Crop Watch: Heatwave leads to pest explosion

The recent heatwave has seem some crops turn, prompting speculation of a very early harvest. Marion Self says barley and rapeseed are ripening quickly and desiccation of both crops has begun, so setting the timer for harvest.

Even north of the border, Mary Munro says Scotland is heading for an early harvest.

See also: Decline in oilseed rape area forecast to halt next season

While some crops suffered, maize enjoyed the heat, with Anthony Wade reporting that it grew “inches each day” in the cover crop undersowing he is carrying out.

However, warmer temperatures also means more pests. Richard Harding reports pea moth numbers are exceeding thresholds in the South.

North: Mary Munro

Mary MunroAICC/Strutt and Parker (Perthshire)

There is always a sense of relief as June draws to a close. The final few sprays have been sorted out and a bit of roguing done to tidy up the odd wild oat.

There are a few patches of barley yellow dwarf virus showing up, but since the rain came, crops have grown away from the stress-related yellowing and spotting that was evident a month ago.

We are still on target for an early harvest north of the border.

Until then, here are a few things you can do now for next season and beyond. Top of the list is to avoid importing blackgrass through seed or machinery purchases (this is still possible in Scotland).

Perhaps buy your fertiliser below the peak price either through a group or with a deal for seasonality and challenge your agronomist to deliver value for money.

Machinery costs

Also look at your machinery costs and review the replacement policy, so if times get really tight, you are prioritising replacements correctly and get competitive quotes for overheads such as insurance and electricity.

Join a benchmarking group to discuss crop costs and glean ideas from fellow growers. Look at your succession plan and your workforce to ensure staff are being used to their full potential, and you are not drifting towards a family battle.

Look beyond the farm gate for opportunities to develop new income streams for the business or for niche markets for your products. Food and Drink Scotland is actively promoting Scottish produce – this sector is vibrant and it is vital for farmers that the links between primary producers, processors and consumers are strengthened. 

My final random thought is about labour. Manual labour has always been cheap compared with skilled labour, but are we now entering an era where this might reverse?

South: Richard Harding

Richard HardingProcam (Sussex)

Being close to the sea still didn’t provide the Downs with enough sea breezes to keep the temperature from reaching 32C in the recent heatwave.

These high temperatures are likely to shorten the grain-fill period for cereals while pulses tend to shut down physiologically whenever temperatures get into the high 20s. On the whole though winter cereals look very promising.

Oilseed rape has turned rapidly in the hot weather, with pod sealants either being applied alone or very soon as a combined application with glyphosate.

Winter barley has now turned a nice golden brown and is not at all far from harvest with recently tested grain at the cheesy ripe stage. It will just be the green tramlines that hold things up a little.

Aphid numbers are high and could be an issue in some of the spring crops, particularly black bean aphids in spring beans. Although nationally the latest AHDB aphid report is showing relatively low numbers, this is something that will be monitored closely here in the South.

Pea moths

Continuing with spring crops, pea moth numbers have now exceeded threshold levels and crops have received a late-night or early-morning application of the insecticide Hallmark (lambda cyhalothrin).

Winter beans this year have seen an excellent number of well-filled pods developing and while these crops are nearing the end of their fungicide programme, some spring beans are now receiving a T1 fungicide of cyproconazole + chlorothalonil to keep them clean as they begin pod set.

Now is the perfect time to update weed maps where control has been problematic this season. Bromes seem to have been a particular issue alongside the usual suspect – blackgrass.

As next season looms and crop planning is starting, much thought is being given to which crops will be the most profitable to grow in 2018. One option to help mitigate the variability of spring crops is to consider combining two plant specier, a technique known as bi-cropping.

A recent bi-cropping event in Suffolk showed just how many possibilities there are for this technique. One example being trialled is a crop of peas and spring oilseed rape or spring oats. It will be very interesting to see how these crops perform this harvest.

West: Antony Wade

antony wadeHillhampton Technical Services (Herefordshire/Shropshire)

When I wrote my previous Crop Watch report, I hoped for June to be a mixed bag, but the temperatures above 30C last week were not favourable for any crops apart from maize.

These crops have grown inches each day, so much so that in some of the cover crop undersowing trials I am involved in, it has been a challenge to get machinery through without damaging plants.

As demo season started, quite a few wheat plots I visited were showing rolling of leaves – a sure sign of crops shutting down in the heat. Fortunately, the heatwave was short-lived and with cooler conditions more recently, we can only hope it has not affected yields too much.

Trial plots are showing good levels of foliar disease, so it will be interesting to see whether this results in any differences between the new fungicide offerings this season.

As well as good levels of septoria, the recent hot weather has seen brown rust explode on some varieties. We have a number of tramline and split-field evaluations to assess performance to help us gain confidence in how they perform on farm.

Oilseed rape still looks as if it has good potential, although it is a difficult crop to predict yield. It was noticeable how the heat started to turn the top of crops last week. However, having looked at a few crops, not much seed colouring was found, so desiccation timing is unlikely to be before early July.

Looking over the hedge, a number of crops have a distinct lean, taking the appearance of waves on the sea. The majority of my crops are standing well. My autumn and early spring fungicide with plant growth regulator (PGR) activity seems to have worked well.

Research work I was involved in quite a few years ago showed that lodging with a compressed pod canopy can have a significant effect on yield and this has influenced my routine use of PGRs on OSR.

East: Marion Self

marion self

Prime Agriculture (Suffolk)

Barley and rapeseed are ripening quickly and desiccation of both crops has begun, so setting the timer for harvest.

The grassweed challenge continues and it is plain to see if we are winning or losing the battle. Take stock of your situation, consider which strategies are working well and what changes are required.

Last summer, blackgrass populations were very high, with relatively high seed dormancy. This year, in the main, blackgrass populations are lower.

In the autumn, large stacks of residuals were used, with less reliance on post-emergence options. Moist autumn seed-beds also enabled residuals to work better. Be mindful that control could be more difficult this autumn and consider the potential seed bank when planning your cropping and cultivation strategies. The legacy of summer 2017 could bite hard this autumn.

As the combine waits for action there is time for you to reflect. Finalise your cropping and plan your cultivation strategies. Where is remedial action and attention to detail required? For example, subsoiling, moling, ditching and encouraging blackgrass to chit. 

I like a plan – it’s good to know where you are heading. However, be prepared to make a diversion if required. Think through harvest logistics and avoid grassweed transfer by combines, balers and muck.

We are not all able to be the full geeky “CTF” types, but we can all think about reducing travel on the land at harvest and encourage good practice to trailer drivers and bale carters. 

Consider your variety choice. There are many to choose from, but this can be simplified. Decide on your market, study the form and pick varieties according to suitability for planned drilling date, first or second wheat situation and soil type.

Pay special attention to standing ability, as no one likes a wobbler. This season is a case in point; crops were stressed at the time of late-season plant growth regulator (PGR) applications, so doses were lowered and then came the rain, wind and a late release of nitrogen. Inherent standing ability has been a blessing on the stronger land.