Categories
Greenhouse News

Army Worm and Bronze Top

Right on cue

 

ARMYWORM:

Following on from an article I wrote two weeks ago, about the Cabbage White Butterfly, and the   “I am expecting to come across the armyworm or cutworm caterpillars which come from moths. I have always found these caterpillars more difficult to eliminate.”  Well like it was on que, I have seen them, in numbers, chewing their way through tomatoes.  The devastation, from the armyworm, happens very quickly and they can destroy a truss of tomatoes.  Hopefully the BT’s (Bacillus thuringiensis) will be eradicating this pest but if not then you will have to use a different chemistry.  You should talk to your supplier about the best options available. 

Hopefully in the next two months this will be less of an issue, the colder it becomes.  Until then it will be another insect to defeat.

 

BRONZE TOP:

I have heard from several growers they have identified what they believe to be Bronze Top, a virus vectored by thrips to tomato plants.  While I am quite sure it is a virus vectored by thrips I am not confident enough to say exactly what type of virus.  When I was researching Bronze Top, which I have always known this as, I found an interesting article below which has identified several relatives of the TSVW which have caused growers issues in recent years in Florida.  If you are interested it is worth reading- but not before bedtime as I don’t want growers to have nightmares.

http://nwdistrict.ifas.ufl.edu/phag/2015/02/27/new-thrips-transmitted-plant-viruses-in-florida-crops/

Considering the number of thrips I have witnessed this summer, you are possibly wondering about the whitefly. It has certainly been well contained at the properties I visit.  There are several properties with unwanted populations but not as many as previous seasons.  Psyllids and plants infected with Psyllid Yellows is another I have not encountered as yet.  From previous experience, Psyllids still pose a very real and potential threat up until the official beginning of winter.  

There is, absolutely without doubt, one chemical that has been superb in controlling whitefly and it does have control over other pests which is an added bonus.  While it is absolutely fantastic that growers have this product available, it is no secret we are genuinely short of other options that have the same 100% effectiveness.   Other products still work well and should be used in a combined programme to combat insect pests.  What I would really hate to see is a resistance build up and then we are back to square one.  Some growers are using programmes with different products which is fantastic, and it is great to see many natural products, with minimal or no withholding periods, incorporated into grower’s pest eradication programmes.

  

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Technical

Why Bumble Bee pressure is essential

Setting in sequential order (Tomatoes)

 

During recent visits I have seen indifferent results with fruit pollintation/set on tomatoes.   There are a multitude of reasons how or why poor setting will occur.  Potentially caused from over loading, leading to plant stress, or simply not enough bee pressure could be one of multiple reasons.  Since it has been extremely warm, I was tempted to blame poor pollination on bumble bees.  However, at one property, where the plants were setting fourth truss, I came across the perfect setting all in sequential order on a very high percentage. 

The most impressive aspect was only one or two flowers were open on any particular truss.  The bees were working so well that as soon as the flower was open it was quickly visited and pollinated.  The photo illustrates the sequential pollination.  The first flower, now fruit is the biggest closely followed by the next four flowers with the sixth recently opening ready to be visited and pollinated by a bumble bee.  It is very important that this occurs, now that the plant has set as quickly as nature will provide, the next truss can now take the energy it requires to repeat the process.

Crop registration forces you to take a close look at flowering verses set speed.  If there are a lot of flowers open at any one time then the flowering speed could be too far in advance of the fruit set speed.  I.e. too many flowers will be open indicating that pollination is slow to occur or not happening at all.  The cost of miss-setting is real.  To actively reduce this, take the time to understand how and why it could be happening.  Bumble bees are the cheapest workers you will ever employ, no holidays, no overtime and when they fly into a cobweb you don’t have to ring Worksafe.   If you are concerned a hive is not performing then call your supplier to order a booster hive.  Bees are not robots and some hives might outperform or last longer than others, so I would be using the numbers from the crop registration to aid in reducing the risk of miss-setting.

The position you keep your bees is also important.  Try to keep them around 1 metre from the head of the plant and semi-shaded.  Using a thick polystyrene hat does the trick to reduce direct sunlight on the top of the box.  If possible don’t stack new hives on top of old ones.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

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Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Integrated Pest Management

Cabbage White Butterfly (Caterpillars)

BT’s give good control

 

Never a dull moment, last week it was thrips, this week it’s thrips and caterpillars. The caterpillar is a pest that is more annoying than crop destroying but if left unchecked will cause crop production losses.  Never the less it should be dealt with.  I was interested to see it attack the cucumber leaf in the cover photo.   With tomatoes the caterpillar will eat leaves, burrow into fruit and eat through the main stem, generally at the top of the plant where the stem is still immature and soft. 

Spraying, using a BT (Bacillus thuringiensis), is an option.  I have always found the products available generally do a good job in supressing caterpillars.  One thing to be careful of, if you are using old product, is that you check with your supplier if it will still be viable.  I am expecting to come across the armyworm or cutworm caterpillars which come from moths. I have always found these caterpillars more difficult to eliminate. 

The photo below is of a blue sticky trap, which I recently came across with a cabbage white butterfly attached.  I was very surprised as I don’t often see this.  Usually the cabbage white butterfly will land and lay its eggs on green foliage.  The green canopy is perfect camouflage. I would be interested to know if growers, that use blue sticky traps, have seen many cabbage white butterflies caught on them? 

Bacillus thuringiensis (Bt) is a natural occurring, soil-borne bacteria that has been used since the 1950s for natural insect control. It consists of a spore, which gives it persistence, and a protein crystal within the spore, which is toxic. That toxic protein differs, depending on the subspecies of Bt producing it, yielding a variance of Bt toxic to different insect species (or none at all). When the bacteria is consumed by certain insects, the toxic crystal is released in the insect’s highly alkaline gut, blocking the system which protects the pest’s stomach from its own digestive juices. The stomach is penetrated, and the insect dies by poisoning from the stomach contents and the spores themselves. This same mechanism is what makes Bt harmless to birds, fish and mammals whose acidic gut conditions negate the bacteria’s effect.

 

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

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Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Greenhouse News

Zac’s First Corncob

“Let’s water the corn Dad”

 

Growing up on a Dairy Farm, one of my fondest memories was wanting to get on my 50cc after school and bring the cows in for Dad to milk.  I had other jobs, such as feeding the chooks and collecting the eggs, but these would always come second to milking or feeding the calves.  I was always encouraged by my parents to be involved.  I cherish those memories growing up on the farm. 

For the past two years my son Zac’s preschool has had a spring planting programme.  They plant different types of vegetables and flowers in small biodegradable pots.   After several weeks, watching the progress of the germination, the children are encouraged to take their plants home and transfer them into the garden.  Last year Zac grew two sunflowers, he did not show much interest but this year he has become very involved in the process.  Firstly, he decided he would help plant the corn, silver-beat and herbs he brought home.   He dug the soil out and planted his small pots and then covered them up with more soil.  He decided he needed to water them.  Zac then proceeded to flood the young plants, I was on hand and explained to him they probably had enough water for now.   What was already evident was he had already learnt the basic principles.

With the hot weather our routine, after day-care, has been to go and water the plants. We have several raised vegetable beds which have capsicums, cherry tomatoes and potatoes.  There is also lots of herbs.  Watering the plants is now a very serious business as my youngest son, 3, who also likes to be part of the irrigation team.  Zac has been taking especially great pride in his corn. I am not sure if this is because he notices the large growth of the plant but he is always insistent this is watered first.  Last week I decided to harvest one of the cobbs with Zac.  I have never seen a kid so excited, he was so immensely proud of his corn that he asked if he could take it to day-care the next day.  I thought it would go missing throughout the day, but to my surprise he was still carrying it around when I went to pick him up.  When we got home, I asked if he would like to husk the corn, he said yes.  I showed him how to do pull the leaf off and with some help he started to expose the corncob.

I think I totally underestimated the thrill and enjoyment my son would have from the process of growing the corn and his other veggies.  It was a delight and has encouraged me to plan a slightly bigger patch for the boys to learn more about growing next season.  It has demonstrated the importance that education can play from a very young age for developing these initial skills but also healthy eating.  I am certain they will eat the food if they are involved in the process of growing it.  Zac has already started digging up my potatoes!

 

Interview with Zac

1, Did you like planting and growing the corn? “Yes”

 

2, What does the plant need to help it grow? “Sun and Water”

 

3, Did you have fun watering the plant? “Yeah”

 

4, How many times would you need to water the corn? “Before School”

 

5, Would you like to be a corn grower one day?  “Yes, I want to grow all over my lawn”

 

6, What else would you like to grow next year?  “Mmmmmm watermelon,  grow Watermelon, can I go and buy a watermelon plant, then I fill my wheel barrow up with water and tip it on my watermelon, and it grows too big”

 

Well done to the pre-school Zac attends.  It has very much highlighted the importance of teaching these skills to children at a young age, and at the same time letting them have fun doing it.  A lesson for us all.

 

 

Zac’s sunflower 2018

 

Cover photo, Zac picking his first corncob (with help from Dad)

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Events/Announcements Greenhouse News

Inaugural Grower2Grower Breakfast Held

Aquasan and BNZ presentation’s informative and insightful

 

Last Tuesday the inaugural Grower2Grower breakfast was held at the BNZ Partners Building in Pukekohe.  The concept is to bring small groups of greenhouse growers together to present them new information, from greenhouse suppliers of products or services, followed by a financial update from the BNZ.   It is also an opportunity for growers to have a brief catch up.

While having breakfast, the growers were shown slides and technical information by Guy Richardson and Grant Bear, from AquaSan International, regarding Huwa.San and Sili-fert P, two products gaining real momentum in the greenhouse market.  After the presentation, Hamish Frizzell, from the BNZ Agribusiness Team based in Pukekohe introduced Michelle Chester, Interest Rate Specialist, from the BNZ. Michelle’s presentation give insight to what is currently occurring in the financial sector including, short to long term rates and foreseeable forecasts.  Michelle talked about the Official Cash Rate (OCR) and what influences OCR decisions.

I would like to thank all growers who attended, especially at this very busy time, made harder by the warm patch of weather we have experienced.  I would also like to thank the BNZ for the use of their fantastic facilities and Guy Richardson and Grant Bear from AquaSan International.  Special thanks to Michelle for taking her time out to come and speak to the growers.

If you are interested in Grower2Grower hosting a breakfast in the future please feel free to contact us for more details.  E-mail marie@grower2grower.co.nz

Above, considerations influential for OCR decisions.

Breakfast was supplied by Whisk Café based in Pukekohe. 10/10 for the quality of the breakfast supplied.

Thanks to all who attended the Grower breakfast.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Irrigation/Substrates

Substrate Focus

Pumice

 

When I first started growing greenhouse tomatoes, in the 90’s, I grew in pumice substrate for at least the first 3 years.  In those days we would grow in small white sausage shaped bags.  The first crop we had to dig the plants into the bags.  It was pre-stone-wool propagation material then.  The hardest part of the job was the placing and removing of the bags.  It was hard and heavy work, but pumice does have its advantages as a growing media.

 

Water Holding and Refreshment:

The water holding capacity of pumice is either viewed as a negative or positive, and it very much depends on the crop and time of the year you are growing.  Pumice allows for roots to penetrate easily through the granules, it is particularly easy for capsicum roots to penetrate.   Pumice is easily dried down, so even though there can be an easy establishment of root systems, growers are able to reduce a vegetative pulse in the plant quickly and restrict water availability.

 

Summer:

As pumice has a reduced water holding capacity, compared to other substrates, it needs regular refreshment, this again can be perceived as a negative or positive.  In the heat of summer, replenishing the root system often, with such an open media, will have benefits, rootzone temperatures stay lower and higher oxygen levels should be achieved compared to other media.  The negative, you have little room for error if there is an irrigation malfunction.  I always found I had to use a higher runoff % to achieve EC targets with pumice, and unless you are recycling you end up with a high % of run to waste.  Even if you are recycling, you have extra costs on electricity and wear and tear on pumps which are working overtime. These hidden costs are rarely considered.

 

Late Autumn, Winter:

This is the time of year I felt the biggest advantage is achieved from using pumice as a substrate, it is easily dried down to easily allow your night time targets no matter what the environmental conditions.  It is very forgiving, if you do overwater then it is very easy to correct.  Controlling the EC is very easy in pumice, and again if you will have the ability to make changes faster than with other substrates, but it does mean it is easy to over correct as well.

 

Root Structure/pattern

Establishing a rootzone that is evenly spread across the entire volume of pumice is a drawback.  You will always end up with a cone effect pronounced more on pumice than on most other substrates currently on the market.  This is why taller bags are still generally used to have a larger vertical root structure.  Multiple drippers will help spread the irrigation water and increase the cone, but it’s still not ideal.    

 

Drippers: 

If you are growing in pumice, then dead set no brainer, you should be only using 2 litre/hour compensating drippers.  When I first started growing I had the whisker irrigation which if you worked it out had an output approx. 9 litre/hour. So the water was going on the substrate ridiculously quick and there was less time for the spread of the water throughout the bag so it caused high and unnecessary runoff percentages.

 

Labour:

The extra time and labour it takes to place in the bags and take them out is a huge negative.  It is also extremely heavy work and takes its toll on the body.  It is however, very easy to dispose of. 

 

Uptake of Root treatments:

As pumice is easily dried, it can be very effective if applying a systemic product via the root systems.  You should be able to get a good result.    

 

Summery:

 

Twenty five years later, some greenhouse grower’s still use pumice or a pumice/sawdust mix.   It is not a substrate that is very popular, but it is still used and growers who use it need the advice to help them achieve the best possible returns. It is also a product that could be used in the future to grow different varieties of crops that are coming under cover.   Like any substrate, understanding its properties, how root systems/plants react is the key to understanding if it is the correct media for you to be growing in for your situation.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Events/Announcements Greenhouse News

February 14th Happy Grower2Grower day

The First year

 

Firstly, Happy Valentine’s Day!  It is a great time of year and marks Grower2Grower’s one-year anniversary since our launch.  My wife Marie and I have had a very busy year. We have strived to bring NZ greenhouse growers, suppliers, students, teachers and anyone else who has taken time to view the site current, relevant and informative articles.  The passion I have for our industry is my key driver, and I 100% believe that covered crop growing is crucial for future food production and security. 

The grower biographies have been wonderful to write, I would like to thank all the growers who have welcomed me into their workplace.   It has just confirmed the amazing talent and knowledge that New Zealand indoor growers have.  The interview with the ageless Tony and Joanne Ivicevich, gave a wonderful insight to how much the industry has changed since the 1980’s and how, knowledge and technology has transformed the greenhouse growing industry from a lifestyle to a serious business.

I enjoyed writing the article on retired flower grower George Wheeler, and the young growers that are emerging.    I hope to bring you plenty more articles on our past, current and future growers over the coming years.

Without doubt the most heart-warming story, in the last year, was the $ 40,000 plus that Raj Sharma raised for Cancer Research.  On the 3rd of February it was 10 years since I lost my father, to an asbestos related cancer, so I felt privileged to help promote Raj’s cause, one very close to my own heart.  I know Raj has lost family and friends to cancer and this gesture from him was simply an outstanding effort. 

The supplier articles have been great, presenting growers excellent products and information which adds real value to business.  All growers use products to assist them grow, without the partnership of suppliers we would not have an industry and vice versa.  We need each other and I am very proud that the Grower2Grower platform is assisting with this.  It is important to note that teachers and students, using this website, are also gaining key insights to different supplier’s products and services available.

The technical grower focused stories have been well received.  I am glad I am able to use my experience, and the contacts, I have in the industry to bring you these informative articles.  At the end of the day we are here to help increase outcomes for growers.

The classifieds section has sold nearly every item advertised.  The ability to list items on a live website that other growers frequently use has made this work well.  So, don’t forget to take a photo and send me what you want sold, new or old products. Let’s get trading.

The NZ total viewer numbers are great and the worldwide exposure has far exceeded any expectation I had.   This is a website predominately for NZ greenhouse growers and is promoting industry locally, the beneficial spin off of this platform has been a growing worldwide viewership.  The Australian Soilless magazine has published two articles and four have been republished in the Hort-Daily worldwide horticulture e-based magazine, which I am proud of. 

This year there are some new and interesting projects I will be working alongside of, and in time I will be sharing these experiences with the viewers. 

If you have a topic you would like written about or you have a growing story to tell please feel free to contact us. 

Now let’s get growing.

MD, Grower2Grower, Stefan Vogrincic

 

Article written by Stefan Vogrincic

All Article’s checked and edited by Marie Vogrincic

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

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Categories
Industry Profile

Grower Profile, Gavin Naylor, Freshwest Ltd

King Sweeties: From Kaitaia to the Bluff

 

Gavin and Vanessa Naylor, owners of Freshwest, have been growing capsicums since purchasing their 8000 m2 greenhouse in 2004.  Situated in Waiuku, New Zealand, the operation has gone from growing a standard blocky capsicum to the niche long pointed capsicum known as King Sweeties.  An extension has since been added to increase the greenhouse to 10,000 m2, comprised of three separate growing compartments.

King Sweeties are the main variety grown by Freshwest

 

Gavin, a born and bred Aucklander, was raised in the suburb of Pakuranga.  Having always been interested in the outdoors, a chance meeting with a friend of a neighbour gave him a short-term opportunity to work on a new kiwifruit operation South of Auckland.  This experience encouraged him to study horticulture after finishing high school.  Gavin went onto complete a Diploma of Horticulture via Massey University.  The course was completed extramurally.  In 1984, at the same time he was studying, he was employed with what was at the time, a very large tomato growing operation in Whitford.  The greenhouse area was approximately 1800 m2.  As fate would have it, a helicopter spraying hormone in the neighbour’s fields accidentally caused a spray drift which wiped out a young crop of tomatoes.  A new crop of tomatoes was planted but remaining active residue caused the second crop to fail.  The owner, who did not want to have a season without any production, decided to plant rock-melons for export to Japan.  From this twist of fate, and the need to learn about growing melons, it was decided to send one of their staff to Japan. Gavin was chosen.  Over the next four years he frequently visited Japan, and after two years he ended up working fulltime for a Japanese seed company in conjunction with an export company.  Then in 1988 the Japanese seed company purchased a property in Kumeu, so Gavin was put in charge of setting the operation up to grow and export rock melons.

 

Wee Sweeties are grown on a smaller scale but are still very popular with consumers

 

All of this happened very quickly for Gavin. By the time he was 25 he wanted a change the decision was made, with partner Vanessa (now his wife), to have a year off and travel overseas.  They spent the next year in Perth, where Gavin worked as a brick layer.  When they returned to New Zealand, the family had a flower growing operation in Patumahoe, he was asked to run the property, which he did for the next two years. Vanessa and Gavin then purchased their first greenhouse property, whcih was for sale close by.  There was no heating system, so it was used to grow melons for the export market during the summer season.   Not long after an opportunity to grow Hypericum Berries (used to fill floral bouquets) came about when a Dutch grower, who was going to immigrate to New Zealand to grow them, decided not to immigrate.  However, he had already sent plants to a friend of Gavin’s, a lily bulb grower in Waiuku, to be bulked up in preparation.  There were now 8000 plants with no one to grow them, Gavin was offered the plants, of an “unknown” crop, which had never been grown in New Zealand before.  Along with another flower grower, they shared the plants taking half each.  The crop proved to be extremely popular and successful. Within a short period of time, a large 20-acre property was purchased where, at its peak, 10 acres of Hypericum was grown mainly for export to Japan and Taiwan.  Such was the size of the operation, at its peak, 50 staff were employed.  Unfortunately, being export based, other countries such as Ecuador and Zimbabwe, started growing huge amounts so it became unsustainable to compete on price. 

Soon after winding up the Hypericum Berry operation, the opportunity to purchase Freshwest presented itself.  In 2004 Gavin and Vanessa became capsicum growers. Initially the main crops grown were standard blocky capsicums along with a small amount of chillies.   

 

Red King Sweetie

 

After many years, with the expansion of the standard blocky industry in New Zealand, which is still mainly an export-based market, the decision was made to start to diversify to new types of capsicums for the domestic market.  First came the Little Sweeties and now the Wee Sweeties and King Sweeties are the mainstay.  When they first started growing the ‘’Sweeties’” range it was not well known to consumers. They were not aware of the point of difference which was the amazing taste that Sweeties have.   Gavin has credited MG Marketing, he said “MG Marketing have been brilliant promoting and marketing the Sweeties range”.  Their assistance has been instrumental in the labelling, barcoding and compliance.”  This has allowed Gavin and Vanessa to concentrate on the growing and packing of the product.  It is certainly great to hear that the relationship they have formed has been so successful.   The Sweeties range is now sold from Kaitaia to the Bluff and is in high demand. It has been so successful that in 2017 the King Sweeties were a finalist for the New Zealand Food Award’s.

 

Red and Yellow King Sweeties ready for the supermarket shelves

 

The main variety, King Sweetie is a tricky plant to keep in balance.  Gavin knows from experience how to manage the fruit load, especially during the summer months.  This has taken time to perfect.  The property is serviced by an environmental computer system, a coal fired heating system and has a fully recycled irrigation system.  The business employs 6 full time staff, excluding Gavin and Vanessa, and during its peak, in the summer months, they employ up to 4 further staff.  Freshwest are very proud to be NZ GAP accredited delivering fresh, tasty produce available for all New Zealand consumers. 

Vanessa and Gavin are the perfect example of a successful growing operation.  They have diversified and adapted to create a point of difference with the King Sweeties.  Long may it continue.

 

Healthy fully loaded plants with King Sweeties

 

Vanessa Naylor is involved in all aspects of the growing operation. On the day I visited she was very busy grading the King Sweeties.

Yellow King Sweeties also have an amazing sweet taste.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Integrated Pest Management

Hot period sparks large populations of Thrips

Zonda Beneficial’s helps to control this damaging pest

 

Over the past two week’s I have witnessed a large influx of thrips into tomato and cucumbers.  The conditions have been perfect, with the hot dry temperatures, and other factors out of the control of indoor growers.  The area I have witnessed the highest levels is in the South Auckland region and close to crops that thrips thrive upon.  I would be interested to know if it has been a problem nation-wide.

The crops severely affected from thrips are more so cucumbers, tomato, capsicum, and eggplant as well as flower crops. Spraying is a very valuable tool to control thrips, but even this seems to be proving difficult, as huge outdoor populations appear to be coming inside with the next gust of wind! Spraying multiple times during a seven-day period is tricky.  

The main consideration is the damage to the leaf with the different types of products available.  Yes, you can control the thrips but at what cost to the plant’s health.  In the end the grower will make these tough decisions as doing nothing is simply not an option.  If you have been recommended biological sprays then you should consider using this in conjunction with beneficial product such as Thripex, supplied by Zonda Beneficial’s.  The Thripex products consist of predatory mite- Amblyseius cucumeris and are now available to growers.

It is recommended that Thripex be started in young crops to build a good population.  Zonda is able to provide information on what “soft” chemicals can be used in combination with Thripex.

If you want a biological solution to the thrips, contact Zonda Beneficial Ltd. Located at 79 Taurangaruru Road, Waiuku, South Auckland (Ph. – 0800 4 ZONDA 96632; Email- zonda@zonda.net.nz, website- www.zonda.net.nz)

Their R& D team, led by Dr. Gunjan Gera (gunjan@nzg.co.nz), is focussed on developing sustainable and holistic methods for the pest control in horticulture using the beneficial bugs. They can provide you a catered plan suitable to your crop for the biological pest management for Thrips and the other pests.

Using Amblyseius cucumeris, could just be the answer to try and get you through the next month.

 

 

Biology: (courtesy of Zonda Beneficials Ltd.)

Thrips go through six stages, namely egg, two larval stages, pre-pupal and pupal stage and finally the adult stage. Adult thrips are found in flowers and on leaves where they deposit their eggs. On sweet pepper leaves the egg laying sites are easily recognized as wart-like deformations; in cucumber and other crops these deformations are not visible. The larvae feed on all above ground parts of the plant and are extremely mobile. Pupation takes place on the ground.

Symptoms:

Thrips cause damage to the plant by piercing and sucking out cells on the leaf surface. This causes silver-grey spots on the leaves, with dark green spots (excretions) and reduces the production of the plant. At high infection levels leaves may even wither.

The most important virus transmitted by thrips is tomato spotted wilt virus (TSWV). Frankliniella occidentalis is the mayor vector of this virus which causes a lot of damage in the Mediterranean countries.

 

Solutions:

THRIPEX – Amblyseius cucumeris in bran 
THRIPEX-PLUS – Amblyseius cucumeris in sachets 
THRIPEX-V – Amblyseius cucumeris in vermiculite 

 

Thrips found in the flowers of cucumber plants will cause the fruit to misshapen and bend, this then makes them second grade.  Blow on the flower if you unsure if you have thrips, they will quickly move and become visible.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

 

 

Categories
Irrigation/Substrates Technical

The Hot Weather Continues

Warm Irrigation Water Will Not Be Helping

 

These last few weeks have been very warm and it is not showing any immediate signs of easing.  It has been very interesting to watch how the medium to older crops cope.   As expected, the root systems are not as crisp as they could be and almost all have a tinge of brown staining.  I have measured and observed substrate temperatures in excess of 25 degrees.   Not much attention is given to how oxygen is depleted in the water at higher temperatures, possibly because the effects for growers is generally a short period in January and February.  However, the damage and stress on the plant in this period is potentially very costly.  It is a time of the year we want plants to produce as much as possible and if there is added stress, problems will quickly occur.  

'The amount of dissolved oxygen that the water can hold depends on the temperature and salinity of the water. Cold water can hold more dissolved oxygen than warm water and fresh water can hold more dissolved oxygen than salt water. So the warmer and saltier the water, the less dissolved oxygen there will be.'

From my own experience as a grower, I have witnessed that when the temperature rises to 20 degrees in the Irrigation water, combined with the mass of the substrate, then maintaining a desired substrate temperature is very difficult or even impossible.  Crops that are older and have a large canopy will help shade the irrigation PE lines and substrate from direct sunlight.  For young plants, even more so if you have black PE lines, the temperature will become totally out of control and possibly go well over 30 degrees.  It makes it difficult if you are trying to control the generative/vegetative growth on young plants. If you are planting in this oppressive weather then I recommend you run large shots to make sure you get some cool water onto those root systems.  It is not an ideal scenario but needs must.

Several years ago, in the heat of summer, I visited an NFT grower that had terrible trouble from damping-off with their young plants.  They were a healthy plant, when received from the nursery, but started damping-off several days after planting.  The main observation, which stood out, was the extremely warm irrigation water temperature, over 30 degrees!  As this was a closed, 100% recycled system, the water just kept returning from the gullies and would become warmer and warmer.  The only solution I could suggest was if they could cool the water.  So, a large amount of ice was purchased and delivered which did bring the water temperature back to a more desired level.  It may seem over the top, but it worked, and basically the problem went away.

 

Many growers use water directly from bores.  This is an advantage as the water is much cooler and if large amounts of water are needed then the water doesn’t have the time to become too warm in holding tanks.  For growers whose main water source is from their reservoirs, it is a different proposition.  The reservoirs will be dropping as there has not been any major rain and the lower they become the warmer the water will become.  Even if bores are used to top up the reservoirs, the water will still be warm.  I believe these growers are at a disadvantage unless they have a way of cooling their water before the point of mixing with the fertiliser. 

I do believe if irrigation water is cooled there would be a lot less root damage and therefore the plant would be able to function better.  What I would struggle to prove is the cost benefit of cooling water as the capital investment could be too high.  However, I believe it is worth discussing.

 

Look closely and you will see the brown staining on the roots I am referring too.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

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Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower