Fruit crops move into spring growth as frost and flowering risks come into focus

Coming into April, spring is well and truly on the way, and many fruit and horticultural crops are now on the move.

Starting with apples and pears, we will soon be into bloom, which is a truly beautiful time of year. However, flowering is also when some rots can take hold, so we need to be vigilant with protection and nutrition.

Flowering also places some restrictions on what we can do to manage pests, as we want to encourage beneficial insects as part of a responsible integrated pest management (IPM) programme.

Pollinators and predators do a good job for us, so we will generally be holding off on insecticides during flowering. This can allow key pests such as pear sucker and rosy apple aphid to become established, so the timing of IPM-compatible insecticides, such as Mainman (flonicamid) and Batavia (spirotetramat), either side of flowering is crucial.

Blackcurrants, vines and, in some cases, Christmas trees should also have woken up by now, with leaves emerging and shoot extension beginning. This is the time to support them with nutrition, giving the crop the energy it needs to go on and produce well. This is especially important after the wet winter, when nitrogen leaching is likely to have been high.

## Frost risk across fruit and horticultural crops

One thing to watch across all crops is the threat of frost. Frost can kill top fruit flowers, resulting in no fruit. It can also damage young shoots and buds in vines, affect growing tips in Christmas trees, and a late frost can kill blackcurrant flowers too. I have seen extensive frost damage during my time in the industry, so it is a risk worth taking seriously.

There are some general husbandry practices that can help reduce the risk of frost damage. These include keeping grass short, keeping cropping rows bare, as bare soil can be significantly warmer than grass, and opening the orchard through pruning to allow air to flow.

It is also worth avoiding planting at the bottom of slopes, where frost pockets can form if cold air becomes trapped by a hedgerow, fence or other obstruction.

There are practical tools that can be used, including candles, air blowers and water sprinklers. I have even heard of helicopters being deployed to fly over orchards to move the air, although probably not much of that occurs in this country.

Being prepared ahead of cold nights

On top of these practices, there are a few products that may help. Sprayguard acts as a physical barrier, helping to protect the plant material underneath. ProAct uses a harpin protein to stimulate the plant’s own resilience.

Again, timing is key to the effectiveness of these applications and techniques, so the biggest piece of advice I can give growers is to keep a close eye on the weather and make sure the right tools are in the shed before they are needed.