27 January 2012: A cold weather alert issued by the Met Office this morning may signal the beginning of winter. There is a 70% probability of severe cold weather between 1800 on Sunday and 0900 on Tuesday in parts of England. This may well put on hold the brown and yellow rust that has been developing in winter wheat crops particularly in the south and east. It should also curtail any aphids which may still be lingering in crops. There is a 60% probability for much colder weather in February with winds mainly from an easterly quadrant to prevail, bringing widespread frosts, and snow to some areas.
Yellow rust: in east and south
Brown rust: in east south and north
Mildew: high levels declining
Winter Oilseed Rape
Phoma lesion in oilseed rape
South East: Bulk of crops are around 7-8+ true leaf stage though many of older leaves have senesced now and are beginning to become more rosette like than upright following some harder frosts in January. Around 70% of crops had a fungicide applied in late October/early November for PGR of growing points.
Cabbage Stem Flea Beetle: only very low levels of Cabbage stem flea beetle larval invasion been found and only in low number of crops.
Phoma: all crops were sprayed against Phoma in November/December, which has generally been controlled by fungicides with no renewed spotting seen to date. Only crops that have required re-spraying have been those with lower Phoma resistance (Cracker and Vision) and that were sprayed at the end of October/early November - in these there is renewed leaf spotting showing now.
Weed control: charlock and runch - some heavy populations in some fields, though much is already flowering so hopefully frosts may well control the bulk of this. Herbicides now mostly all been applied during December or January - badly need a sustained cold spell now to assist with weed control, particularly where runch is evident.
Eastern Counties: Lighter land crops have lost some larger outside leaves during the winter, crops on well structured heavier soil types have maintained leaf and colour. Crops are generally well advance and giving good ground cover, some have excessive foliage and are quite tall others have remained more prostrate and closer to the ground. Will be assessing GAI nearer to timing of first N and making allowances for N already in the canopy.
Phoma: all crops were treated once unlikely to spray for phoma again canopies are very well developed and phoma arrived late.
Pigeons: are about but canopy cover is keeping them at bay except on odd thin patches on headlands or tramlines. Being more of a problem in some crops drilled on wider rows.
Weed control: Charlock flowering above the crop in patches, generally quite spindly plants. Farmers may try cutting the charlock or weed wiping has been mentioned.
East Midlands: Frosts have opened crops up a bit but many still forward and thick and expect to use growth regulator on most crops this season.
Phoma: no new phoma seen with older leaves dying off.
Weed control: charlock in many crops and lack of frosts means spring herbicide will be required where populations are high. Autumn herbicide has been variable with some very good results but a few fields have managed to grow away in the mild conditions.
West Midlands: Crops range from 10 true leaves to 3-4 true leaves. Warm conditions have been a blessing to late emerging crops and all will (as far as I am concerned ) make a crop (some probably better than the 100% ground cover crops!).
Pigeons: just beginning to come into some crops - big flocks around.
Phoma: developing in most crops now and in most cases treatment is now complete.
Weed control: charlock control with herbicide but not too hopeful of any decent kill with continued mild conditions. As with hedge mustard this weed is becoming more and more prevelant.
North East: Crops are still very big but much more open than last November. Crops are in the range of 7-12 leaves.
Light Leaf Spot: the conditions so far have been conducive to LLS development, but no symptoms are evident in crops seen so far, and this included Dimension.
Phoma: lesions are easily found now, with some crops nearing 10 % plants infected level. Treatment is now complete.
Cabbage Stem Flea Beetle: no significant adult feeding has been seen all season, but despite an insecticidal seed dressing followed by a pyrethroid spray a few larvae have been found in the leaf petioles in some crops.
Weed control: some fields had high levels of Blackgrass, and all had propyzamide last November. Mild weather can reduce the efficacy of propyzamide, but the blackgrass control looks good in crops seen to date. Runch and Charlock control by frosts has not happened , so all crops being checked now for treatment.
Yellow rust in winter wheat
South East: All crops have continued to grow through December and early January, albeit slowly, with continuation of largely mild days and nights. Crops range from early tillering (late October+ sowings) to late tillering (September sowings). Soils are generally damp, but there are still surprisingly few wet patches even on heavier and lower lying fields.
Brown rust: high levels still present in most crops of Claire, Cordiale and Solstice. Will need a severe spell of weather to reduce inoculums levels - many crops likely to need a February/March a triazole to knock out infection if weather remains relatively mild, otherwise a 2007 scenario could develop.
Mildew: high levels present in some earlier sown fields of Gallant and Cordiale in particular. Recent frosts in last 2 weeks (down to -5oC) have browned up most pustules, causing any heavily infected leaves to senesce.
Yellow rust: hard to distinguish early pustules from brown rust, but I have my suspicions that it is widely present in Solstice and Gallant in particular and have found the odd small foci in Solstice.
Weed control: blackgrass control from pre-Christmas applications generally looks encouraging so far.
Eastern Counties: Currently, cereal fields appear reasonably green, with many not looking in the least hungry. But it is mainly rust that is causing concern as there is a lot in Oakley and Robigus. At the moment there is no rush to spray as cooler weather and wet field conditions are halting both disease and farmer progression. However, we will proceed once we can get on assuming cold weather doesn't arrive before too long. Also crops are very thick in places over here so disease may be worse than other areas.
Brown rust: easily found in some crops. Varieties include Claire, Grafton, Hereford, Santiago and Invicta.
Yellow rust: quite a lot of rust in Oakley and Robigus, low levels in Viscount.
Mildew: most crops exhibiting fair amount of disease.
Weed control: good autumn control of blackgrass but some cases with resistance. More cleavers around than last year.
East Midlands: Many crops at GS 21+ with a few later crops at GS 14-21. Most crops look well are forward and in some cases lush. Expect to be using a lot of split growth regulators this season. Soils sticky on top but not really wet apart from the odd wet patch. Early nitrogen will be held back on many crops but some will be applied in case we get a dry spell again in spring.
Brown rust: none seen
Yellow rust: none seen
Mildew: old mildew evident on lower leaves but not active
Weed control: blackgrass at variable levels of control mostly very good, but two farms have had poorer control and resistance is suspected and awaiting results of plants sent for testing. If so resistance spreading northwards.
West Midlands: All crops looking well, some crops are both forward and lush with virtually 100% ground cover. Manganese issues on light land and have been applying manganese over the last 2 weeks.
Brown rust: none seen
Yellow rust: none seen
Mildew: slight frosts prior to Christmas followed by the run of sub -5 10 days ago has put paid to mildew for now.
Weed control: spring germinating wild oats emerging on light land and winter wild oats are easily visible in most crops where you would expect to find them ( Unlike last spring). Some impressive patches of cleavers in after oilseed rape.
North East: There have been some cooler spells in the last month but no proper winter so crops have continued to grow despite the short day lengths. Growth stages cover a wide range from GS 21 - 26, and some crops are fairly big with dense ground cover. It has been dry over the last month with a total of only 19mm locally for January, but 10 mm of those were in the last 2 days so the fields are quite wet and sticky.
Brown Rust: low levels seen in the most susceptible varieties, such as Duxford and Grafton.
Yellow Rust: Some heavily infected plants seen in some early sown Oakley
Mildew: only the most resistant varieties are clean such as Warrior and Viscount. All the rest have varying levels of infection.
Weed control: autumn applied Herbicide for blackgrass is giving very good control in some challenging situations. It is not 100% in some cases but overall the results are looking good. There are some dense beds of Cranesbill in a few fields.
South East: Crops now range in growth stage from GS24-29 - all crops have tillered well and grown rapidly to date in the mild conditions. Some very high levels of mildew noted on lower leaves of some crops of Cassia and also Cassata. Brown rust evident in most crops. Many crops will need a TO fungicide to control mildew and brown rust in early spring.
Eastern Counties: Most crops have at least 2 to 3/4 tillers. Most forwards are up to 7 or 8 tillers and just below wellington boot height. Some looking as though could lodge. In the most forward and un treated crops mildew is rife.
East Midlands: Crops at GS 23-24 and look well. Good control from autumn mildew sprays but forward crops may well see another rush of mildew if weather becomes mild and dry.
West Midlands: Earliest sown crops now at four tillers. Frost has resolved any lingering mildew issues for now.
North East: Crops are in range GS23 - 26, and some crops are very dense now. There are crops of hybrid varieties Bamboo and Volume that are already big and lush, which is not what you expect to see at this time of year.