The positive side of spring being suspended for a couple of weeks is that on more forward oilseed rape crops we can hold off the first spray until stem extension, scheduled for the next window in the weather. This saves a pass through compared to last year.
With temperatures so low, I can’t justify pre-T0 spraying on winter wheats. It’s too cold for plant growth regulators to have much activity, disease has been checked by the frosts and grain markets make recreational spraying foolhardy.
A well-timed and robust T0 will address septoria, rusts and eyespot. Bear in mind that T1 and T2 products tend to be partnered with epoxiconazole or prothioconazole, so a sound T0 management strategy would be to use alternative triazoles, mixed with a multisite (for example, chlorothalonil), and in varieties susceptible to eyespot, such as Crusoe, prochloraz. After the wet and warm winter, eyespot is more visible compared to recent years.
Though the most forward wheats will have leaf 4 emerged by this weekend, most won’t be ready for T0 for a good 10 days yet. Going early and leaving too big a gap to T1 is very risky – better to be patient.
Drying soils allowed first fertiliser splits to be applied and with a bit of warmth forecast, this will get both crops and weeds moving, so any herbicides still to be applied are a priority.
Overwintered aphid numbers are high, I cannot recall previously seeing winged grain aphid moving in January and February, and correspondingly risk of barley yellow dwarf virus is significant. Spring cereals will need an aphicide when they emerge.
Finally, continuing the effort to be positive about the weather, last week’s rain did a good job of suppressing any complaints about the perfume of muck applied ahead of the showers.