea, garden pea etc.) and Vicia spp. (faba bean, vetch and lentil). FOLIAR Uromyces pisi is not present in Australia. Uromyces DISEASE vicia-faba occurs widely in Australia on faba beans and vetch, but not on field pea or lentil.

Method of spread Wind (air-borne spores), contaminated machinery

and clothing, contaminated seed and plant debris. RUST

Conditions favouring disease Rust development is favoured by mild temperatures and humid conditions, especially in mid to late spring. Cloudly weather with temperatures of 20-22°C and dense canopy favour the disease. HEAD Confused with? Lentil and field pea rust can be confused with other rust diseases. However, neither rust has been recorded on field pea in Australia.

If rust symptoms are seen on field pea or lentil a

sample should be sent for further testing to identify EXOTIC VIRUSES the species - contact the Exotic Plant Pest Hotline on 1800 084 881.

Where? Middle East, South America, India, Bangladesh, Pakistan and Canada. PESTS EXOTIC

Thank you to Kurt Lindbeck (NSW DPI) for assistance with his contribution of content. WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 19 Exotic Plant Pest Hotline (1800 084 881)

Leaf rust (exotic strains)

Symptoms The disease can be recognised by the orange to brown coloured rust pustules on the plant. The rust pustules produce a fine powder like substance when rubbed. These pustules are slightly raised and occur on both sides of the leaves and very occasionally on the stem, leaf sheaths or ears. Late in the season, some blackish-brown spots may also appear, usually on parts of the plant that are dying. Where formerly resistant lines of wheat are becoming susceptible, symptoms can include small brown spots or small pustules which may have a pale green or yellow halo.

Organism Puccinia triticina (exotic strains)

Host range Wheat, specially bread (Triticum aestivum), durum (T. durum) and Triticale.

Method of spread The spores can be carried several hundred kilometres by the wind, and local spread may also be possible via contaminated clothes and equipment.

Conditions favouring disease Infection is favoured by wet leaves and a temperature of about 20°C for at least four hours. Also favouring disease is a build-up of spores that survived from the previous season or were produced from self-sown hosts. Image 16. Orange to brown coloured rust pustules. Source: Luise Fanning, Agirculture Victoria. Confused with? Other rust fungi. Also, other pathogens (e.g. Alternaria triticina), nutritional disorders and some chemical burns may produce light coloured spots, however these cannot be rubbed off. Rust pustules can be largely removed by rubbing and they also stain the fingers brown-orange.

Where? The fungus causing leaf rust is found around the world, including Victoria. Exotic strains of the fungus are of potential concern to us.

20 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Wheat stem rust, pathotype Ug99

Symptoms Symptoms are the same as other wheat stem rust pathotypes. The symptoms start as oblong blisters on the stems and leaves, developing lengthwise along the plant. These blisters break open after a couple of days to reveal a mass of rust coloured spores. INTRO

If stem rust is detected on a wheat line which is thought to be resistant, samples should be sent for testing. Contact details for Australian RustCereal Survey can be found in the resources section.

Organism DISEASES Puccinia graminis f. sp. tritici, pathotype Ug99 BORNE SOIL

Host range Wheat and other cereal crops.

Method of spread FOLIAR Wind, contaminated clothing, machinery and tools. DISEASE

Conditions favouring disease Image 17. Symptoms of race Ug99 on wheat grains. Generally, for Puccinia graminis, the most important Source: David Mowbray (CIMMYT). requirement for disease is susceptible varieties of wheat. Thereafter, warm (15 to 30°C) and humid conditions are needed together with abundant RUST spring rain. Also, favouring disease is an accumulation of spores from infected and self-sown wheat plants growing before the main crops are planted.

Confused with? Other stem rusts of wheat. Expert diagnosis is HEAD required if a resistant cultivar is being cultivated and develops stem rust. Early detection is important in controlling this pathogen.

Where? A number of stem rust pathotypes are present in Image 18. Symptoms of race Ug99 on stem. EXOTIC EXOTIC Australia and resistant varieties of wheat have been Source: David Mowbray (CIMMYT). VIRUSES bred to limit crop losses. This new pathotype was discovered in Uganda in 1999, and is now found in Kenya, Ethiopia, Sudan, Yemen and Iran. PESTS EXOTIC WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 21 Exotic Plant Pest Hotline (1800 084 881) Wheat stripe rust (exotic strains)

Symptoms The disease may appear as hot spots of one to ten metres in diameter in the crop, prior to the disease becoming widespread. Stripe rust is easiest to identify in the morning. Examine leaves, especially the older leaves, low in the canopy and look for yellow stripes of pustules. These pustules are raised above the leaf surface and can be easily wiped off onto a white cloth or tissue leaving a yellow stain. Stripe rust can also infect the developing head reducing grain number and size.

Organism Puccinia striiformis f. sp. tritici (exotic strains)

Host range Wheat (Triticum aestivum), durum wheat (T. durum), Triticale, and barley (Hordeum vulgare).

Method of spread The spores are dispersed by wind, multiple times during a season. Stripe rust survives from one season to the next predominantly on volunteer self-sown cereals but can also survive to a lesser extent on other cereal and grass weeds that grow over summer.

Conditions favouring disease Spores require temperatures of less than 18°C Image 19. Yellow stripes of pustules. (optimum 6-12°C) with a minimum of three hours of Source: CropPro. leaf-wetness (for example, dew) for germination and infection to occur. Confused with? Leaf rust caused by Puccinia triticina. After infection it can take 14 to 28 days for pustules containing spores to appear on the leaf surface. Where? The fungus causing leaf rust is found around the Stripe rust epidemics are usually more severe world, including Australia. Exotic strains of the in seasons following wet summers that have fungus are of potential concern to us. supported the ‘green bridge’, living plants mostly of wheat and to a lesser extent barley, triticale, barley grass, brome grass and phalaris. In Victoria, Stripe rust can be expected in crops by late August or early September in most years. Stripe rust does not survive on seed, stubble or soil.

22 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Karnal bunt

Symptoms Wheat grains develop dark discolourations at the pedicel or ‘embryo’ end of the grain. The discolouration progresses along the grain until it is entirely discoloured. The infection is difficult to detect on the plant. Infected grain has a distinct

rotten fishy smell. Grain discolouration may be INTRO caused by other fungi, so samples should be sent to a laboratory for diagnosis.

Organism Tilletia indica

Host range DISEASES

Triticum spp., including Triticum aestivum (Wheat) BORNE SOIL and Triticale. Image 20. Grain seed infection. Method of spread Source: Simon Hinkley & Ken Walker, Museum Survives in grain, soil and cereal trash. Seed-borne, Victoria. soil-borne and wind-borne. FOLIAR DISEASE Conditions favouring disease The spores require free water in the soil to germinate. Air temperature ranging from 10°C minimum to 26°C maximum, with high humidity above 75 per cent relative humidity during heading

and flowering are required for infection. RUST

Confused with? Other bunts and smuts, however, a distinctive feature of Karnal bunt is only part of the head is afftected whereas common bunt affects the entire grain head. HEAD Other fungi may cause grain discolouration and so expert diagnosis is often required. Symptoms on the grain may be confused with Black point, a fungal disease common after wet conditions at harvest. Image 21. Head infection. Source: Ravindra Kumar. Where?

First detected in India and now found in many EXOTIC Middle-Eastern countries. Confined to specific areas VIRUSES and under quarantine in specific areas of South America, South Africa and the USA. If Karnal bunt became established in Australia, access to over 45 markets would be significantly reduced. PESTS EXOTIC WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 23 Exotic Plant Pest Hotline (1800 084 881) Case study - Karnal bunt

Karnal bunt is the number one exotic disease risk for To prove that Karnal bunt was absent from Australia Australia given the significant export and economic and maintain our area of freedom from the disease, impact. This is due to Australia producing about 25 thousands of samples needed to be collected, tested million tonnes of wheat per year, accounting for 3.5 and have a negative result. per cent of annual global production. Plant Health Australia commissioned leading The Australian wheat industry is export orientated, experts to develop diagnostic protocols for use shipping about 65-75 per cent of the nation’s total in Australia and Pakistan to effectively test the production to more than 50 countries. The majority samples needed to prove area of freedom. of Australian wheat is exported in bulk cargoes with the top 10 importing countries accounting for 70-80 Of the 28,000 samples of wheat tested, all were per cent of exports. negative.

When one of these bulk cargo ships arrived in Pakistan in 2004, the Pakistani Government claimed that it was contaminated with Karnal bunt. This claim affected $500 million of wheat on the water at the time.

24 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Exotic viruses

Source: Luise Fanning, Agriculture Victoria

CropSafe I Guide to exotic pests and diseases of grain I 25 Exotic Plant Pest Hotline (1800 084 881)

Red clover vein mosaic virus

Symptoms Host range Red clover vein mosaic virus (RCVMV) generally Pulses and lucerne. causes vein mosaic, mosaic streaking and stunting in various legumes. RCVMV causes a Method of spread characteristic chlorosis of leaf veins, veinlets and The virus is spread non-persistently by a range of tissue, and reduces its yield by reducing the foliage aphids (Acyrthosiphon pisum, Cavariella aegopodii, growth, decreasing persistance and increasing Myzus persicae and Therioaphis maculata). Seed susceptibility to root rots. transmission is also possible (but not common) in red clover, peas and faba bean. Mechanical The first report of RCVMV in pulses was of a disease transmission has also been reported. called Wisconsin pea stunt which was characterised by severe plant stunting, tight apical resetting, Aphid vectors currently in Australia leaves of reduced size, often wrinkled and folded Acyrthosiphon pisum = pea aphid upward showing marked vein clearing. In most pea Cavariella aegopodii = Carrot willow aphid cultivars, the first symptoms of systemic infection Myzus persicae = Green peach aphid were usually systemic vein clearing and lead curling Therioaphis maculata = Spotted aphid although some cultivars developed necrotic stem streaking sometimes followed by irregular yellowing and premature plant death. Confused with? Other viruses and plant nutritional deficiencies. Organism Carlavirus flexiviridae Where? Europe, India, South Africa and USA.

Image 22. Symptoms of Red clover vein mosaic virus (RCVMV, NZ isolate) on different host plants. Source: Red clover vein mosaic virus – a novel virus to New Zealand that is wide-spread in legumes - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Symptoms-of-Red-clover-vein-mosaic-virus- RCVMV-NZ-isolate-on-different-host-plants-A_fig1_285742137 [accessed 30 Jan, 2020].

26 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Wheat spindle streak mosaic virus

Symptoms Symptoms of Wheat spindle streak mosaic virus (WSSMV) consist of light green to yellow streaks or dashes that are parallel to the veins and usually are tapered, giving the appearance of spindles. WSSMV INTRO causes a slight stunting. Symptoms of WSSMV do not appear on new growth but may persist on older leaves.

WSSMV cause a mosaic on leaves characterised by chlorotic to nerotic spindle-shaped streaks, dashes

and spots that may coalesce. Chlorosis is light DISEASES yellow-green to bright yellow to orange and more BORNE SOIL pronounced on developing leaves. Chlorotic spindle-shaped streaks may have green centres. Necrosis is orange brown to brown and more Image 23. Wheat spindle streak mosaic virus pronounced on mature leaves. Fewer tillers are infection. produced, plant height and the size and number Source: Nancy Gregory. FOLIAR of grain heads are reduced. Within a crop, groups DISEASE of infected plants appear as light green to yellow patches. When the average temperature remains at or above 15°C, symptoms become hidden by new leaves that are asymptomatic.

Organism RUST Bymovirus potyviridae

Host range Wheat

Method of spread Vector - Polymyxa graminis – soil-borne fungus like HEAD organism. The virus is spread with motile zoospores in saturated soils which then penetrate and infect plant roots.

Conditions favouring disease WSSMV is favoured by cooler temperatures. EXOTIC EXOTIC VIRUSES Confused with? Other viruses and plant nutritional deficiencies.

Where? Limited information regarding spread, however, the virus is present in Europe and the USA. PESTS EXOTIC WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 27 Exotic Plant Pest Hotline (1800 084 881)

Exotic pests

Source: Piotr Trebicki, Agriculture Victoria

28 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Barley stem gall midge

Symptoms, description and lifecycle Host range Feeding damage on cereal plants can cause leaf The preferred host of M. hordei is barley (Hordeum discolouration, from a darker green to bluish green vulgare) but it will also feed on oat (Avena sativa), or slowing of new growth in seedlings. Plants are wheat (Triticum aestivum) and rye (Secale cereale). often stunted and tillers can become weakened Stem galls are produced almost exclusively on causing plants to lodge. The main identifying barley but occasionally on oat, wheat and rye. INTRO feature of Barley stem gall midge is the formation of pea-sized galls (swellings of the plant tissue) at Method of spread the base of host plant between the leaf sheath and Adults spread by actively flying throughout the crop stem. or using wind current. Long distance dispersal also occurs by ‘hitchhiking’ on machinery, clothes and Gall midge larvae have a long-lived larval stage plant material. specialised for feeding whereas adults are short DISEASES lived and generally only last one to two days, during Confused with? BORNE SOIL which time they do not feed but mate, find suitable This species is very similar and closely related to the host plants and lay eggs. Small numbers of eggs are ( destructor). Identification of laid indiscriminately on numerous host plants. Up the two species involves microscopic morphological to 400 eggs are laid per lifetime. Similar to Hessian differences and is best undertaken by an expert fly larvae, they undergo three instars growing up taxonomist. FOLIAR to three to four mm in length. The second instar DISEASE becomes a puparium within which the non-feeding Where? third instar, pupa and adult develop. Larvae are Barley stem gall midge originated in Tunisia. Its initially pale red in colour and become milky white range has expanded through North Africa and has as they mature. Adults are small, mosquito like been recorded in European countries; Spain, UK and about two to four mm long, have one set of wings France. with a few weak veins and beaded, elongated RUST antennae.

Organism Mayetiola hordei HEAD EXOTIC EXOTIC VIRUSES PESTS EXOTIC

Image 24. The white and the dark brown pupa of the Barley stem gall midge. Source: ICARDA. WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 29 Exotic Plant Pest Hotline (1800 084 881)

Cabbage seedpod weevil

Symptoms, description and lifecycle Adults feed on buds and can cause bud blasting and reduced yield potential, however, it is the larve that do the most damage. Each larvae will eat between two to five seeds on a pod which will show discolourisation on the outside. Mature pods will have small visible pinhead-sized emergence holes made by the larvae upon leaving the pod. The weevil presents an opportunity for the pod midge (Dasineua brassicae) to lay eggs on young seed pods using the pre-existing holes.

Larval activity of the midge can lead to swollen yellow pods, pod burst and premature seed shedding.

Based on observations in Europe, Cabbage seed Image 25. Adult Cabbage Seedpod Weevil. pod weevil has only one generation per year. Weevils Source: Rebecca Graham, Department of overwinter as sexually immature adults in soil and Agriculture Western Australia. leaf litter along paddock margins and in woodlands adjacent to Brassica crops. Mature adults emerge in spring and feed on flowers, buds, stems and pods. Females lay eggs by boring a small hole through the Method of spread pod walls with their rostrum and placing a single Diapausing adults overwintering in soil or leaf litter egg inside. Females can lay up to 240 eggs during is a likely entry route into Australia. C. obstrictus their life time. Under the right conditions, eggs can adults can fly well, potentially travelling some hatch after six to ten days. Larvae feed on the inside kilometres, and D. brassicae is small and can also of pods and immature seeds for two to three weeks travel reasonable distances on wind, though tend before leaving the pod by boring a pin sized hole in not to move more than 0.5 km away from host crop the pod wall and dropping to the ground. They dig areas. a hole in the soil up to ten centimetres deep where they pupate. The adults that emerge feed on the Confused with? remaining crop or other Brassica before settling Larvae and adults of C. obstrictus are similar to down to overwinter. mining larvae of Ceutorhynchus species such as the cabbage weevil (C. pallidactylus). Organism Ceutorhynchus obstrictus, also known as C. Where? assimilis. Cabbage seed weevil is considered native to Europe where it is widespread. It is also found in Northern Host range Africa and North America. A wide range of species in the family Brassicaceae. The main species include canola (Brassica napus var napus), broccoli (Brassica oleracea var italica) and turnip rape (Brassica rapa supsp. oleifera). Other affected hosts include various other Brassica species (Indian mustard, cauliflower, cabbage, brussel sprouts, mustard) and oil seed (Crambe abyssinica).

30 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) European wheat stem sawfly and wheat stem sawfly

Symptoms, description and lifecycle Infested stems are filled with frass and are cleanly cut at the feeding site causing lodging. Larval feeding weakens the stems and destroys vascular tissue affecting nutrient transfer to the heads.

Damage varies, depending on the year, locality, INTRO host plant and cultivar. Losses of up to 56 per cent in wheat and 50 per cent in barley have been recorded.

Adult wasps are black with prominent bright-yellow bands across the abdomen. Legs are yellow and wings are clear with brownish veins. Both species lay DISEASES eggs in the stems of grasses. BORNE SOIL

Cephus pygmeus (alternative spelling pygmaeus) have a single generation per year laying a single egg per stem but up to 50 eggs per lifetime. Larvae Image 26. Adult European wheat stew sawfly. feed within the stems of grasses, especially cereals. Source: Ken Walker, Museum Victoria. FOLIAR Early instars have a yellow-white body with an DISEASE enlarged brown head, large mandibles and an Cephus cinctus infests barley, rye, wheat, and anal tubercle. Mature instars become yellow- triticale. Non-crop hosts include wheatgrass green. Larvae cut the stems to construct pupation (Agropyron), wildrye (Elymus), Phleum and Bromus. chambers within the stem where they will pupate Oats and rice are resistant. over winter affecting grain yield and quality. Adult

European wheat stem sawfly (Image 26) are eight to RUST Methods of spread ten millimetres long. Females are larger than males. This species can be spread as larvae within the stems of infected crops. Cereal straw, baled as hay Cephus cinctus females produce 35 eggs on or carried on machinery could potentially transport average which are laid within the stems of host the pest over long distances. Adults are capable of plants. Larvae are white, segmented and legless, flight for localised spread. with tan head capsules and reach about 14 mm in length. Eggs are white, round and 1-1.5 mm in HEAD Confused with? diameter. Larvae are white with tan head capsules Adults could be confused with other small wasps. and have a prominent caudal horn. Pupa are white, Lodging can occur for various reasons. Any larvae darkening as they become mature. Adults wheat found within lodged stems (especially cleanly cut stem sawflies are 7-12 mm long. Females are larger stems) should be investigated further. than males. Where?

Organism EXOTIC The European wheat stem sawfly C.( pygmeus) VIRUSES Cephus pygmeus (European wheat stem sawfly) occurs in Europe, North Asia, Canada, North Cephus cinctus (Wheat stem sawfly) America and Algeria in Africa. Host range The Wheat stem sawfly C.( cinctus) occurs in Cephus pygmaeus is primarily a pest of cultivated eastern Russia, Japan, in western parts of the grass crop species such as oats (Avena sativa), United States and Canada. There are also reports of PESTS barley (Hordeum vulgare), rye (Secale cereale) and EXOTIC this species occurring in Kazakhstan. wheat (Triticum aestivum). Minor hosts include wild oats (Avena fatua), bromegrasses (Bromus) and hoary cress (Lepidium draba) and timothies (Phleum). WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 31 Exotic Plant Pest Hotline (1800 084 881)

Hessian fly

Symptoms, description and lifecycle The Hessian fly is a serious pest of wheat and barley, resulting in stunted growth and reductions in grain yield and quality.

Feeding damage on cereal plants can cause leaf discolouration, from a darker green to bluish green or yellowing of new growth in seedlings. Plants are often stunted and tillers may be prevented from heading, or if they do, they can become weakened causing plants to lodge. The dark pupae imbedded into the cereal stems, particularly on wheat, is the most detectable stage of Hessian fly development. Image 27. Female Hessian fly which are typically a Eggs are 0.5 mm long, elongated with rounded ends bit bigger than the males. and glossy red becoming darker with age. They are Source: Scott Bauer, ARS/USDA. laid on the upper surface of wheat leaves parallel with the veins. Larvae are maggots (legless) and undergo three instars growing up to three to four millimetres in length. The second instar becomes a Method of spread puparium within which the third instar, pupa and Adults spread by actively flying throughout the crop adult will develop. Puparia are two to six millimetres or can be dispersed by wind currents. Long distance long, dark brown and tapered. Adults are small, dispersal also occurs by ‘hitchhiking’ on machinery, mosquito like flies two to four millimetres long, with clothes or straw and other plant material. an elongate cylindrical body tapered at one end. They have one set of wings with a few weak veins Confused with? and beaded elongated antennae (Image 27). This species is very similar and closely related to the Barley stem gall midge (Mayetiola hordei). It has Organism been confused with this species in Africa. Mayetiola destructor Identification of the two species involves Conditions favouring pest microscopic morphological differences and is best Humid, moderately warm periods are prefered by undertaken by an expert taxonomist. adult Hessian flies. Evidence internationally indicates that grain growing regions averaging 450 Where? mm annum rainfall are of greatest risk. Hessian fly is widespread in North America and Europe. It is also found in New Zealand, Africa and Host range the parts of the Middle East. Primary host is wheat (Triticum sp.). Secondary hosts include wheat grass (Agropyron), barley (Hordeum vulgare) and rye (Secale cereale).

32 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Khapra beetle

Symptoms, description and lifecycle Khapra beetle can cause losses of up to 75 per cent from direct feeding. Infested grain also becomes contaminated with beetles, cast skins and hairs from larvae, which can be a health risk and are more difficult to remove from grain storage structures

and transport vessels. INTRO

Larvae can grow up to seven millimetres long, are reddish brown in colour and darken as they mature. They have characteristic long hairs all over their body, especially at the rear end and can survive without food for over 12 months. DISEASES

Adults are two to three millimetres long and one BORNE SOIL to two millimetres wide, brownish in colour with a smooth oval shaped body. There are three Image 28. Adult Khapra beetle. transverse bands (markings) of pale colour hairs on Source: Simon Hinkley & Ken Walker, Museum the wing covers. Victoria. FOLIAR DISEASE Organism Trogoderma granarium

Conditions favouring pest Khapra beetle prefers hot and dry conditions.

Indviduals are able to survive long periods of time of RUST inactivity.

Host range Khapra beetle is a pest of stored grain and dry foodstuffs worldwide. It can cause losses of up to 75 per cent from direct feeding. The larvae of Khapra

beetles are serious pests of oilseeds, damaged HEAD cereals and, to a lesser extent, pulses. The adults rarely, if ever, eat or drink. Image 29. Adult, larva, larval skins and damage to wheat grains. Method of spread Source: Ministry of Agriculture and Regional Khapra beetles are spread through the movement Development, Ministry of Agriculture and Regional of stored grain and products or as contamination of of Development. Bugwood.org

seed, machinery and straw. EXOTIC VIRUSES

Confused with? Other Trogoderma spp.

Khapra beetle is almost visually identical to the Warehouse beetle, Trogoderma variable, which is PESTS establised in Australia. EXOTIC

Where? Khapra beetle is found in Africa, India, Russia and many Middle Eastern countries. WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 33 Exotic Plant Pest Hotline (1800 084 881) Case study - Khapra beetle

Khapra beetle is high on the watch list for exotic pests and diseases for Australia given the economic impact it could have on the industry. Presence of the pest can result in 75 per cent loss of product.

If the pest were to establish in Australia, it could have detrimental impacts on our export orientated grain industry. Many countries maintain quarantine restrictions against possible importation of this pest and prevent market access for infested produce.

Treatments are available but difficult to implement effectively, as larvae can maintain a state of very low metabolic activity and are extremely resistant to contact insecticides during this period. Because of this, larvae can exist in a hiberation state for two years or more under some conditions.

In 2007, Khapra beetle was detected in personal belongings arriving in Perth from overseas. A rapid response under the Emergency Plant Pest Response Deed saw the infested home covered in a shrink- wrap sheeting that was gas proof and fumigated using methyl bromide. This is the only viable and internationally agreed treatment for Khapra beetle. Successful eradication was declared in 2009, following evidence from trapping surveillance that included over 1,000 trap inspections from nine different sites. The eradication was successful because of the speed at which the Khapra beetle was detected and reported. South Australia also had an incursion in 2016, which was successfully eradicated.

In both cases, being able to quickly identify an incursion to mount an eradication program is the most effective way of dealing with Khapra beetle.

To be on the front foot, the Victorian Government established the Sentinel Silo Surveillance program. The program has been running since 2016 and includes 40 specialised pheromone traps set up next to grain storage silos across 12 sites.

The pheromone traps are designed to attract the Trogoderma species, because there are native Trogoderma species, any unidentifiable samples are sent to the Agriculture Victoria diagnostic team at AgriBio, Centre for AgriBioscience in Melbourne.

34 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Leaf miner as a group

Symptoms, description and lifecycle Larvae feed singly, forming an upper surface linear-blotch mine. Pupation either internal or external, with the puparium loosely glued to the leaf. Oviposition near the leaf margin, at some distance from the lead tip. From there develops an uppersurface corridor-blotch. At first the mine ascends as a narrow corridor towards the leaf tip, then the direction turns and the mine, steadily INTRO widening, descends in the direction of the leaf base. Frass irregular, in rather coarse grains. Larva solitary. Pupation mostly outside the mine; in that Image 30. Liriomyza trifolii. case the puparium often sticks to the leaf. Source: Agriculture Victoria.

Liriomyza huidobrensis (Serpentine leafminer) Feeding punctures appear as white speckles between 0.13 and 0.15 mm in diameter. Oviposition DISEASES SOIL BORNE SOIL punctures are smaller (0.05mm) and are more uniformly round. The larva is primarily a leaf miner (on peas the larva also feed on the outer surface of young pods); mines are usually white with dampened black and dried brown areas, and are

usually associated with the midrib and lateral leaf FOLIAR DISEASE veins. Mines are typically serpentine, of irregular shape, increasing in width as larvae mature. Several larvae feeding on a single leaf may produce a Image 31. Liriomyza huidobrensis. secondary ‘blotch’ mine type and leaf wilt may Papa Santiago, 1987, R. Muuoz. occur. Source: Sarah McCaffrey, Museum Victoria. RUST Liriomyza trifolii (American serpentine leaf miner) Conditions favouring pest Liriomyza trifolii feeding punctures appear as white Pupa of Leaf miners are unable to cope with high speckles between 0.13 and 0.15 mm in diameter. humidity or drought. Areas with sub-tropical/ Oviposition punctures are usually smaller (0.05 mm) tropical zones are at highest risk for this insect. and are more uniformaly round. Liriomyza trifolii leaf mines can vary in form with the host plant, Host range but when adequate leaf area is available they are Phytomyza rufipes(Cabbage leaf miner) = canola HEAD usually long, linear, narrow and not greatly widening Chromatomyia horticola (Pea leaf miner) = pulses, towards the end. They are usually greenish white. In canola and sunflowers very small leaves the limited area for feeding results Agromyza albipennis (Black wheat leaf miner) = in the formation of a secondary blotch at the end of cereals the mine, before pupariation. The frass is distinctive in being deposited in black strips alternatively at Method of spread either side of the mine, but becomes more granular are able to move small distances, while EXOTIC EXOTIC towards the end of the mine. Fungal destruction further distances can be traversed with wind, VIRUSES of the leaf may also occur as a result of infection human, soil, plant or packaging. introduced by L. trifolii from other sources during breeding. Confused with? There are shared features within the leaf miner Organism group and expert diagnosis is required.

Liriomyza huidobrensis (Serpentine leaf miner), PESTS EXOTIC Liriomyza trifolii (American serpentine leaf Where? miner), Phytomyza rufipes (Cabbage leaf miner), Pea leaf miner = Africa, Asia and Europe. Chromatomyia horticola (Pea leaf miner), Agromyza Serpentine leafminer = North and South America, albipennis (Black wheat leaf miner) Europe, Africa and Asia. American serpentine leaf miner = Africa, Asia, Europe, North America, South America, Samoa, WEEDS Guam and Tonga. EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 35 Exotic Plant Pest Hotline (1800 084 881) Sunn pest

Symptoms, description and lifecycle Method of spread Sunn pest is a sap-sucking bug that feeds on grain Sunn pests can fly over large distances. Adults crops, damaging leaves, stems and grain heads. migrate up to 250 km, particularly in areas with Symptoms include yellowing and dieback of continuous crops. Sunn pest can also survive long the stem and leaves, and stunting of the growth periods in the soil without food and can be spread of tips and buds. Feeding on other parts of the with the movement of machinery or equipment. plant causes abnormal flower formation and discolouration. Feeding before grains develop can Confused with? result in grain abortion or, if feeding occurs only There are several shield bugs native to Australia after development, the grains are left shrivelled, some of which look similar to Sunn pest. These discoloured (white) and/or empty. include the small brown stink bug, Caystrus pallidolimbatus and the brown shield bug; Dictyotus Adults are 10-13 mm long, brownish is colour and caenosus. have a wide triangular head and oval-shaped body. They have sap sucking mouth parts. Their wings Where? are completely hidden by a hardened ‘shield’ that Found in parts of North Africa, West and Central covers most of the body. Asia and Eastern Europe.

Nymphs are smaller and rounder in shape and normally dark brown to black. Eggs are light green in colour and are laid in two even rows on host plant leaves.

Organism Eurygaster infegriceps

Conditions favouring pest Sunn pest survives temperatures between -30°C to 45°C, and is unlikely to survive past 49.5°C. Adults can survive for up to a year, where they will move to cracks in the soil or beneath leaf litter until conditions are favourable. Most severe outbracks typically occur when grain maturity and nymph Image 32. Adult Sunn pest. phase occur at the same time, which enables the Source: ICARDIA. pest to build fat reserves.

Host range Sunn pest feeds on wheat, durum, rye, oats, and barley.

36 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Turnip moth

Symptoms, description and lifecycle Method of spread External feeding on leaves, stalks and stems results Adult are strong fliers and can fly over large in falling leaves, small holes in the stems or cut distances. stems. External feeding on tubers and roots results in a variety of holes, ranging from those that are Confused with? small and superficial to very large deep ones. Whole There are several noctuid moths native to Australia plants (e.g. lettuces, leeks, maize, cotton or small some of which look similar to Turnip moth. These spruce seedlings) fall over, and on root crops (e.g. include the brown cutworm or pink cutworm, INTRO beetroots) deep holes become visible at and above ( munda) and; the bogong moth, (Agrotis the soil surface. Damage to underground tubers infusa). (e.g. potatoes) may be difficult to recognise before harvest. Where? Europe, Africa, Northern Asia, including China. Adult: 40 mm wingspan; dark brown forewings with, in the middle, a uniform spot and a clearer, circular DISEASES

spot. The hind wings are white in the male and grey BORNE SOIL in the female. The periphery of the wings bears a thin black border. Adults can lay 800-1200 eggs.

Larva: 45-50 mm, reddish head, greyish body with two parallel longitudinal lines in the middle region. FOLIAR

On each segment, two small black spots at the front DISEASE and two at the back, each bearing a small bristle.

Catepillars are voracious, they feed at night, gnawing the foliage and cutting the petioles. During the day, they hide by rolling up under a lump of earth or at a shallow depth in the ground. RUST

Organism Image 33. Adult Turnip moth. Agrotis segetum Source: Merle Shepard, Gerald R. Carner and P.A.C Ooi, Insects and their Natural Enemies Associated Conditions favouring pest with Vegetables and Soybean in Southeast Asia. Turnip moth requires shelter and dry conditions Bugwood.org

to allow for increased activity and development. HEAD Larvae struggle to survive in low temperatures.

Host range Attacks cultivated plants belonging to more than 15 families. Host plants include wild plants, couch grass (Agropyrum spp.), bindweed (Convolvuluv spp.), plaintain (Plantago spp.) vegetables including EXOTIC EXOTIC (cabbage, cauliflower),Solenaceae VIRUSES (capsicum, tomatoes, potatoes), cereals, tobacco and grape vines. PESTS EXOTIC WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 37 Exotic Plant Pest Hotline (1800 084 881)

Wheat aphid

Symptoms, description and lifecycle Wheat aphid outbreaks can be very damaging to cereal yields, especially in wheat. It causes direct damage by feeding on fruits, leaves, stalks and ears, and indirect damage by excreting honeydrew and transmitting viruses. There is no set of clear symptoms for specific infestations on leaves or earheads. Early yellowing of upper leaves and ears could be observed after heavy infestation but is not specific to wheat aphid. The same type of symptoms could also be due to other aphid species or several plant pathogens.

The adult aphids are 1.3-3.3mm long, winged ones are 1.6-2.9mm long. Body colour of Sitobion avenae could be pale green, yellowish, dark green, pinkish orange or brown. It is also a potential vector for several viruses including Barley yellow dwarf viruses. Image 34. Green version of the nymphs stage. Source: Influentialpoints.com Organism Sitobion avenae

Host range Sitobion avenae occurs on all cereal species including wheat, barley, rice and maize and can develop on most cultivated or wild grasses.

Conditions favouring pest Wheat aphid is already established internationally in areas similar to many of the grain growing regions of Australia.

Method of spread Aphids generally can spread via crawling or flying including wind assisted; on plant material and on clothing, machinery or tools. Image 35. Red version of the nymphs stage. Confused with? Source: Influentialpoints.com Aphids look very similar to the naked eye. The same symptoms are also similar and could also be due to other aphid species or several plant pathogens.

Where? Sitobion avenae is widespread throughout the world, mainly in areas with temperate, Mediterranean or steppic climate. It is widespread in all Europe, in North Africa, the Middle East, Central Asia and the Indian subcontinent. It has spread through North and South America and seems to be more recently introduced to Africa, south of the Sahara.

38 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Wheat stem maggot

Symptoms, description and lifecycle Wheat plants affected by Wheat stem maggot show stunting, distortion and decreased tillering. The most obvious symptom is the presence of the “white hand” condition typically produced by stem-boring INTRO insects. In this condition the seed head dies and turns white while the lower stem regions and leaves remain green. Infested stems will pull out very easily, and contain a single maggot just above the last node.

When young tillers are attacked in the autumn or DISEASES early spring, the tillers usually die; infested plants BORNE SOIL show the “white head” condition typically produced by stem-boring insects. The adult flies are about six millimetres in length, and pale green to yellow with Image 36. Adult Wheat stem maggot. dark stripes. Source: Kansas State University. FOLIAR The adult fly is four to five millimetres long, with DISEASE clear wings. They have a mostly yellow body (forms can vary) with three dorsal black stripes, swollen hind femurs, the head protruding forward between the eyes, and the corner of the mouth forming a nearly right angle. Larvae of Wheat stem maggot enter the stem of wheat or other grass species and RUST feed on the soft inner stuctures, usually in close proximity to the top node.

Organism Meromyza americana

Host range HEAD Perferentially attack wheat, but will also attack barley, rye, oats, bluegrass and millet.

Conditions favouring pest Wheat stem maggot can cause signiciant damage in spring sown wheat, while limited damage is likely EXOTIC EXOTIC to occur to autumn sown wheat. Spring sown wheat VIRUSES is of further risk after high rainfall in summer.

Method of spread Movement of Wheat stem maggot typically occurs in plant material. PESTS Where? EXOTIC Meromyza americana is found in North America from Mexico to Canada. WEEDS EXOTIC EXOTIC CropSafe I Guide to exotic pests and diseases of grain I 39 Exotic Plant Pest Hotline (1800 084 881)

Exotic weeds

Source: Jim Moran, Agriculture Victoria

40 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881) Asiatic witchweed

Symptoms, description and lifecycle Asiatic witchweed is an obligate parasite (it cannot develop independently from a suitable host). Plants are normally 15.2-30.5 cm tall but some have been recorded to grow to 61 cm. The stems are hairy, green, to 30 cm tall. Leaves are linear or filamentous

and around 2.5 cm long. Flowers are small, less INTRO than 1.3 cm in diameter, occuring in or on loose spikes, and can vary greatly in colour including white to yellow, red, or purple. The flowers given way to swollen seed pods that contain thousands of microscopic seeds per pod.

Organism DISEASES

Striga asiatica (L.) Kuntze BORNE SOIL

Host range Asiatic witchweed is a parasitic weed of grain (especially summer crops) and sugar crops. FOLIAR

Method of spread DISEASE The small seeds are wind dispersed, can be moved with runoff following heavy rains, on the feet of humans and livestock, on farm implements and in faeces following their ingestion of the seed.

Confused with? RUST Symptoms induced by Asiatic witchweed can be confused with drought damage, nutrient deficiency or vascular disease.

Where? Africa, Asia and America. There are records that Image 37. Asiatic witchweed.

Asiatic witchweed has been found in Australia at Source: Florida Division of Plant Industry, Florida HEAD different stages. Department of Agriculture and Customer Services. Bugwood.org EXOTIC EXOTIC VIRUSES PESTS EXOTIC WEEDS EXOTIC EXOTIC

CropSafe I Guide to exotic pests and diseases of grain I 41 Exotic Plant Pest Hotline (1800 084 881)

Glossary

Biosecurity - procedures or measures designed to Host - an animal or plant on or in which a parasite protect the population against harmful biological or or commensal organism lives biochemical substances Hypocotyl - the part of the stem of an embryo plant Chlorosis - loss of the normal green colouration of beneath the stalks of the seed leaves or cotyledons leaves of plants, caused by iron deficiency in and directly above the root lime-rich soils, disease, or lack of light Instar - a phase between two periods of moulting Coalesce - come together to form one mass or in the development of an insect larva or other whole invertebrate

Conidium - a spore produced asexually by various Leaf mining - is that habit of consuming live foliage fungi at the tip of a specialised hypha while simultaneously dwelling inside it

Cosmopolitan - a plant or animal found all over the Lesion - a region in an organ or tissue which has world suffered damage through injury or disease, such as a wound, ulcer, abscess, or tumour Cotyledon - an embryonic leaf in seed-bearing plants, one or more of which are the first leaves to Longitudinal - running lengthwise rather than appear from a germinating seed across

Cruciferous crops - relating to or denoting plants of Microsclerotia - small, pinhead-sized structures, the cabbage family capable of surviving under unfavorable conditions

Diapause - a period of suspended development in Pathogen - a bacterium, visus, or other an insect, other invertebrate, or mammal embryo, microogranism that can cause disease especially during unfavourable environmental conditions Pedicel - a small stalk bearing an individual flower in an inflorescence Discolouration - the process of becoming discoloured, or the state of being discoloured Periphery - the outer limists or edge of an area or object Dorsal - on or relating to the upper side or back of an animal, plant, or organ Petiole - the stalk that joins a leaf to a stem

Epidermis - the outer layer of tissue in a plant, Pith - the spongy cellular tissue in the stems and expect where it is replaced by periderm branches of many higher plants

Enzyme - a substance produced by a living Pustule - a small raised spot or rounded swelling, organism which acts as a catalyst to bring about a especially one on a plant resulting from fungal specific biochemical reaction infection

Femurs - the third sepment of the leg in insects and Relative humidity - the amount of water vapour some other , typically the longest and present in air expressed as a percentage of the thickest segment amount needed for saturation at the same temperature Forewing - either of the two front wings of a four-winged insect Rostrum - a beak like projection, especially a sniff snout or anterior prolongation of the head in an Frass - the excrement of insect larvae insect

42 I CropSafe I Guide to exotic pests and diseases of grain Exotic Plant Pest Hotline (1800 084 881)

Senescence - loss of a cell’s power of division and Xylem - the vascular tissue in plants which conducts growth water and dissolved nutrients upwards from the root and also helps to form the wood element of the Vascular tissue - relating to or denoting the plant stem tissues (xylem and phloem) which conduct water, sap, and nutrients in flowering plants, ferns, and their relatives

Wilt - become limp through heat, loss of water, or disease; droop

Resources

Plant Health Australia: www.planthealthaustralia.com.au

Centre for Agriculture and Bioscience International (CABI): www.cabi.org

Pests and Diseases Image Library (PaDIL): www.padil.gov.au

Department of Agriculture: https://www.agriculture.gov.au/pests-diseases-weeds/plant

Electronic version of the ‘Victorian guide to exotic pests and diseases of grain crops’ can be found here: www.agriculture.vic.gov.au/agriculture/grains-and-other-crops/cropsafe-program

Rust survey and diagnostics: http://sydney.edu.au/agriculture/our-research/plant-production.html Send samples to: Australian CerealRust Survey University of Sydney Australian CereakRust Survey Reply Paid 88076 Narellan NSW 2567

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