Viper newsletter week 11, 2010

These news and recommendations is specific made for Viper grown in Canada (south western Ontario).

1. Setting and balance.
2. Flag leafs.
3. Picking and how to keep tools clean and disinfected.
4. Crop registration.

Setting and balance:

Many crops are now loaded with first set, and second set is coming along very fast due to fairly good light levels the last weeks. Early planters might not see the greatest setting on first set, but I see that second set will make the fruit count on a good average, where later planters see a very good first set, some up to 6 fruits pr 2 stem. Plants are in general going into a more generative balance due to high light and higher fruit load. It is still important to keep the speed in the plant, work with the light on the sunny days and let the day temperature rise to 25-26 c̊, and be careful to not drop too low for Prenight and night.

Generative plants (flowers very high in crop/high fruit load) need a smoother climate and irrigation strategy, make day/night temperature settings more even and maybe consider to avoid Pre night. Day temperature should not get over 25 ̊̊C in order to not make a too large difference between day/night. Water should be easy for the plant to uptake, so be careful to not irrigate with too high EC.

Vegetative plants (flowers lower in crop, flowers often large and not facing down) need a good pre night, and you can also consider keeping late afternoon temperature high all the way until Prenight start, then you will create a very generative mood for the plants. Ec in irrigation water should be high, and also watch for your start and stop times. Plants have to think into the direction of making flowers, and they do this best under some stress.

Flagleafes:

Viper is already a very generative build plant character, leafs are smaller than some other varieties, so it is important to consider adding leaf area earlier than some other varieties. The extra leafs will provide the plants with more productions of assimilates (sugar to grow), as well some shade for fruits. Shade is important to avoid any sun burn on fruits; this can even happen in March and April where light levels can go very high, so keep that in mind when you make your decision on when to leave flag leafs. One very important note regarding flag leafs, make sure you don’t leave any fruits on the shoots, and leave only fruits on the main stem. Viper sets very easy, so you will probably see flowers in the leaf corner on the flag leaf, and it is very important to remove these flowers/fruits. At this stage you should not leave any fruits on side shoots, fruits on side shoots will in general not get enough size, as well quality can become an issue. Fruit load pr plant will also become too high with any fruits on side shoots and you will end up with a very generative heavy loaded plant who probably will get some problems due to this later in the season.

Picking and disinfection of tools:

Most growers are using skim milk to disinfect tools and hands until picking starts. Due to some food safety concerns some growers switch to use Virkon or other disinfection products when picking start. It is important to keep in mind that many tools need to be in contact with the disinfection for a certain amount of minutes in order for the disinfection to work. I have seen one grower handing all crew members on picking crew 2 knifes, they use one knife for the rows with even numbers, and the other knifes for rows with uneven numbers. The knife they don’t use is stored in a bucket of disinfection during the time it takes to pick one row, this way the contact time is fulfilled. It can be an idea to have different colors on handles on knifes in order to keep everyone on track, use blue knife on even rows, use green knifes on uneven rows.

Crop registration:

We have the option of tracking many data from climate, irrigation and plant growth. This time I will focus on plant growth registration, something that I always found very useful for several things.

Plant growth, weekly:

when you track this data you will get good information if you plant is getting into a vegetative or generative stage. Lesser growth normally means heavier fruit load and growth is slowing down, plants are getting generative. If you measure more growth, you will know that the plants are grown to the vegetative side, and it can also be a sign of the plant unloaded many fruits over the last weeks, creating room for some growth again. When you know how many cm you plant grows weekly, you will be able to catch if the plants are going into a stunned period of growth, so you can react fast to climate and irrigation settings.

Open flowers, weekly:

the count of open flower pr plant/pr m2 will also give you good information if your plants are generative or vegetative. You will also get a good chance to see if flowers start to open too close to the head of the plants, as well flowers shape and size. With this data you might see weeks where hardly any flowers are open, it normally means that you have a heavy loaded plant, and you first will start to see flowers when you have unloaded a certain amount of fruits off the plants.

Set fruits, weekly:

; the count of set fruits pr plant/m2 can be a difficult number to count, sometimes you will see abortion of fruits later on, but in general I would always only count the fruits with a size of 2 cm high, 1 cm wide, a good idea is also to label set fruits, then you will always be able to track it back, as well make sure you don’t count the same fruits in 2 weeks. Set fruits give you lots of information for production later on as well, if you have a lot of fruits set one week, you know that in 6 to 8 weeks these fruits will be ready for picking, so you have a chance to prepare some long term prediction for sales.

Fruits pr plant/m2, weekly:

this really tells you the full fruit load pr plant, count all set fruit + mature fruits. Some weeks you will see very high fruit count, but in general you should aim for 36-40 fruits pr m2, with this count you will maintain fruit size, and new setting. Some week you will be much higher, and it is okay too, especially if you are picking heavy and really unloading the plants.
To get accurate information you should aim to do the crop registration same day every week, then you will get fair data there is useful for many thing.