Crop Watch: Aphids thriving after prolonged wet spell

Our Crop Watch agronomists are reporting high levels of aphids in both peas and beans as a result of the wet spell, with insecticides being needed to keep them under control.

Aphid numbers are higher than average in cereals too, but still within levels that can be controlled by beneficials.

Some oilseed rape is starting to lean, but most winter barley is still standing despite plant growth regulator doses being reduced.

In the south, the rain has seen a massive resurgence in grassweeds, meaning crops are unlikely to be as clean as hoped come harvest.

David Martindale

David Martindale

North: David Martindale

Arable Alliance (Yorkshire)

The storms around the time of the Cereals event were not as severe as predicted. Some winter barley has lodged, mainly on overlaps, but the damage was thankfully minimal.

Some oilseed rape crops have been affected with a few crops starting to lean.

Winter and spring cereals look well and have good yield potential. Now all that is required is plenty of sunshine to deliver the output that is anticipated.

Many T3 fungicides were applied late due to poor weather conditions, so fusarium is likely to appear soon. Fingers crossed the levels do not become so severe as to cause a late season yield penalty.

Yellow rust pressure has kept rumbling on and has devastated leaf area where there have been any spray misses, showing just how effective the fungicides have been.

Looking at untreated variety trial plots, the various traces of yellow rust seem to be one step ahead of genetic resistance.

Looking ahead, it is good to see new fungicides coming through to add to the armoury and help replace some key active ingredients which are being lost.

Aphids

Aphid numbers are higher than average in cereals. However, with so many beneficials, it is hoped they will keep aphid numbers down rather than having to use insecticides.

However, in combining and vining peas, aphicides are being used as thresholds have been regularly exceeded. In the past week pea midge has also started to appear.

Chocolate spot in beans thrives in wet weather, so will need monitoring. Fungicide choice and timing will be important to limit the spread of this disease.

Thankfully the weather has rarely been warm enough to trigger the risk from bruchid beetle.

Maize crops really have not enjoyed the cool damp weather conditions. Their growth in this period has been very slow for the time of year.

As soon as a spell of warmer weather arrives expect their growth to go into overdrive.

Weed control looks good as pre-emergence herbicides have worked particularly well, which has allowed more flexibility with post-emergence herbicides to finish off the programme.

Plans are now being made for next season’s cropping plans. Unsurprisingly some growers are going to remove oilseed rape from the rotation while others are going to reduce the area.

It looks as though oats and beans are likely to be the most popular replacements for oilseed rape.

Tod Hunnisett

Tod Hunnisett

South: Tod Hunnisett

AICC (Sussex)

In my last Crop Watch I said we need some rain, but not too much.

Well, I don’t know what we’ve done to please the Almighty, because we’ve had enough to make a difference.

However, unlike some of our beleaguered colleagues we have managed to escape the extreme rainfall and wind that has caused immense problems in other parts of the country.

Our sympathy goes out to those affected.

With that in mind it seems slightly churlish to start complaining, but the sudden thirst quenching has brought a few problems; mainly a revitalisation of weeds we thought we’d get away without
treating.

Further, there’s been a massive resurgence of blackgrass and ryegrass germinating in the cracks in the soil.

What has looked like square miles of pristine cereals may look slightly less tidy come harvest.

Brown rust

I have been asking myself if I might have overdone wheat fungicide spend this season.

Then I went to some trials and the untreated plots showed me I need not worry. Nearly every variety, regardless of rating, had brown rust.

Septoria was very evident in susceptible varieties, as was eyespot. Chemistry definitely has its place.

The conditions have also favoured aphid populations. Peas and beans are seeing very high numbers.

What amazes (and thrills) me is the concern farmers and operators have about protecting bees and ladybirds and the lengths they are prepared to go to avoid any risk. Somebody needs to inform the  public about this.

Barley is on the turn, as is oilseed rape. The flea-beetle affected crops will need careful monitoring to get the glyphosate timing right.

It will be a fragmented harvest this year but it will be worthwhile if we want to salvage as much as we can from what looked like potential disaster.

Neil Potts

Neil Potts

West: Neil Potts

Matford Arable (Devon)

With the T3s going onto late wheats and the later spring barleys receiving their T2 applications, the season is now pretty much all over bar the shouting.

The main event since last writing is that we have received some very welcome rain.

The downside is that we have had too much and for too long. But when is anyone connected with agriculture ever happy with the weather for very long.

The weather has, however, brought delays to T3 wheat timings, T2 spring barley timings and to maize and fodder beet herbicides.

Yellow rust

Yellow rust has continued to be an unpredictable player in this season. Septoria on the whole has been well controlled, in part, due to the dry spell that preceded the rain.

The past couple of weeks have seen seed crop inspections taking place. As expected KWS Extase is looking exceptionally clean from disease, as is the unlisted Marston.

On the winter barley front, LG Flynn is looking like it might live up to expectation and give us a new two- row barley to look forward to growing.

With the rain has come cooler temperatures which have given maize crops a real shock.

They have, with few exceptions gone from looking really well to looking very stressed. The remedy: heat.

Ben Pledger

Ben Pledger

East: Ben Pledger

Farmacy (Beds/Herts)

The rain in the run-up to Cereals was welcomed by most in this area. We didn’t have as much as Lincolnshire, but the heavy rain did have me questioning whether reducing the second plant growth regulator application rates on barleys to reduce crop stress at the time of application was the right thing to have done.

Fortunately, as I write, there is virtually no lodging to be seen, apart from the odd overlap.

This story may change however with the thunderstorms which are forecast as this piece goes to press.

This lack of lodging can be put down to many factors, but two which have influenced this are: going robust early with the first PGR, coupled with the fact that with it having been so dry for so long, some nitrogen fertiliser hadn’t yet found its way into the plant.

The warm, dry spell in early February gave a good opportunity to get out and control grass weeds with iodosulfuron-methyl + mesosulfuron-methyl before they were too big to shake the chemistry off.

Tank mixes

On the whole, control was good, however the relatively early cracking of the ground this year allowed another flush of grass weeds to come in places from relatively deep in the soil profile.

Alongside these grass weeds came broad-leaved weeds as well, which had no contact with any residual chemistry laid down earlier on.

In places, this led to tank-mixing broad leaved herbicides with the flag leaf fungicide – something which is usually not necessary.

The challenges to agriculture provided by the weather always provide good experience to adapt and take forward.

Looking forward to next cropping year, I will be urging people more than usual to conserve seed bed moisture and bring forward their first spring nitrogen application.

That should guarantee a wet spring next year! May I take this opportunity to wish you a prosperous harvest.

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