Categories
Greenhouse News

Bio controls almost work all of summer

Psyllid yellows spoil good intentions

 

I am privileged to visit many sites and advise on multiple crops.  Whilst I advise I continue to observe and learn.   Growers’ greenhouse sites are like giant on-going research stations.  In the pursuit of constant improvement growers are always looking for an edge.   This is why industry continues to help with projects like the A Lighter Touch programme (ALT). https://a-lighter-touch.co.nz/  However, greenhouse vegetable growers have been implementing and trying lighter touches for decades.  Still, many more are required.

One crop in particular, a cherry tomato crop, has caught my eye this season which was chemical free for four months from the beginning of November to the end of February.  It was contrary to my advice and I was genuinely excited with the results, but I always had that nagging feeling that psyllids could or would cause damage.  Whitefly was controlled sufficiently with Encarsia and other biological products.

Unfortunately, my concern has become a reality, the crop is suffering from psyllid yellow damage.  As it takes over a month or even more to visually see if a plant has been infected the true number of infected plants is still unknown.   Symptoms started showing up in March and even now I am identifying plants that previously that had not shown symptoms. This invisible enemy and the damage it causes is disheartening, especially when the intentions and application of biologicals had been spot on.

Just this week I had another long-term tomato grower contact me for advice to control psyllid yellows that were identified at the property.  The grower had limited experience with psyllid yellows.  It is difficult to explain that even if you immediately apply an insecticide you will continue to see plants showing symptoms for the next six weeks or even longer.  Tomato potato psyllid is the primary vector (transmitter) of a bacterium, Candidatus Liberibacter solanacearum and have been since around 2007 in NZ.  Either this grower has been extremely lucky in previous years not to have had psyllids on his property or routine spraying of insecticides has been effective in reducing psyllid yellow infections.  I believe this grower is trying a lighter approach, the negative is that psyllids single handily have ruined the opportunity for this commercial grower and they will likely go back to what protects their business. 

In conclusion – there is still a lot of work to do, and this is just one reason why I fully support the ALT programme.  If we can control psyllids with a lighter touch then other biological applications will have greater success. 

See links below for more information on the ALT programme and a factsheet on Tomato Potato Psyllid (TPP)

https://a-lighter-touch.co.nz/

https://nzacfactsheets.landcareresearch.co.nz/factsheet/InterestingInsects/Tomato-potato-psyllid—Bactericera-cockerelli.html

 

Cover photo of obvious psyllid yellow infection – below photo is more subtle, possibly the initial stages of the infection.

 

 

Article written and compiled by Stefan Vogrincic

All Article’s checked and edited by Marie Vogrincic

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

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

Categories
Greenhouse News Technical

Melons in Greenhouses 2021

Grow them Vertically or on the Ground?

 

I contacted Sander Fleerakkers to ask if I could re publish an article  featured on the Hortdaily last week, see below.  What caught my eye was the approach of growing certain melon varieties on the ground and not vertically. 

In the past five years several growers have been harvesting greenhouse melons with different results.  I’ve grown melons myself in the past – it was a successfully grown crop. However, the return on investment was poor.  One of the biggest issues is the labour cost required to train melons up a string and prune in an orderly way – similar to the work required for greenhouse cucumber crops.  I have always wondered if any grower would consider growing outdoor varieties by simply letting them grow on the ground in their greenhouses.  

It may be a very easy crop to control at very low costs.  Planting early and by using a small amount of energy you could get the plants well advanced compared to an outdoor crop. To reduce energy cost, simply turn your heating off at a similar point outdoor crops are being planted – or possibly earlier.   For growers that have pipe rail heating simply make sure that one row in the middle of your bay is kept free of the lateral growth.  This will allow trolleys to go up and down for harvesting and spraying requirements.  You may want the laterals to go under adjacent rows pipe rails for ease of harvest.  

For growers that want to avoid the historically low late spring tomato prices and want to schedule their new tomato plantings for the new year, this could be a low investment crop with satisfactory returns subject to a marketing agreement.  If you read the article below you will note the benefits that growers in Belgium have had. 

 

Australian Imports:

I am unsure if melons will be allowed back into New Zealand from Australia due to the detection of cucumber green mottle mosaic virus (CGMMV) found on a consignment of watermelons from Queensland in late 2019.   I would encourage growers to contact MPI to find out if a decision has been approved for the upcoming season.

 

https://www.mpi.govt.nz/dmsdocument/44017-Melon-from-Australia-draft-IHS-amendment-for-consultation

https://www.stuff.co.nz/business/farming/118281005/nz-suspends-fresh-australian-melon-imports-after-fruit-disease-found

 

 

Sander Fleerakkers, Research Station for Vegetable Production

“Warm summers, new cultivation methods and varieties offer chances for Belgian melon farming”

In recent years, several trials have been conducted with melons in Belgium. The Research Station for Vegetable Production is doing these. “The last few summers have been warm. There are new insights and cultivation techniques and a revitalized variety range. All this means there's renewed potential for melons in Belgium,” says the Station's Sander Fleerakkers.

“Growing melons in Flanders isn't anything new. At the end of the last century, farmers were cultivating melons reasonably successfully in greenhouses. Then sweeter, cheaper melons began arriving from Southern Europe. So, Belgian melons were out-competed, and large-scale cultivation disappeared. However, in recent years there have been developments in the country's melon farming. The hot, dry summers and revitalized varieties offer potential to revive this crop.”

“We've been doing trials for three years now. We want to see if melon cultivation is profitable for growers. And if, and how, it's possible. We conducted tests in the greenhouse with wired melons like in cucumber farming. But we also carried out trials with open field cultivation beds,” continues Sander.

“That requires much less work than wired cultivation. There, the plants have to be pruned and tied up. The cultivation bed tests, both in the open and in tunnels, proved successful. The outdoor farming gave excellent results. Tunnel cultivation, however, was an even greater success. It produced far more, larger fruits and a longer harvest season.”

“We ran various tests with different Charentais and Galia varieties too. Last year we started testing with watermelons, but it's not going so well yet. Watermelons are very susceptible to diseases. This year we'll continue testing other watermelon varieties and Piel de Sapo melons,” Sander explains.

He says many farmers are interested in growing melons. “There are several growers who've done independent trials. The BelOrta cooperative also started with locally-grown melons last year. It's a product with which farmers can distinguish themselves nicely. But it's also something that suits a short chain well. Besides melons, other crops are also making an appearance in Belgium. We're cultivating Edamame too.”

“These new products are gaining a lot of attention nowadays. But, it remains risky. We've had a couple of great summers. However, that doesn't mean every summer's going to be the same,” Fleerakkers says. “Last year's weather was perfect for melons. But we might get a lot of rain in August this year. That could greatly impact the crop and the melon's quality, especially the outdoor ones.”

“BelOrta will again market the melons. Sales must go smoothly; these products have to reach stores quickly. Because we're close to end-users, local cultivation has an advantage. We can harvest the fruit a little later. That means a few days difference from Southern European melons. Those are harvested green and ripen during transport. So, Belgian melons taste great and ripen quickly, ready to be eaten. If the trials keep proving successful, Belgian-grown melons have a promising future,” concludes Sander.

 

For more information:

Sander Fleerakkers
Proefstation voor de
Groenteteelt
101 Duffelsesteenweg
2860, Sint-Katelijne-Waver, Belgium
Tel: +32 (0) 153 00 060
Email: Sander.fleerakkers@proefstation.be
Website: www.proefstation.be

Original article source: https://www.hortidaily.com/article/9312728/warm-summers-new-cultivation-methods-and-varieties-offer-chances-for-belgian-melon-farming/ 

Categories
Irrigation/Substrates Supporting Services

Hauiti Berries endorse Flexi Tanks NZ Ltd

Increasing from 4000m3 to 6000m3 of water storage in 2021

 

Company Introduction:

Hauiti Blueberries is located in Tolaga Bay, North East of Gisborne.  The four-hectare blueberry growing operation is using Flexi Tanks to collect and store rainwater.  I asked Operations Manager Steve Phelps for some insights into the growing operation and why they chose Flexi Tanks.

The company first discussed the idea of a protected blueberry farm in 2017.  This was a joint venture between Holdco which is the investment arm of Te Runanga o Ngati Porou and Hauiti Incorporation.  A benefit of the joint venture saw Miro provide information regarding growing blueberries under tunnels. The blueberries are also marketed by BerryCo.

 

The Construction Process:

In June 2018 Resource consent applications were approved.  Work started on all the infrastructure including power, water, roading and, land levelling in September of 2018.  The construction of one hectare of tunnels and windbreak began in January 2019. By March 9000 Eureka blueberries were planted.  By September 2019 the construction of a further three hectares of tunnel houses, all enclosed with wind break and bird netting.  This area was planted with a further 11000 Eureka plants in April 2020.

 

Water Storage:

I asked Steve a series of questions regarding the Flexi Tanks they have successfully erected at the property.  Below are his responses:

 

1   Why did you decide to use Flexi Tanks for your water storage needs?

“As we required water storage before Christmas 2020 and were unable to progress with a lined irrigation pond due to poor ground conditions, so the decision was made to look at alternative water storage options. We looked at several different types and decided to use Flexi Tanks.”

 

2   Do you use the water from the tunnel houses to fill the tanks or is it from a bore/other water source?

“We have a resource consent to draw water from springs but all our water from the tunnels can now be captured and stored in the Flexi Tank bladders.”

 

3   How much water storage capacity did you decide would be sufficient for your operation?

“We have 4000 m3 of capacity at present and have just ordered another 2000 m3 of capacity. This will give us 6 x 1000 m3 Flexi Tanks worth of storage for the 2021/2022 season. Ideally, we would like to get to 12000 m3 of storage capacity or 100 days of water.”

 

4   What was involved in preparing the land the Flexi Tanks were to be positioned on?  And how easy or difficult was it to lay the tanks out into position? 

“Because we are based in Tolaga Bay, one of the contributing factors we went with Flexi Tanks was the site preparation required. All we needed to do was have the site laser levelled and compacted as the soil was ideal for what we needed. Other options required geo tech reports and substantial site preparations.  Laying out the tanks was easy which involved 10 people to roll and position.”

 

5   What are some of the benefits to having Flexi Tanks over ponds?

“Not having any outside influences like ducks or birds and other contaminants getting into the system. Not having to fence the area of as we would need to with an irrigation dam. While we have had to invest in a treatment system due to the water having organic matter the benefits out way the negatives.”

 

6   Would you recommend Flexi Tanks to other growers?

“We have just purchased two more so yes, I would happily recommend Flexi Tanks to other people. Very professional, great service and friendly to deal with.”

 

 

Hauiti Blueberries Operations Manager Steve Phelps alonside the 50% full Flexi Tank bladders.  When the bladders are full they are at 1.6m high.

 

 

If you would like to know more about Flexi Tanks contact:

Andre Meier

Flexi Tanks NZ

Mobile: 0277 063 633

Cambridge 3493, New Zealand

www.flexitanksnz.com

 

 

 

Article written and compiled by Stefan Vogrincic

All Article’s checked and edited by Marie Vogrincic

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

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

 

 

Categories
Equipment Supporting Services

Support for Decision Making

Sensors that continuously monitor Water Content and EC

 

This week I came across athe article below on my LinkedIn page.  Whether you use Cultilene products or not or use the plant empowerment principals this article explains very precise applications.  The paragraph headed ‘Support for decision-making’ looks at the large improvements that have been achieved using sensors to continuously monitor water content and EC in the substrates.  In my view this is key for improving overall growing outcomes. 

Prioritizing humidity- is another very important factor for New Zealand growers.  The negative effects from the lack of humidity control effects all.

Well worth a read and I look forward to your comments.  Please e-mail stefan@grower2grower.co.nz or send a message via our facebook page https://www.facebook.com/StefanGrower2grower/

 

Den Berg Délice group

Since first introducing the Plant Empowerment principles around 18 months ago, Belgian tomato producer Den Berk Délice has made several changes and is already experiencing numerous benefits. Grower Lucas Aertsen explains more in this interview.

“Plant Empowerment will help us to generate optimal growth with every square metre”

Lucas AertsenSalmmeir – Den Berg Délice group

 

Lucas Aertsen is head grower at the 9.6ha tomato production facility of Salmmeir BV in the Belgian town of Rijkevorsel. This company – part of the Den Berk Délice group which has a total of 60ha of production across six locations – has a strong reputation for supplying high-quality and flavoursome specialty tomatoes to major retailers throughout Europe. Its main varieties are the red cherry tomatoes Axiany and Sweetelle, plus a number of others for the production of colour mixes.

Lucas has been working in the greenhouse sector since graduating with a degree in bioengineering from Leuven University around five years ago. “What I love about my role is that it’s so broad,” comments Lucas. “In addition to plant biology, I’m involved in new technology and IT, the energy market and, in view of our expansion plans, even construction.” A brand-new 7.2ha greenhouse is currently being constructed, where the first crops will be planted in late August. Besides that, another 8.5ha facility is being added at the end of this year with production scheduled to start in March/April 2022.

 

Transforming expertise into data

“Our company is expanding so fast that we really need to be data-driven. A couple of years ago we had six or seven growers, but there are now around ten of us and next year there will be 15. Most of the new recruits are relatively young and less experienced. So we asked ourselves how we could transform the expertise of our more experienced growers into data to help the new growers get up to speed quickly,” explains Lucas. In this context, Den Berk Délice installed the LetsGrow.com data platform around 18 months ago and has been working in line with the Plant Empowerment concept ever since.

The ‘Growing by Plant Empowerment’ cultivation method has evolved from the principles of Het Nieuwe Telen (‘Next Generation Growing’), which have been tested and proved around the world ever since first being developed in the Netherlands by P.A.M Geelen, J.O. Voogt and P.A.M. van Weel in 2005. In 2018, the founders wrote a book called ‘Growing by Plant Empowerment’ to explain this integrated approach. It is based on physics and plant physiology and focuses on keeping all the plant balances in equilibrium. Data is continuously collected and analysed during the cultivation process to monitor how the greenhouse conditions are affecting crop performance as the basis for decision-making. The concept is actively supported by a multidisciplinary team of six official Plant Empowerment Implementation Partners, including substrate specialist Saint-Gobain Cultilene, the LetsGrow.com data platform, climate computer provider Hoogendoorn Growth Management and screening specialist Ludvig Svensson.

 

Better comparisons

“Before the LetsGrow.com data platform was installed, we used to have a weekly meeting of all the growers from all the different companies in the group so we could discuss the results from our crops and varieties together. This entailed a lot of Excel sheets and printouts from the climate computer, and the preparation was very time-consuming. Nowadays, the previous day’s climate data is automatically sent to each manager via LetsGrow.com and we receive an overview once a week, plus we can always use our own dashboard at any time. This makes it much easier to access reliable data as the basis for comparing and discussing crop performance,” he adds.

To help Den Berk Délice get the most out of the Plant Empowerment principles, the company has been receiving training since October 2020. “All our growers attend a two-hour online session once every two weeks. The theory from the various chapters in the book forms the basis, but the course is also tailored to our own real-life situation,” comments Lucas. “We use our own dashboard and explore the balances, such as water, energy, assimilates, the influence of the screening strategy and so on, based on topical issues. The course is presented by experts from LetsGrow.com and Hoogendoorn Growth Management with input from the other Plant Empowerment implementation partners behind the scenes.”

 

Sharing knowledge

“We don’t want to be an inward-looking company – we believe it’s important to stay in touch with the market to hear about the latest developments, share knowledge and gain new insights that will help us to continuously improve. And our contact with the Plant Empowerment implementation partners plays a key role in that,” he continues.

Above all, Lucas has noticed that working in line with the Plant Empowerment principles has shifted the focus from subjective intuition to objective data. “That creates some lively discussions!” he says. “We have a very experienced grower on our team who has been in the tomato business for more than 20 years. We see it as a challenge to convince him to let us try things out based on the data insights, and it’s satisfying to see him gaining confidence in the data when he sees that it actually works.”

 

Support for decision-making

The rootzone is one area in which those data insights have made a big difference. In spring 2020, Den Berk Délice worked with Saint-Gobain Cultilene to install CARA MET sensors which continuously monitor the water content, temperature and EC in the substrate and communicate wirelessly via the cloud. All the data is displayed in the Saint-Gobain Cultilene dashboard on the LetsGrow.com platform. “This really supports our decision-making. Flavour is very important for us; we aim for a brix of 10.5 in our tomatoes to achieve the desired sweetness. The brix value is mainly influenced by the EC in the substrate, so if the brix drops below 10 that’s the first thing we look at – and we now have that data constantly at our fingertips.”

All the data has revealed some interesting interactions, according to Lucas: “For example, we can monitor both the EC and the radiation level changing throughout the day to identify when it’s the best time to reduce the EC. And last year, the data enabled us to experiment with the EC reduction in combination with both our irrigation and ventilation strategy. In the right combination, the plants stayed active for longer and were much better balanced in terms of photosynthesis and keeping themselves cool, with no plant stress.”

 

Prioritizing humidity

Another change resulting from the Plant Empowerment approach has been a better understanding of the role of humidity and screening. “In the past we were focused mainly on the temperature in the greenhouse, but thanks to the data insights, we’re increasingly using humidity to create an active climate – particularly in the spring and summer – by balancing our ventilation, lighting and heating strategies in line with the outdoor conditions,” says Lucas. “And our screen supplier Ludvig Svensson, another Plant Empowerment implementation partner, helped us to develop a screening strategy to maintain the optimal temperature, not only in the greenhouse but also in the plants themselves. On cold days, we now use screening more intensively to prevent energy loss from the top of the plants; it’s important to keep them warm to stimulate active growth. However, we always leave the screens around 15-20% open to allow the moisture to escape. So overall, we’re much more focused on achieving the right moisture balance – both in terms of what the plants receive and what they produce.”

The new greenhouse currently being built at the Salmmeir facility will be fitted with a hybrid top-lighting system including LEDs at 265 mmol rather than the 180mmol currently used. “Now that we have even better control over the climate and can maintain a better plant balance thanks to the Plant Empowerment approach, we believe we can work with higher light intensities and for longer periods. Some varieties will perform better under more light than others, of course, so it will still be a matter of combining the data with our own insights and experimenting with things like plant spacings. But the data gives us an excellent basis to start from.”

 

Sustainability

Last but not least, sustainability is important for Den Berk Délice. For example, the company is continuously working to further enhance its closed-loop water system, plus it is building a new storage and sorting facility which will be equipped with solar panels and be directly connected to a local industrial park’s network for thermal energy recovery. “Growing in line with the Plant Empowerment principles also supports a sustainable approach,” states Lucas. “As the agrifood industry continues to scale up, data will enable growers to manage ever-larger crop production areas. Plus by sharing knowledge, gaining new insights and optimizing our use of the very latest technologies, we can generate a better yield from every square metre with the optimum use of resources – and that’s what I personally find most important,” he concludes.

 

Source – https://www.plantempowerment.com/user-story/den-berk-delice/

This article was republished with the permission of Remy Maat, consultant at Saint-Gobain Cultilene. 

Categories
Greenhouse News Supporting Services

Working Capital

Supplied by Mat Wood – Crediflex

 

The following is not to be considered financial advice. For more detail specific to your situation, please contact the writer.

 

Working Capital is effectively the amount of money that your business has sitting in its bank account that can be used to run the business and pay for day-to-day expenses. If you have a shortage of working capital then your business will struggle to pay its bills on time and might need help. Often there can be a gap between when you need to pay your expenses and when your hard-earned money will come in. Subject to approval, this gap can be helped by some of the finance options listed below.

 

  1. Obtain an Unsecured Overdraft Facility – this is not secured against any property or assets and can be used on an ongoing basis. Pay your expenses using this, and then top it back up once your money comes in. You're charged interest monthly only on the amount that you use on a daily basis.
  2. Obtain an Unsecured Term Loan – this is not secured against any property or assets and your business is just given a lump sum of cash. This is repaid in monthly instalments of principal and interest over the term of the loan.
  3. Obtain a Secured Term Loan – this is often called a cash raise against existing assets because your business can offer an unencumbered/freehold asset such as a car, truck or digger to the lender as security for the loan. This is repaid in monthly instalments of principal and interest over the term of the loan. This is cheaper than the above two unsecured options because the lender has security they can repossess and sell to repay the loan if things don't work out.
  4. Obtain an Invoice Finance Facility – this is when a finance company will give you a percentage of your outstanding invoices straight away so that you don't have to wait 30, 60 or 90 days for that money to come in. The finance company will then receive their money when the end customer pays the invoice, along with taking a small margin. Some finance companies will finance a percentage of your total invoices, and some will finance single invoices.

 

The above working capital finance solutions are often used when trying to get through unforeseen cashflow problems, making the most of an opportunity such as bulk buying discounts for large amounts of stock, or for growth/expansion purposes.

 

Other ways to increase working capital without the use of a bank or finance company can be:

  1. Generate more sales: A higher revenue is easier said than done but consider the services you are offering. Is there room for a price increase or even a new service?
  2. Rework your current debt: Look at where your debt is currently sitting. Can you refinance or consolidate loans to lower your debt repayments?
  3. Reduce inventory levels: Take a good look at your inventory and weigh up whether you need it all. Quick turnover equals profit – could that space be filled with something that won’t sit there for 12 months?
  4. Part with long-term: unprofitable assets: If a piece of equipment isn’t earning its keep, this might be the perfect time to sell it. Increasing your working capital means profits outweighing costs. If your asset isn’t profitable, get rid of it.
  5. Negotiate with your suppliers: Many suppliers will reward your regular business with a discount on stock prices. If you’re a frequent customer that is easy to deal with, pays on time and refers other custom to your suppliers, why not ask them if they can give you a better price?
  6. Negotiate with your customers: Reduce payment terms for select customers to ensure you are paid sooner than usual.

learn more about this article or to assist with finance solutions contact Mat today:

M: 027 346 6669

E: matwood@crediflex.co.nz

W: www.crediflex.co.nz

CrediFlex are New Zealand’s largest Commercial & Asset Finance Broker – specialists in finding finance solutions for your business

 

Categories
Greenhouse News Integrated Pest Management

Armyworm Caterpillars

Chewing their way through cucumber and tomato crops

 

Caterpillars are back and causing damage to crops.  In March 2019 I published an article, when caterpillars were equally as difficult to control (see link 1 below to read the article again).  I don’t recall, twelve months ago, caterpillars being as invasive.  Predicting the presence of caterpillars in glasshouse crops, at this time of the year, is normal.  Predicting the amount of butterfly and moth pressure, that will enter your glasshouse, and the various locations is far harder to predict each year.  I am sure there is an explanation as to why some years it appears worse than others (see link 2 below). As an advisor I can only react to the problem, and the degree of the issue, once it is visible.   Personally, my threshold is one.  If I see one caterpillar, I immediately activate a plan of action, with the appropriate tools.

Historically green cabbage caterpillars predominantly cause the most damage but this year I have noticed a lot more destruction from armyworm on multiple sites geographically far apart.   Army worm, in my experience, are much harder to control.  I understand there are several species of armyworm, but I believe this is the tropical armyworm.

Bacillus Thuringiensis (BT’s) have always controlled green cabbage caterpillars superbly. However, the control it has on armyworm is much harder to evaluate.   Purely from observation I believe this sucker is harder to kill.  There may be a scientific reason for this.  However, the BT’s have some effect.  I would suggest that for armyworm you follow the minimum application intervals.

 

Resistance:

Could armyworm have developed a certain level of resistance to BT’s?  I found this extract below;

The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of BT crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and BT corn was withdrawn from the local market. Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4751857/

 

(Link 1) news/post/another-week–another-caterpillar/

 

(link 2) https://www.nrc.govt.nz/environment/weed-and-pest-control/pest-control-hub/?pwsystem=true&pwid=185

 

 

 

 

SEP 09, 2015 6:29 PM PDT

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Better Know a Microbe: Bacillus thuringiensis

WRITTEN BY: Kerry Evans

Bacillus thuringiensis is a Gram positive, soil-dwelling bacterium.  Like all Bacillus species, it is rod-shaped and produces spores.  Aside from being a close relative to Bacillus anthracis (the one that gives you anthrax) B. thuringiensis is probably best known for its use as an insecticide.
 
B. thuringiensis was first described in 1901 by the Japanese biologist Ishiwata Shigetane.  He isolated the bacteria from silkworms that died from what he called “sotto disease”.  Thus, he named the bacteria Bacillus sotto.  Later, in 1911, Ernst Berliner isolated this same species of Bacillus from dead Mediterranean flour moth larvae in the German state of Thuringia.  Berliner named these bacteria Bacillus thuringiensis (and the name stuck).
 
In the course of his studies, Berliner described the formation of inclusion bodies that he called “restkorper”.  These restkorper were actually crystals that form when the bacteria undergo sporulation.     In 1953, Thomas Angus demonstrated that these diamond-shaped crystals are responsible for the insecticidal activity of B. thuringiensis.
 

Gram stain of B. thuringiensis

The crystals, which are attached to B. thuringiensis spores, contain δ-endotoxin.  The endotoxin, encoded by the cry genes, is toxic to insect larvae when ingested.  δ-endotoxin is only active against specific insects such as moths, butterflies, beetles, flies and mosquitoes.  This specificity has allowed for its large-scale commercial use as an insecticide because it has no adverse effects on plants, humans, or other animals. 
 
How exactly does δ-endotoxin kill insect larvae?  First, the unsuspecting larvae ingest the                        B. thuringiensis spores and associated crystals.  The crystals are insoluble until they reach the highly alkaline conditions of the insect gut.  The high pH denatures the crystals, allowing proteases to process the toxin into its active form.  (Human and animal digestive tracts tend to be more acidic, which is one reason the endotoxin is specific for insects.)  Once the endotoxin is active, it binds to specific cadherin receptors inside the gut.  Once bound, the endotoxin punches holes in the cells lining the gut (ouch!), eventually killing the larvae.  It isn’t clear exactly how the larvae die.  Some evidence suggests the toxin paralyzes the gut, causing the larvae to starve, while other evidence suggests the larvae succumb to secondary bacterial infections.  One group from the University of Wisconsin presented evidence that the resident gut microbiota is required for endotoxin-induced mortality. 
 
Regardless of its precise mechanism of action, B. thuringiensis endotoxin has revolutionized the world of pesticides.  The Environmental Protection Agency first approved B. thuringiensis for use as a pesticide in 1961.  Since then, it has become the basis for numerous pesticides regularly used in backyard gardens and on commercial farms (it is even approved for organic farming).  If you’ve used products like Dipel Dust® or Bonide Thuricide® to protect your backyard garden, you can thank B. thuringiensis.
 
B. thuringiensis toxin genes have even found their way into plants, generating so-called “Bt crops” (those pesky GMOs).  In 1985, a Belgian company called Plant Genetic Systems engineered tobacco plants to produce Bt toxin genes.  Since then, numerous crops, from corn to cotton, have been engineered with Bt genes.  As of 2010, at least 50% of cotton and 40% of the corn produced in the United States was Bt-engineered.  Recently, Monsanto developed a variety of soybean that is both Roundup® (glyphosate) resistant and produces Bt toxin.  There is one caveat, however.  In 2009, Monsanto announced that the pink bollworm had become resistant to its first-generation Bt cotton.  The issue was quickly resolved when Monsanto modified the Bt toxin to produce a second-generation Bt cotton plant.   
 

Bt-engineered peanut plants (left) are resistant to insects 
B. thuringiensis is a rather intriguing microbe.  It attaches a toxin to its spore to protect itself from hungry insect larvae and, if that isn’t cool enough, managed to gain rock star status in the pesticide industry.     My point is, remember to thank B. thuringiensis next time you bite into that corn-on-the-cob.
 
Sources: University of California San Diego, National Pesticide Information Center, Bioengineered Bugs, MicrobeWiki, PNAS, Wikipedia

https://www.labroots.com/trending/microbiology/1632/better-know-a-microbe-bacillus-thuringiensis

Categories
Shading Supporting Services

Growers Can Extend The Life Of Greenhouse Film

UV radiation, crop protection agents and metals all adversely affect greenhouse plastics.

 

UV radiation, crop protection agents and metals all adversely affect greenhouse plastics. As a grower you can implement a number of measures to mitigate these effects. The use of coatings also extends the life of plastics. 

Hyplast, located in the municipality of Hoogstraten in Belgium, is a subsidiary of RKW Group and is one of the main producers of films for horticultural greenhouses and tunnels. The company produces 45,000 tonnes of polyethylene film annually. To an outsider the different films very much look alike, but due to a variety of additives, there are dozens of different versions.  

‘We can produce custom-made film for anyone. We take the kind of crop, the local weather conditions, light transmission, growing needs, mechanical properties such as flexibility, and more, into account,’ says Karen van den Bergh, R&D Engineer. 

Plastics do not last forever: they age and their properties change. ‘UV and crop protection agents in particular cause this change,’ she says. 

 

UV DEGRADES PLASTICS 

‘UV radiation affects the chemical bonds in the polymers that make up the plastics. This causes the polymer chains to break. Additionally this produces radicals; highly reactive substances that in turn attack the polymer chains,’ her colleague Hendrik Oudehinken adds.  

This process can be slowed down by adding UV stabilisers. ‘This is comparable to suntan lotion. The UV radiation is “absorbed” causing the stabiliser’s structure to change. This change is only temporary and the stabilizer reverts to the original structure, while releasing heat. This is how UV energy is neutralised,’ he says. Other additives added to plastic capture the released radicals. While they do break the polymer chains, there is no subsequent damage. 

Despite these additives, the aging process nevertheless proceeds at a slow pace. ‘It is impossible to capture 100% of the UV radiation,’ he explains. 

Furthermore, the UV light is needed, for example for the bumble bees in the greenhouse to orient themselves and for the proper colouring of some plants, such as tree nursery crops.  

 

PROTECTION 

So what can a grower do to protect his/her greenhouse or tunnel film? The approach is twofold: be careful with certain chemical substances and reduce UV radiation. ‘By using crop protection agents sparingly, and that definitely includes the use of sulphur evaporators, you extend the life of the plastic,’ says a third colleague Luc Paepen.  

‘Furthermore, chlorinated substances, such as cleaning agents, are disastrous. They break down HALS, the protective substance in polyethylene. PVC gutters, which contain chlorine, also reduce the life of polyethylene. Furthermore, it’s good to know that metals function as a catalyst in degradation processes. Having metal posts in direct contact with the plastic, for example, is not a good idea. The plastic will also degrade when there are rubber pads between the frames, because rubber contains sulphur,’ says Paepen. 

 

PROTECTIVE EFFECT OF REDUSOL AND REDUHEAT IN UV SECTION OF THE LIGHT SPECTRUM

 

 

COATINGS 

By contrast, shading agents that reflect light and/or heat can protect the film, because they block part of the UV. ‘Reflection of UV radiation prevents the film’s breakdown,’ says Paepen. ‘Furthermore, the coatings help reduce the temperature in the greenhouse and that also extends the life of the plastic. At a temperature increase of 10°C, degradation occurs twice as fast; a lower temperature slows down the process.’ 

Roel Weijers, R&D Manager at Mardenkro, explains the UV-reflective properties of coatings: ‘The heat-reflecting coating ReduHeat largely allows PAR light to pass through, but blocks a large part of the near-infrared as well as UV light. The reduction of the latter protects the plastic. A coating like ReduSol uniformly blocks the solar radiation throughout the UV and PAR spectrum. The amount of UV light that is reflected depends on the coating’s thickness (number of buckets per hectare) but it will extend the life of the plastic as it is applied during the season when the UV radiation is the highest.’ 

To read this article and more click on the link below:

https://www.redusystems.com/en/articles/growers-can-extend-the-life-of-greenhouse-film?utm_source=rs-2103-en&utm_medium=email&utm_campaign=redusystems

 

For more information:

ReduSystems®
+3113 507 53 99
sales@redusystems.com
www.redusystems.com

 

ReduSystems products are distributed by Horticentre Group in New Zealand
 

__________________________________________________________________________________

About ReduSystems®
ReduSystems® is a brand of Mardenkro B.V. ReduSystems enables growers to make optimal use of sunlight in the greenhouse throughout the year. The coatings influence the light and heat of the sun during every season to help optimise climate conditions for the crop inside the greenhouse. From a cooler climate in summer and more-light in winter, to diffusing the light and influencing the light spectrum

 

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

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

 

Categories
Energy

Energy

Unintended Consequences

 

 

Update:

One year since I posted an article on energy I am still working through the different alternative fuel/energy options. news/post/energy-options/

 

Natural Gas:

To be frank it is complicated! For example, I have been informed recently that there is ample natural gas available and that growers should still consider converting, if they are close to the gas line. On the other hand I hear from growers that gas contracts are exceedingly more difficult and expensive to secure than ever before. 

 

Electricity (Heat pumps):

Retail electricity prices are increasing at an alarming rate.  With Tiwai point recommitting and exceedingly low hydro levels, increased amounts of Gas and Coal are required to turn the lights on, it is that bad that even the Whirinaki diesel unit has also been restarted!  (click on Total Utilities March update below – I highly recommend reading).  What impact will this have long term?

 

Coal: Banned by 2037

If you were intending to install a coal burner you have approximately 8 months!  I find it interesting that Genesis Energy, which burns coal at its Huntly power station to produce electricity, also steel and chemical factories are exempt from the ban but not growers that produce healthy affordable food during winter….mmmmm

https://www.stuff.co.nz/business/124776647/most-coal-boilers-would-need-to-go-by-2037-under-government-plan

Also read:

https://www.stuff.co.nz/business/124668825/gas-appliances-would-need-to-be-replaced-from-2035-under-first-gas-hydrogen-plan

 

Recycled Oil:

Recycled oil or waste oil seems to be under the radar.  Recycled oil is a good source of affordable fuel to heat with.  I expect this could well be an option for some businesses, if there is a need to safely dispose of recycled oil then burning it to produce healthy vegetables makes sense.   If growers, and other industries, on mass decided to use this alternative option then the unintended consequence is that supply may become an issue, which will in turn make this another non-affordable fuel source for growers.

 

Solar and Wind:

Solar and wind energy generation are still options that need to be explored in more detail. They both could be valuable alternatives.

 

Will you require multiple energy sources?

I represent many growers small and large.  For smaller businesses it is difficult to see them using multiple types of energy for their heating requirements.  High capital costs will be an impediment for those businesses to implement multiple energy/heat sources.   For larger growers/businesses multiple energy/heat sources may be an option worth investigating.

 

Options for small to medium sized businesses:

For smaller growers, that are considering changing their heat source, I would highly recommend you investigate biofuel conversion.  I know that biofuel’s work extremely well, the issue is not whether it works, the issue is security of supply, pricing and transport.   Capital costs are inevitable but so is the phasing out of coal and gas.  There are going to be some unintended consequences, one of which is going to be the demand on wood fuels – this market, like any, will be driven by supply and demand and if many businesses convert to biomass, will there be enough processed wood chip or pallets to go around?

 

For companies looking for opportunities to supply biofuels, now is a particularly good time to talk to growers.

NZ greenhouse vegetable and flower producers will still be able to supply during the warmer months with or without heating, they will just be using more chemicals to control funguses.  However, if feasible solutions are not identified then only growers with geothermal, or alternative biofuel energy sources (green waste land fill gas), will be providing our winter tomatoes, cucumbers, capsicums and even roses.  If real solutions do not eventuate then I hope we are all looking forward to eating irradiated Australian tomatoes during NZ winters.

 

March 2021 Overall Market Situation

 

Source (Total Utilities)

Wholesale spot prices and ASX energy futures pricing continues to escalate with extremely low hydro lake storage and increasing thermal generation. The situation has been severe enough that the Whirinaki diesel unit has also been restarted. 

Total hydro storage is 35% below average for this time of year (47% of total capacity). Inflows which have been well below average levels since November were 59% of average in the week ending 26/03. Coupled with gas production at Pohokura being down by 42%, significant amounts of coal are being required to keep the lights on. 

Without a massive dumping of water in hydro catchment areas, pricing will continue to rise as storage nears supply risk levels.

https://mailchi.mp/e45699c61005/total-utilities-market-commentary-8469153?e=e0ccef427e

https://totalutilities.co.nz/energy-rising-market/

 

Article written and compiled by Stefan Vogrincic

All Article’s checked and edited by Marie Vogrincic

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

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

Categories
Greenhouse News

Welcome rain filling up water storage

Downside – dark warm and humid

 

We have had some very welcome rain in the past few weeks and it looks like more is on the horizon.  Our water tanks are full to overflowing and many growers will have replenished their water storage –much to their relief.

The downside to the rain is that we have had dark rainy days with warm and humid weather.  Night temperatures have been far too high for optimum growing of certain crops. I have noticed cucumber plants stretching and aborting fruit.  Achieving a day/night temperature difference has been impossible.  Light is decreasing quickly and it is simply too warm with not enough light.  Balancing a crops plant growth is very difficult in this weather.  To add to the mix this is great weather for there to be a caterpillar and fungus explosion (see this week’s other articles).  

These are challenges that occur from time to time.  This time last year, for example, it was completely different with perfect growing conditions (remember how good the weather was during the first lockdown?).   This is not a one off, this weather pattern has occurred multiple times within my time, but it still does not make it easy to control a crop, despite experiencing these conditions before. 

There will be challenges in the next few weeks and until the weather cools cucumbers, in some areas, may struggle with stretching and abortion.  Growers have the added pressure from insects and funguses so will have to be incredibly careful to control the watering and environment to limit excessive high humidity.  I would still make sure minimum pipes are on especially in the morning to prevent guttation. 

Pic – cucumbers are aboting due to the warm, wet and dark weather. 

 

Water storage – it is the silver bullet.

 

I am always amused when I hear people complaining about rain.  Coming from a dairy farming background and then moving into horticulture the most important part to prospering in these sectors is water.  It is simple without water we will not be able to grow. 

Even though the current weather pattern has caused issues for growers (as written about above), it does reiterate how important water storage is.  It is a NO brainer that with more water storage you will guarantee food production.  With much, much more water storage New Zealand could also produce a lot more hydro electricity reducing our need for fossil fuels.  But politics will get in the way of that.  For greenhouse growers my advice, when building or even retrofitting, is to make sure you understand exactly your water requirements are and build more than enough water storage to get you though these very uncertain summers. 

 

Auckland Dam level update: https://www.watercare.co.nz/Water-and-wastewater/Where-your-water-comes-from/Auckland-s-dam-levels

The Auckland damn levels are a little over 51% with the historic average at 76%.  Will it take Aucklanders to go thirsty and dirty to get someone to build more water storage?  We have an abundance of land it just makes no sense to me that we are not storing what is lost down the drain and out to sea. 

 

Article written and compiled by Stefan Vogrincic

All Article’s checked and edited by Marie Vogrincic

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

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

 

Categories
Greenhouse News Supporting Services Technical

High tech: no guarantee for success!

The technology driven design paradox. And how to do it better.

 

For good reasons the greenhouse and vertical farm industry is booming. Especially in ‘’newer’’ greenhouse crops like leafy greens and herbs the number of suppliers moving to this industry is high and still increasing. There is no lack of promises on high performance growing systems, vision on the best greenhouse for lettuce production, and the next best spectrum growing light sales pitch. All initiatives to feed future generations.

However, what most of these initiatives have in common is that they sell a promise they more than regularly cannot deliver. Unfortunately, there is an abundance of strong sales pitches. When you puzzle these promises, we see poorly informed decisions ranging from misunderstanding the market, different climate conditions not accounted for, wrongly calculated plant spacing and unsuitable materials actually impeding growing of the crop. As a result the promising numbers do not meet the expectations. In most cases caused by some unfortunate overlooked things in the development of the business plan:

 

Market: Investigate where the market is, what the demands are, and what the prices will be. Did the market asked you directly to grow? Good! Do you want to grow without knowing the demand? Make sure you know in advance where your product will be sold to, what the price will be and what the quality demands are.

Cultivation: Many systems are designed with a pure technology mindset, by itself it is not a problem. It becomes a problem when the technology is not beneficial to the crop. Designing a system without people that understand plants, and more importantly; actually growing plants instead of crops in production facilities often has undesired results. With the growing facilities looking cool and flashy (who does not like the view of multiple stacked layers with purple or white light), but unsuitable for economically feasible plant production.

System integration: A growing facility with components that are not well integrated causes inefficiencies, and sometimes quality issues and productivity losses. Buying a growing system and building a greenhouse around it may not be the biggest success when some pieces of the puzzle are missing.

The ROI: Because in the end your ultimate high-tech facility, simply cannot bring back the money that is invested. Because you can produce a multitude of different crops does not mean it is economically feasible. Especially if you are not able to grow something the market demands, with the right quality specs and in sufficient amounts to pay back the investment. Before the first spade is put into the ground for construction, make sure the economic figures are in place.

 

Some takeaways from our experience for the benefit of this beloved industry:

Knowhow: Do not go for companies (suppliers and consultants) that promise you the cheapest buy, or the fastest solution. Find people with the right mix of competences. The goal must be to develop the best, and the right growing facility for your situation: success by design.

People: You can have invested in the best climate control systems, the most labour friendly growing system,  sensors, autonomous growing models, and management support tools. But most importantly of all, you will need motivated people with the right skills and mindset for your operation. Because without them, your project might not deliver the promised results.

Network: The greenhouse and vertical farming industry has many trustworthy technology suppliers. Find people that can bring you in contact with the right network of companies.

 

Cultivators developed courses and support services for growers, investors, AND technology suppliers. Our aim is to grow your business by realizing better projects everybody in the process needs the knowledge to make the right decisions. To bring this industry to the next level we need better understanding of the plant, the market and the demands. Our team of experts will guide you through the process of business idea, to the design phase of your leafy greens, herbs and potted herbs facility, and support you from construction to commissioning. And when needed, support or organize the daily operation of your facility. That is our commitment.

 

Author – Tim van Hissenhoven, Cultivators

Published on 29/03/2021

https://www.cultivators.nl/high-tech-no-guarantee-for-success-the-technology-driven-design-paradox-and-how-to-do-it-better/

Interested to contribute to our mission and join our team?
Look at: https://www.cultivators.nl/vacancies/