Method for rearing or transporting entomophagous insects

Abstract: Small lumps of foamed plastic may be used as a shelter for rearing or transporting entomophagous insects. A container for keeping entomophagous insects which comprises a hollow body containing small lumps of foamed plastic and is provided with one or more holes on its upper surface, the holes being of a size such that the entomophagous insects can pass through them but the small lumps of foamed plastic can not pass through them, is provided. The shelter is useful to prevent the entomophagous insects from preying on each other, thereby efficiently rearing or transporting entomophagous insects, particularly predatory insects such as lacewings, lady beetles and predatory bugs.

Description: The present invention relates to a method for rearing or transporting entomophagous, particularly predatory, insects and a container for keeping the entomophagous insects. GB-A-2050836 discloses a preparation for combating noxious arthropods in horticultural produce, comprising a spreadable mixture of living mites of prey and a granular light material. EP-A-0204999 discloses a container for storing useful organisms, in particular those useful for destroying harmful bacteria and other organisms. The container disclosed in EP-A-0204999 has a mesh cover which allows organisms to leave the container only if their body cross-section is smaller than the cross-sectional area of the holes in the mesh. In order to control noxious insects by utilizing an entomophagous predatory insect a large number of the predatory insects have been required. They have been reared using paper, rice hull, buckwheat husk or the like as a shelter for the purpose of preventing them from preying on each other. However, these conventional shelters were not always satisfactory in that a large number of entomophagous insects in a small container have been lost while rearing or transporting because of their entomophagous nature. Furthermore undesirable molds are often formed in the rearing container. In addition, it is troublesome to separate the entomophagous insects from the shelter. Therefore, a further method to solve these problems has been desired. The present invention solves the above problems in full or in part by a method for rearing or transporting entomophagous insects, which comprises using small lumps of foamed plastic (plastic foam) as a shelter, and a container for keeping entomophagous insects, which comprises a hollow body containing small lumps of foamed plastic and is provided with holes on its upper surface, the holes having a diameter of 1 to 8 mm such that the entomophagous insects can pass through them but the small lumps of foamed plastic can not pass through them. The container is useful for transporting and the entomophagous insects in the container can be readily scattered over field crops therefrom. Description of the Preferred Embodiment The small lumps of foamed plastic to be used in the present invention are not specifically limited, and examples thereof include lumps of polystyrene foam, polyurethane foam, ABS foam, polyvinyl chloride resin foam, polyethylene foam, polypropylene foam, phenol resin foam and urea resin foam. The expansion of these foamed plastics is usually about 5 to 80 times, preferably 10 to 50 times, relative to the corresponding unfoamed plastics. Lumps having low specific gravity are preferred to avoid possible damage during transportation to the insects being reared. The shape of the lumps of foamed plastic used in the present invention is not specifically limited, and it is preferred to use those having a sphere, disc, cylinder or cube-like shape. In case of the sphere or disc shape, it is preferred to use those having a diameter of 2 to 20 mm. In case of the cylinder shape, it is preferred to use those having a length of 5 to 30 mm and a diameter of 2 to 10 mm. In case of the cubic shape, it is preferred to use those having a width of 2 to 20 mm and a length of 2 to 20 mm. The entomophagous insects which can be reared or transported by the method of the present invention include predatory insects. Examples thereof include lacewings such as Chrysopa septempunctata , common green lacewing ( Chrysopelra carnea ) or Mallada formosana ; lady beetles such as Harmonia axyridis , seven spotted lady beetle ( Coccinella septempunctata ) or Menochilus sexmaculatus and the like; and predatory bugs such as Eocanthecona furcellata or Andrallus spinidens . The rearing method of the present invention is usually conducted by placing small lumps of foamed plastic as a shelter in the space used for rearing the insects, and insects are reared according to a usual rearing method (see, for example, "Rearing Method of Insects", published by Takeshi YUSIMA, issued by Japanese Plant Protection Society). The amount of the small lumps of foamed plastic to be used varies depending on the species of the entomophagous insect, but is normally from 10 to 90 ml (including air space between the lumps), preferably from 30 to 70 ml, per 100 ml of the rearing container. According to a specific embodiment of the operation, two to twenty hatched larvae (per 100 ml of a rearing container) of an entomophagous arthropod insect, e.g. predatory insect, are left in the rearing container, and then eggs of Lepidoptera or Coleoptera (beetles), young larvae of Lepidoptera or aphids are introduced as diet. The kind of insect eggs that can be used as diet varies depending on the species of the entomophagous arthropod insect. In case of the lacewings, for example, eggs of Lepidoptera or Coleoptera (beetles) or aphids may be used. In case of the lady beetles, for example, eggs or young larvae of Lepidoptera or aphids may be used. In case of the predatory bugs, eggs or young larvae of Lepidoptera may be used. For transporting the entomophagous arthropod insects, for example, the container is filled with small lumps of the plastic foam, and then the arthropods and an optional host as diet for the arthropods are put in it. The present container comprises a hollow body provided with one or more holes, preferably a plurality of holes. The holes have a diameter of 1 to 8 mm so that the entomophagous insects can pass through them but the small lumps of foamed plastic can not pass through them. The container is useful not only for transportation of the entomophagous insects but also for scattering the reared insects over field crops simply by putting the holes provided on the upper surface downward and shaking the container. The shape of the hollow body is not specifically limited. The holes provided on the upper surface may be, for example, covered with paper or woven or unwoven fabrics with permeability and of which mesh is smaller than the insects in the container during rearing or transportation, if desired. Fig. 1 shows an example of the present container. The small lumps of foamed plastic and entomophagous insects are usually kept in the container. The hollow body is usually made of plastic or glass and preferably has a volume of 200 to 1000 ml, and preferably 100 to 1000 entomophagous insects are usually kept per one container. Examples The following Examples illustrate the present invention in detail but are not to be construed to limit the scope thereof. Example 1 Polystyrene foam beads having a diameter of about 5 mm (100 ml, volume including air space between particles) were put in a polyethylene cup having a volume of 200 ml, and then a cotton ball (diameter: 1 cm) impregnated with water was put in it. Ten hatched larvae of Chrysopa septempunctata were left in the polyethylene cup and eggs of Mediterranean flour moth (Ephestia (kuehniella) were introduced as diet. The diet was supplied at an appropriate rate during the rearing. After nine days, the number of living last instar larvae was counted to determine a survival rate. An average survival rate calculated from three replications of the experiment is shown in Table 1. An average survival rate obtained by rearing according to the same manner as that described above except for using in the polyethylene cup a shelter obtained by folding a filter paper cut in size of 4 cm x 5 cm in a corrugated shape in place of the polystyrene foam (comparative plot) is also shown in Table 1. Average survival rate (%) Test plot of the present invention 86.7 Comparative plot 46.6 In the test plot of the present invention, no mold was formed. In the comparative plot, however, formation of mold was observed. Example 2 According to the same manner as that described in Example 1 except for using Harmonia axyridis instead of Chrysopa septempunctata , rearing was conducted. After 8 days, the number of living last instar larvae was counted to determine a survival rate. The results are shown in Table 2. Average survival rate (%) Test plot of the present invention 83.3 Comparative plot 46.7 In the test plot of the present invention, no mold was formed. In the comparative plot, however, formation of mold was observed. Example 3 A polyethylene bottle having a volume of 500 ml was filled with polystyrene foam beads having a diameter of about 5 mm and one hundred second-instar larvae of Chrysopa septempunctata and 500 mg of eggs of Mediterranean flour moth (Ephestia kuehniella) were put in it, and then the bottle was transported for 48 hours at 5°C. The survival rate after transportation was not less than 90%. According to the rearing or transporting method of the present invention, it becomes possible to conduct efficient rearing and transportation of entomophagous insects. And also, it becomes possible to separate the entomophagous insects from the shelter readily. The container of the present invention for keeping entomophagous insects can be advantageously used for controlling noxious insects of field crops as it is. A schematic diagram illustrating one embodiment of the container of the present invention for keeping the entomophagous insects is shown in Fig. 1. In Fig. 1, 1 represents a container for keeping entomophagous insects, 2 represents sphere-like shaped foamed plastic lumps put in the container, 3 represents an entomophagous insect (predatory insect), and 4 represents a hole.

Claims: A method for rearing entomophagous insects, which comprises using small lumps of foamed plastic as a shelter. A method for transporting entomophagous insects, which comprises using small lumps of foamed plastic as a shelter. A method according to claim 1 or 2, wherein the small lumps of foamed plastic have a sphere-like shape. A method according to any one of claims 1 to 3, wherein the small lumps of foamed plastic have a sphere-like shape and a diameter of 2 to 20 mm. A container for keeping entomophagous insects, which comprises a hollow body (1) containing small lumps of foamed plastic (2) and is provided with one or more holes (4) on its upper surface, the holes (4) having a diameter of 1 to 8 mm such that the entomophagous insects (3) can pass through them but the small lumps of foamed plastic (2) can not pass through them. A container for keeping entomophagous insects according to claim 5, wherein the small lumps of foamed plastic (2) are as defined in claim 3 or 4. Use of small lumps of foamed plastic as a shelter for rearing or transporting entomophagous insects.

Inventors: SHONO YOSHINORI, UKISHIRO NOBORU, SHONO, YOSHINORI, UKISHIRO, NOBORU
Applicants: SUMITOMO CHEMICAL CO, SUMITOMO CHEMICAL COMPANY, LIMITED
Application year: 1996
Main classification: A01K67
IPC codes: A01K67, B65B55