As I have predicted since July, the perfect storm has happened as far as slugs are concerned. A wet summer followed by a wet autumn, poor seed-beds and slow emerging crops are making for a challenging time.
On many farms the OSR crops have now reached the maximum amount of metaldehyde we can apply to remain within stewardship guidelines. Ferric phosphate slug pellets are proving to be very effective, it definitely does work and it is environmentally responsible.
Phoma could potentially be another issue this autumn, with most crops at the 1-2 leaf stage, they are very vulnerable. A fungicide will be used when 10% of plants show symptoms, do not to apply a PGR fungicide unless the crop is forward. It is years like this when foliar nutrients can play a real part in boasting the late crops, but we do need at least 2 leaves to apply it too. I hope the long term weather forecast is right!
Blackgrass numbers in the OSR crops are quite alarming. The OSR plants are in general between 1 and 2 leaves with this in mind our choice of products is limited to contact only. Most contact OSR graminicide products are now showing their age and new chemistry is desperately needed.
Think carefully before reducing seed rates with low TGW seed. The small seeds have a smaller food source, so vigor is likely to be reduced and potentially less plants surviving. Early foliar nutrition will be important. Phosphite products will help kick start the rooting.
Herbicide decisions on cereals are going to be made on a field by field basis. If drilling depth has been compromised, or there is a massive slug pressure then the first herbicide will be have to be early post-emergence with an insecticide. This will probably compromise the blackgrass control, but crop safety is paramount. Where we have good seed-beds and good seed depth a pre-em will be used.
I will be using 240g/ha of flufenacet as the backbone of all my blackgrass herbicide programs, and probably more with the new options available. Flupyrsulfuron-methyl (FPU) will be a useful addition in either a pre-emergence (wheat and barley) or early post-emergence position (wheat only). Providing the black grass has not emerged, the field can still be sequenced with mesosulfuron + iodosulfuron. FPU is also very active on cranes bill which does not seem to have the same dormancy issues as blackgrass!
With the inclement weather I will be a little nervous of pendimethalin, particularly in a pre-em position, though products with this active have traditionally performed well on my farms. Tri-allate, DFF and prosulfocarb will also have an important role to play as an addition to flufenacet. Most programs will be applied in 2 stages and include at least 3 active ingredients. This will help to keep fresh active on the ground with a likely prolonged emergence of the grassweeds.
Barley yellow dwarf virus is causing concern, with the vector aphid numbers even higher than last year, we must act accordingly. Destroying the green bridge is a must to prevent these harboring the virus vectors, this could effect crops drilled in the same field or neighboring fields. Clothianidin seed treatments are a wise choice this year in the fight against BYDV.