28 October 2011: Phoma still remains hard to find in most oilseed rape crops meaning that a one spray approach this autumn may suffice. Recent rains should help crop emergence where winter cereal has sat in dry soils. High aphid numbers in suction traps indicate a bigger risk of BYDV than last year.
Highlights: * Phoma levels still very low. * Powdery mildew on oilseed rape. * Some advanced crop of oilseed rape will need a growth regulator fungicide. * Slug damage remains rare. * Mildew in some winter barley crops and the occasional early sown wheat. * Brown rust found in eastern counties on some wheat and barley.
Winter Oilseed Rape
Phoma on oilseed rape still rare
South East: Crops range from 5-6 leaves to 9-10 true leaves, with the bulk of crops now around 5-7 true leaf stage, and are all still growing quite rapidly due to ongoing mild day and night weather we are enjoying.
Flea beetle: renewed shot holing of leaves is now evident in some crops, indicating early Cabbage stem flea beetle activity.
Slugs: good seedbeds and dry soils have minimized problems to date.
Phoma: can still only find a few Phoma spots in August drilled crops of Vision and Cabernet, and still only at around the 2% infection level, otherwise most crops remain completely free of infection to date - with such a late onset of visual infection coupled with the large size of many canopies/plants, this may now only be a 1-spray Phoma season for many crops, as fungicides applied in next week or so should give at least 6 weeks protection taking crops through until mid-December.
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. Treatment will be considered from late November onwards, once crops are properly frost hardened.
Eastern Counties: Most crops with 7 leaves+. Some fields starting to show stem extension. Using growth regulator where needed. Crops have used up a lot of the available nitrogen now. Some crops seem a bit un-even with a mixture of compaction, early drought and occasional SU residues on overlaps causing the issues.
Flea beetle: damage only seen where untreated seed has been used.
Slugs: activity extremely low most crops are now well past the vulnerable stage.
Powdery mildew: seen fairly extensively in early drilled forward crops.
Phoma: still finding relatively few obvious phoma leaf spot lesions about. It remains all but absent in some fields, and not above 1% of plants infected anywhere.
Weed control: soil temperatures still too high for soil acting herbicides and delaying applications until mid November.
East Midlands: Crops as forward as I have seen them looking and are more like spring greening rather than autumn. Generally most crops at 5-7 leaves with forward crops at 6-9 leaves.
Flea beetle: only slight damage seen in one crop where no seed dressing.
Slugs: crops out of danger of any damage now.
Phoma: absolutely none seen even in brassicae in game crops. Phoma recommendations out but no panic to apply and hopefully this could be a one spray season. Forward crops with 9 leaves are at a low risk and have a bit of leeway.
Weed control: some blackgrass in crops but dry soils and warm temperatures mean holding off for time being. Also some crops very forward and difficult to penetrate so will need to lose some leaf.
West Midlands: Continuing dry conditions have kept most crops in check. Crops range from still not chitted to 6 true leaf. There are still a lot of crops with small plants which have failed to develop due to the drought. Irrigated crops responding quickly to an inch of water.
Flea beetle: Quite bad on late germinating/thin crops.
Slugs: still none seen.
Leaf miner: damage quite severe in some areas.
Phoma: No sign of disease yet in forward crops.
North East: Conditions continue to encourage rapid growth with many crops at 9+ leaves now. Most crops have 5 - 7 leaves.
Flea beetle: some activity seen, but not damaging.
Slugs: no more activity seen in last 7 days despite the rain making much better conditions for slug activity.
Phoma: Phoma infections continue to be a rare commodity.
Weed control: more grass weeds have come through in many fields now.
Brown rust on early sown Claire
South East: Earliest sown wheats now at GS 22+, though bulk of crops are now at GS 12-21, with later sown fields emerging. Recent rain has enabled those seeds that were sat in dry soils to germinate now, enabling areas of patchy establishment to slowly begin filling in.
Gout fly: very little evidence of new egg laying despite warm weather.
Slugs: following recent rain there has been a slight increase in foliar shredding.
Weed control: blackgrass emerging with later sown crops now and present at 3 Leaves-1 tiller in earlier sown crops where dry seedbeds have limited the efficacy of pre-emergence herbicides, placing a much greater emphasis on timely applications in the next few weeks.
Eastern Counties: Very early sown wheats generally have 3+ tillers. Majority of wheats are between 3 leaves to one tiller. Patches are beginning to fill in now with the backwards areas at 1 leaf.
Brown rust: first signs of disease on early sown Claire.
Mildew: beginning to develop on early sown Claire and Solstice.
Slugs: still only very low levels.
Aphids: no increase on last week
Weed control: blackgrass now at 3 leaves to beginning of tillering. Pre/ early post emergence have probably not worked as well as they did in 2010, this is mainly due to lack of soil moisture and high temperatures. If considering Atlantis treatments, soil temperature needs to be above 6C at 10 cm soil depth and best control last year was achieved on bright sunny days.
East Midlands: Big variation from crops at GS 14-21 to crops with big brown patches in field, examination shows some seed has put out roots and then dried out - difficult to tell how much re drilling needed until soils wet up but should not be a big amount. Seedbeds very dry but some help from showers in last 24 hrs. Good days rain needed.
Slugs: damage remains very low with no problems.
Gout fly: just the odd plant with eggs but nothing to warrant any spraying.
Mildew: odd crops with a few pustules but not a problem ? generally in Solstice.
Weed control: big variation in blackgrass emergence with some fields showing flush but many showing very little to date due to dry soils. Odd field being part sprayed whilst drier cloddier parts catch up. Good flush of volunteer rape in crops. Spraying plans a bit of a mishmash with the dry conditions, lack of crop emergence and lack of weed emergence.
West Midlands: Still a very mixed picture of crop emergence. Early sown crops now at the two tiller stage and established well but later sown crops struggling to emerge due to the drought. Rain on Thursday 27 October should just be enough to help these backward crops.
Gout fly: no further increase in numbers of eggs.
Slugs: Found one!
Aphids: no new recent sightings.
Mildew: early sown crops of Solstice and Grafton are carrying quite a lot of mildew.
Weed control: a flush of oilseed rape in some crops but otherwise weed emergence has been slow to none existent, recent rain will have changed that though.
North East: It's been a dry week, but thanks to earlier rainfall, seed that was at risk in dry areas has now germinated, and crops are evening up very quickly. Most forward crops are at GS21-22. All fields are in good condition for travelling. This means spray program is up to date despite some hold-ups due to strong winds.
Slugs: some seed hollowing found in late sown crops on heavy land. No grazing on emerged crops been seen.
Aphids: Rothamsted has caught much higher than average numbers in their aphid traps, so the assumption is that all emerged crops are at risk of BYDV.
Weed control: it's a bit early to assess the effectiveness of the pre-emergence herbicides, but so far most fields have few blackgrass plants coming through. Now we have had some rain, the situation will become very clear over the next 10-14 days. Most fields will be into November before reaching the Atlantis timing. Some fields are unlikely to have blackgrass to spray until into the New Year.
South East: All crops now emerged and range in growth stage from GS13-22. No disease problems yet.
Eastern Counties: Crops range from two to four leaves. Mildew developing in forward crops of Cassata and Cassia, Brown rust seen on Carat.
East Midlands: Generally at GS 13 - again some patchy crops where seed either not germinated or put out a couple of roots and then dried out.
West Midlands: Earliest sown crops now at two leaves. Mildew appearing in some crops of Cassia.
North East: Established crops have grown quickly in last 7 days, and many crops are at GS21-22 now. Low levels of Mildew on Cassia.