Scotland produces some of the highest yielding and best quality crops in the world because of its long summer day lengths and plentiful rain. While we don't know what kind of summer we are in for, it seems that this year we are heading for a late spring. Winter crops do not generally start to grow until soils reach 5 degrees C upwards, and soil in most areas of Scotland have still to warm up to that level.

It's the same for livestock farmers who are watching their supplies of silage dwindle and anxiously waiting for grass to start growing again. T-sum 200 - a measure which indicates when soils have warmed sufficiently for grass growth to begin - will be two-to-three weeks later than normal.

Heavy snow and frosts may have been a considerable inconvenience for many, but the colder winter has done more good than harm in our crops. Scotland's wet summers bring crop challenges in terms of pests, diseases and weeds that can dramatically cut yields, but this winter's frosts have reduced pests and fungal disease.

Overwintering disease levels aren't high this year and cold snaps have helped reduce any disease already in cereal crops. While that will reduce the need for sprays, arable farmers will still have to carefully monitor their crops to calculate the optimum time to spray. Walking crops and checking accurate growth stages is really important in targeting sprays.

Barley is Scotland's main arable crop followed by wheat and oilseed rape. In barley, yield is driven by the number of tillers that survive before the crop starts to extend away in the spring - so sprays aimed at the start of stem extension (called T1 - as in timing 1) are important in retaining as many tillers as possible to create the maximum number of potential grain sites to fill at the end of the season. These need to fill as well as possible, so second sprays targeted just before ear emergence (T2) will protect the plants from disease and early leaf death which would result in lots of tiny grains instead of the big, bold ones that are needed for quality markets like malting.

In wheat, sprays need to be targeted at the leaves that go to building yield, as yield is strongly driven by keeping as much green leaf going for as long as possible.

With oilseed rape, pests are a real issue and protecting the plants from early damage by slugs, aphids and flea beetles, as well as the flowers and seeds from pollen beetles and seed weevils is key.

A growing problem for arable farmers is increasing resistance to fungicide sprays. As with the development of superbugs in hospitals, fungal pathogens are adept at evolving resistance to fungicides. There have been a lot of shifts in efficacy recently that farmers should factor into their spray plans.

For instance, there have been small shifts in efficacy in foliar diseases of barley, like Rhynchosporium and net blotch, so using balanced mixtures of fungicides is key both to protect the crop and make it hard for resistant pathogens. Using mixtures helps to protect the fungicides against further resistance developments. Arable farmers are now having to seriously address the issue of resistance to sprays.

It's not just farmers who have to regularly check their crops for pests and diseases. Foresters need to keep a careful eye on their trees. The UK's elm, larch and ash trees have all been devastated by imported pests and diseases, and there are many more which threaten both timber businesses and native wildlife.

The problem is now so serious that Confor, the organisation that represents the interests of foresters, has called for the imports of high-risk plants and firewood to be brought to an end within five years, to safeguard the health of UK forests.

One of the threats comes from imported plants in soil-filled pots, widely used by gardeners and landscapers. These enter the country with few checks or regulations and pose serious risks of containing invasive beetles, fungi, bacteria or other pathogens.

Another challenge is the 3,000 tonnes of firewood imported into the UK every month. This can be done safely if the bark is removed and the wood fully dried. However, in a sample of consignments inspected last year, more than a quarter did not meet the required standards.

According to Confor, phasing out firewood imports will have wider benefits for the health of the UK's native broadleaf woodlands, as well as protecting them from disease. A scheme to bring woodlands into management for firewood would supply this product from home-grown sources.