: 29 April 2016. A run of frosts and cold winds has really slowed development particularly in winter oilseed rape crops with many seeming hesitant to fully flower. Winter wheat crops range from GS30 (late sowns in the North East) to GS33 (early sowns in Eastern Counties). T1 applications are underway but hampered by showers and windy conditions. Yellow rust still threatens in North East. Perhaps the biggest surprise this week is the number of reports of slug activity with some crops needing treatment.
|Winter Oilseed Rape||
Short crops make easy transference of disease within canopy (photo from Farming Online).
South East: Crops now range from GS31 to early GS32 – September sown Trinity and Reflection are showing tip leaf 2 10%+ emerged, and late September/early October sown Skyfall and Crusoe are generally at leaf 3, 50-75%+ emerged. Cold conditions again this week with some sharp frosts which have once again tempered speed of growth, however leaf emergence is now being driven more by increasing day length than temperature.
Brown Rust: recent colder conditions have slowed any progression to new leaf.
Yellow Rust: triazole applications appear to be holding disease progression.
Mildew: combination of low Nitrogen status of most soils now and cold conditions has prevented any resurgence to date.
Septoria: very obvious on older leaves of all September and early October sown wheats – cool conditions of last 3-4 weeks have certainly helped in reducing visible inoculum levels on newer growth.
Eyespot: increasingly visible now with cool and damp soils favouring development, particularly in earlier sown crops of Crusoe, along with second wheats and wheat after oats.
Aphids: BYDV symptoms beginning to show up quite widely now as crops respond to N in some late September/early October sown wheats not oversprayed with Cypermethrin until February. Surprisingly high levels also evident in some fields in sheltered coastal locations that were sprayed in early December following Deter seed treatment indicating significant virus transmission in November. Looks like being worst year for BYDV since 2012 in the South, as can even be found in Deter dressed late October sown wheat.
Slugs: some very high levels of leaf shredding now evident in some fields after oilseed rape again, with every emerged leaf being grazed.
Weed control: blackgrass control to date is looking reasonable, with 75-90% of plants now showing shoot yellowing.
Eastern Counties: Earliest drilled have leaf 3 fully emerged (Gallant), most have leaf 3 half to 3/4 out, latest drilled leaf 3 showing. Wet and cold continues slowing growth.
Brown Rust: trace levels only.
Yellow Rust: T0 keeping this disease in check so far.
Mildew: none seen.
Septoria: low levels on all varieties but some bad hot spots in thicker crops.
Aphids: None found but patches of BYDV now showing up in crops from winter infection.
Weed control: Blackgrass evident in all usual hotspots and now heading. Some of the worst areas are horrendous and will be destroyed. Very little over wintered weeds where robust pre-ems used. Little sign yet of spring germinators except some charlock.
East Midlands: Many crops at or near GS32 with leaf 3 50% to 90% out. Later crops have tip of leaf 3 just showing. The run of cold and showery weather has delayed spraying but field conditions good for travel.
Brown Rust: none seen.
Yellow Rust: No new rust as T0 sprays have worked well.
Mildew: Remains very low with the cold nights and frosts.
Septoria: Plenty on lower leaves and results of delayed T0 can be seen. So far leaf 4 and emerging 3 look clean, but at risk.
Eyespot: generally low but some stem based browning seen.
Aphids: none seen.
West Midlands: Crops now range from leaf three just showing to final leaf two 50% out.
Brown Rust: still there at much reduced levels.
Yellow Rust: very much in the decline.
Mildew: now virtually non existent.
Septoria: very evident on older leaves and with wind and heavy showers will be readily transferred to emerging leaves.
Aphids: BYDV patches becoming more evident in many crops now.
Weed control: very few spring germinating weeds so far.
North East: Late drilled at GS30, September drilled up to GS33.
Brown Rust: none seen.
Yellow Rust: Reflection at high levels, trace levels on KWS Lili and Evolution.
Mildew: low levels in variety Leeds.
Septoria: Most varieties really showing signs again, on younger leaves now.
Weed control: Blackgrass at flag leaf. More spring germinators seen, charlock, hemp nettle and wild oat.
Winter Oilseed Rape
Pollen beetle risk in backward crops (photo from Farming Online).
South East: With a continuation of cool days and occasional frosty nights, growth remains slow, with even backward crops finally growing away from pigeons. Crops range from Yellow bud (Amalie and pigeon grazed) to 30% flowers visible (Campus and Ovation).
Light Leaf Spot: conditions remain very favourable for renewed infection meaning that early flowering sprays will need to have good activity.
Phoma: no recent sightings.
Club Root: severe symptoms found in only two fields so far.
Pollen Beetle: with weather looking to remain cool, backward and pigeon grazed crops could remain vulnerable to attack for another 2 weeks.
Eastern Counties: Many varied growth stages in fields. Some are now at mid-flowering with first pods set, some are still only just showing signs of flowering in parts of the field. Mainly linked to wet, pest damage and weed burden. Cold and wet weather is slowing backward crops still.
Light Leaf Spot: Variable levels across different fields and varieties.
Aphids: none seen.
Pigeons: really hitting crops hard still. Some severe grazing.
East Midlands: Many crops at early flowering with first pods forming, a few crops have patches still to flower where pigeon damage. Many crops look well.
Light Leaf Spot: finally all sprays on, especially the at risk crops.
Pollen Beetle: numbers generally low.
Aphids: none seen.
West Midlands: Crops range from yellow bud to full flower. Flowering within crops is patchy due to run of cold nights.
Light Leaf Spot: crops now treated.
Pollen Beetle: low levels especially in backward areas of crops.
Flea Beetle: none seen.
North East: Crops now range from yellow bud to early petal fall. Some crops are looking short where soils have been wet.
Light Leaf Spot: still causing issues and all planned to receive another fungicide.
Pollen Beetle: low levels.
Phoma: trace levels.
Pigeons: have been more problematic than last year, stripping leaf from many crops.
South East: More forward crops now at around GS33-37 and more backward fields around GSS31. All earlier crops have had T1 fungicides applied this week and rest are due now. Only low levels of net-blotch, Rhynchosporium and mildew found.
Eastern Counties: GS33 common. The most forward have flag leaf emerged. BYDV patches evident. Remain short with little straw.
West Midlands: Most forward crops have tip of flag leaf just showing. BYDV patches are starting to stand out more and more. Disease levels still remain low.
East Midlands: Flag leaf just starting to emerge in earlier crops and leaf 2 in later crops. Disease levels remain low so far with clean new growth.
North East: Crops mainly at GS32-33. Rhynchosporium beginning to develop.