19th April 2013: Rising temperatures during the week has provoked growth at last. Early sown winter wheat crops have finally leaf 5 fully emerged so now ready for T0 fungicides. The most forward winter oilseed rape crops are at the green/yellow bud stage with flowers opening on the odd plant. However, many crops remain open and backward and will be vulnerable to attacks from pollen beetle. Spring barley emerging within 10 days of sowing.
: Pollen beetle entering crops in the South
: T1 for early sown winter wheat crops early May
: Rhynchosporium developing in the South.
: Oilseed rape first flowers in the East.
Pollen Beetle: Migration into crops starts when temperatures reach 15 0C which according to the Met Office forecast is unlikely to happen until the end of next week. Damage from pollen beetle could be more severe this year as crops struggle to develop after prolonged pigeon attack and cold weather. Crops are at their most vulnerable stage between the green and yellow bud stage. Threshold levels have been amended recently and are now based on plant population. The rationale to basing the threshold on plant population is that low plant population will produce more branches and therefore more flowers.
Pollen beetle threshold levels of per plant:
- <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
Bayer have a useful tool for predicting pollen beetle migration: click here to view
Septoria on lower leaves of winter wheat
South East: At last Spring has decided to arrive somewhat belatedly and in my last report I requested some warm rain to lift soil temperatures - this has duly arrived and soil temperatures are now up at around 80C, however the weather gods also decided to be generous with the 'rain' bit and deliver 40mm of the stuff last week!! Crops (and weeds) have really thrown off the shackles of winter this week, and are now looking like they should have done at the end of March - however, it has been frustratingly windy all week, largely preventing any meaningful spraying, which is adding to the backlog of work on many farms. Claire/Scout/Grafton and Gallant are now extending rapidly and are between GS29-30+, otherwise most later sown crops are around GS22-29 but are beginning to produce additional tiller buds so may still manage to fill some of the gaps apparent in many crops. It is looking increasingly unlikely that there will be much T0 spraying undertaken, particularly on later drilled crops (c. 70% of WW area), instead a T1/T2/T3 programme looks more appropriate as reproductive crop growth will be inevitably concertinaed into around 6 weeks now.
Weed control: herbicide mixes to go on ASAP.
Eastern Counties: Wheat has grown a lot over the last 5 days it has gotten greener and more leaf. Early fields, those sown around 20th September have their main tillers with the 1cm gap or node visible at the stem base, so will be at GS30 this week. Should get the T-zero sprays on around April 20th.. Fields are dry but with moisture under the surface. It has been warm with showers so perfect growing conditions.
Septoria tritici: trace levels on lower leaves.
Yellow rust: reports of some crops of Torch infected.
Eyespot: can find stem based browning but difficult to diagnose as eyespot.
Weed control: where pre ems were used we have had good blackgrass and broadleaf control.
East Midlands: Crops generally at GS 24-29 - close dissection shows the ear at the base with what may be 4th leaf emerging but with plants at less than 6" high peeling back leaves is not easy. Crops still look patchy and more like February crops. February drilled wheats just starting to show and will be treated as spring crops. Soils continue to dry and crack on top and very dusty but just inches down the soil is very wet
Septoria: on older leaves but not to high levels.
Eyespot: some stem browning but looks more like fusarium than eyespot.
Weed control: many fields remain generally clean of broad leaved weeds and there is no rush for herbicides - waiting to see if any warm rain sets a flush going.
West Midlands: Crops have greened up significantly since the rain end of last week/weekend along with the assistance of warmer weather. Most early sown crops now have final leaf five fully unfurled with leaf four emerging, although reports of early sown Solstice with leaf three emerging. The majority of earlier sown crops unlikely to have final leaf three out until early May.
Mildew: trace levels in base of crop on forward Humber.
Septoria tritici: very evident on the forward crops, whatever variety, none on new leaves.
Yellow Rust: no new sightings.
Fusarium/Eyespot: early symptoms on stem bases in some but not all crops.
Weed control: high winds have kept sprayers out of fields most of the week.
North East: Most wheats still in the tillering date from GS 23/26. The average temperature for the week was 9 degrees which has improved crop appearance with leaves greening up and plants recovering from tipping and purpling.
Septoria tritici: active on lower leaves of some varieties.
Weed control: some crops still need to recover from the winter before they can be treated.
Winter Oilseed Rape
Watch out for Pollen Beetle in backward crops.
South East: At long last even pigeon ravaged crops are beginning to show signs of life, though in some cases any new growth is disappearing almost as quickly. Most advanced and ungrazed crops are between Green bud and very early yellow bud now.
Light leaf spot: infection can be easily seen in unsprayed crops on older leaves in crops that have been relatively ungrazed. Quartz, Agatha and Alienor appear to be the worst affected varieties currently.
Phoma: no new infection.
Pollen beetle: very low levels of adults seen in a few crops - nowhere near thresholds yet though.
Weed control: significant populations of cleavers and mayweed.
Eastern Counties: Crops rapidly moving into stem extension with recent warmer weather most advanced are now knee high at green bud stage. Crops which have kept their foliage now look decent but still about 3 weeks behind! I expect they will now romp through the developmental stages. Pigeon hammered crops are showing signs of life with the centres slowly greening, I expect these will now produce rather spindly plants with little branching more typical of spring rather than winter rape.3rd and final N applications due at yellow bud stage, need to be careful that we are not caught out with crop height preventing even application of solid N. Liquid N applications will be made during late yellow bud/ early flowering.
Phoma: Phoma spotting obvious but the majority of crops were treated in November and the lesions are old.
Light Leaf Spot: still difficult to distinguish which lesions are light leaf spot - I don't believe I have seen a great deal in NW Norfolk we continue to inspect crops. Looks now unlikely if we will use much growth regulator but may consider a spray more targeted against LLS protection during stem extension- there is discussion amongst clients that we may now wait to early yellow bud as we are expecting the crop to romp through its growth stage as as soon as it turns warm.
Pollen beetle: Monitoring for pollen beetle activity. Very few present in crops yet, although temperatures have risen it has been extremely windy. Need to be especially vigilant with the pigeon 'stripped crops' as a threshold more typical of that used for spring rape would seem appropriate
East Midlands: Upside - at last some growth - downside flower buds emerging with crop at 4-5"high, but some crops still resemble sticks in the ground.
Phoma: with a lot of unsprayed crops I expect to see some phoma in crops this year.
Light leaf spot: not a lot of leaf to get any yet.
Pollen beetle: as flower buds emerge will be on look out for early pollen beetle and crops will be treated at spring rape thresholds.
Weed control: Herbicide to go on when conditions allow for mayweed before flower buds get too prominent.
West Midlands: Crops of PR46W21 beginning to take off. There are many crops though that are thin and spindly in appearance and only just beginning to recover from the winter and pigeons. These crops are forming buds almost before the stem extends. Many crops have less green leaf area than they did at the end of February. Yield potential for crops is more on a par with spring than winter crops.
Phoma: still crops in need of treatment.
Light leaf spot: no obvious signs yet. Proline being applied since mid last week to crops that have been looked after, most will probably go beginning of next week
Pigeons: as bad as ever and needs constant attention particularly on the small crops.
Pollen beetle: not seen yet.
Weed control: flush of groundsel and field pansy coming through in pigeon damaged crops. There are going to be some dirty crops come harvest this year.
North East: Growth stage ranges from 3 leaf stage to Green Bud. Good growth with warmer week. Crops are extending.
Pigeons: a lot of damage to crops.
Phoma: no new lesions seen on new leaves.
Light leaf spot: no new signs of disease.
Weed control: wild oats starting to emerge. Odd thistles being controlled
South East: most advanced crops are now at around GS30. Significant levels of Rhynchosporium very obvious now on older leaves of all crops of Cassata and Cassia. Maximising green leaf area will be crucial this year to optimising yield this year in what will be a short growing season.
Eastern Counties: crops picking up at last with very little disease.
East Midlands: generally at GS 25-29 but little stem extension yet. Disease levels remain low.
West Midlands: Barley is winning the race in terms of which crop can catch up the fastest, have plenty of lighter land crops which have gone from tillering to GS 30 in less than a week.
North East: Average GS 24/25. Good tillering generally. Forward crops are pushing toward growth stage 30. No new sightings of yellow rust.