Posts Tagged ‘ bumblebees ’

Issue 98: Greenhouse Production In Japan

January/February 2008
Authors: Mike Nichols & Bruce Christie

Although Japan has a large protected cropping industry, only a small proportion of growers use hydroponic systems, with an emerging trend towards plant factories. Report by Mike Nichols & Bruce Christie

In January 2007, we accepted an invitation to speak on organic hydroponics at the 24th SHITA conference in Tokyo, Japan. It was a very rushed visit, but we took the opportunity of looking at the progress being made in Japan in both plant factories and greenhouse crop production. This article will only look at greenhouse crop production, and plant factories will be the subject of a future article.

There are some 52,000 hectares of greenhouses in Japan, and a further 14,000 hectares of rain shelters. The bulk of the greenhouses are covered in plastic film, and less than 5% of the greenhouses are glass clad. Sixty-nine percent of the total greenhouse area is used for vegetable production, only 17% for flowers, and 14% for fruit tree production.

In such a high-tech country as Japan, it is somewhat surprising to find the area of greenhouses devoted to soilless culture is only 1,500 ha (which is comparable to only 3% of the total protected cultivation area). Although there are a range of hydroponic systems used, rockwool predominates followed by the deep flow technique (DFT), and three quarters of the crops grown hydroponically are vegetables. In Japan, melons, strawberries, and watermelon are all classified as vegetables and make up 30% of total greenhouse vegetable areas.

Our visit was in late January, the middle of the northern hemisphere winter, and our observations must clearly be tempered with this – coming from the middle of a New Zealand summer it is all too easy to be critical of production being undertaken in the most difficult part of the year.

In fact, it would be fair to say that with one exception we were very favourably impressed with what we were shown. We only had time to view a few properties in Chiba Province (just north of Tokyo), but learnt a great deal in just two days.

Chiba Province is at latitude 36°N, but has a far better winter climate than one might anticipate, as winter is the dry season, with very little cloud, and better levels of insulation than one might initially anticipate.

Presentation and freshness was paramount at this Farmers Market.

Our first visit was to a farmers’ market, housed in a specially planned building, and selling a very wide range of locally produced fruit and vegetables. Presentation and freshness was paramount, and the local farmers were clearly providing the local consumers with what they required with minimal ‘food miles’ and possibly a small carbon footprint! Of course, it is still possible that for out-of-season production the carbon footprint would still favour imported produce from a southern hemisphere country producing in the summer with lower production costs!

Our first visit was to a greenhouse strawberry producer. Producing ripe strawberries in the middle of the winter demands real attention to detail, and we were most impressed with the appearance of the crop. It was being grown in rockwool slabs on raised troughs, which were watered and fed using a recirculating hydroponic system. Surprisingly, both honeybees and bumblebees were being used for pollination with excellent results, and the price in the shop was even more impressive. We estimate that the price was between NZ$20-25 per tray, or around NZ$200/kg!

Honeybees and bumblebees are used for strawberry pollination.

In Japan, strawberries are classified as a vegetable crop.


This strawberry crop is grown in rockwool slabs on raised troughs.

The crop did not compare well with the greenhouse strawberry crops seen in Belgium (Nichols, 2006), but of course that was in the middle of the summer.

Perhaps the most interesting aspect of production was the area set aside for runner production – a key component of any out-of-season strawberry growing.

We use tip runners at Massey University (Nichols, 2002), but at this property runners were rooted into individual pots placed just below the rockwool slabs. It looked to be a more labour intensive and tedious system than tip runners.

Our next visit was to a greenhouse tomato producer. This was a little disappointing because the technology of greenhouse tomato production has developed tremendously over the past 20 years, and this was rather like visiting a time warp. High wires and layering are the keys to efficient production these days and yet this house still had low wires and layered so the fruit essentially sat on the floor.

Seedlings are grafted onto resistant rootstocks.

This house has low wires with the fruit sitting on the floor.

This operation is a small family business.

This was very much a family operation, which suggests inevitably that agribusiness will eventually take over greenhouse crop production, if only because it enables the manager to have sufficient time to keep up-to-date with new developments, and to re-invest in new technology.

Of course, it was not all bad; the next crop of seedlings had been grafted onto resistant rootstocks, the fruit quality looked excellent, and the small pack-house was simple but effective.

Deep flow hydroponic systems using floating rafts are something that we have little experience with in New Zealand. One of the main reasons for visiting Japan at this time was to get a feel for the potential of the system for leafy vegetables, particularly with reference to aquaponics. Not that Japan has developed any aquaponic systems to date, but they are well advanced with deep flow systems.

Soilless culture represents only 3% of the total protected cultivation area.

Our third visit was to a grower who produces about 250t per year of mitzudamo (also known as mizuna) from a 0.8ha greenhouse operation using a very sophisticated floating raft system. This is a continuous year-round operation, which starts with five or six seeds per cell being automatically sown on a block of polyethylene foam cells. Following germination in a controlled temperature room, the plants are grown on for a short time, before the individual cells are automatically transplanted by machine into holes in the expanded polystyrene floating rafts, then transferred to the deep flow system.

The initial rafts have their holes close together. When the plants have grown sufficiently they are again transplanted automatically by machine into floating rafts with holes at a wider spacing. The only difference between rafts is the number of holes per raft.

Seedlings are grown in small plant factories.

Mizuna seedlings with their roots suspended in solution.

Seedlings are automatically transplanted by machine into holes in the polystyrene floating rafts.

Typical DFT growing system.

Seedlings are automatically transplanted into rafts with wider hole spacings.

Harvesting rafts of leafy vegetables is still a manual process.


This small pack-house is simple but effective.

The final product ready for distribution.

A key component of successful transplanting is to ensure that the roots all hang down through the hole, and this is achieved by means of a water stream at transplanting.

The next visit was interesting because it involved the growing of spinach in a hybrid floating raft/NFT system. A similar propagation technology was used to the mitzudamo grower, but because spinach is very susceptible to root-borne diseases (e.g. Phytophthora), each planting was modularised with independent reservoirs.

High root temperatures can also increase disease risks so each reservoir incorporated a heat interchange coil, which could be used to cool the nutrient solution in the summer – between crops it could be used to pasteurize the nutrient solution by circulating hot (80°C) water through the heating coil, a novel way of reducing disease problems.

This spinach crop grown in a hybrid raft/NFT system.

Open view of the hybrid raft/NFT system.

A healthy crop of spinach.

Spinach can be susceptible to root disease problems.

Independent nutrient reservoirs prevent any disease spreading.

This grower had also started to use plant factories for some of his crop production, but in this case only for the propagation stage. We saw both tomato seedlings and lettuce seedlings grown in small plant factories, and there is little doubt in our minds that although the development of plant factories for many crops may be some years away, the use of plant factories for seedling production is here and now, if only to ensure the provision of good quality seedlings exactly when required, without reference to time of year or weather conditions. The speed with which quality seedlings can be produced on demand is outstanding.

The same cannot be said about the crop of lettuce being grown in the greenhouse from these seedlings, however. Botrytis was starting to appear, and could easily have been controlled with a single application of fungicide while the plants were small. This would have the effect of preventing Botrytis spores germinating on older leaves as they died due to old age. Initially, Botrytis normally only infects dead plant material – if the older leaves are protected by a suitable fungicide before they die, then Botrytis infection can be minimised.

An alternative strategy is to ensure that the humidity in the greenhouse is kept below 90%, but in practise this is difficult to achieve at the base of a lettuce crop. Botrytis spores require the presence of liquid water if they are to germinate and infect plants, and keeping the humidity down reduces this risk, as well as reducing the risk of tipburn on the leaves.

About the author

Drs Mike Nichols and Bruce Christie are horticultural research scientists at the College of Sciences, Massey University, Palmerston North, New Zealand. Email: m.nichols@massey.ac.nz or C.B.Christie@massey.ac.nz

References
• Nichols, M.A. (2002), Strawberry tip runners, Practical Hydroponics & Greenhouses, 64, 34-5.
• Nichols, M.A. (2006), Berry Fruit in Belgium, Practical Hydroponics & Greenhouses, 90, 41-46.

Issue 89: Blue-Banded Bees Pass the First Hurdle

July/August – 2006
Author: Steven Carruthers

Blue Banded Bee on basil flower. Photo courtesy David Radel.

STEVEN CARRUTHERS looks at the latest published research to develop the native blue-banded bee as an alternative to bumblebees for pollinating greenhouse tomatoes. He writes that while some progress has been made, researchers are still many years away from reaching a commercial outcome.

Commercially reared bumblebees are used safely in over 30 countries to pollinate greenhouse tomato crops, but this technology is not available in Australia. Pressure from NZ imports, with recent approval for importation of Dutch tomatoes, and with Chinese imports on the horizon, means that if the industry hopes to match production standards with its international competitors, all of which use bumblebees, then access to this technology can no longer be ignored.

Following a three-year Environmental Impact Study on Tasmania’s flora and fauna, where bumblebees were inadvertently introduced in 1992, the Australian Hydroponic & Greenhouse Association (AHGA) can find no reason why bumblebees should not be allowed to be imported onto the Australian mainland to pollinate greenhouse tomato crops. Despite the gloom and doom scenario painted by a few individuals, bumblebees have had no adverse effects in the island State. Additionally, an independent CLIMEX modelling study only found limited opportunities for bumblebees to establish on the mainland should they escape to the wild. Subsequently, the AHGA applied to the Department of Environment and Heritage (DEH) to allow their import onto the Australian mainland.

In the meantime, blue-banded bee researchers have been working around the clock over the past four years to develop an economical and viable alternative to bumblebee technology. A newly published study assessing the ability of the native bluebanded bee Amegilla holmesi to buzz pollinate tomato plants does little to reassure growers that blue-banded bees are an economical and viable alternative to proven bumblebee technology. The single experiment, using only four bees, was conducted in a small greenhouse with two chambers to compare blue-banded bee pollination with mechanical pollination and with control plants with no supplementary pollination. The study, recently published in the Journal of Economic Entomology, concludes that the percentage of fruit set of bee-pollinated plants was not significantly different from the percentage fruit set of mechanically pollinated plants. So far so good. This research was conducted in 2002-03.

The experiment was conducted in two adjacent chambers in a glasshouse at the University of Western Sydney, Hawkesbury Campus, NSW, during summer from December 2002 to April 2003. The chambers measured 5.25 x 3 x 4.3m (22.58sqm) and were illuminated by ambient light. The temperature was maintained for optimum tomato production at 23°C during the day and 17°C at night.

Six nesting bricks were stacked in two columns on top of hollow, concrete Besser blocks at the end of each chamber for bees to nest. Mud collected from a site where Amegillanaturally nested was used to construct the nests in the Besser block.

Bees used in this investigation were collected from the wild as prepupae and allowed to develop in an incubator to the winged stage. When the bees were ready to hatch, two females and two males were randomly selected and placed on the nesting blocks in each chamber for emergence. The bees were observed daily and immediately replaced if mortality occurred. The study does not indicate the mortality rate or reason(s) for mortality. Because tomato flowers produce little or no nectar, the bees were provided with sucrose-water solution supplied on blue sponges.

Thirty tomato plants grown to first truss stage were placed in each chamber and arranged in four rows of seven to eight plants with a metre-wide aisle between the inner rows. Plants were randomly allocated to the three treatments – bee pollination, mechanical pollination (with a vibrating wand), and control (no supplementary pollination). As trusses developed they were pruned to four flower buds. Those receiving mechanical pollination or no supplementary pollination were bagged before the flowers opened. Pollination bags were removed as soon as the last flower was set. Trusses receiving mechanical pollination were vibrated with a commercial electric pollinator every second day between 10:00 am and 2:00pm.

Pest and diseases were controlled using methods safe for bees. Encarsia formosawere introduced every two weeks to control greenhouse whitefly (Trialeurodes vaporariorum), and plants were sprayed with 1% petroleum oil every two to three weeks to control aphids and powdery mildew.

Tomatoes were harvested when the fruit were orange-red and considered mature, then weighed using an electronic scale, and their maximum and minimum diameters measured with digital vernier callipers. Seeds from individual fruit were separated from fruit pulp, air-dried then counted. Only fruit grown on trusses 2-6 were used to determine the pollination efficacy.

The study reports both blue-banded bee and mechanical pollination treatments significantly influenced all the parameters assessed – fruit set, weight, roundness and number of seeds – but they did not differ significantly from each other (Table 1). The pollination treatments resulted in 94% fruit set, which was significantly greater than the 82% fruit set for the control treatment, but reported erroneously as notsignificantly different. The fruit was also heavier and had larger min/max diameters than those produced from flowers in the control treatment. Flowers pollinated by bees and mechanical vibrator also produced fruit that was significantly rounder and seedier than those fruits produced with no supplementary pollination.

The study concludes that these results are similar to those reported for bumblebee pollination (Banda and Paxton 1991, Ravestijn and van der Sande 1991, Pressman et al. 1999), and for stingless bee pollination (Cauich et al. 2004).

When interpreting the results of the study, it should be remembered that this is a single experiment conducted in a small greenhouse with two chambers of 22.58sqm using only four bees.

There were 30 plants at first truss stage placed in each chamber, with 10 plants per treatment in each. They were grown through to 6 trusses. The treatments were (i) two female and two male blue-banded bees per chamber, (ii) manual pollination and (iii) self-pollination. Trusses were bagged for the two last treatments so the bees only had access to 10 plants with flower trusses in each chamber.

Trusses were pruned to four flower buds, so the total number of flowers per chamber available to blue-banded bees is 240 flowers (6 x 4 x 10) over a period of 3-5 months (actual dates are not given, only December 2002 – April 2003). If we take a minimum of 90 days, this is 2.7 flowers/day available for two female blue-banded bees, or 1.35 flowers per day per bee (only female bees collect pollen; two males were included with the two females in each chamber to ensure that they were fertilised and therefore collecting pollen). As the only source of food other than artificial nectar, one might guess that this would not only be inadequate for brood production, but is a very high stocking rate per flower: perhaps a starvation diet.

The researchers report only 2-6 trusses were used in the analysis. There are vague comments in the discussion section about bees initially only collecting nectar for brood cell construction, which suggests that the first truss was not adequately pollinated. Why was the first truss omitted from the analysis?

Data for each plant for trusses 2-6 was combined before the treatment analysis, thus obscuring any difference relating to truss position. These differences could be quite informative.

Some bees died and were replaced, but the researchers do not elaborate on their mortality; only that the majority of female bees survived for the duration. There is no mention of brood production and new bees, so presumably we are only dealing with four bees in total?

It’s also worth noting that the bees were confined to an area of 22.58sqm per chamber, so they had very limited distance to travel to find flowers.

There are several reporting errors in Table 1. Percentage fruit set is given as 13.7% for both mechanical and blue-banded bee pollination. Presumably, this should be 93.7%. There are also conflicting claims that there is or is not a significant difference from the control treatment.

The researchers calculate from Morandin et al.’s Canadian data that one bumblebee can pollinate 11-24sqm of greenhouse tomatoes, and they compare this with one blue-banded bee able to pollinate 7.9sqm. An enigma is how they arrived at this calculation from a 22.58sqm chamber. The study ignores the fact that there were only 1.35 flowers/7.9sqm/day = 0.17 flowers/sqm/day per blue-banded bee available. In a commercial situation, bumblebees pollinate 5-7 flowers/sqm/day (D. Griffiths, pers. comm.). Also, we should not forget the substantial differences in travelling distance.

Clearly, this study needs to be replicated on a much larger scale to be credible. The only claim that can be made is that in a small-scale experiment, blue-banded bees were able to pollinate greenhouse tomatoes and achieve comparable fruit set to manual pollination every two days. While some progress has been made, researchers are still many years away from reaching a commercial outcome.

Some facts about bumblebee stocking rates
The number of hives needed at any one time will vary with crop type (cherry tomatoes have more flowers than beefsteak), the season (more needed in summer), crop density, greenhouse covering material (bees work best under high UV light), greenhouse size, Bombus species and sub-species etc. For Bombus terrestris, it is generally recommended that about 5-15 colonies, each with 50-60 worker bees and one queen, are employed initially per hectare, with a colony life of 8-10 weeks. On average, this is one bee per 20sqm, but some bees are tending the nest so only a percentage of workers are actually foraging in the crop.

In Ontario, for Bombus impatiens, it has been calculated that 2000 bee trips/ha/day give sufficient pollination of tomatoes (Morandin et al. 2001). Under high UV light, which was optimal, there were 4.8 trips per bee per day.

The stocking rate of one bee per 20m2 contrasts with claims that a worker bumblebee can pollinate at least 500 tomato plants or 250sqm per day (van Ravestijn and van der Sande, 1991), but might be so if only some of the bees are collecting pollen.

References
Bell, M.C., Spooner-Hart, R.N. & Haigh, A.M.
Pollination of greenhouse tomatoes by the Australian Bluebanded bee Amegilla (Zonamegilla) holmesi (Hymenoptera: Apidae).
Journal of Economic Entomology99: 437-442.

Morandin, L.A., Laverty, T.M. and Kevan, P.G.
2001 Bumblebee (Hymenoptera: Apidae) activity and pollination levels in commercial greenhouses.
Journal of Economic Entomology94: 462-467.

About the author
Steven Carruthers is the Managing Editor of Practical Hydroponics & Greenhouses magazine and Vice-President of the Australian Hydroponic & Greenhouse Association. Email: casper@hydroponics.com.au

Issue 88: Bumblebees for Pollination of Greenhouse Tomato Crops in Australia

May/June – 2006
Author: Steven Carruthers

STEVEN CARRUTHERS provides an update on the Australian Hydroponic & Greenhouse Association’s application to import bumblebees (Bombus terrestris) onto the mainland to pollinate greenhouse tomato crops Crops in Australia.

Following a review period of 40 business days on the Department of Environment and Heritage (DEH) website to allow the public and industry stakeholders the opportunity to comment, the Australian Hydroponic & Greenhouse Association (AHGA) plans to proceed ahead with its application to allow the import of bumblebees (Bombus terrestris) on to the Australian mainland to pollinate greenhouse tomato crops.

The industry’s application to import bumblebees follows an eight-year investigation including a three-year Environmental Impact Study (EIS) following a national workshop to identify all the issues of concern to various groups, and an independent ‘Climex’ study to identify possible impacts on the Australian mainland. The AHGA engaged one of the world’s leading bumblebee experts, Dr Don Griffiths, from the United Kingdom, whose definitive study of all the key questions posed by both sides of the argument concludes with the following statement:

“If one considers all the facts given, then the case is clearly made to permit the commercial introduction of Bombus terrestris onto mainland Australia.”

Bumblebees were accidentally introduced into Tasmania in 1992. Although they have spread throughout the island State, studies have shown that they are mainly found in urban areas rich in imported floral species, the preferred plants of bumblebees. The EIS study found no adverse impacts to warrant their exclusion from the mainland to pollinate commercial greenhouse tomato crops.

“Bumblebee technology is available to almost every country on the planet except Australia.”

Currently, growers pollinate their tomato crops three times a week using mechanical hand-held vibrators touching each plant. The industry estimates that it costs Australian growers $25,000 to manually pollinate 1 hectare (10,000sqm) of tomatoes, against $7,000 for bumblebee pollination, a saving of $18,000 per hectare. This is a 72% saving or in excess of $8 million annually industry-wide, as well as improving tomato yields, quality and shelf life. Without bumblebee technology, Australian greenhouse tomato growers say they will be unable to compete with cheap tomato imports.

“Bumblebee technology is available to almost every country on the planet except Australia,” said AHGA President, Mr Graeme Smith.

“Pressure from NZ imports, with recent approval for importation of Dutch produce, and with Chinese imports on the horizon, means that if the industry hopes to match production standards with our international competitors, all of which use bumblebees, then access to this technology is mandatory.”

Mr Smith said: “The industry is not proposing to release bumblebees into the Australian environment. They will be confined to sealed greenhouses within hives specially fitted with a queen excluder device that allows only non-breeding worker bees into the crop. The technology is currently used in the USA and Canada to prevent the eastern bumblebee species, Bombus impatiens, from establishing in the west of that continent.

“On the basis of existing knowledge and climate restrictions, in the unlikely event of escape or accident, the AHGA predicts any chance of bumblebees establishing in Australia’s harsh environment to be very limited and transient,” said Mr Smith.

“Spurious claims that bumblebees are another cane toad or fox are clearly false.”

According to the industry’s research, bumblebees prefer exotic (introduced) plant species (90%), compared to native species (only 10%); therefore, there is little likelihood of any competition for floral resources.

Mr Smith added: “Spurious claims that bumblebees are another cane toad or fox are clearly false,” and he cited many positive examples of species imported into Australia such as the leafcutter bee, European honeybee, sheep, cattle, brown trout, and even the dung beetle without which inland Australia would be a mess. While Australia has its own native dung beetle, it simply can’t cope with the tonnes of dung expelled by imported animals on a daily basis. The dung beetle is also a friend in the cities of Australia, ridding parks of tonnes of dog droppings that occur every day.

Returning to bumblebees, the AHGA proposes to import only certified pathogen and parasite-free bumblebee stock from reputable producers. Mr Smith said that any parasite or pathogen that has been associated with Bombus terrestrisis unique to bumblebees and poses no risk to Australian honeybees or native bees.

“Despite the gloom and doom scenario painted by a few individuals, no adverse effects have been shown there.” (in Tasmania)

The industry’s detailed report points to previous releases of bumblebees on the Australian mainland in the 1800’s and 1900’s that failed to colonise. Although there were no studies conducted on these releases, Australia’s harsh climate and lack of all-year-round floral resources, are thought to be contributing factors why they didn’t colonise. In their native distribution range, bumblebees are only found between latitude 60°N and 30°N, which helps explain why they have established in New Zealand and Tasmania which enjoy similar climates. Ants are also thought to be a contributing factor for the failure of previous bumblebee releases on the mainland to colonise. Unlike honeybees that build their hives above the ground, bumblebees are ground nesters, usually in damp areas.

In the event that bumblebees do establish on the mainland, an AHGA-funded Climex study indicates that any distribution will be confined to the cooler, wetter areas and limited to Victoria, just over the NSW border, and the southwest corner of WA.

“First reported sightings of bumblebees in Tasmania, which has a much more suitable climate, were around 1992,” said Mr Smith. “Despite the gloom and doom scenario painted by a few individuals, no adverse effects have been shown there.

“Bumblebees have been present in New Zealand for over 100 years, and are popular with farmers and public alike. Over this time there have been no definitive examples of any negative effect on that country’s native flora and fauna, and reports of a negative impact in Israel and Japan are false, having been based on poor and limited research,” said Mr Smith.

“The threat to the survival of the Swift Parrot has everything to do with land clearing, wood chipping and habitat destruction.”

Mr Smith added that any threat to endangered Australian birds is pure speculation. While there has been some suggestion that bumblebees are a threat to the survival of the Swift Parrot, the EIS has shown a low bumblebee visitation rate (2%) to favoured blue gum flowers, compared to 56% for honeybees and 25% for birds.

“The threat to the survival of the Swift Parrot has everything to do with land clearing, wood chipping and habitat destruction,” he said.

Overseas experience has shown that bumblebees work long hours and have a high flower visitation rate, around 450 flowers/hr. They buzz pollinate, can tolerate the physical conditions existing within a commercial greenhouse, are housed in trouble-free hives suitable for delivery to growers, breed in sufficient numbers to provide the correct ratio of bees to open flowers (240,000 flowers/ha/week), and are available 52 weeks per year.

“Can they (blue-banded bees) be reared cost-effectively, 52 weeks a year?”

Mr Smith said that while native bee research is encouraged, the industry must be practical. Current research to develop a commercial solution using native blue-banded bees is now in its third year, and still a long way from developing economically viable commercial hives for pollination.

“Will this ever be accomplished, and if so, in what time frame 5, 10, 20 years,” questioned Mr Smith. “Can they ever hope to meet the requirements of a rapidly developing and expanding high technology industry? Can they be reared cost-effectively, 52 weeks a year? How much research money will be needed, with the possible result of no suitable alternatives at the end of it all?”

Although native bee researchers have been successful in breeding small numbers of blue-banded bees using clay and brick mortar nests in the greenhouse, it is not economical to ship mortar hives around the country. Researchers speculate that growers will maintain mortar hives within their greenhouse, which will be replenished regularly; however, the growers I have spoken to say they are simply replacing one labour cost for another and it is unlikely they will maintain permanent hives. By comparison, bumblebees are delivered in cardboard boxes which come with feeders for the life of the artificial hive – for bluebanded-bees, growers will be required to replenish feeders strategically located throughout the greenhouse. For bumblebees, all the grower is required to do is position the hive and open the cardboard entry/exit flap.

There is also a concern about the unusually large breeding area (5,000sqm) required to supply the entire hydroponic greenhouse tomato industry with fresh native bees on a monthly basis. The industry is currently going through expansion with at least another 24 ha of greenhouse production area due to come online during 2006. Presumably, this breeding area would need to expand to meet the future demand of the industry.

There are still many questions to be answered, and no certainty researchers will be able to deliver a commercially viable native bee alternative to bumblebee technology; if at all.

The AHGA believes it has a strong case for allowing the distribution of secure hives of B. terrestristo mainland greenhouses, and it hopes that the misinformation campaign against bumblebees will not prejudice the final outcome. To date, conservationists have been running a strong campaign against the application and they have succeeded in having the bumblebee listed as a ‘Key Threatening Process’ in Victoria and NSW; however, the Federal Government declined to support their application due to “insufficient evidence to support the claim”.

There have been public claims reporting that bumblebees are a pest in other countries, whereas a search of the scientific literature shows that the bumblebee is not regarded as a pest anywhere in the world. ABC Landlinealso incorrectly reported (12 February) that the Australian Quarantine InspectionService (AQIS) had already rejected an application to import bumblebees, when the application submitted by the AHGA is still with the DEH and has not yet been passed on to AQIS. These incorrect reports should be of real concern to industry for the success of its application.

Cost:benefit calculation
Bumblebees are very efficient pollinators. They can deliver up to a 28% increase in production in ideal conditions, at a cost of only 1% of production. If we assume even 10% improvement, then growers can make their own calculations:

Greenhouse size x Average Yield per m 2 x Average Gross Return per kg x 10% = improved yield by bumblebees.

Sample calculation for 4000sqm:
4,000 x 45kg/sqm x $3.00 x 10% = $54,000
Plus labour savings above – 4,000 x $1.80 = $7,200
Total saving = $61, 200

NOTE: These costings do not factor-in improved working conditions and worker safety that can flow on from the use of bumblebees.

About the author
Steven Carruthers is the Managing Editor of Practical Hydroponics & Greenhouses magazine and Vice-President of the Australian Hydroponic & Greenhouse Association. Email: casper@hydroponics.com.au  Ω

PH&G May/June 2006 / Issue 88

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