28 March 2014: A colder, wetter week for many put most plans and plant growth on hold. A lot of winter wheat crops are ready for the T0 fungicide coinciding with final leaf 4 emergence with yellow rust and Septoria still the main targets. Mildew levels and Eyespot remain low to non existent at the moment. Winter Oilseed rape crops are mainly between green and yellow bud stage with early varieties now starting to flower. Light leaf spot is still the main worry. Pollen beetle numbers have reminded low and it will be a race now as the weather warms up to see if crops flower before pollen beetle numbers increase.
Light leaf spot levels high in south and north east.:
Pollen beetle threat low:
T0 fungicides planned for forward crops of wheat:
Blackgrass - outstanding herbicides need applying:
Yellow rust at low levels in most regions:
Brown rust in southern wheat:
Net-blotch and Rhynchosporium at low levels:
Pollen Beetle.: Migration into crops starts when temperatures reach 12 - 15ºC
- <30 plants/m2 ~ 25 pollen beetles/plant
- 30-50 plants/m2 ~ 18 pollen beetles/plant
- 50-70 plants/m2 ~ 11 pollen beetles/plant
- >70 plants/m2 ~ 7 pollen beetles/plant
Winter Oilseed Rape
Watch out for pollen beetle as temperatures rise (photo from Farming Online)..
South East: All crops now range from yellow bud (Quartz/Ovation/Vision) to first flowers showing (Alienor/Trinity) ? many have retained a significant canopy this year, with GAI of >2 being common. Final nitrogen applications now being completed over the next week before crops get too tall.
Pollen Beetle: low levels only.
Phoma: only very low levels of renewed leaf spotting are evident in crops that were sprayed in November.
Light Leaf Spot: worst affected crops have had canopies badly affected by infection - triazole fungicides are definitely not as effective as they were against Light leaf spot and varietal resistance will become an important consideration in varietal choice for subsequent years.
Sclerotinia: with soil temperatures having dropped in last week to around 7-8ºC, conditions are potentially conducive to the germination of sclerotia, particularly under thick OSR canopies.
Weed control: now too late for further herbicide treatments.
Eastern Counties: Crops have slowed up going through stem extension with most late green bud/early yellow bud. Only a few starting to flower. Many still looking very short of nitorgen with a spindly main stem and very little leaf produced before the rapid change to stem extension. Much more leaf on more fertile sites or when first nitrogen application was made in February and washed in. Second and third nitrogen splits combined on many sites and being applied this week before crop height prevents effective spreading.
Pollen Beetle: activity still low as temperatures are too low for this pest to migrate into crops this week.
Light Leaf Spot: has not developed further in recent very drying conditions.
East Midlands: Forward crops just showing flower but mainly at late green to yellow bud. Later crops at green bud and the odd very late crops at buds just emerging. Colder weather has slowed down development. PGR has gone on many fields where GAI well above 1 and up to 2.5 but a minority of fields will get no PGR with a GAI of about 0.75. Canopies were smaller than originally expected as stem extension got under way early.
Pollen Beetle: continue to be absent with just the odd one found. However, the prospect of warmer weather this week-end may bring them out if they are around but with many crops soon to flower the risk looks low.
Light Leaf Spot: levels remain low.
West Midlands: The semi-dwarfs PX109 and Troy Px109 and still being stubborn and way behind most other varieties, some crops of Cubic, Avatar and Marathon are just starting to flower.
Pollen Beetle: rare.
Light Leaf Spot: trace levels in some crops.
Club Root: two cases now, both on Troy.
Weed control: it is now too late in most crops for control.
North East: Most crops are between green and yellow bud with early varieties now starting to flower. There has been rapid growth in most crops and care is needed on fertiliser rates. Sclerotinia fungicides now being planned.
Pollen Beetle: traps are out but still none seen.
Light Leaf Spot: most serious problem in rape at the moment.
Phoma: traces levels.
Weed control: now too late for post emergence herbicides.
Yellow rust evident in crops (photo from Farming Online).
South East: A cooler week with several overnight frosts and some hefty hail storms has tempered growth, however, most September and early October sown crops of Gallant, Solstice, Crusoe and Cordiale now have leaf 4 50-75% emerged on main shoots ? T0 timing in next 7 days on these. Claire, Scout, Leeds and JB Diego are around 10 days behind developmentally. All fields are now travelling well - it really is remarkable how well many fields have taken the excessive winter rains.
Yellow Rust: only evident in fields/crops that did not have an effective seed treatment (particularly Solstice, Gallant and Claire).
Brown Rust: still only low levels detectable at present but likely to increase rapidly if temperatures rise.
Mildew: no active pustules seen to date.
Septoria: most September/October sown crops are carrying very high levels of Septoria on older leaves.
Eyespot: symptoms becoming more prevalent.
Weed control: later sown crops that did not receive any autumn herbicides are now a priority. Bromes are more obvious on headlands.
Eastern Counties: The majority of crops are at GS 30 and there are some wheats after sugar beet or maize that are GS 20-24. Fields are drying out with available moisture starting to decline.
Yellow Rust: upsurge in visible signs of yellow rust.
Brown Rust: trace levels.
Mildew: trace levels.
Eyespot: becoming more apparent.
Septoria: obvious on lower leaves.
Weed control: wild oats, fool's parsley and Groundsel all appearing.
East Midlands: Forward crops at late GS 30 to 31 but most crops are approaching GS 30 with later ones at GS 29. Most crops look well if a little blue after cold week which has slowed growth right down. Generally fields fine for travelling but windy and showery conditions have stopped most fieldwork with about 12 mm rain in last week.
Yellow Rust: levels remain low and with cooler conditions and frosts, T0 due as soon as weather allows.
Brown Rust: none seen.
Mildew: colder weather has kept it at bay.
Septoria: newer growth is so far clean and awaiting T0, when weather allows, to keep it clean.
Eyespot: some can be found but so far not at worrying levels and not penetrating.
Weed control: some cleavers, generally not a lot to cause concern at moment.
West Midlands: Growth has marginally slowed down over the last week but now we have moisture I suspect there will be some rapid growth as soon as it warms up as crops will access nitrogen applied over the last three weeks. Frustrating 10 days with very little spraying being done.
Yellow Rust: treatable levels on some Solstice.
Brown Rust: none seen.
Mildew: still the same, very little if any mildew.
Septoria: all crops crops carrying high levels.
Eyespot: what looks like Fusarium on stem bases seems fairly common, especially on heavy wet land.
Weed control: more cleavers now showing.
North East: Forward crops now at GS 30, but these are the minority. Most crops are beginning to extend.
Yellow Rust: becoming a bit of a concern as now seen in JB Diego, Leeds and Horatio - T0 planned.
Brown Rust: none seen.
Mildew: none seen.
Septoria: present in many crops.
Eyespot: no obvious signs yet.
Wheat Bulb Fly: dead-hearts in some crops.
Weed control: cleavers and knotgrass beginning to emerge.
South East: Crops now generally at GS 29, with only the odd fertile field of Cassata now at GS 30. Rhynchosporium levels increased rapidly in thicker and more fertile crops of Cassata and Glacier particularly - symptoms showing on new growth.
Eastern Counties: Some are very thick up to GS 28+ and fairly consistent. Low levels of net-blotch and Rhynchosporium.
West Midlands: None more forward than GS 30 with about 30% of crops still in mid tillering. Rhynchosporium and net-blotch present at low levels. Brown rust on Volume.
East Midlands: Forward crops at GS 30-31 with later crops at GS 29-30. Disease levels remain low but wetter conditions may get net-blotch and Rhynchosporium going again. T1 to go on forward crops in 7 days or so depending on weather and growth stage.
North East: Crops range from GS 24 to GS 29. Some crops are lush with many tillers. Low levels of mildew, net-blotch and Rhynchosporium. Brown rust in Cassia.