Recently by Ruth East

Combing peas have received their second fungicide, which included an aphicide plus pyrethroid for pea moth. A second dose of manganese was included for the prevention of marsh spot. Spring beans have, or will be having, their second fungicide, which will include an insecticide for bruchid beetle if required. Vining peas are being monitored for pea midge.

Orange blossom midge did not materialise, even so, there were some prophylactic treatments applied in this area. Pheromone traps were catching large numbers of male midge, but this should not to be used as a threshold to spray, as they are not an indication of what is happening in the crop. They just show that the midge have emerged. It was an interesting result as the yellow sticky traps caught very few female midge. Hopefully HGCA will fund some more research on the use of pheromone traps.

Blackgrass strategies for the season are under review. I  think it is a useful exercise to have blackgrass seed tested for resistance, as once again it is a guide to what is happening in field. Not all poor control may be put down to resistance - a lot may be due to areas of poor crop growth due to  waterlogging caused by compaction or poor nutrient status of the soil.

Excessive temperatures over the weekend, caused flag leaves to emerge at a rapid rate. Hopefully, all flag leaf sprays will have been applied by now, even though the time interval between the T1 and T2 has been short. With soil temperatures rising, and the threat of rain to moisten soils, the next problem to encounter will be the dreaded orange blossom midge.

Where crops are approaching GS52 and are not resistant to orange blossom midge, pheromone traps have been placed in  fields. I actually think the work done by the scientists at Rothamsted to produce these traps is a great piece of scientific research, For those who do not want to go to the expense of pheromone traps, then the yellow sticky traps which can be acquired at garden centres offer another method of monitoring what is happening in the crop, so that  any unnecessary applications of insecticides need not occur.

Uneven flowering crops of rape will receive another fungicide against sclerotinia, as it was these crops which were hit by a late germination of sclerotinia in 2008. Where a triazole has been used previously,  then iprodione + thiophanate-methyl will be used, in accordance with Fungicide Resistance Action Group guidelines.

What a relief to have some rain and some warmer nights last week. Early-drilled wheat crops will have received their T1 spray, and the applications for the later drilled taking place. The threat of yellow rust has declined as whether conditions have not been favourable for its development. The most susceptible varieties received a T0 fungicide.

The biggest threat is septoria, where inoculum level at the bottom of the crop is high - do not be tempted to reduce rates of triazoles, thinking that disease levels are low, as this is the most difficult disease to control, due to triazole resistance. You can not play catch up with septoria. Yellow rust can be found in the spring wheat AC Barrie, which is quite disturbing, so a triazole has been added to the T0 fungicide.

Frost damage to oilseed rape flowers can be found.  Hopefully, the plants will be able to compensate. All sorts of nutritional disorders are showing up due to crops going through rapid stem extension and not being able to take enough nutrients up.  Cold growing conditions are not helping either. Split stems can be found which is caused by rapid growth and not being able to take up enough nutrients, especially boron.

They say when March comes in like a lamb it goes out like a lion and that is exactly what has happened, The middle of March saw air and soil temperatures move into double figures during the day to which winter crops responded to early applied nitrogen by greening up.

Rape crops which had lost their outer leaves now looking respectable. The spring vigour of hybrids varieties is really noticeable as they have flower buds showing above the canopy. These will be treated with a fungicide with a growth regulatory effects , plus a trace element mix containing boron. At present there is little evidence of light leaf spot. My airing cupboard is resembling a growth cabinet , with many samples of oilseed rape plants in plastic bags  in order to try and incubate the disease, at present no symptoms have been exhibited. Grassweed control has proved to be very effective, especially with the later applications of propyzamide and carbetamide. Unfortunately I will have to eat my words as I thought that the autumn applied Atlantis had worked well, however blackgrass plants that looked totally dead six  weeks ago, are beginning to show signs of recovery as small new roots are appearing and new leaves are just emerging.

In the previous Crop watch report I commented how well the crops had come out of the winter, however most of them had been insulated with a cover of snow,protecting them from  freezing temperatures.

Febuary has seen a mean temperature of 2.4 degrees,  with a maximum of 7.3 and lowest of -2.6 degrees, March so far has fared no better. Soil temperatures  got to heady heights of 4.4, but have soon dipped to 3.3and below Winter rape crops with large canopies have lost their  outer leaves,  the nitrogen will have been dissapaited to new growth.

In crops with large canopies I have found evidence of stem cracking, which is associated with frost damege. This pheneomen appeared a few years ago when the term wind chill factor entered our vocabulary. Having done some reaseach ,  I have found a scientific paper that  suggests that large canopied rape is more susceptible to damage from low temperatues and increasing day length.

Snow in January covered crops,  and allowed management plans to be completed. Now the snow has gone and crops are  visible. 

Last week saw an opportunity for the last few outstanding propyzamide and carbetamide applications on oilseed rape to take place. Rape crops appear to have come through the winter so far unscathed, but it is early days and it will be interesting to see if the extremely low temperatures will have effected some of the large canopy crops internally.

Residual herbicides applied to rape prior to Christmas appear to be working extremely well. The hard frosts seem to have taken care of any charlock,  hopefully removing the need to use Fox (Bifenox) . The root structure on most crops I have looked at look are good. Crops  going into winter with large canopies, will allow us to use lower rates of nitrogen, and this may be the first year when fungicides with growth regulator effects will be used on a larger percentages of the crop.

With soil temperatures falling, rainfall due and lower day and night temperatures, application of propyzamide or carbetamide is now taking place. To enhance the activity of both products for blackgrass control a graminicide is also being be added.

Remember  that if a fop i.e  Fusilade Max had be used earlier in the season, then a dim  based product i.e Laser should be used, and vice versa. Also remember that the cut off point for Aramo (tepraloxydim) is end of November or if crop has nine true leaves, which most crops will have by now.

Where canopies are too thick then we will have to wait for some hard frosts or flocks of pigeons to open up to the canopies so that residuals may be applied to the soil surface. These products should not be applied in the rain or if heavy rainfall is immanent, as it goes against the VI guide lines. If we loose these products it will be the end of rape growing on most farms.

Cabbage stem flea beetle larvae can be found in the petioles of outer leaves of some plants, even though treated with the new seed treatments. This is due to the extended and irregular egg laying period caused by the warm, dry autumn. Most crops are large and dense enough not to warrant treatment. Any poorly developed crops should be monitored to see if the level of infestation warrants treatment.
 
Blackgrass control in cereals looks interesting. Where crops were treated at peri-emergence the blackgrass is exhibiting symptoms of death. Of all the pre-emergence treatments, Avadex (triallate) appears to be the most consistent. With no or very little blackgrass coming through, there has been very little pressure on Atlantis this autumn.

Growers who had the patience to wait for rain before attempting to drill into dry cloddy seed beds were rewarded with 20mm of rain on 6 October.

These winter cereal crops were drilled into ideal seed-beds and with warm soil temperatures and moisture, it has not taken them long to emerge. All crops drilled at this time have been treated with a pre-emergence herbicide, based around flufenacet.

Where blackgrass resistance is known, programmes have started with tri-allate as the base, followed by flufenacet mixtures. Where the variety is not sensitive, chlorotoluron has been added.

Winter cereal crops drilled before the rain, and where moisture was not retained, are at various degrees of emergence making herbicide decisions quite interesting.

The 22.6mm of rain we had at the beginning of September has completely disappeared, and some of the later emerging oilseed rape on heavy land looks in need of a drink. However I will not tempt fate by saying we need some.

Where rape has been established in the conventional way it has all been treated pre-emergence with the first dose of herbicide. My preferred product choice has been Shadow or Katamaran Turbo (dimethanamid-P + metazachlor + quinmerac), as it worked exceptionally well last year.

Rape crops established via the sub-soiler technique that are at the fully expanded cotyledon stage are about to be treated post-emergence in mix with a graminicide. Product choice depends on whether blackgrass is present.

With such dry conditions, there is very little evidence of slug activity. Where headlands have been treated I have recommended ferrous phosphate based products.

Oilseed rape crops on light land are rapidly approaching the correct stage for glyphosate application. Those on better bodied soils are hanging on and will probably be at the right stage for desiccation in five to seven days time depending on the whether.

I try and go as late as I can as we've found this keeps the oil content up.

While examining crops it's been evident that there is very little sclerotinia infection. I'm looking out for signs verticillium wilt which looks like being the next big disease problem to hit the crop.

There is very little damage from seed weevil or bladder pod midge, which makes it very gratifying that the right decision was made not to include an insecticide with the mid-flowering spray.