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16

After bunching, tulips should betrimmed andthen

placed in clean, cold water.

tulips with the bulb still attached, especially if they have to be stored over aweekend, so that the flower continues to

be provided with food.It is also possible to delay harvesting

timeby lowering the greenhouse temperature to 5°C for a maximum of 7-10 daysat any stage in the plant development. Itis then brought back to the original temperature. Lowering the temperature does,however, cause a large increase in the relative humidity in the greenhouse and thusmust, at all costs be kept below 80%, forexample, by ventilation.

Tulip plants should be dry when harvested to prevent the development ofBotrytis (leafspots). It is also recommended that harvesting iscarriedout 1-2times every day to increase uniformity of

Tulips should be stored upright and there should besome slight air movement to prevent the developmentof Botrytis.

FlowcrTECH 200J, vol. i/no. 2

the product. The temperature of theflowers should then quickly be loweredto 1-2°Cin order to prevent or limit theeffectsof ethylene, bacteria, fungi andother contaminants on the cut surface of

the stem. This limits the flowers rate of

respiration and thus consumption ofnutritional reserves, and its transpirationrate so that the flower does become limpand the transport of nutritional reservesto the flower can continue unhindered.

Dissication can be prevented by keepingthe relative humidity high.

Once this temperature hasbeen reachedthe tulips can be bunched and settingthem upright will help prevent thecrooked growth of thestems duringstorage.

GradingGrading according to quality and lengthincreases the value of tulips so it isimportant to ensure that when bunchingthat the buds are at the same height andthat the difference in overall length is nomore than 3-5 cm. The rubber band

should not be too high and the packaging must not damage the leaves. Also ifthe bulbs were still attached they shouldbe removed before bunching with a bulbremoving machine or clean, sharp knife.

After bunching trim the tulips and putthem in clean, cold water (1-2°C) for 30-60 minutes. Then store the tulips, preferably upright at 1-2°C and provide aslight air movement to help prevent thedevelopment of Botrytis.

The storage period should be no longerthan 1-2 days but if for some reason thismust be longer, for example over a weekend then it is advisable to leave the bulb

attached to the stem. The longer thetulip has to remain in storage the greaterthe chanceof it suffering from desiccation, presence of ethylene and disease.

Finally the tulips should also be transportedat 1-2°C and the tulip sellersshould be advised to trim the flowers

after their arrival in the shop and putthem in water at 1-5°C for several hours

and not to have any fruit or other ethylene producing products in thevicinity. I

Ethylene blocker

N*— By Helen Armstrong

High levels of ethylene created duringthe storage of tulips pose a significantproblem for bulb quality. Affectedbulbs fail to flower and stock bulbs

split excessively leading to small daughter bulbs. Normally these bulbs willproduce 2-3 daughter bulbs per bulbbut ethylene can cause 5-6 daughterbulbs to be produced, all of which aresmaller than normal.

The problem is that tulip bulbs areparticularly sensitive to ethylene, evenat 0.1 ppm, and the combination ofthe bulb and the ubiquitious fusariumfungus found in the bulbs creates highlevels of ethylenewhile they are beingstored from July to November (northern hemisphere).

So far the only way to prevent theaccumulation of ethylene is to ventilate the storage chambers usually at a

Commerical

For a northern hemispherebased company to additionally be able to produce bulbsin the Southern hemispherebrings both market andquality advantages.

During the last few years many bulbproducing companies, particularlyDutch companies have started operations in the Southern hemisphere inorder to be able to supply fresh bulbsall over the world throughout thewhole year. Being able to supply freshbulbs in the Spring to growers inHolland gives them a much betterquality product than bulbs which havebeen stored for several months.

New Zealand, South Africa and

Chile are all beingexplored as newproduction sites although one Dutchcompany, van den Bos, after trials in

Interaction with fungiMost bulb mite injury is on plant partsbeneath the soil surface, but mites have

sometimes been collected from lily stemsand leaves. In severe infestations bulb

mites may even work their way up intothe stem. Bulb mite infestations can

stunt, distort or even stop plant growth.Miteswill injure apparently healthy planttissue, but infestations develop fasterwhen bulbs are also infected with

Fusarium or other fungi. In fact, theremay be a chemical attraction betweenbulb mites and bulbs infected by fungi.It is not yet known how important fungiare as food, but mites are definitelyattracted to bulbs, conns and tubers

infected with fungi. This relationshipcomplicates trying to estimate how manybulb mites it takes to injure a plant.However, if there are over 100 bulb mitesper bulb one can assume that there willbe some injury visible on leaves and/orstems.

ManagementManagement is difficult and the usualmethod with potted greenhouse crops isto apply an insecticide/miticide or combination of an insecticide/miticide and

fungicide. But, bulb mites are resistant topesticides in several chemical classes.Most products registered specifically formite control are ineffective. Pyrethroidinsecticides are not effective. Most of the

effective pesticides are in pesticide classesnow under scrutiny by theEnvironmental Protection Agency: theorganophosphates and carbamates.

The best bulb mite control seems to be

obtained with the organochlorine miti-cide dicofol (Kelthane) - generally bysoaking bulbs in a suspension of the pesticide for 30 minutes before planting.Drenches of Kelthane after planting are

Hypoaspis aculeifer, apredatory mite whichfeeds on bulb mites.

(Photo: Koppert

B\ 'IGroehten en Fruit).

not as

effective, but do help.The relationship between bulb mites

and fungi complicates control of plantpathogens as well. Research done at theUniversity ol Minnesota found that controlling plant pathogens with fungicideswasonly possible when bulb mite infestations are low. Therefore, the bottom

line is that bulb mites and plantpathogens must be managed together.The question is, how?

Alternative controls include hot water

treatments (soaks and vapor) and biological control. Plot water treatments have

been successful at mite control, but

unfortunately have also injured bulbs.Perhaps someone ought to try a drenchof a pesticide in water that is just belowthe temperature for bulb injury.

Predatory mites in the genus Hypoaspisfeed on all stages of bulb mites. Hypoaspismites also are effective predators of fungus gnats and thrips transformationstages, so introducing these mites at thebeginning of a crop, or as soon as potsare brought into the greenhouse from thecoolstorage facility could help keep bulbmites below damaging levels. Fungicidedrench applications for plant pathogencontrol could still be applied. If furtherresearch shows that Hypoaspis mites cancontrol bulb mites, this would be the

preferred management method. I

Information in ibis article isfrom a number of

sources, butit comes mostly from themost recent

review ofbulbmiles entitled, "Biology, ecology, and

management ofthe bulb miles ofthe genus

Shizogfyphus (Acari: Acaridae)" by Diaz etal. waspublished in 2000in ExperimentalandApplied

Acarology, Volume 2-1: 85-113.

-/ i

BULBS

Post harvesttulip care

Cutting offtulips from theirnutritional supply ivill cause themto rapidly deteriorate unless they aretreatedproperly.

By the International flower Bulb Centre,The Netherlands

If flowers are harvested before they aresufficiently mature the plant will not havetime to lay down nutritional reserves inthe stem and it will be impossible to produce satisfactory flowering. Thus, insome cases it may be better to harvest

If tulips have to be stored over a weekend it may be

better to harvest them with the bulb still attached so

thattheflower continues to receive food.

FlowerTECH 2001, vol. 4/no. 2 15

eliminates need for ventilation during storage of tulip bulb

rate of 100m' /m3 of bulbs/hour. No

other crop requires sucli a largequantity of fresh air but becausethere are no cheap methods of measuring the amount of ethylene gasgiven off, maximum ventilation ratesmust be imposed as a precaution.Bearing in mind that a constanttemperature must also be maintained the energy costs associatedwith tulip bulb storage are extremelyhigh.

Now an alternative procedure hasbeen developed although approval inmanycountries is still awaited. It isbased on a gas which blocks thereceptors to which ethylene binds.Dutch researchers at the Laboratoryfor Flower Bulb Research, in Lisse,

have found the gas, code-namedEB-01, to be harmless to people butespecially effective in preventingdamage to the bulbs.

"It is a chemical gas which hasasimilar molecular structure to ethylene. It binds to the ethylene receptors on the bulb preventing theattachment of ethylene.

"We have been workingwith it forseveral years and the results are verygood," said Henk Gude, of theresearch laboratory.

"When we pre-treat bulbs for 12-24hours with 1 ppm of CB01 the tulipbulbs are completely insensitive tohigh levels of ethylene (200ppm) for10-12days. Repeating the treatmentcan extend the inscnsitivity," he said,

RegistrationAlthough the gas appears to beeffective it must still go through thelong drawn out process of registration in Europe which is beingimplemented by the mulinationalcompany, Rohm & Haas. Also, it is

advantages of setting up in Chile

important that when the gas is available it is affordable so that the producer receives both economic and

quality advantages.It is already registered in the USA

where it is used as a pre-treatment forcut flowers, especially carnationswhich are particularly susceptible toethylene. The only other pre-treatment currently available is silver thio-sulphate.

Anotherapplication for the gas willbe to use it when transporting bulbsby sea container where the ventilation possibilities are limited.

In addition to pretreating cut flowers the gas can also be used toenhance quality of pot plants duringtransportation. Often this involvesseveral days in a dark truck whichstresses the plants causing them toproduceethylenewhich leads toflower and leaf fall. I

BULBS

many countries has found Chile to bethe best for it. Production here is allow

ing thecompany to supply a year-roundprogramme for growers, which means abetter service for customers and due to

the better quality, better margins for thecompany.

One of the major advantages of working with a company in Chile is the ability to supply high quality bulbs to Japanand the USA, the world's first and second largest consumer's of lilies in theworld. Even the South American market

is growing as more people are willingand/or able to buy flowers. Buyers in theUSA appreciate the qualityguaranteeand are prepared to pay a premium pricefor it. Also, according to van den Bos,because more and more flowers are sold

to supermarkets, growers have to supplygood quality all year round or risk beingsqueezed out of the chain. Converselyquality guaranteed products should notonly maintain sales but also cause themto rise.

Adapting Dutch technologyVan den Bos, through Pacific Flowers hasalready set up supply programs to customers in the US with supply of Dutch,French and Chilean bulbscoming mostlyfrom Chile. The company is hoping toextend the program to Japanese customers. The European market is not thefirst priority due to high transport costsand Chilean bulbs would need to be

planted in greenhouses under lightswhich would mean higher productioncosts even though these bulbs are reliableand secure.

Pacific Flowers was founded in 1991

and now has operations in Olmue,Canete, Puyehue.

Olmue has 10 ha of greenhouses inwhich mainly lilies and tulips are grownas well as chrysanthemum, allium andnerin. With modern techniques for temperature and climate control the siteproduces over 6.4 million stems peryear, virtually all of which is soldthrough Duamex Inc,of the USA, the

country's largest lily wholesaler.Canete is the company's central site for

the production for bulbs, with morethan 152 hectares and advanced tech

niques and machinery. The companyworks with small growers, who arebonded together in a cooperation, towhom PF outsources a large part of thework. A small areaof the land belongsto VDB which enables it to increase the

delivery of bulbs and also to secure theplantation of new varieties planned forthe coming years.

A 74 ha site in Puyehue produces flowers and bulbs, mainly tulips and peonies.Flere a cooperation isalso active in orderto provide services to PF. The companyhas been active for four years adapting thebulbs to another hemisphere, by incorporating the technology of the Dutch market. I

FlowerTECH 2001, vol. 4/no. 2 17

1

Currency and competitiondepress Israel's growers

Israel is still managing to maintain its supply ofcutflowers for export despite afall in the number ofproducers, adverse currency exchange rates and asharprise in production costs. However, the number ofgrowersis expected to declinefurther and others are beingforcedto undertake new strategies.

By Aaron Prtel

18

Exports of Israel's cut flowersalways peak in December tomeet the Christmas and New

Year demand and the year2000 was no exception.Between 65 million and 70

million stems were flown out

of the country during a two-

week period. This was thesame quantity as in 1999,despite the sharp decline inthe number of growers andthe shortage of workers due tothe outbreak of hostilities in

the region. The flower sectorremains Israel's largest agricul-

Israel's top export cut flowers

Quantity 2000(million stems)

1999/2000(change in %)

Roses 450 -5

Solidago 130 -20

Greens 125 +3

Gypsophila 115 -27

Standard Carnation 80 -23

Wax Flower 75 -3

Ruscus 75 -9

Anemone 40 +8

Gerbera 40 -15

Limonium 35 -20

Asc.Tuberosa 32 -8

Leuca "Safari Sunset' 28 +10

Hypericum 25 -32

Helianthus 20 -40

Aster 15 -40

Lilium 15 -10

Anigozanthos 14 -20

Trachelium 14 -15

Ornith. "Dubium" 12 -10

Lisianthus 12 + 15

Others 150 -10

Total 1,502 -8

Source: The FlowerBoard of Israel, December 2000

FlowcrTECH 2001, vol. 4/no. 2

Gypsophma is one ofthe most popularflower crops in Israel but many growers aremoving to new cultivation areas to take advantage ofclimatic conditions which aresuitablefor newcrops.

tural exporter and it is forecastto export 1.5 billion flowersduring the 2000/2001 season,but this is a drop of 8% compared with the previous year.According to the Flower

Board of Israel, the number ofactive growers in 2000/2001fell to 1,621, compared with1,957 in 1999/2000 and

2,213 in 1998/99. This islargely attributed to anincrease in the size of individ

ual farms, an upgraded levelof professionalism, the promotion of direct deals

between "rowers and overseas

clients, the introduction of

new crops and the move tonew cultivation regions,specifically from the country'scentral region to its southernareas. This last point indicatesa new approach to cultivationstrategy, according to YaakovSitton, general manager of theFlower Board of Israel.

He said that the move from

the central region to thesouthern region - the Negevand the Arava - "is a processby which the flower cultivators take full advantage of theclimatic and topographical

Export of Plants and Propagation Material

Pot Plants

Quantity 2000('000 pieces)

2000

1999/2000(change in %)

+1.5

Propagation material 170,000 +7.5

Flower bulbs 85,000 +4.5

Source: The FlowerBoardof Israel,December 2000