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Peony newsletter, April 2017

Dear peony grower,

This is our peony newsletter for April 2017. Information that is currently relevant to the crop of peonies will be discussed. We trust that this information will help you in achieving a successful crop. Please contact us for questions or remarks!

Watering

The peony is a sensitive plant. The plant will grow very fast after sprouting and therefore will not be very strong. The plant will abort its weakest flowers when the growth is very fast, but the weather is bleak. Especially during cold nights the frost will be blamed for this. Tough the lack of water will most likely be the main reason of the flower losses. A sudden period of warm weather during the stretching of the plant will increase the risk. Do not wait with watering until the soil is dry. Instead, try to create the most ideal circumstances for the plant as possible.

In the greenhouse or in the plastic tunnel watering peonies is very important for the best result. The plants grow very fast and because of that there is a big change that the plant growth is more important than the growth of flowers buds. Sufficient watering will delay the so-called moment of choice of the plant. The plants will not abort the flower buds anymore when they are large enough. Watering demands paying attention to the climate too. Avoid big changes in temperature and humidity. Open de windows before temperature in the greenhouse increases. Otherwise the plant could be damaged and there will likely be Botrytis. Growing too dry in order to prevent Botrytis causes dried up/aborted flower buds. Irrigation should be optimal for a better development of these flower buds. If not, one problem will be solved at the expense of another one.

Botrytis

The plant is not very resistant to climate changes because of its fast growth. Botrytis will most likely appear due to the damage caused by fast climate changes. Especially when peonies are not protected well enough during the growth, Botrytis and other dangers will cause large problems. Extra sprayings are most definitely needed during this critical period. Good and effective products which are mostly used are: Teldor, Kenbyo, Luna and Switch.

There are now three varieties of Luna. Luna PRIVILEGE can be used for ground application. Luna SENSATION and Luna EXPERIENCE can be used for foliage. Luna SENSATION is effective in cold circumstances too. The effects of using Luna SENSATION before the peonies start the bloom are: a lower percentage of Botrytis and a low amount of losses during storage time.

Do not spray for two days after night frost!

Flower bud Botrytis causes plants to fall over. It goes without saying that parcels which had plants that fell over, are most likely to have problems with this kind of Botrytis. The falling over of flower buds in peonies is an important disease. Even though Botrytis spreads fast during wet and warm weather, the largest problems develop during cold and wet weather, just before the blooming time starts. The flowers will not develop and will stay in a vulnerable stadium for too long. Diseases grow from the small leaves underneath the flower bud into the flower bud. They will fall over when it becomes warm and humid, before blooming.

A few extra sprayings before the blooming can be necessary. Especially Teldor, Kenbyo and Luna SENSATION are mentioned as good and effective pest controllers. The best result will be obtained when the flower buds are wet with dew, because the pest controllers are easier to apply.

 

Phytophthora

A fairly new disease in peonies is Phytophthora. Little wounds in the plants will be infected during humid weather conditions. The fungus can survive in the plant or in the soil for years. If the plant is infected by Phytophthora, the first signs are black, weak foliage. It will show brown to greyish black spots on the stems in the spring. These stems will develop like little black hawks and will not grow further than 10 cm. Once infected, it is almost impossible to get rid of it. The spots feel soft and weak and the inside is dark brown. Among others Kansas and Duchesse are susceptible. Spray with Moancozeb, Rodomil Gold or Signum.

Phytophthora is easily confused with night frost damage. In both cases the flower bud will dry out, colour black brownish and then will turn downwards. The difference can be assessed quickly, because with night frost damage, a cavity will appear in the stem at the border of the affected and healthy plant tissue.

Leaf nematodes can cause the flower bud to die if the infection is serious enough, but the flower bud will not bend down. Often little and partly formed leaves can be seen. Therefore it is advised to have these plants tested for Phytophthora to prevent unnecessary use of expensive disease controllers.

Measures

  • Use healthy starting material
  • Provide a good soil structure
  • Avoid soil that is too moist and provide sufficient water drainage
  • Avoid a soil that has a high levels of salt

 

Potassium – Phosphite

Potassium is an important fertilizer that makes the plant stronger. Phosphite also strengthens the plant. This leads to a defensive reaction by the plant. It causes an increase in the salicylic acid route and it slows down the growth and formation of pathogens. Potassium and phosphite push the plant to grow more roots. The roots also create a thicker cell wall, making them less susceptible to damage from fungi such as mildew, Phytophthora and Pythium

Leaf spot diseases

Leaf spot diseases are causing more and more problems in the growth of peonies. Leaf spot fungus and Botrytis cause a variety of leaf spots in peonies, as shown in the pictures below. Both fungi spread well in a warm and moist environment. Both fungi survive on plants rests.

 

Leaf spot diseases are causing more and more problems in the growth of peonies. Leaf spot fungus and Botrytis cause a variety of leaf spots in peonies, as shown in the pictures below. Both fungi spread well in a warm and moist environment. Both fungi survive on plants rests.

Symptoms

Leaf spots are can be distinguished from Botrytis easily. The symptoms. 

Botrytis:

  • Develops from the top
  • The infection is often at the ends of the foliage
  • Botrytis causes light brown spots. The whole or half leaf is affected quickly
  • During humid circumstances you will find a gray fungus on the affected leaf

Leaf spots:

  • Spots spread over the whole leaf
  • The spots start as light red/purple red specks
  • Later these specks will develop into purple brown spots

Measures:

  • Use healthy starting material
  • After mowing discard the plants rests
  • Water in the morning so that the plants will not be moist during the night
  • Spray preventively with Daconil, Flint, Ortiva or Switch. Switch regularly between these products to prevent resistance

Colour of the crop

A peony can get a lighter colour in spring. The reason is that the soil is still cold and the root is not active enough. Meanwhile the temperature is rising and the plant is growing fast or there is a shortage. This shortage can be caused by an absence of micro-elements. Especially iron and manganese can be important. The young foliage will colour yellow when there is a shortage of iron. Older foliage is more sensitive for a shortage of manganese. Iron is hard to take in at higher pH levels (this also counts to manganese), wet and dry ground and a cold/inactive soil. This shortage can solved in two ways: spraying micro-elements or fertilize the foliage directly. It is better to prevent than to solve the problem. Do not wait too long with adding micro-elements.

Micro-elements sprinkled

Lately there is a slow releasing micro element mix available, called as DCM Micro-MIX. These micro-elements are contained in organic matter. They are released slowly for the plant. This mix contains iron, manganese, boron, zinc, copper and molybdenum. If sprinkled on time, the soil supply will stay at a higher level which can prevent a shortage. The microelements are composed in a way that they can be taken up easily, also at higher pH levels.

Leaf fertilization

Besides spreading micro-elements it is also possible to apply iron by means of the leaves. DCM Olega® FER is a leaf fertilizer which contains iron, urea and seaweed extract. The iron in this product is bound to a natural plant-complex (citrate).This in contrary to most other iron leaf fertilizers which are tied to chelates. This natural iron has the advantage that the iron will be ‘recognized’ by the plant and will be built in at once. DCM Olega® FER works quickly, is safe to use (smaller molecule than chelate) and its effectiveness is stronger in combination with seaweed extract. If leaf fertilizers are used it is important to apply this several times (3-4 times).

DCM Olega® COMPLEX can be used too. This leaf fertilizer also contains all micro elements next to nitrogen, phosphate and potassium. The micro elements are chelated and in combination with seaweed extract this will provide an extra stimulant. DCM Olega® FER and DCM Olega® COMPLEX can very well be used together in a ratio of 1:1. It might be possible to add a preventive spray controller, but the mixing schedule has to be consulted first.

This can be obtained from an advisors via: www.dcm-info.nl/pro/adviseurs/

Silicon

Silicon is important for the strength of the cell walls of the plant. A strong cell wall decreases the chance of diseases and insects in harming the plants. Silicon also works for fructification. Dia-Life contains a high concentration of fulvic acid. Diatomaceous earth contains fine relics of seaweeds and consists largely of silicon, but also contains a variety of micronutrients.

Products from the Life Range, including Dia-Life, contain fulvic acid among other things. As a result, the plant completely takes in the served minerals within 6 days. Plus the soil life gets stimulated, which causes other minerals to be made available for the plant. This increases the effect. Soil life Fytaforce Soil is a high quality biofertilizer with a concentrated mix of positive microorganisms that also occur in the soil under natural conditions. Fytaforce Soil delivers a large amount of positive micro-organisms like trichoderma, bacillus, pseudomonas and lots of other positive fungi, bacteria and protozoa. Flytaforce Soil is specially developed for use in the container and open ground cultivation outside. It ensures that the natural balance of micro-organisms is restored on and around the plant. In a natural balance, the plant is more resilient and vigorous. It stimulates the formation of humus and the mineralization in soil too.

For more information about Dia-Life on: www.soiltech.nl

Dia-Life and Flytaforce are available at:

KaRo
Tulpenmarkt 4, Zwaagdijk
the Netherlands
+31228563135

Marco Culurgioni
E: mc@karobv.nl
M: +316-86823006

Danny Rood
E: dr@karobv.nl
M: +316-51147142


Taxus Beetle

Recognition

Both adult beetles and larvae can cause damage. Adult beetles eat round holes in the foliage, starting at the edge. The so-called Taxus beetle is a pest in many ornamental plants. This insect is also known as a grooved vine weevil.

 

Roots, tubers and rhizomes can be seriously affected by the larvae, but also because at the stem base the bark of the plant is being gnawed on. Due to this there is no sap available so the plants will wither and die. One larva can be enough to allow a plant to die. Harmful organisms such as fungi and bacteria can enter the plant at the wounds that arise at the root.

Behavior

An adult Taxus beetle is 8-12 mm. long, has a brown/black colour and has pale yellow spots. The elytra are grooved and fused with the body. They are not able to fly and forced to walk.

From May to October the females lay eggs. The eggs are round and white in colour at first, but they are turning brown quickly. The larvae live in the soil, are initially 1 mm. in length and finally become 12 mm. long. The head is brown, the body translucent white to pinkish. The Taxus beetle winters as larvae in the soil. The mature larvae pupates in spring in the ground. Outdoors there is one generation Taxus beetle per year. In the greenhouse they develop much faster and several generations can occur every year.

Measures

  • Taxus beetles can be controlled both chemical and biological
  • Chemical control is possible using Calypso
  • Biological control is possible by using parasitic nematodes insects


Green Works Care™

After extensive testing and doing research together with various institutions in the Netherlands and abroad we are happy to introduce Green Works Care™ for peonies. The difference between a warm water treatment and Green Works Care™ became very clear after our tests, read the benefits below:

Benefits:

  • No damage caused by warm water treatments
  • The treatment is carried out in-house. The plants are less dehydrated
  • Special preventive treatment against root knot nematodes and leaf nematodes
  • Plants retain more content and vigor
  • Plant grows better in the first year
  • Blooming more in the second and third year

In order to deliver a superior quality of plant material our peonies meet the following requirements:

  • Young and healthy plant material (2-year crop)
  • No flowers have been harvested
  • True to variety
  • Free of nematodes
  • Free of root weeds
  • Dutch grown and NAKT inspected
  • Treated with Green Works Care™
  • For customers professional photography available

Visit http://www.green-works.nl for more information, or contact

Daan Kneppers
M: +31 (0)6 51 82 47 12
E: daan@green-works.nl