Article taken from Agronomist & Arable magazine
The value of using advanced pest and disease prediction software in top fruit orchards has been clearly illustrated in a tricky season, says Agrovista agronomist Alex Radu
An unusual year weather-wise, 2015 provided a fresh challenge for Growers Choice Interactive (GCI), Agrovista's cloud-based pest and disease forecasting service for UK top fruit growers. The program has been providing growers with exceptionally reliable scab and codling moth forecasting for several years. GCI uses software that combines real-time weather data collected across key fruit-growing areas with information on life cycles of diseases or pests stored in the program, calculating the likely hood of attack. The program also provides a 10-day projection of all the models. More recently, additional modules, including canker and fireblight, have been included and increasing numbers of growers are now relying on the service to help to keep crops clean and free from damage to maximise yield and class 1 pick. Differing weather patterns influence the life cycles of pest and diseases, so each season provides new challenges for GCI. In 2014, it continued to provide growers with reliable advanced warnings of attacks from scab and illustrated the evolution of codling moth activity. The canker model was introduced towards the end of the season. So how did GCI fare in 2015? The year saw several tweaks to the program to make it more robust, and the new fireblight model was introduced in April. ""The service delivered all that was expected of it, despite some very different weather," says Agrovista fruit agronomist Alex Radu. ""In 2015 we had a benign and quiet winter —unlike the stormy, wet 2014. Temperatures and rainfall were similar to historical averages, but the spring was drier in the South. Some long, dry spells were noted, but a number of important rain events also occurred. The summer was relatively sunny, but cool, with some spells of rain in August. The start of autumn was dry, but November was unsettled and stormy."" The scab model proved its worth in orchards across the UK. At one site at Old Wives Lees, near Canterbury in Kent, it picked up several significant rain events during the season that triggered ascospore releases (see graph). Due to suitable weather conditions at the time, five of these — one in early April and four in May triggered infection events that required treatment. However, data recorded at Wisbech in Cambridgeshire revealed a completely different picture, says Mr Radu. ""Although again we saw a number of wet spells, only two turned out to be major events during the season — one in early April and the second about five weeks later.""
At Tillington in Herefordshire, there were a number of rain events followed by three major infections during the first half of May. ""Depending on the region, the station and the farm, the situation can vary quite dramatically. GCI helps growers see when orchards get a significant infection event and the necessity of applying a curative treatment, and helps ensure it is timed to provide the best efficacy. Growers using the Premium GCI account can also access information on residual cover and curative kick-back for eradicants.""
APPLIED ONLY WHEN NEEDED
The service also ensures that sprays are only applied when they are needed, offering potential significant savings in crop protection and labour costs, says Mr Radu. The codling moth module also performed faultlessly, picking up female moth flights, egg laying and larval hatch as they occurred. ""At Old Wives Lees, flights of mated females started at the start of June, with most egg laying occurring in the second half of June and the start of July," says Mr Radu. ""Larval hatch started towards the end of June. This provided an accurate timing for spraying, which should take place just before larval hatch and before the bulk of eggs are laid," he adds. Some stations provided warning of a partial second-generation hatch. The Old Wives Lees site revealed a couple of days of egg laying at the end of August, while others in the county indicated a significant larval hatch towards the
end of August and into September. ""This was significant as the second generation can cause significant damage to stored apples," says Mr Radu. The new canker model was a success. From the second half of August through September and November there were lots of infections in Kent, and several were quite significant, he recalls. ""GCI recorded four important events at Old Wives Lees, two during leaf fall when the threat of infection is at its highest."" Fungicides need to be applied before infection, so this sort of advanced warning is critical for effective control where leaf wound levels are significant and the trend is rising. ""It is really important to time your sprays according to the GCI model," says Mr Radu. The new fireblight model recorded no conditions conducive for development in its first commercial season across the UK. GCI has again proved to be a valuable ally in helping growers to assess the need for sprays and when to apply them, says Mr Radu. ""It has simplified management while targeting pesticide applications for better efficacy, and also has the potential to reduce applications, minimising residues and reducing spray costs."" Apple sawfly is the next pest to feature in tilt GCI programme. A module to help grower predict attack is planned for the spring, showing the activity of egg-laying females, egg deposition, the development of eggs, likely infection levels and the optimum time for insecticide application.