So it is now official, last month was the wettest April for 100 years. Geoffrey Chaucer had it spot on when he said that April with its sweet showers has pierced the drought of March to the root.
Sprayers have been in and out of the pit lane like a Formula One team and one or two are wondering whether they should switch back from row-crops to proper wet weather flotation tyres.
We are doing our best to make the most of all spraying opportunities by storing the maximum amount of water – in many cases rain water from roofs – and ensuring chemicals are laid out ready. This means we can maximise the time spent in the field spraying. Where possible we are using a bowser to ferry water and packs of chemicals to the sprayer to reduce downtime.
A large proportion of the rape has been treated for sclerotinia between the showers. After starting early, flowering has dragged on slowly and many crops will require a two spray programme.
I have been surprised at the number of seed weevils in the crops despite the cool conditions. At the moment the rape is still standing, although in exposed areas the outside plants which catch the wind are leaning a little. Continuing wet weather and soil softening in the rooting zone will be a real test of a variety’s standing power, particularly when plants become more top heavy.
No doubt there will now be a surge of growth as crops pick up nitrogen from the wet soil. I would not be surprised to see certain varieties’ resistance to lodging ratings reduced in the HGCA listings this season. Wet weather also brings a real threat of alternaria so we will ensure that any second sprays are active on this disease.
In wheat our major concern is Septoria. Rain splash events have been frequent and unprotected crops are greatly at risk. Where T1 treatments have not been applied we are ensuring that triazole doses are at least 75% of either epoxiconazole or prothioconazole. In some cases leaf two is emerged with the tip of the flag just visible. We will still target GS39 (flag fully emerged) with our SDHI/triazole formulations even if the gap is only a week or so. If part of leaf three has been lost to septoria we can ill afford to sacrifice any of leaf one.
I am often asked how spraying jobs should be prioritised in current conditions. There is no easy answer given that sclerotinia treatments are protectant only, whereas we have a bit of kickback to work with in wheat.
Because of this I am tending to favour the rape, especially as nearly all the wheat has had an earlier T0 treatment. Barley T2s are waiting in the wings, although if the crop had an adequate dose of a strong SDHI/triazole at T1 this is still likely to be giving good protection and it is usually the barley which generates the biggest response.
That leaves the vexed question of growth regulation. As long as stocks are in store, ethepon-containing products are the most effective late season. If only a limited quantity is available think carefully about where it goes, prioritising high potential crops and areas of structurally weak, light soils where top heavy plants can cause root cone rocking and early lodging.
I wonder what the situation will be in three weeks when I write again – fire or water?