The 2008 survey of commercially grown winter wheat is now complete. Isolations to identify species responsible for Fusarium head blight symptoms have been completed. Sixty-four per cent of samples were affected, and isolation results indicate that Microdochium species (non-toxin producers) were responsible for the majority of symptoms present. Twenty-five per cent of crops samples were infected with Fusarium graminearum (toxin producer). To see full results click here.  

The survey of commerically grown oilseed rape has now been completed. One-hundred crops were sampled and visually assessed for disease levels at pod ripening. Click to view results  

• Phoma canker was recorded at a low incidence. Autumn fungicides gave good control of phoma leaf spot but even in untreated situations few plants have shown moderate or severe stem cankers.
• Light leaf spot was found widely compared to previous years, but severity of stem and pod infection was low.
• Sclerotinia stem-rot nationally was recorded at the highest incidence since the survey begin in 1987. Incidence was relatively consistent across regions in 2008, compared to 2007 when incidence in the South West was markedly higher. Generally, the flowering period lasted almost 8 weeks, about 2 weeks longer than usual. The main infection occurred during wet weather in late May and early June, and sprays applied up to mid April had little effect on the final level of disease. Treatment in late April or early to mid May gave quite good control. However, two spray programmes appear to be required to protect crops over an extended flowering period.

 

Over 90 per cent of samples from the national survey of commercially grown winter wheat have now been assessed for disease symptoms. Of these samples, 68% are showing symptoms likely to be caused by Fusarium head blight pathogens.
Isolations to identify the species causing the symptoms have been carried out on over 60 samples. Microdochium species (non toxin producers), Fusarium poae and F. graminearum are the most common pathogens found (on 60%, 53% and 33% of samples respectively).  

Of the commercially grown wheat samples assessed to date, symptoms likely to be caused by Fusarium Head Blight (FHB) pathogens have been found on 73% of the national sample. Regionally, symptoms have been assessed on 45% of samples from Yorkshire and Humberside, 79% from the East Midlands, 50% from the West Midlands, 58% from the East, 89% from the South East and 68% from the South West.

Isolation results from the first 18 samples received with FHB symptoms are now available. See details  

Approximately thirty-five per cent of samples from the survey of commercially grown winter wheat crops have now been assessed. Samples assessed so far are from Yorkshire and Humberside (11 of the 42 samples expected), East Midlands (24 of 57), West Midlands (10 of 28), East (19 of 80), South East (18 of 40) and South West (22 of 34).  

Of the commercially grown wheat samples assessed to date, symptoms likely to be caused by Fusarium Head Blight pathogens have been found on 75% of the national sample. Regionally, symptoms have been assessed on 29% of samples from the East Midlands, 38% from the West Midlands, 67% from the East, 75% from the South West and 89% from the South East. The first set of isolation results indicating the species responsible will be available on CropMonitor next week (week beginning 7 July).  

Disease assessments of commercially grown crops are now underway - almost twenty per cent of the crops to be surveyed have been assessed at GS73-75. Samples assessed so far are from the South East (18 of 40 samples expected), South West (12 of 34), East (6 of 79), East Midlands (7 of 57) and West Midlands (8 of 28).  

At four of the five fusarium monitoring sites (Caythorpe, Morley, Andover and Cirencester) M. majus, F. culmorum and F. graminearum were isolated on leaves one and two during flowering. Fusarium head blight symptoms have already been reported in the south east.  

Although levels of infection are still lower than at the equivalent time last year, isolations indicate that fusarium head blight (FHB) pathogen inoculum is developing at the stem base and in the crop debris. The met office outlook for the next few weeks suggests that rainfall is likely to be more prevalent in the North and the East, indicating that the risk of FHB infection will be higher in these areas. The optimum time to apply sprays against FHB is mid flowering (GS65).  

In the North East particularly, high numbers of OWBM were caught in traps last weekend. After recent wet spells conditions are favourable for midge activity. Risk remains high in South East, Eastern Counties and North East.  

Update 03 June 08: Traps in Yorkshire have been checked over the weekend and today, and reports have been received from AICC members that many of the traps in this region have caught between 200 and 400 midges. Although lower counts have also been reported from traps in this region, the risk of damage remains high as crops progress through ear emergence, and the weather remains warm and wet.  

Yellow rust is now present in Robigus in all of the CropMonitor sites, and at Morley, Boxworth and Caythorpe is present on the flag leaf. These levels are very similar to those recorded at the equivalent stage last year, and are higher than the preceding three years. AICC members report that there few problems in treated farm crops. The risk to inadequately protected crops of susceptible varieties, such as Robigus, remains high.   Click for further images .

AICC members report that, in the South East, many pheromone traps have reached thresholds within 48 hours in the last 4-5 days. In other regions soils temperatures are at or approaching 13°C and soil moisture levels are sufficient to trigger pupation. Inspect susceptible crops regularly during mid-ear emergence (GS 53-57). Click to view HGCA Guide to Assessment & Control.  

Although levels of infection are still lower than at the equivalent time last year, isolations indicate that fusarium head blight (FHB) pathogen inoculum is developing at the stem base and in the crop debris. The met office outlook for the next few weeks is one of unsettled weather. This includes warm and wet periods which are likely to coincide with the wheat crop coming into flower - when the crop is at its most susceptible to FHB infection. The optimum time to apply sprays against FHB is mid flowering (GS65).  

Cooler temperatures and misty mornings during this last week are likely to favour further rapid development of yellow rust. Whilst few problems have been reported in appropriately treated farm crops, Robigus remains at high risk across much of the country if fungicide protection is not maintained.   Click for further images .

Orange wheat blossom midge will start to pupate after a period of rain (forecast for bank holiday weekend) and soil temperatures of at least 13°C. Thus, if air temperatures are adequate (over 15°C), adults may emerge and fly during ear emergence - when crops are at risk. AICC members report that pheromone traps are being put out in high risk crops this week. Inspect susceptible crops during mid-ear emergence (GS 53-57). Click to view HGCA Guide to Assessment & Control.  

We are experiencing technical problems which are preventing us sending the latest CropMonitor email alert to all our registered users. Therefore, if you are registered to receive CropMonitor alerts, but did not receive an email on the afternoon of Friday 16 May, you may click here to view CropMonitor Update. We will re-issue this email as soon as technically possible.  

After the hot week all CropMonitor crops have now reached GS37, and Einstein at the Somerset site is at GS39. At Terrington, yellow rust is starting to take hold of the Robigus crop, and the odd spot of Brown rust is appearing in Solstice and Einstein. Yellow rust is also increasing in Robigus at Boxworth, and has been recorded on all leaves including eventual leaf 2. Brown rust is also present on eventual leaf 4.  

The stem base results are now available for all five sites.
Microdochium species (non toxin producers) have been isolated at all sites. In general, the level of stem base infection is lower than at the equivalent time last year.
Isolations from leaves are being carried out for the first time this season. Data are currently available for three sites (York, Caythorpe and Morley). Click to view results  

Reports of high numbers being found in spring barley after long term set-aside in the South-West. Cereal crops following grass or grassy stubbles should be inspected immediately after brairding (emergence of the coleoptile above the soil surface). Thirty cm lengths of drill should be examined in a diagonal across the field. If 15 or more leatherjackets are found per 10 lengths of drill, treatment is probably justified.  

The spring laboratory pest assessment on commercially grown winter oilseed rape is now complete. Only 1 site, located in the North, had more than the published threshold of 5 Cabbage Stem Flea Beetle larvae per plant. Click here to view all the results.   Click for further images .

No reports of aphids found in the field. The Rothamstead Suction Trap Network shows few aphids are flying, so the risk of BYDV transmission remains low. Growers should remain vigilant however as a sustained period of warmer weather could enable numbers of aphids to build up quickly.   Click for further images .

Live-monitoring for the 2008 season is now underway. As each site reaches Growth Stage 30, weekly assessments will begin. The first assessment has been completed for most of the sites (Taunton, Boxworth, Cirencester, Andover, Morley, Caythorpe), York and Tterrington are expected to reach GS 30 week beginning 21 April. To accompany the assessments a weekly CropMonitor report, based on the live-monitoring data, will also be available. Click to view latest report.  

The spring survey of commercially grown oilseed crops is now complete. Incidence of light leaf spot, at 62% crops and 23% plants affected, was markedly higher than last year and also higher than the 10 year mean. Click to view results of spring assesment   Click for further images .

A risk forecast for downy mildew on spring beans is now available. Risk of infection at 10 locations around the country is being regularly updated, based on local weather data.Click to view current risk  

The in-field assessments of commercially grown oilseed rape crops are now underway. Of crops assessed to date, only 1 crop has reached the lower threshold (for thin or backward crops) of 5 pollen beetles per plant. This was in Kent and had 10.2 beettles per plant. Click to view assessment results.   Click here to view HGCA fact sheet.   Click for further images .

The spring laboratory assessment on WOSR for Cabbage Stem Flea Beetle (CSFB) and Rape Winter Stem Weevil (RWSW) is well underway. Of the samples completed only 1 site (from the North) was found to be above the spray threshold of 5 CSFB larvae per plant. Click here to view assessment results.   Click for further images .

Low numbers of pollen beetles are being reported from most regions. Backward crops should be monitored closely. Spray thresholds are over 15/plant at green/yellow bud, over 5/plant for backward crops and over 2/plant for varietal associations. Click to view HGCA information sheet.   Click for further images .

The spring survey of commercially grown winter oilseed rape is currently underway, and most of the crops have now been assessed for disease. Provisional results show that light leaf spot levels are higher than in recent years. Sixty-six per cent (66%) of crops assessed were affected. Severity of disease, although low (a mean of less than 1% leaf area affected), is also higher than in recent years. As usual, the highest incidence has been found in samples from the North and the South West. See the light leaf spot forecast for details of risk in your region. More detailed results of the spring assessment will be available next week.   Click for further images .

Once WOSR crops reach the green bud stage, checks should be made for pollen beetles. None found yet, but the weather has been too cold in the last week. Migrations occur at over 15ºC. Spray thresholds are over 15/plant at green/yellow bud, over 5/plant for backward crops and over 2/plant for varietal associations. Click to view HGCA information sheet.   Click for further images .

West Midlands are reporting signs of gout fly damage in Winter Wheat, with worst cases affecting 40% of the crop. Eastern counties also finding symptoms of attack. Early application of Nitrogen may be needed to increase numbers of healthy tillers.   Click for further images .

No reports of aphid flights yet, but a sustained period of warmer weather could enable numbers to build up quickly.  

The spring survey of commercially grown winter oilseed rape is currently underway. Preliminary results indicate that light leaf spot has been recorded on fifty-six per cent (56%) of crops assessed so far. See the light leaf spot forecast for details of risk in your region. Vigilance is advised, particularly for high risk crops. Inspect crops carefully, as nitrogen scorch may make diagnosis difficult.   Click for further images .

The 'latest news from the regions', compiled from reports by AICC members around the country, will now be available weekly until late June.  

Eastern counties are reporting symptoms of Gout fly attack in some fields. Attacked tillers become swollen and gouty and remain short, however winter cereals appear to recover well from attacks affecting up to 50% of plants.   Click for further images .

Reports from Eastern counties confirm egg hatch is now well under way. Winter wheat and Barley crops should be monitored, especially when previous crops were harvested early and if on light land, following crops of potatoes, other root crops, celery and onions.   Click for further images .

Few aphids are being found, but a sustained period of warmer weather could result in numbers building up.  

Brown rust is more evident in crops in the South. Temperatures from now to April will be important in determining risk from brown rust this season.   Click for further images .

Weather stations are being set up at the live-monitoring sites and data will be presented on the CropMonitor website as they become available. To view weather data click site name on the map of 2008 live-monitoring sites  

A December assessment is being carried out at each of the live-monitoring sites. Mildew, and to a lesser extent, Septoria tritici are the only diseases recorded to date.  

Newly hatched larvae of cabbage stem flea beetle may enter winter oilseed rape plants from October until early April. These larvae tunnel first in the leaf stalks of the lower leaves and then into the pith of the stems before pupating in the soil. Heavy infestations can result in destruction of the growing points of primary and secondary racemes, severe stunting and yield loss. Low levels of larval invasion have now been reported in the South.   Click for further images .

The Rothamsted suction trap network shows very few aphids have been caught this week. As long as previous aphid activity has been dealt with, the risk of BYDV transmission is now reduced.   Click for further images .

There has been no further increase in Phoma over the past month. Continued monitoring, especially after wet weather, is advised.   Click for further images .

The latest bulletin from the Rothamstead suction trap network shows relatively few migrating Bird cherry-oat aphids (Rhopalosiphum padi) have been caught this week. As long as previous flights and subsequent colonisation in fields have been dealt with, the risk of BYDV spread is now reduced. Growers should remain vigilant however, as there are still aphids flying and another sustained period of mild weather could trigger colony build-up and in-field movement between plants, and therefore an increased risk of virus transmission.Click to view latest bulletin.   Click for further images .

The latest bulletin from the Rothamstead suction trap network shows a sharp drop in the numbers of migrating Bird cherry-oat aphids (Rhopalosiphum padi) in all regions. As long as previous flights and subsequent colonisation in fields have been dealt with, the risk of BYDV spread is now reduced. Growers should remain vigilant however, as there are still aphids flying and another sustained period of mild weather could trigger colony build-up and in-field movement between plants, and therefore an increased risk of virus transmission. Click to view latest bulletin.   Click for further images .

There has been no further increase in Phoma over the past 2 weeks. Continued monitoring, especially after wet weather, is advised.   Click for further images .

Mild weather and the presence of migrating aphids has increased the threat of BYDV in some regions. Rothamsted suction traps are showing high levels of migrating Bird cherry-oat aphid (Rhopalosiphum padi) at present, indicating a high risk of aphid transmitted BYDV to autumn cereals for the second year running. Click here to view latest bulletin.   Click for further images .

Phoma has reached threshold levels in some crops in the South and East. There has been no further increase this week, from the low levels reported by AICC members in the Midlands and North East.   Click for further images .

Phoma has reached threshold levels in some crops in the South and East. Although currently low, levels are also increasing in the Midlands and North East. Check crops carefully as reports indicate that whilst some crops remain clear, other crops in the same region have reached threshold.   Click for further images .

Phoma levels are increasing in the South East. Monitor carefully. Trace levels reported in the North East and Midlands.   Click for further images .

Continued reports that flea beetle damage is quite pronounced on late emerging plants in some fields of oilseed rape in the South East and South West.   Click for further images .

Gout fly eggs found in some wheat crops in the East and West, on early sown crops.   Click for further images .

Gout fly eggs found in some wheat crops in the West Midlands and Eastern Counties, and levels increasing.   Click for further images .

Phoma has been reported at threshold levels in a small number of crops in the South east. Trace levels seen in Eastern counties, East Midlands and North East. Careful monitoring required.   Click for further images .

The first signs of Phoma leaf spotting have been reported by AICC members in the Eastern Counties and the East Midlands.   Click for further images .

Aphids found in some regions. Winged migrants noted in the south. In the Eastern Counties populations are building on early drilled crops. Be vigilant for Rhopalosiphum padi, the bird-cherry aphid.   Click for further images .

Gout fly eggs found at low levels on newly emerged wheat in the West Midlands.   Click for further images .

Reporting has now begun for the 2007/2008 season. Reports will be available weekly (fridays) until end of October. From November reports will be available each month until GS 31, when weekly reports will resume.