Supporting decisions about botrytis management

1. Supporting decisions about botrytis management Kathy Evans Tas. Institute of Agricultural Research University of Tasmania

2. My task to today is to give you a brief reminder about how botrytis develops and then focus on the key factors that increase the risk of botrytis. A key point is that you need multiple control measures to control botrytis in high risk situations....and given the short time we have, I’m just going to focus on two aspects of management, including the new Botrytis Decision Support Model…which is all about helping you understand the risk of botrytis during the growing season and then responding with appropriate control measures.My task to today is to give you a brief reminder about how botrytis develops and then focus on the key factors that increase the risk of botrytis. A key point is that you need multiple control measures to control botrytis in high risk situations....and given the short time we have, I’m just going to focus on two aspects of management, including the new Botrytis Decision Support Model…which is all about helping you understand the risk of botrytis during the growing season and then responding with appropriate control measures.

4. We are talking here about a bunch rot caused by Botrytis cinerea. This fungus likes to colonise dead and decaying plant material and generally infects plant tissues via wounds.We are talking here about a bunch rot caused by Botrytis cinerea. This fungus likes to colonise dead and decaying plant material and generally infects plant tissues via wounds.

5. There are two main pathways that botrytis can infect grapes.There are two main pathways that botrytis can infect grapes.

6. Natural spore trap in the gap between the ovary and torus (receptacle) Necrotic tissue at the tip of the torus exposed when cap falls Photo: M. Longbottom, University of Adelaide 6 The earliest time of infection is at flowering when fungal spores land on a nice band of necrotic tissue created when the caps lift off the torus. So, the fungus infects but it then stops growing because of the high concentration of antimicrobial compounds in the green floral tissues.The earliest time of infection is at flowering when fungal spores land on a nice band of necrotic tissue created when the caps lift off the torus. So, the fungus infects but it then stops growing because of the high concentration of antimicrobial compounds in the green floral tissues.

7. Once the berries soften and ripen, the concentration of those antimicrobial compounds declines and the fungus can resume growth. Sometime between veraison and harvest the symptoms of bunch rot become evident. If the fungus resumes growth in one berry, then it can then spread from berry to berry, and possibly from bunch to bunch. Once the berries soften and ripen, the concentration of those antimicrobial compounds declines and the fungus can resume growth. Sometime between veraison and harvest the symptoms of bunch rot become evident. If the fungus resumes growth in one berry, then it can then spread from berry to berry, and possibly from bunch to bunch.

9. Bunch crowding can facilitate the spread of the diseaseBunch crowding can facilitate the spread of the disease

10. 10 The other pathway to infection involves direct infection of the berry, usually via wounds, such as berry splits. This pathway requires a source of botrytis spores. Here is a picture of an aborted grape berry which botrytis has colonised and which is supplying an abundant source of spores to neighbouring berries. So the fungus infects the berry directly and can then spread from berry to berry and bunch to bunch.The other pathway to infection involves direct infection of the berry, usually via wounds, such as berry splits. This pathway requires a source of botrytis spores. Here is a picture of an aborted grape berry which botrytis has colonised and which is supplying an abundant source of spores to neighbouring berries. So the fungus infects the berry directly and can then spread from berry to berry and bunch to bunch.

11. Key risk factors for botrytis 11

12. Any graphs or data I present next come from our recent Trans-Tasman collaboration supported by the GWRDC and NZ Winegrowers. We managed the project from Tasmania and enjoyed a very productive collaboration with DPI Victoria and Plant & Food Research in New Zealand.Any graphs or data I present next come from our recent Trans-Tasman collaboration supported by the GWRDC and NZ Winegrowers. We managed the project from Tasmania and enjoyed a very productive collaboration with DPI Victoria and Plant & Food Research in New Zealand.

13. Study sites The project allowed us to synthesise a standard set of data from 51 trials conducted over six years. The majority of data came from New Zealand, but that’s only because they had a 3-year head start on us. The outcomes of our study relate specificlaly to cool-climate viticulture and white varieties such as Chardonnay, Riesling and Sauvignon blanc. The project allowed us to synthesise a standard set of data from 51 trials conducted over six years. The majority of data came from New Zealand, but that’s only because they had a 3-year head start on us. The outcomes of our study relate specificlaly to cool-climate viticulture and white varieties such as Chardonnay, Riesling and Sauvignon blanc.

14. We often wonder when is the most critical time to spray. Is it during flowering? Is that 80% capfall the most important one. Is it the mid season spray? We know that we can get good coverage before the bunch closes. Or is it the late season sprays, when the visible epidemic is actually occurring. Well, we know that late season sprays can be helpful but its kind of academic when we have such severe restrictions on late-season fungicide use. So, I guess that answer depends on the region and the growing season.We often wonder when is the most critical time to spray. Is it during flowering? Is that 80% capfall the most important one. Is it the mid season spray? We know that we can get good coverage before the bunch closes. Or is it the late season sprays, when the visible epidemic is actually occurring. Well, we know that late season sprays can be helpful but its kind of academic when we have such severe restrictions on late-season fungicide use. So, I guess that answer depends on the region and the growing season.

15. 15 The risk factors for botrytis fall in three categories. These are the environmental, pathogen and vine factors that contribute to the severity of botrytis at harvest.The risk factors for botrytis fall in three categories. These are the environmental, pathogen and vine factors that contribute to the severity of botrytis at harvest.

16. Starting with the pathogen, three potential factors include the botrytis severity last season, the amount of latent infection established in flowers and fruit, and the amount of decaying bunch trash colonised by the botrytis fungus. And by bunch trash, I mean, aborted berries, the dead floral caps and even dead leaves that get trapped in the bunch.Starting with the pathogen, three potential factors include the botrytis severity last season, the amount of latent infection established in flowers and fruit, and the amount of decaying bunch trash colonised by the botrytis fungus. And by bunch trash, I mean, aborted berries, the dead floral caps and even dead leaves that get trapped in the bunch.

17. We looked at the relationship between latent infection and botrytis severity at harvest for 44 site-years. Data were collected from small plots that were left unsprayed for botrytis. At each site we collected bunches at pre-bunch closure and sampled 20 berries per bunch to estimate the percentage of berries that had latent botrytis. The y axis represents botrytis severity at harvest, but the data has been mathematically tranformed. All you need to know is that a logit of about -3 is the same as 3% botrytis severity, which is about where this line is, and a logit of 0, at the top of the graph is 50% botrytis severity. We looked at the relationship between latent infection and botrytis severity at harvest for 44 site-years. Data were collected from small plots that were left unsprayed for botrytis. At each site we collected bunches at pre-bunch closure and sampled 20 berries per bunch to estimate the percentage of berries that had latent botrytis. The y axis represents botrytis severity at harvest, but the data has been mathematically tranformed. All you need to know is that a logit of about -3 is the same as 3% botrytis severity, which is about where this line is, and a logit of 0, at the top of the graph is 50% botrytis severity.

18. You can see that there is a very weak relationship between latent infection at pre-bunch closure and botrytis severity. However, latent infection might have some predictive value, because bunches with more than 15% latent infections were always associated with a botrytis severity at harvest of greater than 3%You can see that there is a very weak relationship between latent infection at pre-bunch closure and botrytis severity. However, latent infection might have some predictive value, because bunches with more than 15% latent infections were always associated with a botrytis severity at harvest of greater than 3%

19. Floral debris in bunch Another pathogen factor that was examined was the number of floral debris pieces in grape bunches that were colonised by botrytis . All these data come from sites in New Zealand and you can see that the relationship is loose…. but there is still a general trend for there to be a higher botrytis severity at harvest as the amount of infected floral debris increases.Another pathogen factor that was examined was the number of floral debris pieces in grape bunches that were colonised by botrytis . All these data come from sites in New Zealand and you can see that the relationship is loose…. but there is still a general trend for there to be a higher botrytis severity at harvest as the amount of infected floral debris increases.

20. Looking now at vine factors. We know that the infection efficiency of botrytis increases with increasing sugar level and that the pathogen colonises the berry faster at higher sugar levels. We also know that thin-skinned varieties that are prone to berry splitting and loose pedicels develop botrytis more readily. Bunch compactness and crowding favour the spread of disease and excessive vigour can create the humid canopies that botrytis thrives in.Looking now at vine factors. We know that the infection efficiency of botrytis increases with increasing sugar level and that the pathogen colonises the berry faster at higher sugar levels. We also know that thin-skinned varieties that are prone to berry splitting and loose pedicels develop botrytis more readily. Bunch compactness and crowding favour the spread of disease and excessive vigour can create the humid canopies that botrytis thrives in.

21. Leaf layer number We used leaf layer number as a proxy measure for canopy density and like every other single variable studied, there was a weak but significant relationship between leaf layer number and botrytis severity at harvest for the 16 site-years were it was measured.We used leaf layer number as a proxy measure for canopy density and like every other single variable studied, there was a weak but significant relationship between leaf layer number and botrytis severity at harvest for the 16 site-years were it was measured.

22. Grape yield per vine Similarly, there was a weak but significant relationship between grape yield per vine and botrytis severity at harvest for the 24 sites where it was measured.Similarly, there was a weak but significant relationship between grape yield per vine and botrytis severity at harvest for the 24 sites where it was measured.

23. Curiously we didn’t find any significant relationships for bunch compactness or bunch weight. Nevertheless I would still consider bunch compactness a major factor based on data from other studies. Within a single vineyard, I imagine you would detect a difference in bunch rot severity, for example between a clone of Pinot Noir with very compact bunches compared to another clone that had very loose bunches. Curiously we didn’t find any significant relationships for bunch compactness or bunch weight. Nevertheless I would still consider bunch compactness a major factor based on data from other studies. Within a single vineyard, I imagine you would detect a difference in bunch rot severity, for example between a clone of Pinot Noir with very compact bunches compared to another clone that had very loose bunches.

24. In terms of environmental factors, what we are worried about here is the Duration of surface moisture in the fruiting zone as influenced by wind, temperature and relative humidity. Site factors also come into play here, such as row orientation and vineyard rows close to large bodies of water or shelter belts. Anything that causes berry wounding is a factor, including LBAM, powdery mildew, hail and bird damage Environmental factors also include vineyard inputs that affect vine vigour, compactness and berry skin integrity. And here you would be looking at things like irrigation, nutrition, vine architecture, shoot training and so on.In terms of environmental factors, what we are worried about here is the Duration of surface moisture in the fruiting zone as influenced by wind, temperature and relative humidity. Site factors also come into play here, such as row orientation and vineyard rows close to large bodies of water or shelter belts. Anything that causes berry wounding is a factor, including LBAM, powdery mildew, hail and bird damage Environmental factors also include vineyard inputs that affect vine vigour, compactness and berry skin integrity. And here you would be looking at things like irrigation, nutrition, vine architecture, shoot training and so on.

25. There is also another factor known simply as ‘time’. An there can be a big difference between regions in the number of days between veraison and harvest...also known as the late season interval.There is also another factor known simply as ‘time’. An there can be a big difference between regions in the number of days between veraison and harvest...also known as the late season interval.

26. Late season interval Among regions, there was a clear association between the mean late season interval and the mean botrytis severity. In this graph, A represents Auckland, HB is Hawke’s Bay, M and T, represent Marlborough and Tasmania and then there was the Yarra Valley, that had the shortest late season interval and also the lowest mean botrytis severity. The period of this study was a time when Victoria was experiencing prolonged drought and it all ended with those horrendous bushfires. This graph tells us that when the late season interval starts to exceed 40 days, then we start growing grapes in regions that are prone to developing severe botrytis.Among regions, there was a clear association between the mean late season interval and the mean botrytis severity. In this graph, A represents Auckland, HB is Hawke’s Bay, M and T, represent Marlborough and Tasmania and then there was the Yarra Valley, that had the shortest late season interval and also the lowest mean botrytis severity. The period of this study was a time when Victoria was experiencing prolonged drought and it all ended with those horrendous bushfires. This graph tells us that when the late season interval starts to exceed 40 days, then we start growing grapes in regions that are prone to developing severe botrytis.

27. Within any single vineyard, botrytis severity is determined by harvest date. When botrytis epidemics are explosive, disease severity can increase by 2% per day. Sometimes its’ better to get the crop off and sacrifice quality rather than lose the whole lot.Within any single vineyard, botrytis severity is determined by harvest date. When botrytis epidemics are explosive, disease severity can increase by 2% per day. Sometimes its’ better to get the crop off and sacrifice quality rather than lose the whole lot.

28. Now with so many factors determining the severity of botrytis at harvest, it makes sense that we need multiple measures to control it. And I haven’t even touched on how different factors interact with each other to make botrytis worse. This pie chart is a concept of integrated botrytis management to remind us that its not just about spraying – spray coverage and timing are important, but its also about canopy management, crop loads, irrigation, nutrition, vectors like LBAM and, in the future, prediction systems that allow us to assess botrytis risk accurately Now with so many factors determining the severity of botrytis at harvest, it makes sense that we need multiple measures to control it. And I haven’t even touched on how different factors interact with each other to make botrytis worse. This pie chart is a concept of integrated botrytis management to remind us that its not just about spraying – spray coverage and timing are important, but its also about canopy management, crop loads, irrigation, nutrition, vectors like LBAM and, in the future, prediction systems that allow us to assess botrytis risk accurately

29. We often wonder when is the most critical time to spray. Is it during flowering? Is that 80% capfall the most important one. Is it the mid season spray? We know that we can get good coverage before the bunch closes. Or is it the late season sprays, when the visible epidemic is actually occurring. Well, we know that late season sprays can be helpful but its kind of academic when we have such severe restrictions on late-season fungicide use. So, I guess that answer depends on the region and the growing season.We often wonder when is the most critical time to spray. Is it during flowering? Is that 80% capfall the most important one. Is it the mid season spray? We know that we can get good coverage before the bunch closes. Or is it the late season sprays, when the visible epidemic is actually occurring. Well, we know that late season sprays can be helpful but its kind of academic when we have such severe restrictions on late-season fungicide use. So, I guess that answer depends on the region and the growing season.

30. Less interior bunches: No: 92% Yes: 83%Less interior bunches: No: 92% Yes: 83%

32. I’m now going to show you some results from Tasmania, to illustrate the types of trials that regions can conduct to answer questions fungicide timing. Here’s a simple trial conducted in Sauvignon blanc, showing just 4 of the 7 treatments that were tested. We divided the season into early, mid and late, and there were two fungicide applications per time of season. We also selected fungicides that were used commonly at that time. So we used Bravo and Scala during flowering, Captan and Switch mid season, and Rovral late season.I’m now going to show you some results from Tasmania, to illustrate the types of trials that regions can conduct to answer questions fungicide timing. Here’s a simple trial conducted in Sauvignon blanc, showing just 4 of the 7 treatments that were tested. We divided the season into early, mid and late, and there were two fungicide applications per time of season. We also selected fungicides that were used commonly at that time. So we used Bravo and Scala during flowering, Captan and Switch mid season, and Rovral late season.

33. In this trial, the two sprays applied mid-season (pea size and pre-bunch closure) was the most effective treatment. In fact, the sprays applied at flowering were not necessary in this particular season.In this trial, the two sprays applied mid-season (pea size and pre-bunch closure) was the most effective treatment. In fact, the sprays applied at flowering were not necessary in this particular season.

34. Here is another trial at the same site a couple of years later. This time we used the same product for each spray timing, except for the late season sprays...and we only used one spray for each timing. Note that in practice you would never apply Switch at veraison...this was purely an experimental treatmentHere is another trial at the same site a couple of years later. This time we used the same product for each spray timing, except for the late season sprays...and we only used one spray for each timing. Note that in practice you would never apply Switch at veraison...this was purely an experimental treatment

35. A single application of Switch applied mid season or late season reduced botrytis severity from 5% in the non-treated plots to less than 1%. The early season application of Switch also had a significant impact, but the late season Rovral didn’t do much. Now resistance to dicarboximide fungicides was suspected but not confirmed at this site. So across a number of trials, we concluded that for our region, a single mid-season spray was often sufficient when botrytis severity in non-treated plots exceeded 3%.A single application of Switch applied mid season or late season reduced botrytis severity from 5% in the non-treated plots to less than 1%. The early season application of Switch also had a significant impact, but the late season Rovral didn’t do much. Now resistance to dicarboximide fungicides was suspected but not confirmed at this site. So across a number of trials, we concluded that for our region, a single mid-season spray was often sufficient when botrytis severity in non-treated plots exceeded 3%.

36. Of course it makes sense to spray at pre-bunch closure because this is the last chance for good spray coverage inside the bunch where latent infections often emerges.Of course it makes sense to spray at pre-bunch closure because this is the last chance for good spray coverage inside the bunch where latent infections often emerges.

37. Lest now look at our effects to predict botrytis riskLest now look at our effects to predict botrytis risk

38. The last part of this presentation is about introducing you to the Botrytis Decision Support Model. This model was developed initially by researchers in New Zealand but it has been calibrated with Australian data during recent Trans-Tasman collaboration. I must emphasise here that the model is currently a prototype in an Excel speadsheet, so it is not quite ready to implement across our cool climate regions. Nevertheless, this a good opportunity for you to see what it will do and I would welcome your feedback on this sort of approach. The last part of this presentation is about introducing you to the Botrytis Decision Support Model. This model was developed initially by researchers in New Zealand but it has been calibrated with Australian data during recent Trans-Tasman collaboration. I must emphasise here that the model is currently a prototype in an Excel speadsheet, so it is not quite ready to implement across our cool climate regions. Nevertheless, this a good opportunity for you to see what it will do and I would welcome your feedback on this sort of approach.

39. The purpose of the model is to track and predict botrytis development. It can help answer the question: Are we in for a bad botrytis year? It is designed to be used during the growing season to aid decisions, such as do we need a full season fungicide program and do we need to harvest early to avoid substantial crop loss. The model also allows retrospective analysis of the previous season and will help us diagnose where we can do better next time.The purpose of the model is to track and predict botrytis development. It can help answer the question: Are we in for a bad botrytis year? It is designed to be used during the growing season to aid decisions, such as do we need a full season fungicide program and do we need to harvest early to avoid substantial crop loss. The model also allows retrospective analysis of the previous season and will help us diagnose where we can do better next time.

40. The basis of the model is that botrytis epidemics are predictable once botrytis becomes visible pre-harvest. We know that some disease is established early in the season, and that vineyard factors interact with the weather to influence botrytis severity at harvest.The basis of the model is that botrytis epidemics are predictable once botrytis becomes visible pre-harvest. We know that some disease is established early in the season, and that vineyard factors interact with the weather to influence botrytis severity at harvest.

41. This graph shows what we mean by a botrytis epidemic. Once we know how it starts, we can predict where it is going to head based on all the 51 epidemics we have analysed to date and the weather associated with those epidemics.This graph shows what we mean by a botrytis epidemic. Once we know how it starts, we can predict where it is going to head based on all the 51 epidemics we have analysed to date and the weather associated with those epidemics.

42. Surface wetness & temperature – Bacchus model The weather variable that we have found that consistently aids our predictions is a thing called the Bacchus Index. This index describes the effect of temperature on the rate of infection of grape berries by B. cinerea spores during wet periods. Now the Bacchus Index is not new, but we have calibrated its application for our model. Now in order to calculate the Bacchus index, you need a weather station that has leaf wetness sensor attached to it…and these sensors are relatively cheap.The weather variable that we have found that consistently aids our predictions is a thing called the Bacchus Index. This index describes the effect of temperature on the rate of infection of grape berries by B. cinerea spores during wet periods. Now the Bacchus Index is not new, but we have calibrated its application for our model. Now in order to calculate the Bacchus index, you need a weather station that has leaf wetness sensor attached to it…and these sensors are relatively cheap.

43. There are in fact two models. The early season model predicts late season risk, and The late season model projects future disease once botrytis becomes visibleThere are in fact two models. The early season model predicts late season risk, and The late season model projects future disease once botrytis becomes visible

44. Focussing now on the early season model. This model provides a daily prediction of whether or not botrytis severity at harvest will be greater than or equal to 3%. At its heart is a daily weather index, which is the mean daily bacchus index for the previous 2 weeks which is accumulation daily from 5% capfall to veraison.Focussing now on the early season model. This model provides a daily prediction of whether or not botrytis severity at harvest will be greater than or equal to 3%. At its heart is a daily weather index, which is the mean daily bacchus index for the previous 2 weeks which is accumulation daily from 5% capfall to veraison.

45. To run the early season model, we need to be able to measure the duration of surface wetness and the hourly average temperature. Disease last year is ranked as being greater or less than 3% We rank crop load & vigour as low, medium or high..with medium being what is ‘normal’ for your vineyard. And any management actions are also entered. Eg fungicide applications, leaf plucking and so on.To run the early season model, we need to be able to measure the duration of surface wetness and the hourly average temperature. Disease last year is ranked as being greater or less than 3% We rank crop load & vigour as low, medium or high..with medium being what is ‘normal’ for your vineyard. And any management actions are also entered. Eg fungicide applications, leaf plucking and so on.

46. On any day between 5% capfall and veraison the model will spit out a traffic light warning system...low, medium or high. Once we know what the relative risk is, then we can tailor our management accordingly. Now I’ve given an example of the alternative management options for each level of risk, but in practice, this can be determined on a site by site basis. For example, if the risk of botrytis was low, then one might rely solely on good canopy management to keep the risk low. If the risk was medium, then a single fungicide application might be applied to supplement canopy management. If, however, botrytis risk was high, then this would support decisions to apply a full season fungicide program as well as pay jolly good attention to canopy management.On any day between 5% capfall and veraison the model will spit out a traffic light warning system...low, medium or high. Once we know what the relative risk is, then we can tailor our management accordingly. Now I’ve given an example of the alternative management options for each level of risk, but in practice, this can be determined on a site by site basis. For example, if the risk of botrytis was low, then one might rely solely on good canopy management to keep the risk low. If the risk was medium, then a single fungicide application might be applied to supplement canopy management. If, however, botrytis risk was high, then this would support decisions to apply a full season fungicide program as well as pay jolly good attention to canopy management.

47. The late season model is triggered once botrytis becomes visible. Botrytis must be monitored and assessed to start the model and then the Bacchus weather index helps determine the shape of the curve that projects future disease. The model will indicate whether or not we are on for an explosive or more gradual epidemic.The late season model is triggered once botrytis becomes visible. Botrytis must be monitored and assessed to start the model and then the Bacchus weather index helps determine the shape of the curve that projects future disease. The model will indicate whether or not we are on for an explosive or more gradual epidemic.

48. Again, we need to be able to measure the duration of surface wetness and average hourly temperatures. The late season model also requires implementation of a vineyard monitoring protocol Harvest date is entered when it is known and regular assessment of Brix can also be entered to utlise the Brix development model.Again, we need to be able to measure the duration of surface wetness and average hourly temperatures. The late season model also requires implementation of a vineyard monitoring protocol Harvest date is entered when it is known and regular assessment of Brix can also be entered to utlise the Brix development model.

49. Here is an example of what the model output might look like...and this will display will be made more user friendly in due course. The bottom line shows botrytis development whereas the top line shows brix development. The vertical line here is veraison and the vertical line over here is the anticipated harvest date. The crosses on the bottom line show actual estimates of botrytis severity. The open triangles show how the botrytis curve was fitted using the actual observations and the solid line shows how the model predicted future botrytis development in relation to actual botrytis severities. Obviously model accuracy improves the more times botrytis is monitored, but we reckon two assessments soon after botrytis appears can provide for useful predictions.Here is an example of what the model output might look like...and this will display will be made more user friendly in due course. The bottom line shows botrytis development whereas the top line shows brix development. The vertical line here is veraison and the vertical line over here is the anticipated harvest date. The crosses on the bottom line show actual estimates of botrytis severity. The open triangles show how the botrytis curve was fitted using the actual observations and the solid line shows how the model predicted future botrytis development in relation to actual botrytis severities. Obviously model accuracy improves the more times botrytis is monitored, but we reckon two assessments soon after botrytis appears can provide for useful predictions.

50. As I said, the model is currently a prototype that operates via an Excel spread sheet/ The New Zealanders are proceeding with web-based delivery, but obviously their front end will be pitched at New Zealand growers, especially those growing Sauvignon Blanc I have here an ‘Expression of Interest’ document that outlines what has to happen next for the model to be delivered and implemented in Australia. If this is something that you want, then there are some suggestions about how to get involved. There are many ways this thing could be tailored to be more useful and that will be part of the final stages of development and implementation.As I said, the model is currently a prototype that operates via an Excel spread sheet/ The New Zealanders are proceeding with web-based delivery, but obviously their front end will be pitched at New Zealand growers, especially those growing Sauvignon Blanc I have here an ‘Expression of Interest’ document that outlines what has to happen next for the model to be delivered and implemented in Australia. If this is something that you want, then there are some suggestions about how to get involved. There are many ways this thing could be tailored to be more useful and that will be part of the final stages of development and implementation.

51. It’s time for me stop this rant and leave you with three messages that I hope will be well cemented in your minds. The first message is that...It’s time for me stop this rant and leave you with three messages that I hope will be well cemented in your minds. The first message is that...

52. The second message is that botrytis risk can be reduced by appropriate canopy management and judicious use of inputs for vine balance. If you want to remove fungicides from your arsenal, then there is no better way than trying to be the best grape grower you can. Grow grapes well and you are well on the way to managing botrytis.The second message is that botrytis risk can be reduced by appropriate canopy management and judicious use of inputs for vine balance. If you want to remove fungicides from your arsenal, then there is no better way than trying to be the best grape grower you can. Grow grapes well and you are well on the way to managing botrytis.

53. Finally, there are just going to be some years when very favourable weather for botrytis can undo your best efforts. Either shrug your shoulders and go home or track the disease progress and harvest early.Finally, there are just going to be some years when very favourable weather for botrytis can undo your best efforts. Either shrug your shoulders and go home or track the disease progress and harvest early.

54. The END is the beginning....“If you do not change direction you may end up where you are heading” Lao Tzu, 600-531 BC 54 Thank you for your attention!Thank you for your attention!

55. Less interior bunches: No: 92% Yes: 83%Less interior bunches: No: 92% Yes: 83%