Wheats that have received a robust and timely fungicide programme are looking clean at the moment, and should remain so, assuming that they continue to receive a fungicide application at three weekly intervals. Oakleys still demand close attention in order to stay on top of yellow rust, in some cases with the use of holding fungicide sprays between the T applications. With T1 PGR’s applied the concern, in terms of height, will be if the outlook for dry weather changes and heavy rain washes in applied nitrogen that has been unavailable to plants due to the dry conditions.
Aphids can be found in many cereal crops; consider control in spring barleys as there is potential for transmission of BYDV at this stage. Depending on crop growth and weed emergence it is time to start planning and applying broad-leaved weed herbicides. A mixture of sulphonylurea and hormone chemistry will control a wide range of weeds including thistles.
Sugar Beet crops continue to struggle with dry seedbed conditions. Unfortunately broad-leaved weeds that have been able to chit from a depth need controlling, even where full crop emergence has not been achieved. Herbicide applications are tricky when plants are still emerging, but weeds such as bindweed must be treated at or ideally before the one true-leaf stage.
The most advanced oilseed rape crops are starting to reach 50% petal drop growth stage. Sclerotinia forecasts were high this spring and although dry conditions might have had the potential to reduce the risk of infection, recent April showers are creating the moist micro-climate within canopies that is conducive to the disease developing at petal fall. Therefore crops should receive a second fungicide three weeks after their first early flower application. Seed weevil is easily found in many crops and in these cases the addition of an insecticide to the second sclerotinia fungicide will be beneficial. This helps to prevent subsequent damage by brassica pod midge, which can result in more yield loss than initial feeding damage, caused by the seed weevil. Tau-fluvalinate has the lowest toxicity to bees, but nonetheless we must bee responsible; don’t buzz around your fields in the day – remember to spray in the early morning or evening when fewer bees will be foraging.
An interesting find last week: a rat tailed maggot, commonly found in or near wet decaying areas such as muck heaps and which develops into the drone fly. It is totally harmless but still caused a stir due to its unusual appearance.