ES2345593B1 - COMPOSITION OF ACAROS, PROCEDURE FOR THE RAISING OF THE SAME AND USE OF SUCH COMPOSITION IN BIOLOGICAL CONTROL PROGRAMS. - Google Patents

Abstract

Mite composition, procedure for breeding of them and use of said composition in programs of biological control.

The present invention relates to a mite composition, its breeding procedure, as well as its use in biological control programs. In particular, the present invention relates to a composition composed of the species of predatory phytosid mite Amblyseius swirskii and a factitious host of the order Astigmata, in particular Acarus siro , Linnaeus, 1758, to its breeding procedure and the use of said composition in biological control applications.

Description

Mite composition, procedure for breeding of them and use of said composition in programs of biological control.

In general, the present invention relates to a mite composition, its breeding procedure, as well as its use in biological control programs. In particular, the present invention relates to a composition composed of the species of predatory phytoseid mite Amblyseius swirskii and a factitious host of the order Astigmata, Acarus siro , Linnaeus, 1758, its breeding procedure and the use of said composition in applications of biologic control.

The introduction of biological programs that employ arthropod species as control agents comes waking up, from the second half of the 20th century, a continuum interest from producers of a wide range of crops, particularly from warm geographical regions, such as the basin of the Mediterranean. So much so, that this practice has gone from one amateur-driven management by individual farmers to be articulated under large commercial farms, where international companies produce the beneficial agents in large quantities throughout the year, agents that are supplied to countries worldwide.

Thus, the practice of biological control is growing steadily, year after year, according to the growing demand for food products free of chemical waste by part of government health and safety legislators, wholesale companies and their retail customers.

The benefits obtained by the producers and consumers as a result of the corresponding decrease in the use of chemical pesticides are obvious and quite considerable.

Therefore, there is a great need to increase the current portfolio of commercially available beneficial agents. In particular, of being able to produce those that are specific or almost specific to the target pest, and of produce them in quantities large enough to be able to sell them at cheap prices to farmers.

Many of the commonly used agents are monophages, which means they can only be raised in pest species that constitute your diet, and that, of course, They are the ultimate goal of the beneficial agent. Since you are pests live in plants, producers are forced to incorporate the use of heated greenhouses in their systems production, which constitutes an increase in the productive cost that It affects the farmer's chain to the consumer.

In recent years, research and Commercial companies have shown that many acarinides (mites) common crop predators can be raised without pest species.

To date, most of these species have not plague are mites belonging to the order of acarigids Astigmata and, as such, they are small soft-bodied individuals who have proved to be ideal hosts to feed the species larger predators. Another advantage is that many of these astigmatid species are not predatory, nor show cannibalism and easily feed a wide range of foods from farinaceous nature. In addition, the populations of these mites astigmatids increase very rapidly when the correct food and physical conditions, providing a continuous supply of prey for the selected predator.

While some members of the Astigmata order, for example those of the genera Calvolia and Tyrophagus , including the species T. putrescentiae , can exist in plants within the habitat of phytoseid predators and, therefore, can be found in fruit trees, others never they occupy these habitats of phytoseids, but are associated with stored food and warehouses or dwellings that contain food products.

Therefore, when used as food for the predators, these astigmatid spices by definition are They classify as "factitious guests."

Currently, there is a limited number of phytoseid species commercially reared in factitious astigmatid hosts. The first and most common application was the development of commercial breeding of phytoseid Neoseiulus cucumeris and, to a very limited extent, of Amblyseius mackensie , using astigmatida species Acarus farris , Oudemans as a host.

More recently, due to the increasing problems with whitefly infestations, especially in Spain, a combination of phytoseido Amblyseius swirskii with the astigmatid host Carpoglyphus lactis has been developed for commercial use, and is being sold in Spain by various control companies biological.

Because there is currently a very number limited of phytoseid species commercially raised in hosts astigmatid factitious and to the growing demand of the market of the biological control systems there is a real need for increase the number of products available, both to increase the agent portfolio, as to, in this way, help reduce production costs.

In EP 1686849 B1, "METHOD FOR REARING THE PHYTOSEIID PREDATORY MITE AMBLYSEIUS SWIRSKII , REARING SYSTEM FOR REARING SAID PHYTOSEIID MITE AND METHODS FOR BIOLOGICAL PEST CONTROL ON A CROP", a mite composition comprising a population of the species species is described Phytoseid predatory mite Amblyseius swirskii and a factitious host population (Carpoglyphidae), which can be used for the breeding of said species of phytoseid predatory mite or for the release of the phytoseid predatory mite species in a crop. Likewise, in another aspect, the invention described in EP 1686849 B1 refers to a method for the breeding of the phytoseid predatory mite species Amblyseius swirskii , to the use of said composition and to a method for biological control in a crop using said composition. -
tion.

WO 2008104807 (A2), "MITE COMPOSITION", describes a composition comprising a population of predatory mites and a host population of the family Suidasiidae or Chortoglyphidae, claiming a composition where the predatory mite is the phytosid mite Amblyseius swirskii .

The object of the present invention is, according to a first aspect thereof, a new combination consisting of a predatory phytoseid mite and a factitious host, the predatory phytoseid mite Amblyseius swirskii , Phytoseiidae, Acariña, and the factitious host belonging to the species astigmatida Acarus siro , Linnaeus, 1758. Preferably, the combination of the invention has a ratio of predatory individuals: factitious hosts between about 1:10 and about 1: 100.

Another object of the invention, according to a second aspect thereof, relates to a new breeding method of the predatory phytoseid mite Amblyseius swirskii , Phytoseiidae, Acariña and a new breeding system using the astigmatid species Acarus siro , Linnaeus, 1758, as factitious host for the breeding of the aforementioned predator Amblyseius swirskii .

In a third aspect of the invention, this refers to the use of the Amblyseius swirskii predator produced in the aforementioned system for the biological control of agricultural pests in accordance with the methods and procedures according to the invention for the application of the composition in programs of Biological control in agricultural crops.

The introduction of commercial use of this combination will increase the portfolio of biological agents available for whitefly control, generating it competition time between producers and reducing in this way The costs for farmers.

In accordance with the first aspect of the invention, in the implementation of the present invention, Acarus siro meets all the requirements for the success of commercial development, since it is a simple, reliable and cheap system that provides large sustainable populations for its use as a factitious host for this predator, being also one of the fastest breeding species in the group.

In this regard, Acarus siro is a prolific egg producer and the physical requirements for breeding success are very reasonable, preferably at a temperature of approximately 20-25ºC, especially 24ºC, and a relative humidity of 75-85% .

The previous technical documentation on Acarus siro contains exhaustive data on its biology, ecology and on the distribution of its habitat, which allows the selection of the ideal conditions for its commercial breeding (Cunnington, 1965 and 1985; Griffiths 1964 and 1966; and Hughes , 1976). For example, Cunnington (1985), in his treatise on the oviposition and fecundity of A. siro , showed that, in optimal physical conditions, the females reach an average of 435 eggs, with a maximum of 858, being the daily average of Egg production of 28 eggs per female and day for six days at approximately 20-25 ° C and with a relative humidity of approximately 90%.
mind.

Griffiths (1964) showed that, with a powdered yeast diet, the development time from egg to egg was only 9.0 days. In view of the literature cited above, the effectiveness of Acarus siro as a viable factitious host is well proven.

Trials on the intrinsic rate of development of Amblyseius swirskii in the factitious host Acarus siro have been completed (see example 1). Such results demonstrate that this combination has several advantages over those known in the state of the art produced using any other astigmatid host.

In an implementation of the invention, these can be raised in containers of adequate size, providing adequate adjustments to ensure the exchange of oxygen.

In another embodiment and according to the second aspect of the invention, the food supply consists of a artificial mixture of baking powder and vermiculite pieces of a adequate size, in addition to a proportion of sterile particles of dried fruit.

This mixture of inert material vermiculite and dried sterile fruits avoids the problems that arise when bran flakes are included in the medium. The bran, which is the most commonly used vehicle to introduce predatory phytoseids in crops by means of sachets, is naturally infected with storage fungi, such as the Penicillium and Aspergillus species, so that when they get wet after application in the crops, for example as an ornamental plant and cut flower, there is a growth of fungi, which disfigures the leaves and makes them less attractive to the retail customer. With this new breeding diet according to the present invention, the producers of these crops will now be able to safely use the product supplied in sachets, which is a great advantage over the previously known breeding diets.

Assigning another utility of this new guest diet, qualified people of the applicant firm have shown that another advantage of using this mixture of fine particles of vermiculite and dehydrated sterile fruits is that it improves the state of A. siro and, therefore, favors a better development of the mite populations
factitious.

Such advantages derive from the use of these particles, which help maintain the correct content of humidity of the medium, which is especially important when the mixture of predator and prey is found in paper envelopes hanging from the crop. In this way, the prior art problems, when envelopes were hung from the plants shortly after the transplant of the crop and the absence of leafy leaf cover, as well as proximity to low paths of heating pipes, caused the content to dry very quickly. Astigmatid mites, breathing through the skin, are very vulnerable to changes in humidity of the environment, and Cunnington (1965) showed that at relative humidity below 70% many species of astigmatids die.

In relation to the pest attack, this moment in the life of the plant is fundamental and needs a full complement of beneficial agents. Therefore, the content of an envelope that clearly helps to survive under these conditions to factitious mites and provide food to predators, more robust, it is an innovative success.

In the implementation of the use of Acarus siro as a food source for Amblyseius swirskii , and also with respect to many other phytoseidic predatory mites, A. siro can be described as a "true" factitious host, since it has a very restricted habitat that is It limits food stores and domestic pantries, feeding on a wide variety of whole grains and their farinaceous by-products, in the same way that it is one of the main pests of stored cheeses (Griffiths, 1966). It is not found naturally in plants and has never been reported to damage plants at any stage of their growth. It is not found in any wild habitat occupied by any other astigmatic mite species, nor in the habitats associated with the predatory phytoseids that are employed or that are intended to be used in biological control.

Although it is common to find in the technical literature previously published until the mid-twentieth century many records that can be found in wild natural habitats, these are, without exception, incorrect identifications. Griffiths (1966) showed that Acarus siro , sensu stricto , L., 1758 currently represents a complex of three species, two of which he identified or described as Acarus farris , Oudemans, and Acarus immobilis , Griffiths, and both are ephemeral inhabitants of the stored food, especially from recent grain crops. These do not survive under the physical conditions of the storage, leaving Acarus siro , L. as the only store species of the complex, probably because the relative humidity needs of the Acarus siro are less restrictive than those required by the other two species of the complex.

Thus, in the use of Acarus siro according to the present invention, this is the only true store food species and, therefore, can be defined as a true factitious host for predatory phytoseid species.
Doras

Unlike one of the most commonly used astigmatid species, Tyrophagus putrescentiae , they do not actively move away when they accidentally escape the breeding system. This is a considerable advantage over the typically used T. putrescentiae , which is well known for contaminating other commercial systems within a company. The low activity of A. siro also implies that they do not disturb the females of the predator during egg laying.

Therefore, for the commercial producer of biological control agents, Acarus siro is an ideal factitious host for Amblyseius swirskii , and most likely for many other species of phytoseids.

According to an embodiment of the invention, it is used to provide a source of predatory phytoseids for the control of whitefly and thrips species. For example, the whitefly Bemisia tabaci is one of the main pests of Mediterranean crops and Trialeurodes vaparariorum is one of the main crop pests in this region, as well as in the rest of Europe.

According to the second aspect of the present invention, the breeding substrate, due to its inert nature and its arrangement in loose particles, provides advantages for your application in relation to the nature of the crop, densities of cultivation, the configuration of the plant and the practices of management. For example, the predator can be applied directly to individual plants using agitable biodegradable bottles of the appropriate size. In another application, it can be provided to bulk in bulk to farmers for their transfer to the bags of backpack vacuum machines, thus facilitating distribution over large areas of plants Ornamental In some sophisticated greenhouses, these tanks are attach to machines that move automatically through guides placed at a certain height for the distribution of the predator on high density crop surfaces, for example in crops of chrysanthemums

According to the third aspect of this invention, small amounts of active substrate, between approximately 50 and 100 grams, are placed in paper envelopes Breathable, supplied with small exit holes to through which predators can leave, and with small hooks, so that the envelopes can be hung over the different plants at the required intervals (Sampson, 1998).

In a special application, depending on the proportion of predators and prey present inside the bag, it can remain active for one to four weeks. For a short time of departures, the system is called an "Envelope of quick release ", for the period of four weeks is called "Controlled release system". The first one is used when the plague has invaded the crop recently, before The predator can be introduced. The second can be introduced into the crop before the expected arrival period of a pest, thus offering a protection system later immediate.

Thus, in the embodiment of the invention, the combination of the predatory phytoseid species Amblyseius swirskii and its factitious host, Acarus siro , will be used in multiple biological control programs as a biological control weapon against the most serious pests, namely the species of whitefly and thrips. Preferably, crop pests are selected from whitefly such as the Bemisia tabaci and Trialeurodes vaporariorum species, and from the Thrips tabaci and Frankiniella occidentalis thrips species. According to a further embodiment also, they are useful for application in cultures infested with species of tetraniquid mites (red spiders) of the Tetranychidae family and tarsonémids, Tarsonemidae family. Commercial cultivation is selected from protected horticultural crops, glass greenhouses, plastic or low-mesh crops and also outdoor crops, for example pepper, cucumber, melon, watermelon, zucchini, eggplant, beans and soft fruits, such as strawberry, raspberries, etc.

       \ vskip1.000000 \ baselineskip
    

Example one

Technical tests to assess the development potential of Amblyseius swirskii when feeding on its factitious host Acarus siro

The objective of these tests is to determine the intrinsic capacity of growth and certain parameters of the life cycle of a population of A. swirskii when it is raised in the factitious host A. siro .

       \ vskip1.000000 \ baselineskip
    

Materials and methods

Both predatory individuals and dams used in the trials were selected so Randomized base crops of both species. All the trials are carried out in heated chambers at 25 ± 1 ° C and with an 84 ± 5% relative humidity.

       \ vskip1.000000 \ baselineskip
    

Oviposition

To assess the fertility of A. swirskii feeding on A. siro , small populations, as described below, were placed in a series of individual cells made in a black plastic strip. Five circular holes 14 mm in diameter were drilled at intervals along a black strip approximately 35 mm wide, 4 mm thick and 130 mm long. The lower faces of the cells were sealed with a breathable paper, which was glued to the plastic strip with a white non-toxic wood glue. To close each cell, transparent Plexiglass® squares were used, each with a hole in the center of 3 mm in diameter. For the test, 4 strips were used, with a total of 20 females of A. swirskii , five in each cell.

On the zero day of the trial, a small population of the factitious host A. siro was placed in the first cell of each strip, in sufficient quantity to support five young predatory females for three days. Five of these females were collected from a brood with a brush and placed in cell no. 1, through the central hole, which was then sealed with a glass coverslip, all of which is held by two clamps placed on each side of the main strip.

After a period of two days, the predatory females were collected from the first cell and placed in the next cell of the strip, where a small population of the factitious host mite A. siro was also provided as food. Then, the number of eggs present in the first cell was counted, and also the number of nymphs two days later, to ensure that no eggs had been discounted in the first count. This procedure was repeated until the last cell of the strip was used.

The average egg production was examined laid by five females every two days (see section Results, Table 1).

Development time of the different stadiums

Using the same cells described in the previous section, 3 females were left per cell laying eggs for 48 hours After 24 hours the females were collected from the cells and were placed in a new cell, where they were left putting on for 24 more hours. Then the females withdrew, letting the eggs develop along with a small population of prey mites in each cell. Only the eggs laid during the second day. With an average of 2.4 eggs per female and day, each cell at the beginning of the trial had between 6 and 8 eggs

To evaluate the rate of development, the cells were examined every 24 hours until all individuals predators had reached the adult stage. Was identified Always the stadium of individuals. When all individuals they reached a certain stage, the data were analyzed and He calculated an average development rate for that particular stage.

It was followed up to adults of the posts of a total of 20 females. Mortality was not determined (see section Results, Table 2).

       \ vskip1.000000 \ baselineskip
    

Intrinsic Rate of Development

To evaluate the intrinsic rate of development, small plastic lunch boxes of approximately 11.5 cm in length, 8.5 cm in width and 4.5 cm in height. It has been made a hole in the lid, which was sealed with breathable paper to avoid leaks and to ensure gas exchange.

A population of predators and dams was divided into several lots, with an average density of about 25,000 predators per kg, using the quartered technique to estimate the population density (individuals per kg of crop), and each batch was individually placed in a container maintained in the same conditions described above, with a predatory ratio: sufficient prey to ensure development for 7 days. This is a suitable period for the test, since most commercial production systems are handled in cycles of 7 to 10 days. At the end of the period, after 7 days, the populations were counted again and the intrinsic population growth rate was estimated. Ten repetitions were performed, two of them were not taken into account since the populations did not have enough food and, therefore, the results were only based on 8 repetitions (see
Table 3).

       \ vskip1.000000 \ baselineskip
    

Results

       \ vskip1.000000 \ baselineskip
    

TABLE 1 Amblyseius swirskii oviposition rate fed with the factitious host Acarus siro

one

TABLE 2 Development time of the different stages of Amblyseius swirskii (from egg to adult) when feeding on the factitious host Acarus siro

2

       \ vskip1.000000 \ baselineskip
    

       \ vskip1.000000 \ baselineskip
    

TABLE 3 Growth rate (final population / initial population) of Amblyseius swirskii when raised on the factitious host Acarus siro for 7 days

3

The results on the intrinsic rate of development of Amblyseius swirskii in the factitious host Acarus siro demonstrate that this combination presents multiple advantages over known combinations of the state of the art produced using any other astigmatid host, both with reference to the ease of breeding on Acarus siro as to the results obtained from development and growth. Therefore, for the commercial producer of biological control agents, Acarus siro is an ideal factitious host for Amblyseius swirskii , and most likely for many other species of phytoseids.

Claims (12)

1. Composition of mites comprising a viable population of the species of predatory phytoseid mite Amblyseius swirskii , a viable population of a factitious host comprising at least one species of mite of the Astigmata order and an artificial breeding substrate that also acts as a carrier during the distribution, characterized in that the astigmatid mite is Acarus siro , L., 1758 of the Acaridae family. 2. Composition of mites according to claim 1, characterized in that the artificial breeding substrate comprises a mixture of baking powder, pieces of vermiculite of a suitable size and sterile particles of dried fruit. 3. Composition of mites according to claim 1, characterized in that the ratio between predatory individuals and factitious hosts ranges from about 1:10 to about 1: 100. 4. Method for the breeding of the species of predatory phytoseido Amblyseius swirskii comprising providing a mite composition according to claims 1 to 3 and allowing individuals of said species of predatory phytoseido Amblyseius swirskii to feed on the individuals of said host population factitious 5. Method according to claim 4, characterized in that the mite composition is maintained at a temperature of 20-25 ° C, preferably 24 ° C, and with a relative humidity of 75-85%. 6. Method according to claims 4-5 characterized in that the composition according to claims 1 to 3 is kept in a container suitable for the proper development of the predator and its prey guaranteeing the exchange of oxygen and allowing the exit of the different mobile stages of life of the species of predatory phytoseid mite. 7. Use of the composition according to claims 1-3 for the biological control of pests in cash crops. 8. Use according to claim 7, characterized in that the crop pests are selected from among white flies, such as the species Bemisia tabaci and Trialeurodes vaporariorum , and the thrips species Thrips tabaci and Frankiniella occidentalis , and mite pests of the Tetranychidae family and the Tarsonemidae family. 9. Use according to claims 7-8 characterized in that the commercial crop is selected from protected horticultural crops, glass greenhouses, plastic or mesh crops and also outdoor crops. 10. Procedure for the biological control of cultures by use according to the claims 7-9 of a composition according to claims 1-3. Method for the biological control of crops according to claim 10 characterized in that the composition according to claims 1-3 is distributed in the cultures in a container according to claim 6 suitable for direct sprinkling of its content on the crops. 12. Method for the biological control of crops according to claim 10 characterized in that the composition according to claims 1-3 is distributed in the crops in a container according to claim 6 suitable for being hung directly on the individual plants.