09 April 2012: Rain over the bank holiday (what did you expect) is most welcome but it has increased the risk of Sclerotinia infection in oilseed rape as most crops at the yellow bud to early flowering stage. Winter wheat crops have moved on and the most forward crops have final leaf 3 emerged so T1 fungicide timing is upon us. Rhizoctinia barley stunt a little too prevalent in the West Midlands.
Sclerotinia risk: increases with recent rain
Pollen beetle: threat declines as crops flower
T1 fungicide: timing in winter wheat
Winter Oilseed Rape
Sclerotinia on stems of oilseed rape
South East: All crops now range between yellow bud (Ovation, Vision and Cabernet) and 1st flowers showing (Alienor, Expower and Camelot). All nitrogen applications now been completed.
Phoma: no significant renewed spotting seen to date.
Light Leaf Spot: was being found widely at around 10-20% infection levels in most crops/varieties in last two weeks and particularly those that only had one autumn Phoma/PGR spray applied.
Pollen beetle: generally only low levels of pollen beetle have been found to date and mostly well below threshold levels - a few later developing crops located in smaller and sheltered fields have needed treating.
Sclerotinia: conditions are potentially conducive to the germination of sclerotia, particularly under thick canopies as crops move towards early flowering.
Eastern Counties: Crops have slowed up as we returned to much cooler weather with frosts at night. Some are coming into flower slowly, rest at late green bud / yellow bud stage. All second applications of nitrogen now completed. At last some rain to wash the nitrogen in.
Light leaf spot: remained at low levels none on upper leaves, recent conditions have not been conducive to spread of this disease.
Pollen Beetle: numbers have only got to an average of about 3 per plant in a few locations in other crops they have been very hard to find. Many crops are now coming into flower and so the period for possible damage is over. Backward crops or pigeon grazed areas may need attention if the weather returns to being warm and settled.
Sclerotinia: planning our first sclerotinia sprays for early / mid flowering.
East Midlands: Most crops starting to flower with a few with a good cover of flowers. Rest are at yellow bud but with first flowers opening. Vast majority of crops have had a growth regulator fungicide with a few having additional treatment where growth very vigorous. Most crops have now had final nitrogen as some concern as to whether spreaders can get above forward crops.
Light Leaf Spot: just odd pieces but nothing of concern yet.
Pollen Beetle: numbers have remained below threshold on the whole with only one or two crops needing a spray. With the early flowering, pressure is now off.
West Midlands: All crops now at green to yellow bud stage to early flowering. The most advance crops are starting to drop petals.
Phoma: no new infections.
Light Leaf Spot: very low levels which have not developed.
Pollen beetle: majority of crops now out of danger.
Sclerotinia: rain over the last few days has increased the risk of disease.
North East: The recent warm spell has brought a lot of crops of Excalibur and Ex-Power into flower. Cabernet and Compass are still at green to yellow bud.
Light Leaf Spot: a few lesions can be seen in crops now but the level is not causing concern.
Phoma: no further infections seen.
Pollen Beetle: crops coming into flower are no longer at risk, but above threshold numbers have been seen in a few crops still at green-yellow bud.
Sclerotinia: most crops being grown in fairly tight rotations so assume all are at high risk of infection.
Yellow rust in Oakley
South East: Most crops now responded to applied nitrogen and have grown rapidly in last few weeks of particularly mild weather - however, recent cold nights with some frost have "put the brakes on" again. Crops now range from GS 30 (late October+ sowings) to early stem extension GS 31-32 (September sowings) with Leaf 4 25% to fully emerged, and Leaf 3 just showing or up to 50-75% emerged now on main shoots of Gallant/Solstice. Even seen tip of leaf 2 emerging in one particularly strong and early drilled crop of Gallant.
Brown rust: odd pustules can be found in thicker crops and more particularly in September sown crops of Claire, Target and Solstice.
Mildew: with very little sign to date of any fresh pustules.
Yellow rust: no foci or leaf pustule stripes seen, in crops but on untreated trails Oakley has quite high levels of infection.
Septoria: most lower leaves now completely senesced due to Septoria infection.
Eyespot: quite a lot of stem based browning now appearing in many September/early October sown crops.
Weed control: spring headland and field applications for brome control mostly completed.
Eastern Counties: Crops range from 4 tillers after sugar beet to 10 tillers and some wheat at GS 32, final leaf 3 emerging. Very tall thick crops. T1 timing is upon us for the early crops.
Brown rust: present on Claire, Grafton, Hereford, and Invicta.
Yellow rust: quite a lot of rust in Oakley and Robigus, low levels in Viscount.
Mildew: the more backwards crops showing quite a lot of mildew.
Eyespot: more eyespot symptoms seen this week.
Weed control: the mild winter has given rise to more cleavers this year than usual. Good autumn control of blackgrass but some cases with resistance.
East Midlands: Forward crops at GS 31 and will be ready for T1 from 14 April onwards. Many crops between GS 30 and 31. The odd crop showing stress before rain came. Many crops have had nitrogen applied in expectation of rain. Some BYDV beginning but so far not at high levels.
Brown rust: none seen.
Yellow rust: easily found in Oakley but not much grown. Gallant, Duxford and Solstice remain clean.
Mildew: levels remain very low to non existent and seems to have dried up.
Septoria: plenty on lower leaves and T1 timing will be critical with the crops so forward. The question is how long between T1 and T2 i.e. will wheat development slow down to normal ear emergence dates or keep going at the present 2 weeks early?
Eyespot: can easily be found.
Weed control: Fumitory appears to be the crop of the moment but easily controllable.
West Midlands: Early sown Solstice is at GS 31 on the main stem and approximately 12" tall some Grafton getting towards a similar state. The recent rains have helped speed up growth and now have a lot of early sown wheat with leaf 3 fully out.
Brown rust: none seen.
Yellow rust: still only traces in Oakley and Conqueror. No new infections seen.
Mildew: levels have declined in the last week and new growth is clean.
Eyespot: some lesions in early drilled crops but not developing.
Septoria: lots of septoria in the base of many crops.
Weed control: some large cleavers and wild oats about.
North East: Most wheats at GS 31. The local clay soils have retained enough moisture for wheat crops not to be showing any drought stress despite a 26 day period with no rainfall. There have been heavy dews most nights that have helped, and a forecast significant rainfall started this afternoon 3rd. April. Most crops look fine, but some are very 'ginger' due to severe leaf tipping. This is most obvious in forward first wheats. In some of the Oakley it is partly due to the dead leaf left after the Yellow Rust has been controlled, but in others such as Invicta it is probably a result of the sharp frosts a couple of weeks ago just as the T0 fungicide was being applied.
Brown Rust: low levels seen in the most susceptible varieties, such as Duxford and Grafton but well controlled so far by the T0 fungicide.
Yellow Rust: most crops were sprayed just before a severe level of infection developed. For a few the application was a bit late and these have yellow areas visible now where there is a lot of dead leaf. This should be transitory as new leaf develops over the next couple of weeks.
Mildew: only the most resistant varieties are clean such as Warrior and Viscount. All the rest have varying levels of infection.
Eyespot: more lesions penetrating the outer leaf sheath seen this week.
Septoria: fairly high levels seen on older leaves of most forward crops, but development halted for now by T0 fungicide.
Weed control: cranesbill is the most common broad-leaved weed, and there are some severe infestations.
South East: Crops have moved quickly in response to warm conditions last week and now range in growth stage from GS30-31 with leaf 3 emerging - T1 time has arrived for Cassata and Cassia, and will be in around 10 days or so in the slower developing 6-row Volume. Any remaining N to be applied in next few days.
Brown rust: still very evident in many crops and getting active again - have seen one crop of Volume where only top 2-3 leaves are green and rest have largely senesced due to brown rust.
Eastern Counties: Forward crops at GS 31 and quite tall.
Net-blotch: at treatable levels in some varieties such as Flagon and Cassata.
Brown rust: present in Carat and Pearl.
East Midlands: Generally crops at GS 30 and about to get their first fungicide. Levels of mildew, net-blotch and Rhynchosporium all remain low in the dry conditions.
West Midlands: Quite a few crops affected by rhizoctinia barley stunt confined to the lighter patches of fields. Most are smallish areas worst is about 2 hectare patch (approximately 20% of fields have this to a greater or lesser degree).
North East: Most forward crops at GS 31. Crops look fine so far. Only low level of diseases now following early application of fungicide.