Növényvédelem Plant protection

In greenhouse cut flower production presence of different pests and diseases has to be expected, according to cultivated species, however there are more harmful organisms, which may cause significant economic damages on several host plants. The harmful organisms of the main cultures are the followings:

The protection against powdery mildew is the backbone of plant protection in rose production.

Furthermore, botrytis, downy mildew, rose rust and spot diseases – which damage on foliage – may occur. Out of pests, spider mite, greenhouse whitefly and aphids are the most notably.

White rust is the most important disease on chrysanthemum, but botrytis may also cause great damages – especially in traditional production, in autumn. It may be infected by Fusarium from the soil, as well as by different viruses and Micosphaerella from propagation material. Piercing and sucking insects (aphids, mites, thrips) are important virus vectors. Lygus bugs may cause significant damages in production of disbudded chrysanthemums. It injures flower buds and so causes distorted flowers. Its quarantine pest is the soil dwelling chrysanthemum leaf nematode.

Out of diseases on gerbera Phytophthora has outstanding significance. It multiplies mainly in cold and wet soil dangerously, and it occurs often together with other wilt diseases. Other most commonly found disease is grey mold, which may cause symptoms on every above-ground part of the plant. In pests, greenhouse whitefly, two-spotted spider mite and American serpentine leafminer could be extracted.

4.5.7 Timing

It is written in detail about timing of blooming in the chapter about growth regulation of ornamental plants. There is wide range of applied methods, and the significance of timing – in Hungarian conditions

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– is the most outstanding in cut flower cultures. Hungarian customers buy cut flowers on the so called specific days, therefore market demand is very wavering, and sale period is often really short.

In this regard, chrysanthemum is commanding among of cultures, around its 70 % is sold up to this day in All Souls‟ Day. Applied timing methods in several cultures are summarized in the table bellow.

Timing methods of the main cut flower cultures

Culture Timing methods Resorts Main sale periods

Rose phytotechnical

operation pruning,

harvesting, bending

all-year-round, as well as for specific days, typically from early spring (Valentine‟s Day) to autumn (Katherine, Elizabeth)

Chrysanthemum Short-day

treatment Black plastic foil

or fabrics all-year-round, demand of spray varieties is more or less steady, outstanding sale period: All Souls‟ Day

Carnation phytotechnical

operation pinching all-year-round, as well as for specific days 4.5.8 Szedés

Harvesting

Storage life of cut flowers is influenced by harvesting time and method, therefore acquirement of typical technology of species is very important. Optimal harvesting time is determined by typical phenological stage of several species. It is also influenced by the date of harvesting (winter or summer), because in summer fast-blooming flowers may be harvested in an earlier developmental stage. There are differences in harvesting in the case of outright and after-storage sale.

Rose is ready for harvest, if calyxes split and bud is slightly open. The opening of carnation is defined by flower shape. In summer flowers are harvested in „V” stage, while in winter in „T” stage. For post-harvest flower bud opening (see later) flowers may be picked in tight bud stage, too. Practically, chrysanthemum is harvested in whole opening, while in gerbera harvesting time is determined by the opening of tubular flowers (circles of male flowers): in winter it is picked with 3-4, in summer with 1-2 opened circles of male flowers. Picking of Inca lily starts, if at least one flower opens and shows its colour in the inflorescence. Bird of paradise may be harvested, if at least one flower rises from the inflorescence spathe. Flamingo flower is mature for picking, if bract expands completely, and half of the spadix is coloured. Cymbidium flowers may be harvested singly or in cluster, in the latter case it is more advantageous to wait for the opening of last flower. In the time of blooming stand has to be protected from humble-bees, because due to pollination senescence speeds up, flowers fade away and they can not be sold. Flowers of bulbous plants are harvested typically as undeveloped as possible. Vase life can be so increased: tulip can also be picked in green bud stage, while daffodil in closed bud stage, however customers do not have an open mind in every time on these „immature” flowers. Lily has to be harvested in closed bud stage, because opened flower is fragile, it is difficult to transport them.

Harvesting method depends also on species. It is worth picking rose with special rose shear, with which flower stem may be held and pulled out from the stand. Carnation is broken at nodes, while gerbera is broken by twisting. It is worth harvesting chrysanthemum also with braking. Tulip and hyacinth are cut by shear, or picked together with bulb and cut by machine. Daffodil is cut, or pinched from stool by hand. Bird of paradise may be harvested by cutting, while calla lily by twisting from leaf sheath.

Cymbidium is cut by knife, for prevention of virus transmission knife is sterilized after every plant, or private knifes are used for plants showing virus symptoms.

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Cut rose ready for harvest

Stages of opening of carnation

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Anthurium ready for harvest

Harvesting of cut lily

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79 4.6 Marketing, trade