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Wheat - diseases, physiological disorders and frost
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- Mosaic-like symptoms characteristic of wheat streak mosaic virus infection
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Disease management
Diseases may severely affect yield and quality in wheat.
In some cases, these diseases are controlled through the use of simple cultural practices and good farm hygiene. One of the major practices used in the control of diseases is crop rotation.
To minimise the effect of diseases:
- use partially resistant varieties
- use disease-free seed
- use fungicidal seed treatments to kill fungi carried on the seed coat or in the seed
- keep farm free from weeds which may carry over some diseases
- rotate crops.
See Wheat varieties for Queensland 2011.
Rusts
In Queensland, there are three rust diseases of wheat:
- stripe rust
- stem rust
- leaf rust.
They are caused by three closely related fungi all belonging to the genus Puccinia.
The 'rusts' are so named because the powdery mass of spores which erupt through the plant's epidermis have the appearance of rusty metal. These spores can be spread over considerable distances by wind but may also be spread on clothing and equipment.
Wheat rusts have a number of features in common. They can only infect a limited number of specific host plants (mostly volunteer wheat, triticale and barley) and can only survive on green growing plant tissue. Plants facilitating the survival of rust fungi through the summer are known as the 'green bridge'.
Rust diseases of wheat can be eliminated or significantly reduced by removing this green bridge. This should be done well before the new crop is sown, allowing time for any herbicide to work and for the fungus to stop producing spores.
Rust diseases occur throughout the wheat-growing northern regions, frequently causing economic damage. In Queensland, in recent times, stripe rust has been the more important of these diseases.
Wherever possible, resistant wheat varieties MR (moderately resistant = 6) and above should be sown. See Wheat varieties for Queensland 2011.
Rust fungi continually change, producing new pathotypes. These pathotypes are detected when disease is found on a previously resistant variety. Even if a resistant variety has been sown, the crop should be monitored for foliar diseases on a regular basis.
This should start no later than growth stage 32, the second node stage on the main stem and continue to at least growth stage 39, the flag leaf. This is because the flag leaf and the two leaves below it are the main factories contributing to yield and quality. It is very important that these leaves are protected from diseases.
Management of wheat rusts and yellow spot
See images of wheat rusts and other diseases.
Yellow spot
Yellow spot is caused by the fungus Pyrenophora tritici-repentis. It survives in wheat and occasionally triticale stubble. In rare cases, the fungus may survive in barley stubble. Wet spores (ascospores) develop in fungal fruiting bodies on wheat stubble, spread during wet conditions and can infect growing wheat plants.
As the crop develops, masses of a second type of spore (conidia) are produced on old lesions and dead tissues. Conidia result in rapid development of the epidemic within a crop and spread of the disease to other crops and areas. Again, wet conditions are necessary for spore production and infection. Strong winds are needed to spread the disease any great distance.
Severe yellow spot may result in short, spindly plants with reduced tillering and root development. Where conditions are favourable, plants may be fully defoliated soon after flowering.
Grain yield can be substantially reduced and losses of more than 50% may occur in extreme situations. Pink grain with reduced value is also a frequent result of severe yellow spot epidemics. Where wheat follows wheat and some stubble is left on the soil surface, losses may be around 10-15%, and up to 30% in wet seasons.
Yellow spot is likely to develop in wet years in fields where wheat residues remain on the soil surface. The impact of the disease can be reduced by:
- planting partially resistant varieties
- rotation with resistant crops such as barley, oats or chickpea
- incorporation of stubble into the soil
- grazing or burning the stubble late in the fallow period.
Incorporation or burning stubble is not recommended unless infestation levels are very high. Correct identification of the yellow spot fungus in infected stubble should be carried out before the stubble is removed. Varieties partially resistant to yellow spot offer the only long-term solution and should be considered for planting where yellow spot could be a problem.
Fungicides used against yellow spot in Australia include:
- Propiconazole
- Tebuconazole
- Azoxystrobin + Cyproconazole
- Propiconazole + Cyproconazole.
Timing for applying the chosen fungicide is crucial. The most effective time of application is at 90% flag leaf emergence with disease levels of less than 10% on the flag leaf.
The higher rate of application has been shown to provide longer protection under periods of high disease pressure. Fungicide effectiveness is greater on susceptible varieties and is reduced with increasing levels of resistance.
Information on fungicide effectiveness has been gathered from irrigated field trials and does not confirm the economic viability of such applications during the extreme pressure of large-scale epidemics.
See images of Yellow spot.
Rot
Common root rot
A soil-borne fungal disease which attacks wheat, barley and triticale. It survives from one season to the next through fungal spores, which remain in the cultivated layer of the soil. The disease increases in severity with continuous wheat or wheat-barley sequences.
Barley increases the soil population of fungal spores rapidly. Infection is favoured by high soil moisture for six to eight weeks after planting.
Common root rot symptoms:
- a dark-brown to black discolouration of the stem just below the soil surface
- black streaks on the base of stems
- slight root rotting.
Common root rot can cause yield losses of between 10-15% in susceptible varieties.
The disease may be controlled by planting partially resistant varieties or by crop rotation. Where the disease is severe, rotation to non-susceptible crops for at least two years is recommended. Summer crops such as sorghum, sunflower, or white French millet can be used for this purpose. See Wheat varieties for Queensland 2011.
Crown rot
This is a fungal disease that affects wheat, barley and triticale. It survives from one season to the next in the stubble remains of infected plants. The disease is more common on heavy clay soils.
Infection is favoured by high soil moisture in the two months after planting. Drought stress during elongation and flowering will lead to the production of 'deadheads' or 'whiteheads' in the crop. These heads contain pinched seed or no seed at all.
If the leaf bases are removed from the crowns of diseased plants, a honey-brown to dark-brown discolouration will be seen. In moist weather, a pink-purple fungal growth forms inside the lower leaf sheaths and on the lower nodes.
The disease may be controlled through planting partially resistant varieties or crop rotation. If the disease is severe, rotation to a non-susceptible crop for at least two and preferably three years is recommended. A winter crop such as chickpea, oats or any summer crop may be used as a disease-free rotation crop. See Wheat varieties for Queensland 2011.
Smut
Bunt or stinking smut
This disease affects mature wheat ears in which a mass of black-fungal spores replaces the interior of the grain and forms a bunt ball. Infected plants are shorter and have darker green ears and gaping glumes than healthy plants. Bunt is usually only noticed at harvest when bunt balls and fragments are seen in the grain. Grain deliveries with traces of bunt balls are not accepted by AWB Limited.
If a bunt ball is crushed, a putrid fish-like odour is released. Spores released during harvest contaminate sound grain. The spores germinate with the seed when planted and infect the young seedling. The fungus then grows inside the developing wheat plant, finally replacing each normal grain with a mass of spores.
Bunt has not been recorded in commercial wheat crops in Queensland for more than 30 years. This is probably because of the widespread use of fungicidal seed dressings.
Bunt control recommendations:
- Seed that is sown to provide the following season's wheat seed should be treated with a fungicidal seed dressing.
- Seed obtained from plants grown from untreated seed should be treated with a fungicidal seed dressing before planting.
- All seed entering Queensland should be treated with a fungicidal seed dressing which will control bunt.
- Grain from a crop with bunt should not be used for seed.
- On farms where a crop has been affected by bunt, all wheat seed should be treated with fungicidal seed dressing for at least six years.
These recommendations could be adopted in one of two ways:
- Treat all wheat seed with a fungicidal seed dressing every second year.
- Treat a small quantity of seed of each variety with a fungicidal seed dressing every year and use the grain from this as planting seed in the following year.
Loose smut
Loose smut is a fungal disease that becomes evident at head emergence. A loose, powdery mass of fungal spores is formed in the head; these spores are readily blown away leaving a bare, ragged stalk.
If the spores settle on healthy flowers, they may germinate and infect the embryo of the developing seed. When this seed is planted, the smut grows inside the plant until flowering when the disease appears. Because loose smut is carried inside the seed, systemic seed dressings are needed to control it. These are more expensive than the others and should be used only when a high incidence of loose smut is expected.
Wheat streak mosaic virus
Wheat streak mosaic virus (WSMV) was found in commercial wheat crops in Queensland during the 2003 season. However, its geographic distribution throughout the region is still unknown as are the potential impacts from the virus on yield.
Wheat plants infected with WSMV have discontinuous yellow-streaked and mottled leaves. Plants infected before tillering are often stunted, discoloured and rosetted. The host range of WSMV is wheat, barley, oats, rye, maize and some grass species including brome grass, barley grass, ryegrass, phalaris and liver seed grass. In Australia, the virus has been found on wheat, Setaria and Urochloa.
WSMV is unable to spread without the aid of a vector to transmit it from a diseased plant to a healthy plant. The wheat curl mite (Aceria tosichella) is the vector for WSMV. Wheat curl mites are microscopic, about 0.2 mm long and can only be seen with magnification.
The mite consumes plant sap from a diseased plant and the virus remains alive in the mite's mouthparts and is transmitted to other plants as the mite feeds and moves between plants. Wheat curl mites cannot survive for long periods off living plant material.
WSMV cannot survive outside of a host plant or the vector, the wheat curl mite. Therefore, during the period between summer harvest and planting of the next wheat crop, WSMV persists in the 'green bridge' of volunteer wheat plants and other grasses.
Disease management should involve eliminating the 'green bridge' by controlling:
- wheat volunteers between crops
- grass hosts growing on the borders of areas to be sown to wheat
- grasses in fallows.
This means green plant material should be dead, as a minimum, two weeks before sowing the next wheat crop.
See images of wheat streak mosaic virus.
Botryosphaeria head blight - BHB (white grain disorder)
White grain was conspicuous in harvested samples of wheat in the 2010 season. This symptom is the result of infection with one of principally two fungal pathogens - Fusarium graminearum and Botryosphaeria zeae. Fusarium Head Blight (FHB) or head scab is the disease that causes white grain and head blight from infection by Fusarium species. White grain or white grain disorder is the terminology currently used to describe the disease caused by B. zeae. It is proposed that this disease be known in future as Botryosphaeria Head Blight (BHB).Nematodes: root-lesion nematode (RLN)
Root-lesion nematodes (RLN, Pratylenchus thornei and P. neglectus) are migratory root endoparasites that are widely distributed in the wheat-growing regions of Australia and can reduce grain yield by up to 50% in many current wheat varieties.
P. thornei is the most damaging species and occurs commonly in the northern grain region. P. neglectus occurs less frequently than P. thornei but is still quite common. A third nematode, Merlinius brevidens (stunt nematode), is the most commonly identified plant-parasitic species but is not thought to be damaging to wheat.
Two species of root-lesion nematodes (Pratylenchus thornei and P. neglectus) occur in the soils of southern Queensland and northern New South Wales. In a survey of soil samples from 596 paddocks in this region, 42% had P. thornei alone, 27% had both P. thornei and P. neglectus, 5% had P. neglectus alone, while 26% had neither species.
These nematodes can severely affect wheat yields and the term 'wheat sickness' is commonly used to describe deteriorating yields in a succession of wheat crops. Some other crop species are also hosts of root-lesion nematodes and care should be taken in sowing wheat after crops such as black gram and chickpeas in nematode-infested paddocks.
Nematodes penetrate the plant root, digesting the cells' contents and laying eggs within the roots. High populations develop quickly following planting, so that the root systems become inefficient in absorbing water and nutrients.
Crops are patchy, show lower leaf yellowing and appear drought affected and nutrient deficient. As peak nematode numbers often occur at depths in the soil of 30-60 cm, the condition of the plant deteriorates as the roots go deeper. Grain yield can be severely reduced in susceptible varieties.
Nematodes can spread through a district in surface water (e.g. floodwater) and can be moved from one area to another in soil adhering to vehicles and machinery. They have the ability to quickly build up populations in the roots of susceptible crops and remain in the soil during fallow. As a result the yield of following wheat crops can be significantly reduced.
There are no wheat varieties fully resistant to root-lesion nematodes. Nematodes can be managed through crop rotation and varietal selection. The wheat varieties Sunvale, Baxter, Hartog, Sunstate and Kennedy are tolerant to P. thornei and will yield well in nematode-infested soil.
Most barley varieties and the durum wheat, Yallaroi, are also tolerant to P. thornei. The wheat varieties with tolerance to P. thornei are not necessarily tolerant to P. neglectus and care must be taken to diagnose which species are present in a paddock.
Root-lesion nematodes can take half your yield. The Department of Employment, Economic Development and Innovation's (DEEDI) Leslie Research Centre can test for and diagnose their presence for $169.40/paddock (inc. GST). Test your farm for nematodes.
Crop rotation with resistant crops such as grain sorghum, millet, sunflower and canary will reduce the numbers of nematodes in the soil to a level where susceptible wheat varieties can be grown but will not eliminate them completely.
| Crop | Resistance status | Nematode build-up in the crop |
|---|---|---|
| Barley | moderately resistant | medium |
| Canary | resistant | none |
| Canola | resistant | none |
| Chickpea | susceptible | medium |
| Linseed | resistant | none |
| Millet (Setaria italica) | resistant | none |
| Mungbean | susceptible | medium |
| Black gram | very susceptible | high |
| Sorghum | resistant | none |
| Triticale | susceptible | medium |
| Wheat | very susceptible | high |
It is important to know whether nematodes are on your farm and if so, which species are present. This is important because varietal tolerance information for P. thornei does not hold true for P. neglectus, as they are distinct species.
Proper species identification can help minimise losses that arise from planting intolerant varieties in nematode-infested land. The nematode status of any paddock can be determined by laboratory analysis of appropriately sampled soil at a cost of $169.40/paddock (inc. GST).
Samples for analysis
Since nematodes may not be evenly spread across a paddock, particularly with new infestations, it is important to take samples from several locations within a paddock. For practicality, we suggest nine cores bulked in groups of three.
Nematodes are often more numerous in the sub-soil than in the topsoil and for experimental purposes we often analyse soil in layers to 120 cm depth.
However, for practicality we recommend two layers, 0-15 cm and 15-30 cm, which can be sampled with a hand corer (or a mattock if no corer is available). Topsoil (0-15 cm) only samples can give inaccurate results and should always be accompanied by a 15-30 cm sample. If deeper samples are already being taken for other analysis (e.g. nitrate), a nematode assessment can be made of the depths 0-30 cm, 30-60 cm and 60-90 cm.
Procedure
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Take nine cores across the paddock in two depths, 0-15 and 15-30 cm.
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As you go, bulk the topsoil of the first three cores in one plastic bag labelled A0-15 and in a second bag labelled A15-30, the next three cores as B0-15 and B15-30 and the last three cores as C0-15 and C15-30.
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Note which parts of the paddock were A, B and C respectively. Break up the soil by hand in a bucket so that all pieces are less than 1 cm in size keeping the six lots separate. We require about 500 g of soil or more in each bag. Seal the bags securely with a twist-tie or string to prevent the soil drying out.
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Do not expose the bags of soil to heating from sun in the field or in vehicles or from proximity to exhaust pipes etc. Preferably place the soil in a polystyrene box for transport to Leslie Research Centre although a cardboard box or a poly or hessian bag will do if heating is avoided.
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Fill out the sample submission form with details on the paddock history and forward this with the samples to Leslie Research Centre. Completed forms must be sent with the samples for them to be processed. We will then determine which species are present and their population for each of the six soil samples for a cost of $169.40/paddock (inc. GST). This will provide a good indication whether RLN are present and likely to pose problems.
Send samples to:
Soil Microbiology Section
Leslie Research Centre
PO Box 2282
Toowoomba Qld 4350
13 Holberton Street
Toowoomba Qld 4350
Phone: 07 4639 8888
Fax: 07 4639 8800
Physiological disorders
Black point
Black point is a dark discolouration at the germ end of otherwise healthy wheat grain. Winter cereals, particularly those grown outside a classic Mediterranean climate, often encounter harmful weathering conditions during grain development.
Winter crops in the subtropics often ripen with high humidity or rain. High humidity alone can stall or prolong ripening, initiate germination, induce excessive enzyme activity and establish colonisation by saprophytic fungi and bacteria. In wheat, high humidity induces a clean-edged symmetrical-melanized pattern in the pericarp and testa cells covering the germ and adjacent areas.
Black point does not affect grain health or germination. It has been found that black pointed wheat grain actually germinates faster than normal grain and is consequently predisposed to sprouting should further rainfall occur. However, in combination with shrivelling, field mould or disease, grain health may be affected and germination rates reduced.
Black point occurs more often in wheat grain of larger size and high-yielding wheat crops are generally worse affected. In areas where black point is a recurring problem, farmers should avoid highly susceptible varieties. Growing more than one variety with multiple planting times will reduce losses if black point occurs.
Although various fungi are associated with black point, there is no conclusive evidence that black point melanism is a direct result of fungal action. The often reported association between symptoms and the most common grain coloniser, Alternaria alternata, is not strong and several studies have been unable to confirm any link.
Black point first appears when the grain begins to lose moisture. Prolonging or reversing the drying process allows interaction between enzymes and substrates that normally lie dormant until subsequent germination. Black point does not occur after grain maturity.
See images of black point.
Melanism
Melanism (sometimes referred to as false black chaff) is not a disease. It is an over expression of melanoid pigments in the plant causing a dark-brown to black discolouration of heads and exposed stems below the head. It is associated with the Sr2 gene, which is used as one of the primary sources of stem rust resistance in a number of our current varieties.
The degree of discolouration is controlled by several modifier genes and is strongly influenced by environmental conditions. Melanism is induced by prolonged wet weather, high humidity and high levels of UV radiation. It was very conspicuous in the 1998 season, particularly in the variety Pelsart.
Wheatman frost probability
The DEEDI computer program, Wheatman, demonstrates the interaction of planting time, varietal selection, frost risk and yield in detail. A higher yield potential can be achieved from earlier planting but this must be balanced with the consequent increase in frost risk.
The higher slopes of undulating country may have minimum temperatures 1°C or so warmer than the meteorological station while the lower slopes or flat melonhole country may be 1°C or so colder.
A temperature of -4.0°C at head height is a light frost, often causing minor damage (5 to 30 %) in wheat. A temperature of -5.0°C at head height at any time from flowering to grain fill is a severe frost and will cause total loss of grain in many years. The difference between screen temperature and temperature at head height is about 3.5°C. The risk of a -5.0°C frost is about 20 % less than the risk of a -4.0°C frost from an early planting.
The tables below are from Wheatman and include minimum temperature probabilities for the three main maturity groups, temperature variation and planting dates for the major centres in the state. The Bureau of Meteorology has recently changed many recording stations to airports and these are often colder than the previous sites.
The information in these tables has been adjusted to allow for these differences and relate to the major farming soils in the districts. In the Wheatman program you are able to enter the adjustments for each paddock.
The varieties used in the tables represent the three broad maturity groups:
- Strzelecki (slow) - similar in maturity to Petrie
- Baxter (medium) - similar to Sunvale
- Hartog (quick) - similar to Sunstate, Kennedy and Leichhardt.
| Variety | Your site compared to met. station | Planting dates | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| April | May | June | |||||||||||
| 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | ||
| Strzelecki | 1°C warmer | 46 | 37 | 30 | 21 | 13 | 7 | 4 | 2 | 1 | 0 | 0 | 0 |
| Similar | 58 | 48 | 36 | 27 | 17 | 9 | 7 | 5 | 2 | 2 | 1 | 1 | |
| 1°C colder | 74 | 66 | 54 | 42 | 30 | 18 | 10 | 8 | 6 | 4 | 2 | 2 | |
| Baxter | 1°C warmer | 60 | 55 | 51 | 38 | 22 | 9 | 5 | 4 | 2 | 1 | 0 | 0 |
| Similar | 74 | 71 | 64 | 50 | 33 | 22 | 9 | 7 | 4 | 2 | 2 | 1 | |
| 1°C colder | 90 | 86 | 81 | 67 | 42 | 35 | 26 | 15 | 8 | 7 | 4 | 2 | |
| Hartog | 1°C warmer | 60 | 58 | 54 | 49 | 32 | 20 | 11 | 6 | 3 | 2 | 1 | 0 |
| Similar | 76 | 73 | 70 | 60 | 39 | 26 | 14 | 9 | 5 | 4 | 3 | 2 | |
| 1°C colder | 91 | 90 | 84 | 76 | 58 | 40 | 27 | 15 | 9 | 8 | 6 | 5 | |
| Variety | Your site compared to met. station | Planting dates | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| April | May | June | |||||||||||
| 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | ||
| Strzelecki | 1°C warmer | 63 | 60 | 47 | 38 | 24 | 12 | 5 | 3 | 2 | 2 | 1 | 1 |
| Similar | 94 | 90 | 80 | 63 | 44 | 28 | 20 | 9 | 5 | 3 | 2 | 1 | |
| 1°C colder | 98 | 98 | 90 | 86 | 65 | 47 | 38 | 29 | 23 | 15 | 7 | 4 | |
| Baxter | 1°C warmer | 72 | 70 | 69 | 65 | 55 | 36 | 18 | 8 | 3 | 2 | 1 | 1 |
| Similar | 98 | 98 | 98 | 94 | 81 | 60 | 33 | 24 | 10 | 5 | 2 | 2 | |
| 1°C colder | 98 | 98 | 98 | 95 | 95 | 85 | 55 | 43 | 30 | 23 | 12 | 8 | |
| Hartog | 1°C warmer | 72 | 71 | 70 | 65 | 52 | 41 | 17 | 16 | 4 | 2 | 2 | 1 |
| Similar | 98 | 98 | 98 | 96 | 84 | 70 | 48 | 30 | 13 | 6 | 4 | 2 | |
| 1°C colder | 98 | 98 | 98 | 96 | 95 | 88 | 68 | 50 | 32 | 26 | 20 | 10 | |
| Variety | Your site compared to met. station | Planting dates | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| April | May | June | |||||||||||
| 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | ||
| Strzelecki | 1°C warmer | 26 | 21 | 10 | 6 | 4 | 2 | 2 | 1 | 0 | 0 | 0 | 0 |
| Similar | 53 | 44 | 36 | 26 | 18 | 10 | 5 | 2 | 2 | 1 | 1 | 1 | |
| 1°C colder | 68 | 63 | 56 | 46 | 28 | 18 | 14 | 9 | 3 | 2 | 2 | 2 | |
| Baxter | 1°C warmer | 34 | 31 | 26 | 19 | 5 | 4 | 3 | 2 | 1 | 1 | 1 | 0 |
| Similar | 65 | 62 | 57 | 43 | 23 | 20 | 13 | 6 | 2 | 2 | 1 | 1 | |
| 1°C colder | 81 | 80 | 69 | 62 | 43 | 40 | 22 | 15 | 8 | 4 | 2 | 2 | |
| Hartog | 1°C warmer | 36 | 34 | 32 | 28 | 16 | 8 | 4 | 2 | 2 | 1 | 1 | 0 |
| Similar | 67 | 65 | 63 | 60 | 41 | 30 | 20 | 12 | 4 | 2 | 2 | 1 | |
| 1°C colder | 82 | 81 | 80 | 70 | 61 | 50 | 40 | 20 | 12 | 8 | 4 | 2 | |
| Variety | Your site compared to met. station | Planting dates | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| April | May | June | |||||||||||
| 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | ||
| Strzelecki | 1°C warmer | 81 | 71 | 52 | 40 | 26 | 15 | 8 | 6 | 4 | 3 | 2 | 2 |
| Similar | 91 | 88 | 76 | 66 | 45 | 28 | 19 | 14 | 9 | 7 | 4 | 3 | |
| 1°C colder | 95 | 93 | 90 | 81 | 68 | 53 | 40 | 28 | 22 | 16 | 11 | 7 | |
| Baxter | 1°C warmer | 90 | 88 | 80 | 66 | 48 | 33 | 21 | 10 | 6 | 3 | 2 | 2 |
| Similar | 92 | 92 | 90 | 84 | 71 | 60 | 38 | 23 | 11 | 7 | 5 | 3 | |
| 1°C colder | 98 | 98 | 96 | 93 | 87 | 76 | 63 | 46 | 25 | 16 | 9 | 8 | |
| Hartog | 1°C warmer | 91 | 91 | 90 | 82 | 64 | 48 | 33 | 24 | 10 | 7 | 4 | 3 |
| Similar | 93 | 92 | 92 | 91 | 82 | 71 | 60 | 42 | 23 | 15 | 9 | 6 | |
| 1°C colder | 98 | 98 | 99 | 95 | 92 | 87 | 76 | 67 | 46 | 30 | 20 | 14 | |
| Variety | Your site compared to met. station | Planting dates | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| April | May | June | |||||||||||
| 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | ||
| Strzelecki | 1°C warmer | 36 | 26 | 16 | 10 | 6 | 3 | 2 | 2 | 2 | 1 | 1 | 1 |
| Similar | 61 | 53 | 43 | 32 | 18 | 9 | 5 | 3 | 2 | 2 | 2 | 1 | |
| 1°C colder | 69 | 66 | 62 | 56 | 42 | 28 | 19 | 11 | 5 | 4 | 3 | 2 | |
| Baxter | 1°C warmer | 48 | 43 | 37 | 24 | 11 | 7 | 4 | 2 | 2 | 2 | 1 | 1 |
| Similar | 70 | 66 | 61 | 51 | 36 | 20 | 10 | 5 | 2 | 2 | 2 | 1 | |
| 1°C colder | 81 | 80 | 70 | 65 | 60 | 46 | 30 | 19 | 8 | 5 | 3 | 2 | |
| Hartog | 1°C warmer | 52 | 48 | 45 | 40 | 21 | 10 | 6 | 4 | 2 | 2 | 2 | 1 |
| Similar | 71 | 70 | 67 | 62 | 49 | 34 | 18 | 10 | 4 | 2 | 2 | 2 | |
| 1°C colder | 81 | 81 | 80 | 71 | 64 | 58 | 42 | 30 | 16 | 9 | 5 | 4 | |
| Variety | Your site compared to met. station | Planting dates | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| April | May | June | |||||||||||
| 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | ||
| Strzelecki | 1°C warmer | 10 | 10 | 8 | 6 | 5 | 3 | 2 | 1 | 0 | 0 | 0 | 0 |
| Similar | 14 | 13 | 12 | 11 | 10 | 7 | 4 | 2 | 2 | 1 | 0 | 0 | |
| 1°C colder | 33 | 32 | 31 | 30 | 24 | 14 | 8 | 6 | 4 | 2 | 1 | 1 | |
| Baxter | 1°C warmer | 11 | 11 | 10 | 9 | 6 | 4 | 3 | 2 | 2 | 1 | 0 | 0 |
| Similar | 15 | 14 | 13 | 12 | 11 | 10 | 8 | 5 | 4 | 2 | 2 | 1 | |
| 1°C colder | 34 | 34 | 33 | 32 | 30 | 23 | 15 | 10 | 8 | 5 | 3 | 2 | |
| Hartog | 1°C warmer | 12 | 11 | 11 | 10 | 8 | 6 | 4 | 4 | 2 | 2 | 1 | 0 |
| Similar | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 5 | 4 | 2 | 1 | |
| 1°C colder | 35 | 34 | 33 | 32 | 31 | 30 | 23 | 17 | 10 | 8 | 5 | 2 | |
| Variety | Your site compared to met. station | Planting dates | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| April | May | June | |||||||||||
| 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | 1 | 8 | 15 | 22 | ||
| Strzelecki | 1°C warmer | 39 | 32 | 22 | 18 | 15 | 10 | 2 | 2 | 0 | 0 | 0 | 0 |
| Similar | 56 | 51 | 44 | 40 | 34 | 23 | 3 | 5 | 2 | 2 | 1 | 1 | |
| 1°C colder | 80 | 72 | 59 | 56 | 54 | 50 | 34 | 19 | 11 | 7 | 4 | 2 | |
| Baxter | 1°C warmer | 52 | 50 | 47 | 41 | 26 | 18 | 11 | 4 | 1 | 1 | 1 | 0 |
| Similar | 62 | 62 | 61 | 58 | 47 | 39 | 25 | 16 | 4 | 2 | 2 | 1 | |
| 1°C colder | 84 | 83 | 82 | 81 | 62 | 56 | 51 | 38 | 18 | 12 | 7 | 4 | |
| Hartog | 1°C warmer | 52 | 51 | 50 | 47 | 41 | 35 | 25 | 15 | 4 | 2 | 1 | 0 |
| Similar | 64 | 63 | 62 | 61 | 58 | 53 | 46 | 34 | 16 | 10 | 4 | 2 | |
| 1°C colder | 84 | 84 | 83 | 82 | 81 | 76 | 60 | 54 | 38 | 27 | 17 | 11 | |
