MXPA99006037A - Plant protection - Google Patents

Abstract

Improved protection of plants and their crops is achieved by growing the plant under a construction having a roof with at least a substantial portion being made of a net of a mesh size allowing adequate ventilation. The net is made of a transparent or translucent polymeric material having incorporated therein a UV-light absorber.

Description

PROTECTION OF PLANTS FIELD OF THE INVENTION The present invention is generally in the field of agriculture or horticulture and provides a method and construction for protecting plants and their crops against insect infestation. The term "insect infection" as used herein, means direct infection by plant insects, for example by insects or their larvae that feed on plants or their crops, as well as indirect infection, as a result of diseases caused by microorganisms, for example viruses, for which the insects serve as an infection vector.

BACKGROUND OF THE INVENTION AND PREVIOUS TECHNIQUE The infection of plants or their crops by insects, is a main concern in both agriculture and horticulture. There are many ways to combat such an infection, for example through the use of insecticides or through the use of insect traps, or through protective nets and other means. In recent years there has been increasing popularity, particularly in intensive harvests, for plants to grow within enclosures with a network, specifically enclosures where the walls are made or consist of nets. Such networks have the advantage of allowing ventilation, blogging strong winds to some extent and preventing the entry of insects. However, such completely hermetic enclosures can not be manufactured, since sometimes there are tears or gaps in the network. In addition, each such enclosure needs to have an entrance for people, and insects can penetrate through it when the entrance is opened. Once an insect enters such an enclosure, it has the ability to infect the plants during harvest. This is a main concern in the case of insects with a short life cycle, in which case, the entire life cycle can be completed quickly within the enclosure, which provides a large number of descendants, which again can infect plants, and so on.

GENERAL DESCRIPTION OF THE INVENTION The present invention is based on the use of networks which are made of a transparent or translucent polymeric material in which there is a built-in substance which absorbs UV light (UV light absorbing substances). It has been found in accordance with the invention that the use of such networks in enclosures made of or consisting of such networks provides more effective protection of plants or their crops growing in such enclosures compared to the use of conventional networks which they do not incorporate UV absorbing substances. In the following, the term "plant protection" or "Plant protection" will be used to indicate the protection of plants or their crops from insect infection. The term "greenhouse covered with a network" will be used to indicate an area having at least one roof which is made of or has at least a substantial portion which is manufactured from a network. In addition to its roof, a greenhouse covered with a net may also comprise side walls made of or having at least a portion fabricated from a network. The term "substantial portion" indicates a portion of the walls or ceiling which is dominant and which defines the characteristics and properties of the roof or walls. In this context, a substantial portion is that portion which is sufficient to ensure adequate ventilation of the plants, for example, a portion comprising at least 40% of the entire surface of the walls or ceiling, preferably by at least 50% and more preferably at least 70%, and desirably greater than 80% of the entire roof surface or sidewalls.

According to one of its aspects, the present invention provides a method for protecting plants or their crops by preventing insect infection, which comprises growing the plants under a construction having a roof with at least a substantial portion constituted of a net or a mesh of a size that allows adequate ventilation, the net is made of a transparent or translucent polymeric material which has incorporated therein an absorbing substance of UV light. According to another aspect, the present invention provides an enclosure for growing plants comprising a roof and having at least a substantial portion fabricated from a network of a mesh size that allows adequate ventilation, the network is manufactured from a Transparent or translucent plastic material, where a substance absorbing UV light is incorporated. The construction may be a permanent construction, or it may be a temporary construction erected on the plants or on an area designed for plant cultivation. The construction can be similarly erected as is known in the art of greenhouses covered with a network. The requirement for a roof in which at least a substantial portion is manufactured from a network with the above specification, is a minimum requirement according to the invention. Even in cases where the construction comprises only one roof, without side walls (specifically the construction is open on its sides), the fact that it has a network with the above specification, provides a relatively high degree of protection against insect infection. . Preferably, however, the construction also has side walls, preferably side walls where a substantial portion is constituted of a network with the above specifications. According to a further aspect, a network is also provided for use in the above method and construction. Such a network will be referred to in the following as the "network of the invention". The network of the invention can be manufactured with a mesh size greater than that required for the physical prevention of entry of insects through the network. However, as will be appreciated, the mesh size of the network in a greenhouse covered with a network is preferably, but not necessarily, small enough to prevent the entry of insects through the network. The mechanism of action of the network of the invention in the prevention or reduction of infection by insects is not clear, although, without wishing to be limited to any theory, it is considered to be the result of a change in the spectrum of light reaching the plants and consequently the way in which plants appear before the eyes of insects.

The net may have, for example, openings of a mesh from about 4 / cm, preferably from about 12 / cm to about 30 / cm, preferably to about 25 / cm from a mesh of about 20 per centimeter, particularly preferred. . The openings can be square or they can be rectangles. In the latter case, the openings may have a mesh size in a direction of about 6 / cm, preferably from about 12 / cm to about 30 / cm, preferably to about 25 / cm, with about 20 per centimeter particularly preferred; and in the other direction, from about 4 / cm, preferably from about 8 / cm to about 25 / cm, and preferably to about 12 / cm, with about 10 per centimeter particularly preferred.

DETAILED DESCRIPTION OF THE INVENTION The present invention makes use of a network made of a transparent or translucent polymer material, with a built-in UV light absorbing substance. Examples of polymeric materials which can be used in such networks are polyvinyl, polyethylene, polyester, polypropylene, and high density polyethylene.

An example of UV light absorbing substances is benzotriazole. The UV light absorbing substance must be present in an amount sufficient to absorb a substantial portion of the UV light radiation. Typically it will be in such an amount that it filters approximately more than 60%, preferably more than 70%, and desirably more than about 90% of the UV light of the solar radiation which impinges on the polymeric material. For example, the UV light absorbing substance may be present in the polymeric material in a concentration range of about 0.1% (w / w), preferably from about 0/2% (w / w) to about 2% (preferably to approximately 1% (w / w)). In experiments carried out according to the invention, a variety of networks are used which have a mesh size from about 8 to about 24 per centimeter in one direction, and from about 4 to about 12 in the other direction with filaments in the range from 0.15 to approximately 35 mm. The UV absorbing substance which has been used is benzotriazole, at a concentration of approximately 0.4% w / w. Experiments were carried out on such networks in various crops. In the experiments greenhouses covered with a network were built, with walls and roof which were manufactured from networks with the previous specifications and the level of insect infestation was determined. This was compared to the level of infestation in greenhouses covered with a network, under similar conditions, where the networks were conventional networks. It was found that when the networks of the invention are used, only about 5% of the plants showed signs of damage inflicted by the insects, whereas in the controlled experiments, approximately 30% or more of the plants showed signs of damage inflicted by the plants. insects

Claims (4)

1. A method for protecting plants or their crops against insect infection, characterized in that it comprises growing plants under a construction having a roof with at least a portion thereof which is dominant in the defining characteristics and properties of a roof manufactured from a network of a mesh size that allows adequate ventilation, the network is made of a transparent or translucent polymeric material having a UV absorbing substance incorporated therein.

2. The method according to claim 1, characterized in that it comprises growing the plants under a construction comprising a roof and side walls that have at least a portion thereof dominant because of the defining characteristics and properties of the roof made of such a network.

3. An enclosure for growing plants, characterized in that it comprises a roof having at least a portion thereof which is dominant with the defining characteristics and properties of the roof manufactured of a net of a mesh size that allows adequate ventilation, the network It is made of a transparent or translucent polymer material, where a UV absorbing substance is incorporated.

4. The enclosure according to claim 3, characterized in that both the roof and the walls each have at least a portion thereof which is dominant in the defining characteristics and properties of the roof and wall, respectively, made of such a network.