Cultural and natural pest control methods have been the focus of recent Maize Growers Association trials in preparation for possible seed treatment losses. Results were presented at the recent MGA conference.
Eyespot in maize is becoming more widespread, bringing with the potential for large yield losses.
Grainseed technical director Neil Groom, said: “It tends to be regional but is becoming more widespread. Its development is favoured by cool, wet conditions of less than 30 deg C. The East doesn’t get as much as development is halted if temperatures rise higher than 30 deg C.
All maize varieties are susceptible to eyespot, however, there is quite a range in tolerance from Emmerson, the least tolerant at 2.6, to Es Marco, the most, at 7.1 on the BSPB Descriptive List 2018.
MGA carried out trials on member, Simon Davies’ farm near Carmarthen in South Wales. Fungicides were applied on July 20 when the crop was 1.8m (6ft) just before tassel to an early variety with a high eyespot tolerance rating.
Three fungicide treatments were applied – Quilt (azoxystrobin + propiconazole), Comet (pyraclostrobin) and Opera (epoxiconazole + pyraclostrobin). “At full rate all were giving good control and reducing eyespot. At a reduced rate, we were seeing a little more eyespot. All fungicides protected green leaf area, allowing maize to mature better.”
Comet at 1l/ha and Opera at 1.5l/ha performed best in the 2017 season, said Mr Groom. The yield of the Comet-treated maize was 45.6t/ha (18.4t/acre) and Opera-treated maize, 46.7t/ha (18.9t/acre). Untreated yield was 40t/ha (16.2t/acre). Harvest took place on October 5.
With maize seed treatments Sonido (thiacloprid) and Mesurol (methiocarb) under possible threat of losing their authorisations next year (2019), growers need to consider alternative ways to control pests including wireworm, frit fly, leatherjacket and birds.
Later drilling in early May and fast emergence helps avoid wireworm damage, said Simon Draper of Indagronomy. “Also roll it tight. Wireworm larvae are unable to move more than a few centimetres so germinating maize seed needs to be very close to larvae for there to be a problem. Rolling tight decreases larvae movement.
“For frit fly, if you can get the crop up to more than 4-leaf by mid-May, then it is normally reasonably safe. For leatherjackets the crop needs to emerge as early as possible but then grow away as it is susceptible until the 6-leaf stage. Drilling early and then not germinating may be fatal for the crop if leatherjackets are around.”
Deeper sowing can help to control rook damage, he said. “We can learn from organic growers. Sow a minimum of 10cm deep. Drill later to get fast emergence and use higher seed rates; slow drilling helps avoid seed being left on the surface.”
MGA trialled novel seed dressings as bird deterrents in the 2017 season, measuring the percentage maize remaining from 1-7 days after treatment. “Coffee granules had nearly the same effect as Mesurol and Sonido,” said Mr Draper.
In the trial there was 91 per cent of maize left after seven days with the coffee granule treatment compared with 99 per cent where thiram + Mesurol were used and 97 per cent for thiram + Sonido. With pepper there was 65 per cent left and chocolate powder, 61 per cent.
AD company Future Biogas, which operates nine AD plants and provides a feedstock service on a further two, is carrying out a number of trials on alternative crops this season.
It is establishing what it says is the only commercial crop of sylphium cup plants in the UK - a perennial crop - for AD.
Innes McEwen, head of farming at Future Biogas said: “We are comparing gas yields from szarvasi grass, cup plants and wildflower mixes. We are also working with the Norfolk Broads Authority to establish the viability of harvesting reeds for use in AD.”
While maize remains a key crop for Future Biogas, it is also trialling whole-crop barley this season.