Article taken from The Fruit Grower, March 2018, written by Spence Gunn
Good light levels throughout the orchard, together with correctly targeted applications of feed and growth regulators, are three key ingredients for quality in cider apples. Tree fruit consultant Leon Jahae told growers at Agrovista's Cider Technical Seminar in Herefordshire in January that he often saw cider orchards where the trees were too shaded. ""The lower parts of the trees are not getting any sunlight," he said, ""But light is important to everything we do, if you are to get the best quality fruit.""
Low light levels are just one factor that can delay ripening or result in fruit being harvested too early, before sugar levels have reached optimum, he said. ""Heavy crop loads, seasonal weather conditions and soil-type all affect ripening. And, while it's best to time the harvest by monitoring fruit ripening using the starch test, sometimes the harvest date is based on when the contractors are available. But if you harvest too early, when starch levels are still too high, your processor won't be happy.""
As in any orchard, a north-south row alignment is best for light penetration into the tree canopy, assisted by a pruning regime to prevent the trees from getting too tall. ""Pruning also helps to accelerate ripening by controlling the fruit number," he said. ""But yield is maintained, as fruit size increases to compensate, and the fruit will have higher levels of both potassium and sugar"". Raising potassium levels, with foliar applications if concentrations in the soil are low, which they often are in Herefordshire, can also speed up ripening, said Leon. Late applications of nitrogen, either foliar or to soil, should be avoided. ""The end of July should generally be the last time for a soil application," he said.
Using the ethylene regulator Cerone, under an EAMU, can help to manage ripening and consequently the cider apple harvest. ""You do need the starch test to monitor ripening, as you shouldn't apply Cerone until starch conversion has started, but it does accelerate the process," he said. ""It can also trigger fruit drop if used at too high a rate or when the weather is too warm"". By applying to orchards in a sequence, or to some but not others, to bring them on earlier, you're not having to harvest all at once and can better plan your use of machinery, or programme the harvest with your contractor, he said.
Perry pears
Perry pears are not only much more sensitive to light levels than cider apples, they are also generally more demanding to grow, said Leon Jahae.
One reason is, like pears generally, that they flower early so are at greater risk from frost; and most varieties bloom when the small rosette leaves present at blossom time can barely support the demands of the developing flower. ""So, although pollination can be good, the subsequent fruit-set is a problem," he said. Poor fruit-set can be mitigated by using a programme of foliar feeds, starting early, to support the development of the rosette leaves. ""Correctly timed applications of macro and micronutrients will get the leaves as big as possible as quickly as possible, and so reduce early drop [of fruitlets] in June," he said.
Growth regulator applications can also help. Giberellin can improve fruit-set and, once the rosette leaves are big enough to take it up, Regalis Plus can reduce early drop by inhibiting the tree's ethylene production.
While light distribution is even more critical for pears than for apples, Leon said that growers could benefit from planting new perry orchards at slightly higher densities than is traditional. ""When planting, most perry pear growers establish a low-density orchard, but that means that it takes several years for the tree to fill its space," he pointed out. ""During that time fruit production will be very limited, as you're pushing the tree to fill out. Then you will suddenly want to convert the tree from being a wood producer to a fruit producer and that is challenging - it won't be producing many flower buds, for example.""
Trees tend to be bigger in low density orchards, which, in turn, impacts on light distribution within the canopy.
At a slightly higher density, by which Leon meant only around 1,400 - 1,500 trees/ha, fruit production after six to seven years would be similar to that of a low-density planting.
However, unless carefully managed, production in the lowdensity orchard will migrate to the edges of the canopy because of shading, so a large volume of potential yield is being lost. ""Any pruning you then do to correct the imbalance also has to be done very carefully, or it can make the tree more imbalanced," he said.
Increasing the planting density obviously entails a greater initial cost, but the trees should fill their space sooner and so come into production earlier, and more consistently, in years three or four, he said. ""With smaller trees it's also easier to manage light distribution. After 10 years you could have double or treble the cumulative production that you'd have had from a low-density orchard.""
Leon added that his first choice for a rootstock for such an orchard would be Eline, a relatively new Romanian quince variety that is not only very precocious and hardy, but compatible with all pears, eliminating the need for an interstock.
Safeguards against resistance
It's more important than ever for cider apple growers to follow scab and mildew spray programmes that minimise the risk of the pathogens developing fungicide resistance, said Agrovista's head of fruit agronomy, Paul Bennett.
""We have lost some products recently, and although we have also gained one or two, we need to be careful about resistance-management to make sure their effectiveness lasts as long as possible," he said. ""Remember, those acting on more than one aspect of the pathogen's metabolism, or products that are a mixture of actives from different resistance groups, are less prone to resistance issues. Captan, which has been used for years and is often applied several times in succession, acts in many differing ways on scab, and that's why you don't see resistance to it. Fontelis, one of the newer ones, is good against both mildew and scab, but only has a single mode of action.
""Nimrod used to be regarded as an effective mildew control and remains the only available anti-sporulant. But, because its dose rate has been reduced so much over the years, it's no longer as effective, though still useful for its anti-sporulant action if mixed with another product. Scala is the only really effective curative product against scab, so should only be applied with a protectant. There has been a definite shift in sensitivity [of the pathogen] to it in Europe, so it's very important not to overuse it. Indeed, it now has a limit of four applications per year, rather than the previous five.""
Paul Bennett presented a 'template' scab and mildew programme using products in different resistance groups, timed when they would each be most effective, while keeping within the maximum number of applications allowed on the labels and without breaking any guidance over back-to-back applications of products with the same mode of action. Disease risk models, such as those used by Agrovista's Growers Choice Interactive service, will time applications accurately, he said.
The programme starts with Syllit 400 SC at green tip for scab, a good choice for early sprays, he said, because it works well at low temperatures. Subsequent applications will depend on how quickly temperatures rise, but if they remain low, a second spray can be made at mouse-ear as this backto-back application is permitted. With warmer weather at early green cluster, Delan Pro will now control scab better than Syllit. Primary mildew is likely to become active at green cluster, so Paul suggests Cosine as the first mildew spray, alongside a second application of Delan Pro for scab. ""By pink-bud, the mildew risk is really getting going, and the results we had in trials in 2017 show Talius to be a good choice here, with Syllit again for scab, as this would be your last opportunity to apply it.""
At early bloom, a combination of Bellis and Sercadis serves several purposes: ""Sercadis gives excellent control of both mildew and scab, while Bellis will include some protection against blossom rot as well as giving a boost to scab control. Sercadis can only be applieq alongside a non-SOHi product, so the pyraclostrobin component of Bellis enables that.""
Mildew will still be a risk at petal fall in May, so Paul suggests applying the second spray of Cosine that is permitted; while Delan Pro, as a multisite product, can continue being used for scab. Once extension growth gets going, the mildew risk increases, so Talius is a good option, with Delan Pro again for scab, he said. The programme then sees scab and mildew products applied at weekly intervals. ""Fontelis with Captan controls both and that gives you your first application of each of these, followed by Sercadis with Delan Pro," he said. Topenco and Stroby for mildew are then alternated until the end of extension growth, while the final sprays of Captan and Delan Pro against scab can be made in June.
Agrovista agronomist David Taylor reminded growers of the importance of adjuvants. ""Agrovista's Velocity, for example, is designed for use with fungicides, giving better distribution on leaves and improved uptake, enhancing scab control in particular," he said. ""Don't forget the importance of water quality in spraying and use a water conditioner in hard water to aid uptake by leaves and prevent alkaline degradation of products such as Captan.""
Good light levels throughout the orchard, together with correctly targeted applications of feed and growth regulators, are three key ingredients for quality in cider apples. Tree fruit consultant Leon Jahae told growers at Agrovista's Cider Technical Seminar in Herefordshire in January that he often saw cider orchards where the trees were too shaded. ""The lower parts of the trees are not getting any sunlight," he said, ""But light is important to everything we do, if you are to get the best quality fruit.""
Low light levels are just one factor that can delay ripening or result in fruit being harvested too early, before sugar levels have reached optimum, he said. ""Heavy crop loads, seasonal weather conditions and soil-type all affect ripening. And, while it's best to time the harvest by monitoring fruit ripening using the starch test, sometimes the harvest date is based on when the contractors are available. But if you harvest too early, when starch levels are still too high, your processor won't be happy.""
As in any orchard, a north-south row alignment is best for light penetration into the tree canopy, assisted by a pruning regime to prevent the trees from getting too tall. ""Pruning also helps to accelerate ripening by controlling the fruit number," he said. ""But yield is maintained, as fruit size increases to compensate, and the fruit will have higher levels of both potassium and sugar"". Raising potassium levels, with foliar applications if concentrations in the soil are low, which they often are in Herefordshire, can also speed up ripening, said Leon. Late applications of nitrogen, either foliar or to soil, should be avoided. ""The end of July should generally be the last time for a soil application," he said.
Using the ethylene regulator Cerone, under an EAMU, can help to manage ripening and consequently the cider apple harvest. ""You do need the starch test to monitor ripening, as you shouldn't apply Cerone until starch conversion has started, but it does accelerate the process," he said. ""It can also trigger fruit drop if used at too high a rate or when the weather is too warm"". By applying to orchards in a sequence, or to some but not others, to bring them on earlier, you're not having to harvest all at once and can better plan your use of machinery, or programme the harvest with your contractor, he said.
Perry pears
Perry pears are not only much more sensitive to light levels than cider apples, they are also generally more demanding to grow, said Leon Jahae.
One reason is, like pears generally, that they flower early so are at greater risk from frost; and most varieties bloom when the small rosette leaves present at blossom time can barely support the demands of the developing flower. ""So, although pollination can be good, the subsequent fruit-set is a problem," he said. Poor fruit-set can be mitigated by using a programme of foliar feeds, starting early, to support the development of the rosette leaves. ""Correctly timed applications of macro and micronutrients will get the leaves as big as possible as quickly as possible, and so reduce early drop [of fruitlets] in June," he said.
Growth regulator applications can also help. Giberellin can improve fruit-set and, once the rosette leaves are big enough to take it up, Regalis Plus can reduce early drop by inhibiting the tree's ethylene production.
While light distribution is even more critical for pears than for apples, Leon said that growers could benefit from planting new perry orchards at slightly higher densities than is traditional. ""When planting, most perry pear growers establish a low-density orchard, but that means that it takes several years for the tree to fill its space," he pointed out. ""During that time fruit production will be very limited, as you're pushing the tree to fill out. Then you will suddenly want to convert the tree from being a wood producer to a fruit producer and that is challenging - it won't be producing many flower buds, for example.""
Trees tend to be bigger in low density orchards, which, in turn, impacts on light distribution within the canopy.
At a slightly higher density, by which Leon meant only around 1,400 - 1,500 trees/ha, fruit production after six to seven years would be similar to that of a low-density planting.
However, unless carefully managed, production in the lowdensity orchard will migrate to the edges of the canopy because of shading, so a large volume of potential yield is being lost. ""Any pruning you then do to correct the imbalance also has to be done very carefully, or it can make the tree more imbalanced," he said.
Increasing the planting density obviously entails a greater initial cost, but the trees should fill their space sooner and so come into production earlier, and more consistently, in years three or four, he said. ""With smaller trees it's also easier to manage light distribution. After 10 years you could have double or treble the cumulative production that you'd have had from a low-density orchard.""
Leon added that his first choice for a rootstock for such an orchard would be Eline, a relatively new Romanian quince variety that is not only very precocious and hardy, but compatible with all pears, eliminating the need for an interstock.
Safeguards against resistance
It's more important than ever for cider apple growers to follow scab and mildew spray programmes that minimise the risk of the pathogens developing fungicide resistance, said Agrovista's head of fruit agronomy, Paul Bennett.
""We have lost some products recently, and although we have also gained one or two, we need to be careful about resistance-management to make sure their effectiveness lasts as long as possible," he said. ""Remember, those acting on more than one aspect of the pathogen's metabolism, or products that are a mixture of actives from different resistance groups, are less prone to resistance issues. Captan, which has been used for years and is often applied several times in succession, acts in many differing ways on scab, and that's why you don't see resistance to it. Fontelis, one of the newer ones, is good against both mildew and scab, but only has a single mode of action.
""Nimrod used to be regarded as an effective mildew control and remains the only available anti-sporulant. But, because its dose rate has been reduced so much over the years, it's no longer as effective, though still useful for its anti-sporulant action if mixed with another product. Scala is the only really effective curative product against scab, so should only be applied with a protectant. There has been a definite shift in sensitivity [of the pathogen] to it in Europe, so it's very important not to overuse it. Indeed, it now has a limit of four applications per year, rather than the previous five.""
Paul Bennett presented a 'template' scab and mildew programme using products in different resistance groups, timed when they would each be most effective, while keeping within the maximum number of applications allowed on the labels and without breaking any guidance over back-to-back applications of products with the same mode of action. Disease risk models, such as those used by Agrovista's Growers Choice Interactive service, will time applications accurately, he said.
The programme starts with Syllit 400 SC at green tip for scab, a good choice for early sprays, he said, because it works well at low temperatures. Subsequent applications will depend on how quickly temperatures rise, but if they remain low, a second spray can be made at mouse-ear as this backto-back application is permitted. With warmer weather at early green cluster, Delan Pro will now control scab better than Syllit. Primary mildew is likely to become active at green cluster, so Paul suggests Cosine as the first mildew spray, alongside a second application of Delan Pro for scab. ""By pink-bud, the mildew risk is really getting going, and the results we had in trials in 2017 show Talius to be a good choice here, with Syllit again for scab, as this would be your last opportunity to apply it.""
At early bloom, a combination of Bellis and Sercadis serves several purposes: ""Sercadis gives excellent control of both mildew and scab, while Bellis will include some protection against blossom rot as well as giving a boost to scab control. Sercadis can only be applieq alongside a non-SOHi product, so the pyraclostrobin component of Bellis enables that.""
Mildew will still be a risk at petal fall in May, so Paul suggests applying the second spray of Cosine that is permitted; while Delan Pro, as a multisite product, can continue being used for scab. Once extension growth gets going, the mildew risk increases, so Talius is a good option, with Delan Pro again for scab, he said. The programme then sees scab and mildew products applied at weekly intervals. ""Fontelis with Captan controls both and that gives you your first application of each of these, followed by Sercadis with Delan Pro," he said. Topenco and Stroby for mildew are then alternated until the end of extension growth, while the final sprays of Captan and Delan Pro against scab can be made in June.
Agrovista agronomist David Taylor reminded growers of the importance of adjuvants. ""Agrovista's Velocity, for example, is designed for use with fungicides, giving better distribution on leaves and improved uptake, enhancing scab control in particular," he said. ""Don't forget the importance of water quality in spraying and use a water conditioner in hard water to aid uptake by leaves and prevent alkaline degradation of products such as Captan.""