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Objectives for this workshop Help you save money and energy by improving your understanding of disease control: Fundamentals of botrytis and fungal disease How to limit energy use but have good humidity control Get an insight into how the Dutch are tackling the problem How to put theory into practice HDC PC301 R&D project results for the basis of our information today
What determines tomato stem botrytis? Dr Tim O Neill www.adas.co.uk
Overview Botrytis the problem Sources and spread Effect of moisture Other factors determining botrytis damaged tissue senescent tissue temperature crop age and condition inoculum source and level fungicide / biofungicide use air movement Integrated control Future directions
Botrytis cinerea (grey mould) the problem in tomato
in cyclamen
on primula and calluna
Botrytis causing stem base rot on zinnia and fuchsia
in soft fruit
Botrytis sources Dispersal spore (conidia) Insects Contact spread Symptomless (latent infection) Fungal mycelium in debris Sclerotia in soil (survival body) Seed-borne / Systemic
Life cycle of Botrytis cinerea Spore dispersal in air Sporulation Attach to leaf / flower LATENT PERIOD Germinate and infect Visible spot or rot Symptomless limited infection Symptomless systemic infection
Germination, infection and growth of botrytis within plant tissues
Moisture a key factor determining botrytis in many crops High RH or free moisture for spore germination High RH for spore production Watersplash can disperse spores
RH and germination of Botrytis conidia 60 100% ation germin % 50 40 30 20 10 98% 93% 88% 83% 0 2 4 8 24 40 Time (hours)
Botrytis ti cinerea: importance of surface wetness 2.5 everity Mean s 2 1.5 1 0.5 y = 0.07x+0.01 R 2 = 0.71 0 0 10 20 30 Symptoms on susceptible flowers with just 1 h wetness Hours wet
Background to HDC project PC 301 energy saving and stem botrytis control in tomato Condensation can occur on stems does this determine botrytis level? Warwick HRI work: control of RH based on stem temperature, and aggressive humidity control in early morning, both reduced stem botrytis and saved energy
Objectives of PC 301 2010 Determine occurrence of stem condensation in commercial tomato crops, and variation 2011 Use stem temperature to control humidity more precisely and save energy
Methods RH and stem temperature monitored; periods at dew point calculated 3 crops examined Mar Sep (Lancs, Yorks, Isle of Wight) 2 further crops examined briefly
Results No condensation recorded at 4 sites; brief periods only at site 5 Yet severe stem botrytis at one site, slight y, g at a second, nil at third
Conclusions on PC 301 Botrytis intensity in tomato is not necessarily correlated with condensation on stems Condensation is not a prerequisite for stem botrytis Plant temperature sensors are a useful tool to check RH control and rule out condensation as a predisposing factor
Factor 2 determining botrytis Damaged tissue Increased infection risk on petiole stubs and trapped side-shoots Moisture and sugars stimulate botrytis growth Effect of variety
Susceptibility of two stem wound types in a Belgium crop - 2008 Natural botrytis infection in a crop with high disease pressure: Petiole stub present: 210 lesions /1186 sites (18%) Clean, smooth wound: 0 lesions /1186 sites (0%)
Effect of wound age on botrytis stem rot 30 r inoculatio on Extent t of rot (mm m) 17d afte 25 20 15 10 5 Temp 20 C Cv. 144 High RH after inoculation 10 3 spores/wound 0 0 1 3 6 13 0 1 3 6 13 Age of side shoot scar Age of leaf scar
Factor 3 determining botrytis Senescent (dying) tissue Infection of senescent or dead tissue: saprophyte food base Impaired host resistance High inoculum potential Effect of variety
Spent truss removal and stem rot 10 Sep No. stem lesions s/plant (at truss sit te) 0.7 0.6 0.5 0.4 03 0.3 0.2 0.1 0 Left on Pull of green CV. Saporo, Norfolk Pull of part brown Cut off green Left on + Fungi Pull off green + Fungi
Method of fruit truss removal Cutting off with secateurs many stubs and 31% developed botrytis Pull off part-brown fewer stubs and p only 17% developed botrytis
Factor 4 determining i Botrytis ti Temperature Effect of temperature on stem infection
Eff t f t t b t ti Effect of temperature on botrytis sporulation on stems
Factor 5 determining botrytis Crop age and condition Young plants and old plants Soft, fleshy tissue Effect of variety, light, nutrition, heating and occurrence of other disease (e.g. root disease)
Factor 6 determining i botrytis ti Inoculum level and source Greater risk with high inoculum Contact spread Debris as a food base
Spore concentration and botrytis stem rot on tomato 100 90 80 No. spores/stem wound % st tems rott ting 70 60 50 40 30 20 10 10000 1000 100 10 0 0 2 4 5 6 8 10 Time after inoculation (days)
Inoculum source Greater risk from botrytis spores originating i from the crop Remove affected stem lesions / dead plants Crop hygiene (removal of infected debris, fallen petals and old tissue)
Factor 7 determining botrytis Control products on tomato Fungicides Biofungicides Paints Rovral WG Prestop Scaniavital Switch Serenade ASO Scala (Trianum) Bravo? Fenamid
Control products Fungicides on tomato with activity against Botrytis Control products Approval Expires Amistar 1685/01 31-12-11 Bravo 500 Label 31-08-11 Cercobin WG 1969/09 28-02-16 Agrovista Fenamid 0482/08 31-12-15 Rovral WG Label 31-12-13 Scala 0282/11 31-12-17 Switch 0302/11 01-11-14
Control products Biofungicides on tomato for Botrytis Control products Approval Expires Prestop Label 31-03-15 Serenade ASO SOLA 0246/09 25-11-12
Chemical and biological control of tomato stem Botrytis (HDC trial) 20 No. of stem lesions 15 10 Unt Fung Clo Gli 5 0 30-May 11-Jul 28-Jul 15-Aug 02-Sep 22-Sep Fungicide prog: Elvaron, Scala, Rovral, Scala, Elvaron, Scala
Example fungicides id for Botrytis ti control on protected ornamentals Products Active ingredients Notes Amistar Azoxystrobin SOLA Serenade ASO Bacillus subtilis SOLA Signum Boscalid + pyraclostrobin SOLA Bravo 500 Chlorothalonil Final use 31.08.11 Switch Cyprodinil + fludioxonil Rovral WG Iprodione Stroby WG Kresoxim-methyl Final use 31.12.11 Scotts Octave Prochloraz Scala Pyrimethanil LTAEU Prestop Gliocladium catenulatum
General guidance on fungicide use Start fungicides early (susceptible crops and houses) Monitor Botrytis development and weather and adjust spray programme accordingly Alternate fungicide groups to reduce resistance risk Always check SOLA or label approval regarding harvest interval, maximum number of sprays, integration with IPM etc
Factor 8 Air movement Aim: as uniform an environment throughout the house as possible, with no high humidity areas - Glasshouse air circulation fans - Fan and duct for air movement - Fan and ducts for climate control -Plant spacing of ornamental crops
F d d t f li t t l Fans and ducts for climate control and energy saving
Fans and ducts Fans and ducts for botrytis control?
Fans and ducts 8 July 2009 House Number of botrytis Number of missing Total number heads stem lesions stem bases missing or affected* Standard 22 18 69 Fans and ducts 19 8 54 720 plants assessed per area (5 rows of 144) ; botrytis found on 3.1 and 2.6% of plants *Assuming all missing heads are due to botrytis
Fans and ducts conclusions to date No increase in stem botrytis with fans and ducts No consistent pattern to Botrytis occurrence (across or along rows) Worse Botrytis occurred: - In glasshouse without fan and ducts, near the side wall - In an area with new crop workers
Summary on Botrytis tis control in tomato Know the infection points in your crop Check RH records Check for stem condensation Remove botrytis lesions/dead plants Remove trapped debris Separate layered stems Use grow tubes Air movement Good cool chain management (transport/storage)
Less effect Building integrated control? Control root disease Crop condition Fungicide/biofungicide Reduce inoculum Remove dead/dying tissue Minimise crop damage Control GH environment Large effect Variety choice/grafted plants
Future directions potential ti tools and tactics for Botrytis control Increasing range of biofungicides (SCEPTRE project) Induced systemic resistance Sensors for early detection of B. cinerea spores / infected plants (volatiles) Improved detection methods Use of bees to vector biocontrol products
Improved detection methods Quantitative TaqMan PCR Specific, very sensitive and rapid LFD kit for Botrytis y now available
Strawberry botrytis & bee vectors Bumble bees and honey bees dispersed Binab T Vector (Trichoderma) to strawberry flowers But no significant effect on visible or latent botrytis
Work planned for strawberry Botrytis control in 2011 Fully IPDM managed tunnel to include: - Prestop (Gliocladium) spray - Prestop Mix dispersed with: native bumble bees (Audax) - Prestop Mix dispersed with honey bee Prestop is UK registered but not yet the bee-dispersed formulation
Future directions Strategic research developments B. cinerea genome sequenced Symptomless systemic infection Multiple drug resistance
Further information HDC Factsheets (23/02, 24/02, 25/02, 29/11) www.frac/info f for fungicide id group information HortLINK projects with HDC as partner: - strawberry IPDM (SF 94) - raspberry IPDM (SF 74) - Sceptre project: fungicides & biofungicides (CP 77)
Acknowledgements Research Funders (HDC, HortLINK, Defra) Collaborating nurseries ADAS colleagues Tim Pratt, Steve Adams (PC 301)
Energy efficient i humidity control Tim Pratt
Topics The basics of humidity & condensation HDC Project PC 301 what did we learn? Condensation focused control strategies FEC Services Ltd 2011 55
Measuring box maintenance A continuous supply of clean water A salt / calcium free wick Clear airflow both to and from it Clean / replace filters If fitted Check at least monthly, if not weekly don t wait for the alarm to go off! FEC Services Ltd 2007
Mollier diagram RH % Dew point temperature Temp ( o C) Absolute humidity Saturated moisture content kpa Humidity deficit AH ( g / m 3 ) FEC Services Ltd 2011 57
Condensation & plant temperature If your plants are warmer than the air temperature The micro climate around the plant heats the air RH falls and HD increases No problems If your plants are colder than the air temperature The micro climate around the plant cools the air RH increases and HD falls Air approaches saturation / dew point Higher disease risk Ensuring that the dew point temperature of the air is always below the temperature of the coldest part of the plant is a key part of disease control. FEC Services Ltd 2011
Humidity control to avoid condensation Should we use HD? Temp HD Dewpoint dt 10 2.5 5.6 4.4 12 2.5 8 4 HD gives a variable plant temperature - dew point difference 14 2.5 10.7 3.3 16 2.5 12.9 3.1 18 2.5 15.3 2.7 20 2.5 17.6 2.4 22 2.5 19.8 2.2 24 25 2.5 21.9 21 2.1 26 2.5 24.2 1.8 28 2.5 26.2 1.8 30 25 2.5 28.6 14 1.4 FEC Services Ltd 2011
Humidity control to avoid condensation Should we use RH? Temp RH Dewpoint dt 10 92 8.8 1.2 12 92 10.8 12 1.2 14 92 12.7 1.3 16 92 14.7 1.3 18 92 16.7 13 1.3 20 92 18.7 1.3 22 92 20.7 1.3 24 92 22.7 13 1.3 26 92 24.6 1.4 28 92 26.6 1.4 30 92 28.6 1.4 RH control gives a consistent plant temperature - dew point difference FEC Services Ltd 2011
Summary which measurement? Relative humidity (RH) - % Best for condensation avoidance Humidity deficit (HD) - g/m 3 Tells you the drying power of the air Best for drying wet plants / wounds Also best for helping/driving transpiration The answer Use both! If your computer lets you Plant temperature is critical FEC Services Ltd 2011
HDC Project PC 301 Followed on from work done by Dr Steve Adams, WHRI Focused on direct measurement of plant temperature Worked with various nurseries Red Roofs Nursery Mill Nurseries Ltd Wight Salads Group Buckland Gardens R&L Holt FEC Services Ltd 20011
HDC Project PC 301 Stage 1 - identify appropriate p sensors Surely infra-red is the answer? But what about simpler, cheaper & possibly more effective contact sensors? FEC Services Ltd 2011
HDC Project PC 301 Infra-red Expensive In practice difficult to keep on target Mounted close to the plant they heated it! Accuracy in practice not great FEC Services Ltd 2011 64
HDC Project PC 301 Contact sensors Considerably cheaper But don t forget connection costs Easier to keep on target Accuracy in practice superior to IR FEC Services Ltd 2011 65
HDC Project PC 301 Sensor locations Top of crop Subject to chilling from cold air and radiant cooling De-leafing line Fresh leaf wounds Stem bundle Disease tends to develop FEC Services Ltd 2011 66
32 HDC Project PC 301 30 28 26 oc 24 22 20 18 16 Air temp top Air temp bottom 14 12 FEC Services Ltd 2011 67
HDC Project PC 301 100 90 80 % 70 60 50 No simple / predictable relationship between them RH bottom RH top 40 FEC Services Ltd 2011 68
oc 30 28 26 24 22 20 18 HDC Project PC 301 Top responds quickly to rising temperatures (when greatest risk of condensation). De-leaf & bottom similar Radiant heating on top. Highly dependent on shading effect of leaves. Also dependent on regular sensor relocation. Avg plant top Avg plant D-leaf Avg plant bottom 16 Some radiant heating on De-leaf. Highly dependent on shading effect 14 of leaves. Also dependent on regular sensor relocation. 12 Bottom of crop (stem bundle) is the best measurement with regard to disease control. FEC Services Ltd 2011 69
32 30 28 HDC Project PC 301 Bottom plant suffering from thermal inertia + cooling effect of irrigation? Bottom plant - cooling effect of irrigation? oc 26 24 22 20 18 16 Bottom plant & air similar Air temp top Air temp bottom Avg plant bottom 14 12 FEC Services Ltd 2011 70
30 HDC Project PC 301 28 26 Too close for comfort? No, this is the dew point at the top. 24 oc 22 20 You need a measuring box at the bottom of the crop. Avg plant bottom Dewpoint - top 18 Dewpoint - bottom 16 14 12 FEC Services Ltd 2011 71
HDC Project PC 301 Contact sensor based plant temperature measurement is Possible and representative of reality True value can only be realised with a bottom measuring box Software based plant temperatures Give you a clue But can be misleading if you do not appreciate their limitations FEC Services Ltd 2011 72
HDC Project PC 301 Few condensation events recorded Some natural selection Interested it = focussed on it One site used 5kWh/m 2 /week low energy use and no condensation events is possible. Avoiding condensation events is only part of the disease jigsaw. Sensors such as those used can Help pyou to refine humidity control strategies Provide you with the confidence to reduce energy use Tell you when it is safe to push harder FEC Services Ltd 2011 73
Computer set points to avoid condensation Do everything slowly Increase greenhouse heating or vent temperatures Don t forget light influences in particular Increase minimum pipepe Use ramp times Avoid heat-vent dead spots Parallel lines Constant gaps closer when the humidity is bad Refine e all aspects of climate control o Strive for consistency & stability FEC Services Ltd 2011 74
Heat / vent strategy a common approach 26 Dead zone Fast ramp up 24 22 20 o C 18 16 14 Fast ramp up Dead zone 12 00 03 06 09 12 15 18 21 Time Heating temperature Ventilation temperature Note Always look at calculated heat & vent temperatures FEC Services Ltd 2011
Heat / vent strategy a better approach 26 24 Slow ramp 22 20 o C 18 16 No heat-vent dead zones 14 12 00 03 06 09 12 15 18 21 Heating temperature Ventilation temperature Time Note Apply radiation influences to both heat & vent FEC Services Ltd 2011
But humidity control using influences on vent temperature gives erratic vent movement and causes dips in temperature SOLUTION Apply small influences over as big a humidity range as possible Use an appropriate P-band Proportional band The amount of venting is in proportion to how much the measured temperature is above the ventilation temperature FEC Services Ltd 2011
P-bands how they work 120 100 ition Vent pos 80 60 40 20 0 0 1 2 3 4 5 6 7 8 9 10 11 12 delta T (above ventilation temperature) P-band = 3 P-band = 10 FEC Services Ltd 2007
P-bands Say you are venting at 25 o C P-band = 10 o C You only get 100% vent at a greenhouse temperature t of 35 o C!!! Outside temperature influence on P-band 25 20 P-band o C 15 10 5 0 0 5 10 15 20 Outside temperature o C FEC Services Ltd 2011
Minimum pipe temperature Why do we use it? Air movement 15 o C above greenhouse temperature = reasonable air movement e More than 20 o C higher = little point for extra air movement The reason >20 o C works well in practice is it usually makes the vents open So why not open the vents in the first place? FEC Services Ltd 2011
Minimum pipe Heating temperature = 20 o C Pump on = 30 o C, pump off = 25 o C Basic minimum pipe of 30 o C 60 50 o40 C 30 20 1 2 3 4 5 HD o C 5-6 3.5 +5 2.5 +15 22 2.2 +20 Calc MP Basic MP HD g/m 3 FEC Services Ltd 2011
Minimum pipe temperature radiation influences Radiation influences - high light levels mean Warm plant Good humidity Vents will be open Low minimum pipe temperature required Judging the right light levels to use High light + warm day = vents open + good humidity High light + colder day = vents open? good humidity? Maybe not FEC Services Ltd 2011
Minimum pipe temperature the alternative to radiation influences? Humidity influences To reduce minimum pipe High light + warm day Humidity will be good, vents will be open Minimum pipe will be reduced High hlight + cold ldday If humidity is good minimum pipe will reduce If humidity is poor, minimum pipe will stay on Low light + very cold day Humidity will be very good = minimum pipe very low? FEC Services Ltd 2011
Some problems Unstable pipe temperature Unstable air temperature 24 80 o C 22 20 18 16 60 40 20 o C 14 20 22 00 02 04 06 Cyclic venting Time 0 Heat Vent Air temperature HD(x10) Meas pipe Meas lee FEC Services Ltd 2011
The answers Venting Reduce the vent temperature using humidity influences to open the vents sooner and help control the rate of rise of temperature Avoid over-venting by increasing P-bands with low outside temperature Take the bottom out of cyclical vent movement using minimum vent. But make sure it varies according to outside temperature Minimum pipe Influences - gradual change over a wide humidity range Don t push it up so high it can actually make things worse! Don t change it all at once It probably won t work If it does you ll never know what did it FEC Services Ltd 2011
Dutch economical way and botrytis
Dutch economical way Low input of gas 33 41m 2 Lower levels l of HD < 15HD 1,5 HNT (New econimical growing) 27 m 2 Humidity control with outside air < 30 % Water management Screens Extra fixed poly screen
Energy saving and climate
Treatments Scala Teldor Signum Rovral Daconil Topsin M
Botrytis research a survey of 100 growers in NL There was no significant relation between the use of high or low pipe heat and botrytis There was no significant relation between the energy input and botrytis There is a strong relation between botrytis and dthe amount of given water in the first 6 weeks after planting.
Relation outside weather and botrytis In the research project there is found a very strong relation between the out side climate and the infection of botrytis in the greenhouse A period with less sun (weaker plants) and more rain ( more humid) gave a higher pressure of infection That infection was after 3 weeks visual
Water management during dark weather With a stop time too late during a darker period, we can expect more botrytis pressure In a darker period it is important to keep the EC in the slab at the same level or even let it increase a little bit Be alert that during a darker period the drip EC will increase or as minimum keep it at the same level as in the period with more sun
Increase EC during darker weather
Climate strategy during dark weather Be alert that with rain and closing the windows the inside temperature should not increase above the temperature that we wanted. If the 24 average temperature is more than we want we will get a weaker crop which h is more sensitive for botrytis. ti When the temperature is too high, we see that the setting speed is behind to the expectation in relation to the 24 average temperature. With the more humid and vegetative weather we can expect more botrytis. That will be shown by the plant with an increasing of the truss height.
Low light period and botrytis pressure Necessary and available light 16000 14000 12000 Joules per we ek 10000 8000 6000 4000 2000 0 52 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 weeknumber Average Trelleborg light maximum usefull light Necessary light Extra shoot plant density
Weak growth botrytis
Avoid cold air effect
Cold drip water and condensation on stem
Uniformity in the greenhouse Temperature: Avoid temperature differences Concrete Compartments far away from heating installation Colder parts in an compartment Bigger day and night differences by sun radiation Decrease of temperature no problem, increase 1 ⁰C per hour for uniform increase of temperature.
Wet spots on the floor Wet spots with spores Dry floor without spores
HD Control Open windows above screen when HD is too low Increase pipe temperaturet but not the actual greenhouse temperature Opening the screen partly is given a very uneven climate with botrytis risk Check measuring boxes!
Effect after 1 week with low HD
Labour De leafing with a knife reduce the pressure with 90 % Ddo not de-leaf after 12.00 during rainy weather Quality of labour is an important factor to avoid botrytis
Good cut
Cut upwards = cut in fruits
Oops!
Cutting and breaking is not good
Bad cut, good for botrytis later
Good cut!
Clips and botrytis bad combination
Botrytis control Matter of attention and detail Thank you!