Contents. Crop info 1 WK 3 5 Crop info 2 WK 7 11 Crop info 3 WK Crop info 4 WK Crop info 5 WK Crop info 6 WK 36 25

Transcription

1 Baby Plum Tomato Summary 2015

2 Contents Crop info 1 WK 3 5 Crop info 2 WK 7 11 Crop info 3 WK Crop info 4 WK Crop info 5 WK Crop info 6 WK

3 Crop info 1 WK 3 Current situation Week number Average Difference to average % % % % 53/ (year 2014) 1588 (year 2015) % (year 2015) % Current situation For the third successive year we observe an increase in top-grafted plants with three heads. For the January seedlings this is an effective way of starting with a higher head density so that the grower should have one extra shoot around week 10 to attain the final distance. December was a disappointing month in terms of the amount of light in the Benelux. January has not started well in that respect either. There was a particular lack of daylight in early December, as a result of which the 24-hour average temperatures were extremely low. Conditions were easier for seedlings planted after Christmas as the amount of light in that week was above the long-term average. The first flowering for the early seedlings was consequently delayed and less prolific. The later seedlings are on schedule. The outside temperature is not particularly cold but clearly lower than last year. Last season there was hardly any frost all winter. Topgrafted plants are known to produce less vigorous trusses than side-grafted plants. In combination with a lack of light, top-grafted plants are more likely to have truss issues unless the 24-hour average temperature is adjusted accordingly. Large trials have been set up this year with plants that have been stopped above the third leaf. The lowest shoot has been removed by the grower reducing it to two heads. The plants supplied have more volume Climate The use of a plastic film screen under the mobile screen has risen in the Netherlands. It is also noticeably that, due to the recent mild weather, condensation forms on the plastic more quickly. Many growers have already had to make extra holes or pull gaps in the plastic. If temperatures and a little more excess than plants stopped above the second leaf. This type of plant can often tolerate higher temperatures but must be grown with a greater day/night difference to convert its more vegetative character into generativity. This could perhaps be beneficial to more generative varieties such as Sweetelle & Bamano. We advise against this for Angelle and Babeno, however. Whether or not this is actually a step forward will become more evident as we approach harvest. For the third successive year we observe an increase in top-grafted plants with three heads. For the January seedlings this is an effective way of starting with a higher head density so that the grower should have one extra shoot around week 10 to attain the final distance. This is a finer method, balance is easier to achieve and early production is higher. It is nevertheless important that the plants we buy from the grower are not too large as this is more likely to result in weaker trusses. Set large day/ night differences immediately after planting and ensure that the initial 24-hour average temperatures are not too high. This will ensure a strong first truss, which is certainly an advantage. peak during the day, air humidity will be higher and the moisture deficit consequently greater. Generative growth management is fine up to the beginning of the fourth truss. Work towards a peak of 26-27, especially in adequate light. On darker days this may be Crops with little plant load will respond to light more quickly. The settings 4 5

4 Crop info 1 WK 3 should be such that the crops can attain colour every day. Especially on light days, the day may be extended to ensure the plant does not become too succulent and to achieve the required speed of growth. A higher daytime peak will have only a limited effect on the 24-hour average temperature as the nights are still so long. Act quickly on light days. We have endeavoured to show how in the table below. Obviously a strong crop will require a higher 24-hour average temperature than a weaker crop; this will also depend on the planting distance. Time of day Temperature Influences Morning light Afternoon light Extended daylight based on amount of light Pre-night Dark mild -1 with light/cold +1 Post-night (based on amount of light) Use less light impact in the morning than in the afternoon to prevent a sweltering climate. In addition, a higher morning temperature will unnecessarily result in more elongation and a greater chance of longer truss stalks. It may be difficult to encourage Sweetelle & Bamano to produce extra shoots. Ensure the temperature drops slightly in the week before you want to retain the shoot. You can do this by increasing the daytime temperature less sharply for several days. 24-hour average temperatures It is extremely important that the first truss develops strongly. A bit too slow is preferable to a bit too fast, at this stage. In the current conditions of little light and mild temperatures, the 24-hour average temperatures for top-grafted plants is lower this year compared with last year. 24-hour average temperatures often given for snack tomatoes at this stage are It is essential that we respond effectively to the light for trusses 3 and 4. Obviously plant strength and development are also vital in this respect. Moisture Moisture causes less of a problem during cold weather than in milder conditions. Especially if the plant load is limited, as a result of which the crops can easily become succulent on the stems and flowering slow. Keeping the greenhouse closed and converting everything to 24-hour average temperatures will result in elongated crops and a weak fruit formation. Later seedlings should also be heated to a slightly higher 24-hour average temperature but not bloated with moisture. Careful monitoring of the daytime moisture deficit/relative humidity is therefore advised over the coming period. Aim to ensure that during the day the relative humidity is less than 75% and the moisture deficit more than During the night humidity levels should certainly not rise above 85-90% for too long and the moisture deficit should not drop below 1.5. It is important that the moisture is removed as condensation on the glass. The greater the difference between the temperature under and above the glass, the more moisture will be removed. The moments the mobile screen is opened and closed play a key role in this. Early opening will remove more condensation (resulting in a dryer screen). Take care to ensure the screen does not close too soon, which could delay cooling in the pre-night. An option may be to close the screen in the late afternoon to achieve a good temperature, but then to open it again temporarily in the pre-night. A slit in the screen could help here but too great a slit could result in a less uniform temperature. During the day, ventilation can enhance evaporation. When using plastic film, do always limit the maximum window position. For example, limit the wind side to 5-10% and the lee side to 30% or 40% at most. Never ventilate above the plastic film at times that the mobile screen may close, to avoid the film from getting caught in the rolling mechanism (with all the associated consequences). Moisture Aim to ensure that during the day the relative humidity is less than 75% and the moisture deficit more than During the night humidity levels should certainly not rise above 85-90% for too long and the moisture deficit should not drop below

5 Crop info 1 WK 3 Planting distances Allow for the translucence of the glass. It is not logical that plants in old greenhouses, with a translucence of barely 75%, are grown at the same distance as plants under newer types of glass with a translucence of up to 97%. It is recommended to grow a maximum of heads/ m 2 in older greenhouses, and up to 5.1/m 2 in the lighter greenhouses. Early seedlings will produce an extra 2-3 heads. The later January seedlings usually do this in one go. A little more space in spring will produce more branched-off trusses and greater coarseness. Coarseness remains essential not only to production, but also to harvest performance. This is more of an advantage for the more vegetative varieties, such as Angelle and Babeno! Irrigation In addition to promoting generative growth, controlling the plant hole also provides good insight into the uniform irrigation for each drip feed. Sparse watering results in irrigation differences, that are often larger than expected. Close monitoring is of the essence. A maximum of one dripping run per day will often be sufficient initially. It is important not to irrigate the plants in the afternoon so as to allow them to attain the proper colour. With one dripping run or after rooting, it is recommended that irrigation is moved to the evening. With two dripping runs, you can opt for one dripping run in the morning and one in the evening. Note that smaller dripping runs may result in larger irrigation differences. A slightly larger dripping run, of cc per pot for example, may result in a little more moisture under the pot but will prevent irrigation differences between the various pots. Plants can be planted in the plant hole from the first or second truss flowering. Ensure that the pot and slab are properly connected. After rooting, irrigation can be reduced to one run at night. Drainage of the slab must be no more than 2% each day and the slab must not get any dryer than 50-55% (check measurement). Drip EC levels may be set to a minimum of 4.0 EC from the outset. Following the fourth truss, irrigation can again be conducted more rapidly and some drainage may be performed. Always take a sample of the dripping water to verify that it contains all nutritional elements (especially trace elements). We nevertheless see many (small) mistakes in this respect every year. The first filling will also last the plant quite a ling time. We can also help stimulate more generative growth by working with a lower No. 3 irrigation run at the start of cultivation. The values in the analysis must not be lower than mmol. Bioline: Create a good basis for biological pest control from the start! It is vital that certain measures are taken from the start to ensure effective pest control in the greenhouse. After all some pests, such as whitefly, Tuta absoluta and spider mite, can appear in a new crop quite early if they were still present in the greenhouse to a certain degree at the end of the crop in Listed below are tips to ensure your biological pest control gets off to a good start: Whitefly Start monitoring immediately with yellow fly papers to detect the first whitefly as soon as possible. As soon as the first whitefly has been detected, it is important to introduce Encarline as quickly as possible, evenly distributed throughout the greenhouse. Encarline is best hung in the top half of the plant, approx cm below the head. While Encarline will keep the first whitefly under control, it is important to introduce Macroline as early as possible in the cultivation process. Growers who have also sprayed an insecticide, to make a clean start or to remove the first Tutas, are advised to observe a safe period of 14 days before introducing Macroline. Most growers can commence introduction from week 4-6. The start is crucial to the good build up of Macrolophus. As a predator it plays an extremely important part in the biology of tomatoes; a good approach and good feeding during the first months after introduction is required to ensure a good basis for the rest of the season. which can find their own food in the greenhouse and thus disperse themselves. Tuta Absoluta: Good monitoring from the start of the season is also vital to the effective control of Tuta Absoluta. This can be done by hanging several Delta traps with a specific pheromone in the greenhouse. Three or four traps/ha are sufficient if they are intended primarily to monitor the presence of or increase in Tuta. If the traps are intended to actually catch and remove the Tuta, the number of traps required is double that. The traps with pheromone are best hung as soon as possible. Tuta pupa from the previous crop often develop once the greenhouse is heated, and it is important to know how many there are and, on the basis of that, to decide whether corrective treatment is needed. Spider mite Spider mite is not a problem at the moment. Caution is advised, however, in greenhouses which had a high population of spider mite in 2014! In the autumn spider mite easily hide in the greenhouse fixtures and reappear shortly after the greenhouse is heated. These spider mite can cause the first infestation as early as late February-early March. At that time, the Macrolophus will not yet be up to strength to control the spider mite and vigilance is essential to ensure infestations are detected as quickly as possible. Phytoline or chemical correction could then be used as preferred. Other provisions > Distribute the plants evenly in rows immediately after arrival. Light is vital at this time. Half of the feed recommended by Bioline, Bugfood E, is therefore Ephestia. This is a high-quality nutrient source which ensures that Macrolophus lay significantly more eggs than when a lesser quality nutrient source is used (e.g. 1000% Artemia) or if it can feed on plant sap only. The chances of survival of nymphs and the speed of their development also increase visibly, and the population in the greenhouse consequently grows more quickly. We recommend feeding in the introduction sites for a period of eight weeks. At this stage the first adults will appear, > Make sure there are enough bumblebees during prolific flowering, also monitor the pollination regularly. > During the development of extra heads, ensure the stems are adequately separated. Fixing the head after splitting saves work but take care to avoid bending (timely fixing advised). Parent plant in front. > Check the alarm settings now and then and also check that the C02 in the greenhouse is measured correctly. Also check the dosage times. 8 9

6 Crop info 2 WK 7 Climate Remember that removing the film screen will always allow more natural light in, especially if there is also a movable screen above it. Growers who have a moveable screen only will also have to respond quickly to the rising temperatures. Current situation Increasing light significantly influences both the strength of the plant and the truss vigour. At this time of year as the days lengthen, the amount of daylight does indeed increase. Over the past few weeks the plants had had less substance compared to other years, but things have clearly started to change. The trusses forming now are stronger and the length to the tip longer. We can also see more split trusses and the colour of the top is clearly darker and more vigorous. We are a little late in terms of development but the plants will soon be all the stronger for it. In the earlier, unlit crops the first fruits are already changing colour. This year it is again clear that snack tomato varieties require specific generative management on the part of the plant breeder. Plant breeders who allowed the lower drops in night-time temperature and higher peaks in daytime temperature have produced the most generative plants with more substance. This is essential for all our Sweetelle, Babeno, Bamano & Angelle varieties. Growers also often want the plants to retain extra shoots straight away. Plants with substance do this much more easily which accelerates the development. Bear this in mind and discuss it carefully when ordering your plants next year. Climate Screen: A number of growers are still using a fixed film screen. This last week we have seen more and more blossom-end rot appearing here. Meanwhile, the plants in the greenhouse have developed strongly enough and produce a lot of moisture themselves. As daytime temperatures rise and the amount of sunlight increases, it s difficult to say how much longer the film screen can remain in place. In many cases openings have already been made and the greenhouse is ventilated on 2 sides to allow the moisture to evaporate. The ventilation temperature has also been lowered to prevent the daytime temperature from rising too high. We should nevertheless ask ourselves whether there is very much to be gained by delaying removing the plastic. Obviously that also depends on the processing capacity, the strength of the plant, how dirty the movable screen is and on the type of greenhouse. Remember that removing the film screen will always allow more natural light in, especially if there is also a movable screen above it. Growers who have a moveable screen only will also have to respond quickly to the rising temperatures. From sunrise, the screen can open more rapidly, especially if the pipe heating demand drops quickly. In the early evening the temperature must also have dropped sufficiently before the screen is allowed to close. Also be critical about closing the moveable screen in the afternoon. Generative growth is fine, but certain conditions do apply. During this period, the pipe temperature may not decrease too rapidly, not too much daylight must be screened off and the moisture deficit must remain above 3.5. The climate will otherwise soon be sweltering and growth will consequently be less generative if at all. Temperature: Generally speaking, we want to encourage generative growth. We do this mainly by responding promptly to the light and by maintaining vigour in the top. Around this time last year we had to reduce the temperature. This year, with less plant load, we would do better to maintain the temperature and accelerate with light. If the tops are strong enough much is to be gained, particularly in the morning, by using light to achieve the afternoon temperature sooner. The advantage of this is, as opposed to staying cold in the morning, is that it extends the daylight, so to speak. The plant will attain the proper colour sooner. Around midday (without plastic screen) the temperature may rise to /6 light. Always work with a morning drop from 1 hr before sunrise to 1 hr after sunrise if there is sufficient heat left from the post-night. By this we mean post-night temperatures of 16 and warmer. This will ensure the plants and truss stalks stay compact. This particularly benefits Sweetelle

7 Crop info 2 WK 7 Example temperature settings: Time of day Start time End time Temperature Influences Remarks Morning drop 1hr before sunrise to 1 hr after sunrise Explanation table: Morning drop: Starts 1hr before sunrise and ends 1hr after sunrise if plant is in balance or too strong. If plant is too weak and/or poor light conditions the morning drop can be extended to 3hrs after sunrise. Morning drop temperature should be set to 1 degree below the post-night temperature. The advantages of a morning drop are: Avoids elongation of the plant, keeping it compact. Has a reducing effect on the length of the truss stalks, keeping the trusses more compact. Afternoon: From 1hr after sunrise for strong plant/ light weather and 3hs after sunrise for weak plant/ dark weather build up to afternoon temp. of 21 to to 6 light impact. If good weather/strong plant we can extend the daylight based on the light sum. In dark weather the day ends 1hr before sunset, if light weather/strong plant the day ends 2hrs before sunset. Pre-night: This starts when the afternoon temp. ends i.e. 1hr before sunset if weak plant/dark weather, to 2hrs after sunset if strong plant/light weather. Pipe temperature can temporarily be switched off and a little air can help achieve the pre-night as quickly as possible. From we very gradually start to heat towards the post-night temp., which we will reach around 3 a.m. If the plant is too strong, which is often the case for every late plantings, the pre-night temperature could be higher and very brief to keep the 24-hour average temperature high enough. In the above table we must allow for the fact that for Angelle the pre-night should be even shorter if truss development is insufficiently generative. Setting to light Rise more quickly in light Afternoon light 1hr before sunset Dark mild -1 Pre-night with light/cold +1 Post-night Sunrise (light sum) Extended daylight based on the light sum Shorter setting for strong plants and colder weather could be necessary to ensure a vigorous truss, especially during warmer/cloudy nights. The pre-night is also an ideal means of encouraging generative truss growth in Babeno & Sweetelle. Bamano naturally produces a generative, branched-off trusses. Pre-night temperatures that do not dip as low can benefit Bamano and prevent excessive branching off or overload. The advantages of a low pre-night are: Encourages split trusses and ensures that the truss heads remain strong and develop better. This is labour-saving, due to the more uniform coarseness and the truss heads. Moisture reducing effect. Ventilation and/or allowing the screen to open again to achieve the pre-night lets us start the night period with a lower humidity. It enables us to lower the 24-hour average temperature, in turn enabling us to allow the day-time temperature to rise. This can save energy. Post-night: If the balance of the plant is good we want to reach the post-night temp by around 3 in the morning. In dark weather 16 will suffice; and if the weather is extremely bad or the plant very weak, 15 will also suffice. At 16 there should be a light sum increase of 1 to 2. The light sum settings will depend on the stage of the plant. If the plants are too strong (often later planting) the post-night temp can also be extended by shortening the pre-night period and thus reaching the post-night temperature sooner. The screen will also open more easily without too much pipe heating demand. Try to achieve an active climate by the middle of the day, target moisture deficit should be at least above 3.5 as mentioned above. Respond to this with a minimum pipe temperature and possibly also leaving windows ajar for air. Be careful not to ventilate too much (plastic screen excepted) and use slow P-bands. Daytime peaks already result in a better climate without the need for ventilation, although this will of course depend on the outside temperature. Ventilation will often be required once outside temperatures rise above So act quickly on light days. We have endeavoured to show how in the table on the left. Other significant influences are plant distances, plant strength, lighting period and plant load. If a side shoot is not to be removed it can be important to respond slightly less to light to allow the side shoot to develop strongly enough. This is certainly a point worth noting for Sweetelle, Bamano, Babeno. Angelle produces its suckers the quickest. 24-hour average temperatures Truss stages 1st to 2nd truss 3rd to 4th truss 4th to 6th truss Dark < 500 joules Light < 500 joules Weak crop Strong crop (late planting) Responding strongly to the light will also keep the truss heads strong; check this regularly. Planting distances The seedlings that have been lit will soon be spaced to their final planting distance. The unlit seedlings will be or have been spaced to between 3.3 and 3.6 tops/m 2. The final extra suckers will be kept from week 10/11 (earliest). It is important that the sucker is vigorous enough. If the plant is just a little too weak at that time, it is better to postpone it 1 or 2 weeks. We have noticed that this year growers are increasingly determining the distance between the tops according to their greenhouse. Very old greenhouses go up to 4.2 tops/km 2. Greenhouses more than 10 years old often go up to tops/m 2. Greenhouses of 3 to 5 five years old often go up to 5 tops/m 2 and the very latest greenhouses with diffuse and AR coated glass even go up to 5.3 tops/m 2. In the latter case, shoots should be developed in three stages. Irrigation The water control stage is over after truss 4. Do not allow the water level of the mat to drop below 50/55%. Our experience is that excessive drying would cost you growth and you would lose mat volume, resulting in too open, too generative and too weak a plant later in the year with poor production. We sometimes measure considerable weight differences between the mats. Check the irrigation, but remember that these differences can also be due to differences between the plants. Beware of too many manual actions as you ll often find yourself one step behind. We have to get out of the habit of only watering at night and not during the day. Drip irrigation should not start until 1.5h after sunrise. Early drip irrigation is likely to produce light plants and the plant is not active before then. As a result of the mat drying recently and the limited/lack of drain the EC will usually have risen a little. From truss 4 it is important to achieve a drain on both dark days and light days. On a dark day this need only be 5-10%. On a light day this may now be as much as 25% drain. More drain is preferable now but the dripping Ec must still kept high enough ( Ec). Always repeat the process at set times to ensure that the first drain is achieved around 3.5 hrs after sunrise. Irrigate between and according to radiation. The dripping runs can be larger in the morning than the afternoon. In the afternoon, radiation will often achieve sufficient drain. Smaller runs are then to be preferred. The evening run is no longer necessary although this will 12 13

8 Crop info 3 WK 14 depend on the choice of substrate (it may still be needed for dry coco / perlite). Monitor the potassium feed as the potassium content can drop rapidly at this time. Points of attention for the period ahead > For Babeno & Sweetelle, approx. 1 week before retaining an extra shoot reduce the 24-hr average temperature to promote stronger shoot development > Let the top sucker to grow on the main string and secure the plant itself to an extra string once it has dropped a little. Take care not to leave it too long otherwise it could easily bend > Monitor your CO 2 dosage to check the measurement is still accurate. The meter can deviate more than you think > Watch closely for any signs of mildew. The first spots are already appearing here and there > Try to achieve a difference of 10 between the minimum and maximum temperatures measured in the greenhouse every day, especially on dark days to retain generativity Bioline Things are quiet on the pest front for most companies at the moment. The first whitefly have been detected here and there but this is easy to combat with Encarline in a weekly dosage of 2/m 2. Macroline has already been introduced in many cases but, even with additional feeding, will often take weeks to reach an effective population. Feeding will ensure that, in the absence of pests, Macrolophus will have sufficient nutrients and lay enough eggs. If whitefly has not yet been detected, frequent (weekly) monitoring of the yellow fly papers is important and the introduction of Encarline should be started as soon as the first whitefly is discovered. Other pests will not occur for the time being. There seems to be very little Tuta absoluta as yet but, to be on the safe side, we would recommend setting up several Delta traps or pheromone traps per hectare. For a good biological balance it is important to pay close attention over the coming weeks to the development of a good Macrolophus population and to scout thoroughly. We also advise companies that suffered from spider mite in 2014 and still had some spider mite at the end of the growing period to examine the warm, dryer corners and rows closely. After all, good biological pest control starts with good monitoring and timely detection! Current situation Over the coming weeks, outdoor temperatures will continue to rise. This is no guarantee for sufficient daylight, however. The plants have now built up a reasonable plant load. The extra stems are not yet fully loaded and the fruits to be harvested generally came off fairly easily so, for the time being, the plant load will only increase. The coarseness of the first trusses is good, often coarse (especially the first truss) and they start changing colour sooner. With less daylight this year, retaining extra stems for longer has had a positive effect. In these crops, it was easier to keep the vigour in the plant and to maintain a better pace. Since last week, most unlit crops have been spaced to their final planting distance, which varies from 4.2 (older greenhouses) to 5.3 heads (lightest greenhouses with AR coating and diffuse glass) per m 2. Points to consider in the period ahead Keeping enough vigour in the heads is a particular point to consider during this period of increasing plant load. It is therefore important that the 24-hour temperature is in keeping with the amount of natural light. A pre-night is sometimes said to be important to stimulate the coarseness of the fruit. While a pre-night significantly affects the coarseness of the fruit, the 24-hour temperature has an even greater influence. If the plants retain sufficient vigour, the trusses will be retained for longer and have more strength to make the fruit coarse. Of course, stem density, the strength of the moment and natural circumstance all play an important part in this. A dark day is one with light levels of less than 800 Joules and a light day one with light levels of 1500 joules. On a dark day it is important to reduce the 24-hour period temperature. Achieving a 24-hour average of will certainly require a longer pre-night. On a dark day, the transition from post-night to morning should also be slower. On a light day, the pre-night can be shorter and the postnight to morning transition sooner. We can also adjust to dark conditions during the day by setting a shorter peak temperature period than on a light day. The daytime period will only lengthen over the coming period and will consequently have more effect on the climate/average 24-hour temperature. Open the screen promptly in the morning. Opening it later will only increase the shock to the plants, thus increasing the risk of them becoming wet. Be careful with the maximum window positions. The P bands greatly influence the temperatures achieved, take a critical look at them. In the morning, work with less delay from the wind side on the lee side. From a.m. onwards, a greater delay is permitted on the wind side. This is certainly advisable in bleaker/dryer climate conditions. Irrigation As the plant load increases and the days lengthen the water requirement will also increase. Variables such as light and humidity also play an important role. During the recent cold period we saw that even at 1500 joules, when Example: How to adjust 24-hour temperatures to light levels Irrigation We have to get out of the habit of only watering at night and not during the day. Drip irrigation should not start until 1.5h after sunrise. Early drip irrigation is likely to produce light plants and the plant is not active before then. 24 hour period Influence of light Pre-night Night/morning Afternoon temperature temperature Dark weather 6 to 8 hours Building more slowly 3 hour peak to <800 joules to Light weather Shorter hours joules Light weather Shorter Building faster to hours >1200 joules The plant strength will obviously also affect the 24-hour temperature achieved 14 15

9 Crop info 3 WK 14 Example of irrigation Period Min. rest period Max. rest period Light sum (example) Drip size Drain % 2 to 2.5 hours 4% of 8 litres = 10 mins mins J 1st drain 3rd run after sunrise 320 cc per m 2 4 hours after sunrise to 3% of 8 litres = 10 mins 60 mins J 30-40% 5 hours before sunset 240 cc per m 2 5 hours before sunset mins 180 mins Stop time irrigation was 3cc per joule, drain percentages quickly raised in the afternoon. The effect of ventilation and humidity is equally important as, if not greater than that of light. At this time of year, start the first run hours after sunrise. Setting the maximum rest periods to minutes will ensure that drain will be achieved hours after sunrise, also on a dark day. The size of the run is obviously is significant. In the afternoon a drain may be achieved or around 30-40%. Smaller runs can be set accordingly. In the afternoon dripping should be based mostly on the amount of direct light and less on maximum rest periods. For smaller tomatoes, such as snack tomatoes, it is particularly important to adjust to darker/damper days more quickly in the afternoon. From 5 hours before sunset, you can irrigate on the basis of direct light, possibly in combination with a sunlight threshold. The stop time is approx. 3 hours before sunset. It is preferable not to work with evening or night runs and to check that the slab dries well. Drying of 10-15% during the night is permissible. Drip size should really only be given per m 2. This will of course also depend on the available slab volume per m 2. Small runs are 1-2% of the slab volume, normal are 3% and large runs are 4% of the slab volume or more. (The example above is based on 8 litres per m 2 ). Regular analysis of the drain water or slab water is important now. The best time to draw slab water is around the first drain. This will give the best indication of what is happening in the slab. Later sampling will result in more 100 (*+ condition sunlight 2% of 8 litres = 20% threshold 250 watt) 160 cc per m to 3 hours before sunset drip water being analysed. The potassium content of drip water is higher. Anyone wanting to take afternoon samples would do better to analyse drain water. Regular sampling is a must at this time of year as analysis figures can change rapidly. Potassium, in particular, is essential to the fruit quality. It is also a good idea to compare the drip water and drain water analyses. Try to maintain a ph of around at this stage. Too high a ph can adversely affect the absorption of (trace) elements. Tips > Over the coming period more flowers outside in the wild will open. Monitor pollination closely to avoid failures > The formation of more than 100 fruits per m 2 (80 in older greenhouses) for several consecutive weeks will lead to a risk of a loss of coarseness and vigour in the heads. Temporarily pruning a truss or removing double trusses can be advisable to maintain homogeneous growth and production during periods of explosive fruit formation Bioline In greenhouses where Macrolophus had already been introduced in January and these predatory bugs have been sufficiently fed, new adults will gradually begin to spread. For the time being, until the adults have spread well throughout the greenhouse, it remains important to be particularly cautious about cutting leafs near the release points. Regularly check the position of the nymphs at the release points and avoid mass removal of the nymphs by cutting away too much leaf. Be alert to spider mite and whitefly Whitefly: the earliest plantings will often attract whitefly fairly soon. While the Macrolophus are still in the development stage it is important to monitor the yellow fly papers closely and to increase the number of ichneumon wasps if necessary. If the population of whitefly is at risk of rising too quickly, this may be corrected chemically. These correctors need to be mild for the biology, which is vital at this stage of the growing period. Spider mite: Various growers have already detected spider mite, which usually appear in warm, dry corners first. Thankfully, the outbreak seems to be less severe than in 2014, when the warm spring led to an explosive development of spider mite very early in the year. Many growers plagued by spider mite last year, will have applied Vertimec shortly after planting, which will delay or delay the development of the first spider mite damage. If you do encounter spider mite, you could follow this advice: if the number of infestations is still small, it could prove effective to treat each spot with Phytoline, in a high dosage of per m 2. If there are more than 5 infestations per hectare it is advisable to introduce Phytoline throughout the greenhouse in a dosage of 15 per m 2. When using chemical correctors it is important to thoroughly spray the underside of the leaves, to use enough water and to spray to the end of the rows. Any horizontal growing gutters at the ends of rows should also be sprayed well for the best results. The choice of the right product is equally important: some recognised products also have an impact on the biology. During this stage of growth, when Macrolophus is still developing, it is important to use sufficiently selective correctors when applying throughout the greenhouse. Spider mite and whitefly When using chemical correctors it is important to thoroughly spray the underside of the leaves, to use enough water and to spray to the end of the rows. Any horizontal growing gutters at the ends of rows should also be sprayed well for the best results

10 Crop info 4 WK 21 Vigour If a daytime temperature of 21 is realised in 16 hours, the night-time temperature over 8 hours would have to be 15 to achieve a 24-hour average of 19. Keeping the morning well ventilated/cool will help keep the day-time temperature under control. Allow little or no lag on the wind side in the morning. Adjust the P-bands according to the outdoor conditions, ventilating sooner when temperatures are warmer. Current situation The generative weather of the last 7 weeks has influenced the growth of the plants. The ample amounts of light, the relatively cold outdoor temperatures and the low outdoor humidity levels have made the plants more generative. In general, this results in shorter leaves at the top and slightly shorter trusses. The fruits towards the top have already filled out considerably. There are fewer split trusses at the moment, due to the high plant loads. The vigour in the top will vary per grower. Much depends on the chosen growing strategy. Has the grower opted for wide growing or narrow growing? For fast growing (more energy) or cold growing (less energy)? Does the grower plan to prune the trusses or removing double trusses, or allow all the fruit develop? There are many other factors besides those summarised above that will affect how strong the top of your Sweetelle, Angelle, Babeno, Bamano or Bambello is right now. The colder weather and the lower light intensity up to week 14 has delayed the productions slightly compared to last year. The plant loads will decrease a little over the coming period and production will rise. Growth will also increase again. Especially as the outdoor climate conditions will change. Points of attention for the period ahead Over the coming weeks, outdoor temperatures will rise. Cooler outdoor temperatures are forecast for the shorter term, however, both daytime (16-18) and night-time (8-9) temperatures. Present opinions regarding temperature settings consequently vary. While we do know that more degree days generally tend to encourage a shorter grow-out of the fruits, a higher temperature can have a negative effect on the vigour in the head and the coarseness. The vigour in the heads should remain the main guideline in this respect. Take care not to be over enthusiastic if the plants have weaker heads. We are certainly approaching a period during which the settings and the temperatures actually achieved must be monitored critically. It is also a period in which the climate can change considerably during the course of the day under the influence of the sun. A dark morning followed by an afternoon with strong sunlight ( watt) can give the plants a bit of a hard time. From now on, adjust the settings to the realisation of the required temperatures. The night-time temperature can correct the 24-hour average temperature but don t forget that the night-time temperatures are shortening and consequently have less influence on the 24-hour average. The days are lengthening from hours to a maximum of hours per 24 hours, and the outdoor temperatures will rise. The effect of light will be a lesser, limited factor. Vigour in the head versus temperature 24-hour Vigour Pre-night Night Morning Afternoon period Weak Normal Strong If a daytime temperature of 21 is realised in 16 hours, the night-time temperature over 8 hours would have to be 15 to achieve a 24-hour average of 19. Example: Target 24-hour 8 hour night-time Day of 16 hours average temperature

11 Crop info 5 WK 29 Keeping the morning well ventilated/cool will help keep the day-time temperature under control. Allow little or no lag on the wind side in the morning. Adjust the P-bands according to the outdoor conditions, ventilating sooner when temperatures are warmer. Remember that narrowing the windows on the wind side can also help lower the temperature in the greenhouse, provided humidity is low both inside and outside the greenhouse. Beware of narrowing the windows too soon in the afternoon when outdoor temperatures are higher, as this could cause the greenhouse temperature to rise to 28 or more too soon. Placing the wind side under cover can be sufficiently effective in maintaining the humidity level in the greenhouse. Narrowing the windows more is usually easier after and this will almost always have a positive effect. Take care not to ventilate too quickly in the evening as too much moisture will be lost unnecessarily. Irrigation At this time of the year irrigation should not restrict the growth of the plant. In the morning, always work towards drainage and monitor this regularly. At present we see that more irrigation also means more differences in the tap sections and between the different drip feeds. Be alert to this and check the monitoring regularly. Aim for a draining percentage of 10 to 15%. Other points > If the plants near the paths are turned and too weak, remove a truss to ensure they retain enough strength Example of irrigation Period Min. rest period Max. rest period 2 to 2.5 hours after sunrise 10 mins mins J 4 hours after sunrise to 5 hours before sunset > Once plants have been turned, the distribution is often not optimal. Check this. Take care not to hang plants at too much of an angle as this will make turning and harvesting more work intensive > The crops on the south wall will often be quite poor. Chalk this wall or use the side wall moveable screen if you have this > Allow a maximum setting of approx fruits per / m 2, depending on the type of greenhouse/glass used. If more fruits are set than the given limit, it could be better to remove the double trusses or to prune the plants > Opinions vary as to whether or not the leaves at the head should be removed. The fact remains however, that if the crop is open and perhaps weaker, it is better to stop removing the leaves at the head temporarily > Crazy roots will also appear here and there. Remove more leaves at the front of these plants, cut the mats open and/or remove the pot lining. Be careful to avoid cross contamination between one mat/pot and another. Also consider how you disinfect the water and draw your conclusions as to how you could perhaps do this differently or better Light sum (example) Drain % 1st drain around (10%) 10 mins 60 mins J 30-40% 5 hours before sunset mins 180 mins 100 (*+ condition sunlight threshold 250 watt) Stop time 2.5 to 3 hours before sunset 20% Current situation Partly due to the length of the days and the good weather of late, we had plenty of daylight. Temperatures were somewhat high. With 24-hour average temperatures peaking at 26, even over 27 locally. The tops have consequently become a little thinner and the leaves shorter. The trusses are often still forked but clearly shorter. In general setting is poor, as a result of which 3-5 flowers per stem will not have set fruit. Production will consequently drop around August. The reason for this is the high temperatures, as a result of which the bumblebees did not fly out and the quality of the pollen was poor. In Britain, a production can sometimes be shorter nearer the coast, where 24-hour average temperatures are lower and we never see any such poor setting. The high temperatures have in no way affected the fruit quality of Sweetelle, Angelle, Babeno & Bamano, although the fruit is slightly less coarse. Also due to the warmer weather, the tomatoes are not quite as firmly attached to the trusses than usual. During the extreme weather the plants were screened (movable screen) more often compared to other years, but this was soon found to lead to a close atmosphere. Narrowing the windows on the wind side during the evening did have a positive effect as the plants themselves cooled the greenhouse as it were. The temperature was clearly lower inside the greenhouse than out, especially during evening hours. Generally speaking, productions are approximately the same level as last year. Well worth following is the new variety t312090, a Babeno type with promising prospects. Contact your Syngenta representative for more info. Points of attention for the period ahead Now into the second half of July, the days will grow perceptibly shorter (by half an hour a week). During this period however, this is often coupled by high daytime and night-time temperatures and higher humidity levels. Indeed, this was already the case last week, to a certain extent. On the positive side, leaf lengths may increase again slightly. During hot weather there is little we can do besides seeking to cool conditions in the morning. Especially when minimum night-time temperatures of 14 are forecast, we have no choice. We must set a cooler night-time temperature, of course, but you should certainly try to achieve a temperature of at least 16.5 one hour before sunrise. It is especially important during this period to work with a morning drop to lower the 24-hour average temperature. A morning drop can also prevent the plants and trusses from stretching, which is a big advantage with such varieties as Sweetelle. Also check night-time humidity. In recent weeks we have seen this rise to 90% or more. Set a higher pipe temperature, especially between 3.00 and 8.00 a.m. Allow little or no lagging on the wind side in the morning. The windows could be narrowed slightly more on the wind side from a.m., although this will greatly depend on the outdoor temperature and indoor humidity. Only reduce ventilation if the moisture deficit is more than 4. The ventilation on the wind side may be reduced from Keeping the wind side under cover during the day can have a positive effect when humidity is low. At high relative humidity levels (low moisture deficit) the excess heat can be vented before sunset. At low relative humidity levels (high moisture deficit) it is recommended to reduce ventilation for longer and not to ventilate to the lowest pre-night temperature until around sunset. The 24-hour average temperature achieved in combination with the amount daylight should also be monitored closely

12 Crop info 5 WK 29 Vigour in the top versus temperature and light 24-hour 24-hour Vigour Pre-night Night Morning Afternoon average dark average light Weak Normal Strong Dark = < 1000 joules, light = > 1200 joules With falling light levels this is easily too high, especially on a dark day. Make use of the period that allows cooler cultivation. Too warm a night easily leads to more elongation and weaker trusses, which will have an adverse effect on the final production. The table above shows what we consider to be the ideal temperature settings in relation to the vigour in the top of the plant. Irrigation During the recent hot weather we saw a slight increase in the slab EC. The plants EC requirement was obviously reduced. Over the last week however, this EC has fallen again slightly and we even have to take care to ensure the dripping EC is not set too low for the crop to maintain a good colour. Set this to a minimum of between 3.0 and 3.5 with a light decrease of 0.5. Do not do this too soon, to ensure that the last runs provide sufficient EC. There has also been a rapid increase in ph in some places. Check the dripping ph for the drip feed and if there is sufficient HCO 3, add more ammonium nitrate. When analysing the sample, check that the iron and manganese levels are not too low. (iron above 50 umol and manganese umol). This is to prevent the tops from turning yellowing. Neither is a high sodium content in the drain beneficial in this respect. Poor roots are another possible cause. To ensure adequate drainage of water, it may be helpful to create an additional drainage hole or to enlarge the existing one. The roots should not be left standing in water for too long. This makes it necessary to adjust the irrigation strategy strictly, particularly during dark, humid weather. Generally speaking, the start and stop times should now be closer together. Take care to avoid more than 20% drain during the last period of irrigation. Final planting distance? In the Netherlands relatively fewer heads are being grown per m 2 than in Belgium and the UK. On average, Dutch growers maintain a 7-8% smaller distance between the heads. Up to 1 July, the more spacious cultivation has clearly not been detrimental to production. The fruits are Example of irrigation Period Min. rest period Max. rest period Light sum (example) Drain % 2 to 2.5 hours after sunrise 10 mins mins J 4 hours after sunrise to 5 hours before sunset 5 to 7 hours before sunset mins mins 1st drain around (10%) 10 mins 60 mins J 30-40% 100 (*+ condition sunlight threshold 250 watt) 20% coarser which enables faster harvesting. In fact on 1 July, with the smaller distances between the plants, the plant load was as much as 20% higher compared to the more spacious planting. You would expect the smaller planting distances to generate more production over the coming period, or will the lower fruit weight prevent that? We hope to be able to tell you more in the next growing info. Should you top or prune your plants? There is much debate about whether or not stems should be topped off. What you need to ask yourself is whether or not cultivation is to continue after week 44 and whether you are growing a vegetative or a generative crop. If you do plan to continue after week 44, prune or topping your plants will be more necessary. If you top them, you will have to consider what to do with the empty stems. Should they be removed or not? If you choose to top your plants, this is best done in last week July/early August. For Angelle, we recommend topping. Sweetelle & Bamano are more generative breeds, which makes topping less necessary. Babeno are rather in between Angelle and Sweetelle. In Belgium and the UK almost all growers choose not to top Babeno, Sweetelle & Bamano, preferring to prune the last 3-4 trusses to maintain more vigour in the top and trusses, helping to keep the coarseness through to the last harvest. We then also harvest from fewer trusses and the fruits are more uniform. Large volumes of crop/stems will often require the removal of head leaves to start a little sooner. Growers in the Netherlands however, are increasingly likely to opt to top their plants. It is interesting to see how different opinions prevail in different growing regions. By the end of the season we will hopefully be able to draw our conclusions here too. Bioline Over the last few weeks of hot weather, we noticed that the bumblebees sometimes flew out less than usual during the day. They often collected their pollen in the morning or evening. While setting up an extra hive before a hot spell certainly won t do any harm, it will not always result in a better flight. The quality of the pollen is not at its best at the hottest time of the day. Bees know this and therefore fly to flowers much less. Many growers have also commented on the bees being aggressive, so there is some activity. Populations of leaf-miner fly are increasing slightly in greenhouse horticulture. Leaf-miner flies have numerous host plants and large populations can cause problems. Their presence is usually first noticed by the mines they make in the leaves, which are enlarged by the growing larvae. Despite their concealed living habits, they can be destroyed using Macroline or, better still, Digline. An adequate population of Macrolophus will also fight leafminer flies. In the absence of Macrolophus or if the impact is high, we recommend the timely use of Diglyphus. These ichneumon wasps are specialised in fighting leafminer flies. Please note that it takes some time for them to accomplish this so Digline are best introduced upon detection of the first mines. Many growers encounter spider mite, which can be suppressed well using Macroline & Phytoline. Phytoline roof mites specialise in fighting spider mite and can destroy red spider mite completely. Areas of spidermite damage at the top of the plant are best corrected chemically. This will give the biology more time to get a grip on the spider mite. All greenhouses have more than adequate populations of Macrolophus. Do start corrective spraying in good time to prevent fruit and setting damage. If there are sufficient macrolophus prolonged use of sulphur evaporators is still recommended (advice: 8 hours). Sulphur will help suppress emerging mildew, have a restraining effect on the macrolophus, ensuring they stay healthy later in the year without the population diminishing. Stop time 3 hours before sunset in light weather and 5-7 hours sunset in dark weather conditions 22 23

13 Crop info 6 WK 36 Should you top or prune your plants? There is much debate about whether or not stems should be topped off. You need to ask yourself whether or not cultivation is to continue after week 44 and whether you are growing a vegetative or a generative crop. Current situation The 24-hour average temperatures were frequently somewhat high in the last few weeks. Nonetheless, we are seeing a renewed increase of crop vigour due to a decrease in plant load. This decrease was caused by a somewhat difficult setting quality, which was harvested in the weeks of There was also a temporary decrease in the coarseness due to the faster grow-out, but this is gradually increasing once again. Even though it is still officially summer, it is clear to us that autumn has already begun. Days are quickly becoming shorter, with less high peak sunlight. The plants are responding by increasing leaf length and there is more elongation in the tops. Trusses are once again increasing in length. In light of the closer distances between plants, it is important to keep an eye out for excessive vegetative growth. The majority of growers have once again begun to remove head leaves from the plant tops. A few growers have already topped their plants, but most will be removing the tops over the coming weeks. This naturally depends on the intended planning date, energy availability, stem distance and sales market. In other words, the situation varies per grower. The table below serves as a guide. The use of final ripening, temperature and natural light can affect this period. Topping date with 2 flowers open Final harvest 25 August 5-10 October 1 September October 7 September 3 November 15 September 15 November 22 September 1 December 1 October 1 December and later Points of attention for the period ahead: Climate In addition to the decrease in sunlight, the increase in humidity is also playing a role in the visible emergence of vegetative growth. Growers who have applied (diffuse) chalk are advised to remove it as quickly as possible. Screens above the main path can now also be removed. Otherwise, the main focus should be on encouraging generative growth with the aim of maintaining vigour in the top. Loss of vigour in the top always has an adverse effect on the final production. The outside temperature (particularly night-time temperatures) plays a big role in this. It is okay to vary the duration of the pre-night, but do not allow too much of a drop in temperature (i.e. lower than ), as the nights are becoming increasingly longer. Raise the temperature to every morning. Also continue to monitor the night-time moisture deficit. Do not allow the deficit to fall below 1.2. It is once again the time that a morning drop can help keep reduce elongation of the truss stalk and stem. Allow little or no lag in the wind side in the morning and only begin reducing ventilation on the wind side at 10:00 a.m., provided the humidity deficit is higher than 4-5. On sunny days, allow the temperature to peak at 26 and try to retain this heat as long as possible with the diminishing light, especially if the humidity deficit remains above 4. However, make sure that the humidity deficit does not fall below 3.5. If the deficit is lower than this, reducing ventilation is not advised. Depending on the humidity level, always ventilate on both sides, as this also has an effect on a lower night-time humidity. Also closely monitor the CO 2 capacity that is dosed between 9:00 a.m. and 3:00 p.m