08 November 2013. Phoma now taking off in parts of the East and South with reports of crops with 50% infection. Rain and wind have reduced the number of spraying days and treatments are getting behind. A cold dry spell would be useful. Frit fly numbers in wheat after spring and winter oats are higher than usual. Bean Seed Fly damage also reported in the South. Mildew in some crops of winter barley in the West is at highest levels for years.

• Phoma levels high in East, South and south Midlands
• Slug still active
• Large oilseed rape crops may need PGR
• Blackgrass emerging quickly
• Frit fly damage in wheat after oats
• Mildew developing in some barley and wheat crops
• BYDV - use T Sum to predict risk

BYDV T sum
‘T sum’ system of accumulated day degrees above 3ºC can be used to predict best spray timings. Temperature accumulation should be started from: six weeks after sowing for imidacloprid-treated crops date of emergence for other crops one week after application for pyrethroid-treated crops.
1 Calculate ‘T sum’ by subtracting 3ºC from the daily mean temperature and adding the result to the running total.
2. If ‘T sum’ is 170 (second generation could be starting) – consider a tank-mix insecticide if treating the crop for another purpose.
3. If ‘T sum’ is 340 (significant spread imminent)

source HGCA.

Winter Oilseed Rape 

South. Crops now range from 5 True leaf to 6-8+ True leaves – many crops are now  5-6+ true leaves. Mild conditions continue to favour rapid growth and around half of crops will have had a PGR Fungicide applied by early November.
Phoma: leaf spotting has increased rapidly in the last 7 days and varieties with resistance scores of 6 or below now have 20-50% plants with leaf spotting, though most crops with stronger ratings are only showing around 5-10% infection levels. Control will be based around either 0.3-0.4lt/ha Proline or 0.4-0.6lt Punch 25/Contrast applied between 5-10% Phoma spotting. Where PGR needed will add in 0.5-0.6 lt/ha Tebuconazole.
Slugs: good seedbeds and dry soils have minimised problems.
Aphids: no Myzus Persicae adults seen to date.
Weed control: blackgrass control Kerb is planned to be sequenced later in November/December.

Eastern Counties. Rape has continued to grow and cover the ground well. However there is a great variation in canopy size with the early drilled light land fields almost to the top of your wellingtons and the last drilled heavy land with some plants only 10 cm across. However all has established well with few thin areas. Some unevenness in growth and purpling now showing in areas but we have had a lot of rain recently.
Phoma: Levels have exploded some fields well over thresholds with several phoma lesions per leaf on some plants. Phoma levels often higher on earlier drilled crops and also to the South of region. Getting behind now with phoma sprays few opportunities to get sprayer out.
Weed control: waiting for soil temperatures to fall below 10C before applying Kerb. More and more poppies have come through the Novall. Hope to get the Astrokerb on asap.

East Midlands. Crops still continue to grow but rate has slowed a bit – later drilled crops now at 4 leaves with forward at 7-9 leaves.
Phoma: first spotting seen in last few days and fungicides due to go on when weather window allows with later small crops first priority, but levels still below 10% although expect this to rise in next week. Metconazole to go on stronger crops although if weather continues to delay something may be added to boost the eradicant activity.
Slugs: a few backward crops showing some damage and will require a low rate of pellets.
Weed control: Kerb to go on when soils cool but this may well mean splitting the phoma sprays out as Kerb application is delayed. Excellent results on blackgrass control from Centurion Max. Very good results from Centurion Max even on ryegrass shown to be fop and dim resistant. Headland usage has shown definite de waxing to a line.

West Midlands. Crops continuing to grow and the majority look well. There are some crops that are too far forward and will need an autumn PGR when the weather clears.
Slugs: damage to some backward crops continues.
Leaf miner: in some crops but not at damaging levels.
Phoma: levels increasing and becoming very obvious in the south of the region where now at threshold. However, in the east of the region it is difficult to find any lesions.
Weed control: quite a few broad leaved weeds now appearing in crops. Follow up herbicide treatments planned. Large patches of Charlock in some crops.


North East. There are some large canopies developing. Average temperature for the week:  7.5 degrees, Rain 11.2mm for the week and a frost this week.
Slugs: a little activity.
Phoma: still no disease seen.
Weed control : various weeds seen emerging, shepherds purse, few cranes bill, chickweed etc.

Click here to view the Rothamsted Phoma forecast

Winter Wheat

South. Ongoing unsettled and wet conditions means that this is around 5% of wheat area left to drill  after maize/vegetables. With soils still warm, crops continue to develop rapidly - earliest sown crops (20th Sept) now at GS 22+, with most crops typically being between GS 13-21. Really could do with weather settling down now to enable post-emergence spraying to get caught up.
Aphids: none seen yet, but can be readily found on volunteers in oilseed rape. Pyrethroid will be applied 6-8 weeks after Deter dressed crops were drilled.
S: low levels of damage now being found in fields after short term leys and after spring oats.
Bean Seed Fly: damage in wheat following oats that had FYM applied and incorporated ahead of min-tilling.
Slugs: activity still evident, particularly in crops after oilseed rape. Most of damage appears to be being caused by juvenile/pin-head grey field slugs and/or black keeled slugs (Arion spp), with damage of the latter often indicated by subterranean damage leading to yellowing of main shoots – most effective pellet in either case is a methiocarb based treatment.
Weed control: with seedbeds now thoroughly wetted, pre-emergence herbicides have been fully activated and those applied at peri- or pre-emergence in early October appear to be working very effectively. Where blackgrass is emerged and already at 2 leaves+, will be overspraying these fields with Atlantis at the first opportunity. Atlantis applied two weeks ago seems to be giving good control.

Eastern Counties. October has seen over 100mm of rain in the area, with more expected. Fields are now at or near to field capacity and walk very wet. Fingers crossed for a dry spell to finish drilling and cereal herbicides.
Aphids: still being caught in suction traps. BYDV follow up sprays may be needed this year.
Frit fly: larvae have been found on a couple of fields with meadow/black soils.
Slugs: there are a minority of fields after rape where slugs continue to graze the emerging wheat crop.
Weed control: residual herbicides have worked well, in most case with clod free and well consolidated seedbeds yielding little or no blackgrass at present especially where pre/peri-em’s where applied close to rainfall or the presence of moisture. There have been some autumn Atlantis recommendations made where heavier infestations of blackgrass have come through residuals. Contact herbicides like Atlantis need to be applied to a dry leaf, which isn’t easy at present and be given at least 2-3 hours rainfastness.

East Midlands. With the wetter weather crops have slowed a bit, but forward crops at 3-4 leaves and later drilled crops at 1-2 leaves. In spite of heavy rain fields are quite good on top but too wet for cultivations or drilling but in some fields sprayers would carry but wet headlands and patches hinder many. However,  the combination of wind and rain has meant that no fieldwork has been possible.
Aphids: none seen.
Slugs: odd fields show damage requiring treatment and slug levels have risen with the wet but a lot of slug pellets remain in store.
Weed control: blackgrass at 1-3 leaves and requiring treatment when weather allows. On fields with resistance and with no pre em or Avadex to date due to conditions they may well have to be burnt off. Pre ems working now but thicker areas have had a lot of plants left.

West Midlands. Crops continue to grow at the most forward have 2 tillers. Fields are now getting a bit wet after recent rains and there are some crops going yellow on headlands as a result of wet feet. We could do with a dry cold spell to catch up on herbicide and BYDV sprays.
Slugs: renewed activity in some fields after oilseed rape.
Aphids: can be found.
Frit fly: quite a lot of damage in crops after spring or winter oats
Mildew: obvious in crops of Grafton, Leeds and JB Diego.
Weed control: recent rains have helped activate pre-emergence herbicides. Bromes are more obvious this year on headlands.

North East. Crops continue to grow although temperatures are cooling done, most forward crops now at GS 23. All first wheats are in now.
Aphids: few winged aphids sighted.
Slugs: seen surface grazing, increased activity from last week.
Weed control: more blackgrass emergence this week. Pre emergent herbicides are now working well on broad leaved weeds.

Winter Barley.

South. All crops emerged, with earliest sown crops now at GS22 (most crops are at GS13-21).
Eastern Counties. Most crops now in but later sown crops have patchy emergence due to dry seed beds. Main varieties are Cassia and Glacier with a bit of Volume.
West Midlands. Most forward crops at 2 tiller stage. Light land crops have high levels of mildew. Manganese deficiency showing up on light land.
East Midlands. Crops at 3 leaf and look well although some yellowing showing where pre ems used, but on the whole plants look healthy.
North East. Earliest sown now at first tiller stage. Powdery mildew seen on Glazier.