RAPID ACCESS TO THE LATEST REGIONAL CROP PEST AND DISEASE LEVELS
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Crop Report: 04 May 2007

Report compiled by Farming Online from reports received from members of the Association of Independent Crop Consultants

Pest Alert - West Midlands. Gout Fly eggs on spring wheat. This is an early arrival of a potentialy serious pest to spring cereals. Gout fly larva can cause deformities in the developing ear and stem, leading to greatly reduced grain set. Further info. on Gout fly.

Disease Alert - Brown Rust becoming more widespread. Now in Alchemy, Claire, Consort, Robigus and Solstice in South and East at low to treatable levels. Disease reappearing after early applications of triazoles. Trace to low levels, in Alchemy, Claire, Robigus and Solstice in West Midlands and North East. Yellow rust mainly controlled by T1 fungicides.

Crop development - Soil type shows up. Another week without rain and with drying winds is beginning to bite on lighter land. Leaf rolling occurring in some wheat crops. Continued tiller loss is leading to some very open crops. Disease levels, particularly rust, are higher on stressed crops. Wheats on heavier and better structured land are coping well. Crops, though, are generally shorter everywhere.
See also www.leaf-emergence.co.uk to compare winter wheat variety development by sowing date and site
.

Highlights
Winter rape
  • Petal fall 50-90%.
  • Pod set good.
  • Crops are short.
 
Winter Wheat
  • Many crops at flag leaf emerging.
  • Ear emergence on some early sown crops in SE.
  • Brown rust becoming more widespread on Alchemy, Claire, Solstice and Robigus.
  • Yellow rust mainly under control.
  • Dry conditions still hindering N uptake.
  • Eyespot declined.
  • Last nitrogen going on.
 
Winter Barley
  • Crops at awn to ear emergence.
  • Disease levels low.
 
Spring Beans
  • Bean weevil damage still rife.
 
Soil Temperatures
  • 12-13°C. Reports of large cracks in heavier soils and light land parched.

Winter Oilseed Rape
Pod set in winter rape.
Photo Farming Online.
South East: All crops now nearing end of flowering and pod set looks encouraging and with a long pod-filling period likely, hopefully yields will be respectable. Sclerotinia: continuing very dry weather and soil surfaces, coupled with very little petal sticking, means that the risk of infection remains very low. Turnip sawfly: we are monitoring fields where larvae were problematic last autumn, and will apply pyrethroid if adults found.

South West: Several crops now looking green rather than yellow as flowering ends. No lodging seen anywhere. Crops generally shorter than average although have ended up taller than anticipated earlier.

East: Most forward crops coming towards end of flowering. Low risk sites have not received a flowering fungicide or insecticide. Pod set looks good in warm, dry conditions. Little petal stick. Crops generally very short. Pollen beetles caused little damage. Mealy aphids levels low to date.

East Midlands: Flowering well forward as main racemes come to end of flowering. Many fields showing a definite "greening" as flowering enters final stages. Leaf bulk still below average on most crops. Slow uptake of N. Poor N uptake obvious in several crops - lighter canopies than normal. Castille and Astrid very short. Mealy aphids: numbers remain low. Seed weevil: numbers also low and below threshold with only odd ones found on headlands.

West Midlands: Main stems have set majority of pods, crops now at 30% pod set. Sclerotinia sprays already applied to high risk crops. Monitoring of Sclerotinia at Rosemaund has shown a big jump in spores recently.

North East: Most forward crops have 80 % pods set now. Conditions have been ideal for good pod and seed set so as long as crops finish well the yield potential is high.
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Winter Wheat
Brown rust on Alchemy.
Photo Farming Online.
South East
Crop development: Many September sown crops with Flag-leaf up to 2/3 emerged whilst some are at early ear emergence (late September sown Xi19/Einstein). All late September and early October sown crops of Einstein and Solstice now have the flag-leaf 25-100% emerged. All crops of Soissons drilled in October/November are now at GS 49-52 - some fields may be flowering in next 10 days. Crops looking much greener after sewage sludge, than non sludged fields. Rain urgently needed, as it is now 7 weeks since any notable rainfall and soil moisture deficits are now approaching 4 inches. Windy conditions over last 5 days are causing wheats on gravely soils to look very stressed, with leaf rolling in evidence.
Brown rust: still very widespread on lower leaves all September sown crops of Alchemy, Claire and Solstice. T1 fungicides now mainly applied.
Mildew: still hard to find.
Septoria: lesions very obvious on all older leaves of all September/early October sown wheats - but very little evidence of Septoria in many crops from leaf 5 and above.
Eyespot: can still be found in earlier sown second wheats and Solstice/Robigus as first wheats.
Yellow rust: so far under control from fungicides already applied.

South West
Crop development: Many crops in sheltered forward areas are at full flag leaf emergence. On the South Wales coast boots are swelling. Very early-drilled crops (pre mid September) have lost tillers and yield potential appears diminished as these crops may reach maturity with sub optimal ear numbers and will need grains the size of marrowfat peas to compensate. Late drilled crops with poor root systems are suffering from the sustained dry conditions, especially where the soil surface was capped over the wet winter. Fields on low moisture retentive soil will soon reach limiting soil moisture deficits as larger canopies transpire around 3mm water per day. We generally expect soils to return to field capacity in early April, which gives crops a head start. This year this did not happen.
Brown rust: Contained by T1 triazole on all varieties. Inclusion of fenpropimorph certainly helped on Alchemy. Brown Rust has been most severe on stressed crops on thin soils.
Mildew: levels still very low even on very susceptible varieties.
Septoria: levels not increasing with all spring emerged leaves totally clear.
Yellow rust: earlier epidemic now well contained by rust active triazoles.
Eyespot: progression still slow although prevalence of R strain means we should not fully relax as rain in the near future may spark it off again.

East Midlands
Crop development: Crops very variable, from GS 32-3 up to GS 39. Continued dry weather is resulting in plant tiller numbers reducing down to one in driest conditions. Most extreme plants 'bolting'. However, on best soils crops still look good. Ground now very hard and dry - clay soils cracked. Spraying conditions good. While most forward crops at T2, will delay spraying as T1 only 2-3 weeks ago. Nil rain this week. Second part of nitrogen main split now going on but winds are causing problems re spreading. Main problem is with bread wheat - how much N to top up for protein considering N still to be taken up. Will take tissue analysis for N after rain (if any!) - tissue analysis now would give a misleading result due to dry weather. Some forward and thick crops will have PGR imminently but many crops even where thick are short, particularly where PGR used at T1.
Mildew: levels very low.
Septoria: some on leaf 5 but four upwards very clean.
Brown rust: not a problem so far.
Yellow rust: only present in Robigus but controlled by fungicides.
Eyespot: only odd lesions found on older leaf sheaths with very little penetrating - dry weather has also helped.

West Midlands
Crop development: Range GS 23-39. Mid September sown crops have flag leaf emerging. Alchemy has been slower to develop over the last week than other varieties. Bulk of remaining crops are at leaf 2 emerged. Another dry week and drying winds is not helping wheats on lighter or drier land. These crops continues to loose tillers leaving some very open. Yield potential has already been reduced in these crops.
Brown rust: still very little present even on Alchemy. However, it is easier to find it on lighter land and can be found in crops aof Alchemy, Solstice and Robigus.
Mildew: beginning to develop on some late sown crops.
Septoria: high levels on older leaves, especially Einstein, but most crops remain free of it from leaf 4 upwards.
Eyespot: low levels on Alchemy, Einstein, Robigus and Solstice.
Yellow rust: some reoccurrence seen on treated crops.
Slugs: feeding on aerial parts of plants on damp mornings, some places have severe shredding.
Bromes: patches, some dense, after min-tilled crops.

East
Crop development: Most crops GS 37. Forward fields at GS 39, flag leaf fully emerged. Poor nitrogen uptake in continued drought (now 44 days since rain). Late drilled crops with poorer rooting showing drought symptoms.
Brown rust: on leaf 4 on Alchemy treated with T1 2 weeks ago and present in Robigus and Solstice on lower leaves.
Yellow Rust: controlled by fungicides.
Mildew: on lower leaves of Robigus and Solstice.
Septoria: no increase - with the exception of Einstein and Nijinski, crops are generally clean from leaf 4 upwards.
Eyespot: at low levels.
Take all: monitor these areas, and make necessary economies in terms of fungicides + other inputs where possible.

North East
Crop development: Most crops at GS 32-33, and a few forward first wheats have flag leaf just emerging. Its been a wet week with 1.5mm rainfall recorded. This is also the total for April. Crops not showing any drought stress symptoms yet on our boulder clay soils but there are some lighter soils in the area where some leaf rolling is evident now. Some growers debating whether to wait until we get some significant rain before applying last of the nitrogen, but generally the crop growth stage dictates when operations should be done so most are going ahead this week.
Brown rust: present at low to moderate levels in Alchemy and Claire when T1 applied last week.
Mildew: slight increase on light land.
Septoria: despite dry conditions there are still high levels on older leaves so robust control required at T1.
Eyespot: low levels, no increase.
Yellow rust: low levels in Robigus, but T1 fungicide applied and control looks good.
Take-all: low levels now showing in second wheats.
Problem fields have lots of cleavers in them now.


UPDATE Leaf Emergence in Winter Wheat. Comparing this year's growth rate with last year's.



Comparison of leaf development 2006 vs 07. Crops sown at Andover trial site. The crops were sown on the 11 - 12 September, in autumn 05 and 06.

The graph shows the rate of leaf emergence over time and shows that Robigus has continued the same growth rate, putting out a leaf about every 8 days. Leaf 3 emerged in about 8 days across all three varieties. Alchemy, by comparison, took 2 days longer for leaf two to completely emerge and has remained about a week behind the other two varieties.

See leaf-emergence.co.uk for more sites and varieties. This study is sponsored by Bayer Cropscience.

Implications for fungicide timings.

At this site Robigus had final leaf 3, 75% emerged, on 15 April. A T1 fungicide should have been applied by the 17th. Applying a T1 fungicide to Alchemy on the same day would have resulted in less than half of final leaf 3 receiving a fungicide. Translocation of the fungicide may occur within the leaf, but it will never be as effective as if it had been applied to the whole leaf. Robigus at this site should receive a flag leaf fungicide (T2) over the next few days. Applying it to Alchemy on the same day would be pointless, for as you can see from the graph, the flag leaf has only just started to emerge.

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Winter barley
Ears emerging in winter barley
Photo Farming Online.
South East: Most crops of Sequel/Pearl are now at GS 45-52 with awns emerging, whilst Boost is at full ear emergence and flowering. Very little active disease present in crops. T2 applications timed for awn emergence.

South West: Many crops flowering and all treatments except pre harvest glyphosate now complete.

Midlands: Tiller abortion as wheat. Backward crops at GS 37/39 - many with awns. In the West, crops range from GS 37-50. Crops are short but mainly free of disease.

East: Crops varying from GS 39 to GS 55. Most crops have awns emerging (GS 49). Poor N uptake may lead to high grain N if it eventually does rain. The dry has meant no late growth regulator as crops are stressed, particularly on lighter soils. T2 fungicides now about to go on and all over bar the shouting for barley.

North East: Awns emerging in most crops now. Very dry, but crops still looking Ok on the well bodied soils. Applied low rate of PGR to taller varieties ie. Pearl, Flagon, and Pict and to some Saffron where pig slurry been applied.
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Spring Beans
Sitona weevil in spring beans
and typical "U" shaped notching
on leaf.
Photo Farming Online
South West: Early February sowings emerging vigorously and evenly. Sitona (pea and bean weevil) severe damage seen.

Midlands: Now trying to emerge - some good on lighter and finer seedbeds, but those crops in heavy clods are struggling and are immediately being attacked by weevils - so cyper applied to all crops, and many crops had 2nd application. Also bird (crow) damage - young shoots being eaten when the attempt to emerge. No disease seen yet.

North East: Full in the row now. Dry on top, but still plenty of moisture at drilling depth. High level of Weevil damage seen. Applied pre-emergence herbicide soon after drilling, but need rain very soon if its going to work well. Traces of chocolate spot.
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Crop Report compiled by Farming Online from reports received by members from the Association of Independent Crop Consultants


 
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