DD290999A5 - METHOD OF CONTROLLING LARVES OF THE LARGE CARB LOFT AND THE CARROT FLY IN NEAR MEDIUM - Google Patents

Abstract

The invention relates to a method for controlling larvae of the large cabbage fly (Delia floralis) and the cabbage root fly (Delia radicum) in the nutrient medium by adding fungi of the species Beauveria bassiana or Metarhizium anisopliae to the nutrient medium {large cabbage fly; Cabbage root fly-combating; Adding mushrooms; Species Beauveri bassiana}

Description

Field of application of the invention

The invention relates to a method for controlling the larvae of the great cabbage fly (Delia floralis) and the cabbage root fly (Delia radicum) in the nutrient medium.

Characteristic of the known state of the art

Previous attempts have been made to chemically control cabbages by treating the roots of both seeded and unballasted seedlings with insect-causing chemicals such as diazinon, dimethoate or isofenphos. The control of cabbage root larvae by chemical means using Dimethoat and Linden has been reported in the scientific journal Agric. Soc. of Finland, Vol. 52 (1980), pp. 7-13. However, the pesticides decompose in the soil due to the activity of microorganisms, etc. In addition, it has been found that the repeated use of pesticides over several years accelerates these decomposition processes. The pesticides therefore protect the plants only in early summer against the first generation of larvae of the cabbage fly. The second generation of larvae of the cabbage fly, which occurs in the middle and end of the summer, as well as the larvae of the large cabbage fly can not be controlled by chemical means economically justifiable.

Object of the invention

By the method according to the invention larvae of the large cabbage fly (Delia floralis) and the cabbage fly (Delia radicum) are effectively controlled in the nutrient medium.

Explanation of the essence of the invention The present invention has for its object to provide a method for controlling large cabbage larvae and

to provide the cabbage fly.

Unexpectedly, it has now been observed that by the addition of fungi of the species Beauveria bassiana and / or Metarhizium anisopliae optionally together with a biocompatible carrier to the nutrient medium

effective control of larvae of both species of cabbages is possible. The effect of these microorganisms in

Nutrient medium is maintained throughout the growth period, so that the cabbage fly larvae, the middle and the end

occur in the summer, be combated.

The fungi used in the method of the invention, Beauveria bassiana and Metarhizium anisopliae, have been described by

isolated different soil types of different local origins.

Mushrooms of the species Beauveria bassiana and Metarhizium anisopliae have been previously used for pathogenic purposes Used pest control. In a method known in the art, biological Pesticides become mushrooms of the species Metarhizium anisopliae the nutrient medium for combating the common Added cockchafer. Australian Patent Application 54766/86 also describes a biological method and preparation for control

of insects. The method is used to control larvae of the Pillendreher beetle using a mixture of Metarhizium anisopliae and Bdauveria bassiana by adding an effective amount of the fungal species to the nutrient medium. However, it has not hitherto been observed that these fungal species would be effective against the hard to control larvae of cabbage fly.

Beauverla bassiana (Deuteromycetes) belongs to the group of Fungi imperfecti, d. H. of them no stage is sexual Reproduction known. When the fungus grows on a nutrient medium, it forms white or cream-colored, occasionally light

pink colored colonies, which take on a powdery appearance during sporulation. The spores (conidia) are round, have a smooth surface and have a diameter of 2-2.5mm.

Beauverla bassiana is a fungus that is common in nature and has many pathogens

can infect different insect groups. In trials its effectiveness against Acridiidae,

Hemipteroidea, Aphididae, Hymenoptera, Coleooptera, Lepidoptera, Acarina, and Brachycera. The mushroom needed

appropriate humidity and temperature to develop its effectiveness. Ultraviolet radiation damages the spores.

For the reasons mentioned above, soil is the best environment for B. bassiana. The minimum temperature required by B. bassiana to infect an insect is 3-8 ° C. When the spore with the body

When the insect comes into contact with the insect, it begins to form a germ tube, which first enters the insect's organism mechanically and then through the epidermis with the help of enzymatic reactions. The insect dies as its

Life functions are stifled by the growth of the fungal mycelium. B. bassiana also excretes toxins (beauvericin),

that are deadly to the insects. After the death of the insect, the fungus continues to grow saprophytic in its body, and as the mycelium grows out of the insect, it forms new spores. Taking advantage of the ability of saprophytic growth, B. bassiana can be cultured in mass cultures on artificial, solid or liquid nutrient media.

Metarhlzium anisopliae, like Beauveria bassiana, belongs to the group of Deuteromycetes and Fungi imperfecti. The species

is easily recognized by the spores that grow in dense conical bunches. They are dark green in color and have one

Length of 5-8 pm. The Hyphennetz is initially white or yellowish colored, but later completely from the green spores

covered.

M. anisopliae is also an insect pathogenic fungus that is abundant in nature and suffering from muscardiosis Insects and can be isolated from the ground. The temperatures required for M. anisopliae are slightly above those for B. bassiana. To infect an insect M. anisopliae needs a temperature of about + 1O ⁰ C. M. anisopliae can infect and kill the representatives of a large number of different insect groups. That happens in the

in the same way as in B. bassiana, M. anisopliae produces destrruxin toxins and also proteases, which are also toxic to insects. The various strains of M. anisopliae and clean images and B. bassiana can have hinsicb ^fli ch required temperature, pathogenicity and virulence are considerable differences.

Beauveria and metar-heme fungi isolated from the soil are grown in a fermenter on a normal nutrient medium

(PDB medium) at a temperature of 25-35 ⁰ C and maintaining a pH of 5-7 cultivated. The fungi cultivated in this way are added to the nutrient substrate of the plants, for example, by the root ball of the to be converted

Seedlings are treated with an aqueous suspension of powdered fungi, which receives at least 1 x 10 ³ fungal traces / ml. Each plant is treated with at least 15 milliliters of suspension to achieve effective control. Alternatively

For example, the roots of seedlings to be transplanted may be dipped into the aqueous solution without bales.

The microorganisms used in the invention were on June 1, 1988 at the German Collection of Microorganisms (DSM) Society for Biotechnological Research mbH, Grsebachstr.8, Göttingen, Federal Republic Germany, deposited. The accession numbers of strains of Beauveria bassiana are DSM 4646, DSM 4647 and

4648, and those of the strains of Metarhizium anisopliae have been deposited under numbers DSM 4649, DSM 4650 and DSM 4651.

embodiments The invention will be explained in more detail below with reference to examples. example 1

A cabbage-infested field was populated with beet plants whose root balls were treated with 15 ml / plant of a suspension containing fungi of the species Beauveria bassiana or Metarhlzium anisopliae. The concentration of the solution was 8 × 10 ⁷ Piusporen / ml. The other test plants were treated with 0.1% Oftanol (with the active ingredient Isofenphos) or remained untreated. After the autumn harvest, the number of cabbage fly larvae and pupae present in the cabbage roots was noted. The results are shown in Table 1.

Table 1 The effect of Beauveria and Metarhlzlumpilzen on the occurrence of cabbage fly Treatment Average number of larvae

and dolls per plant

Beauveria bassiana 12,26 Metarhizium anisopliae 46,10

Oftanol 0.1% 80.95

Untreated 70.83

It can be seen that both Beauveria bassiana and Metarhizium anisopliae significantly reduced the number of cabbage larvae and pupae per plant.

Example 2

The pest to be controlled in the experiment was the larva of the cabbage fly (Delia radicum). For this purpose, eggs of the cabbage root lily were placed in sterile vessels filled with sterile wet sand and planted in the middle with a complete radish. Each vessel contained 10 eggs. The eggs were placed around the radish so that each j in one

about the same distance (about 3cm) from the radish was removed. Before the eggs were placed, 10 milliliters of a suspension containing spores were distributed around the radish with a pipette or applied directly to the radish. The suspension concentration was 1 × 10 ⁹ spores / ml. The concentration was also the same in the vessels where spores of Beauverla (Bb) μπα Metarhizlum (Ma) were co-applied. In this case, half each consisted of Boauverla and Metarhlzlumsporen. The fungi were cultured on PDA agar. For each treatment 5 vessels were used. They were kept at a temperature of 23 ⁰ C and a relative humidity of about 70%. The number of larvae in the vessels was controlled 10 days after the start of the experiment. First, the number of infertile eggs was determined. The radishes were cut into thin slices to find the larvae inside. At the time of the inspection, some of the radishes were in such poor condition that the vessels in question were not included in the calculation of the final results. No larvae could be detected in the decomposed radishes. They had either gone out for lack of food or withdrew from the radish into the sand, where they could not be found due to their small size. Table 2 shows the numbers of infertile eggs found, both live and dead larvae, and percent mortality after each treatment.

Table 2

treatment total infertile survivors Not found percent eggs larvae and dead larvae A total of 1 2 3 4 Control I 1 6 3 Control Il 2 7 1 Control III 2 7 1 total 5 20 5 percent 16.7 80 20 Bb I - 2 8th Il - 4 6 III - 3 7 IV 3 6 4 total 3 15 25 percent 7.5 40.5 67.5 Ma I 3 3 4 Il - 5 5 III 2 3 5 IV _ 3 7 V - 2 8th total 5 16 29 percent 11.1 35.6 64.4 Bb + Ms I - 6 4 Il - 10 - III _ 1 9 IV - 3 7 - 20 20 - 50 50

On the basis of the results it can be stated that both individually and in combination Beauverla basslana and Metarhlzium anisopliae represent an extremely effective remedy for cabbage fly. A true synergistic effect of these fungal species could not be observed from this experiment. However, it should not be forgotten that the concentration of each of the two species in the vessels in which they were used in combination was only half as high as in the cases when applied individually. Nevertheless, the mortality rate was almost as high as in the vessels where only one of the two species was used. The applied concentration of 1 x 10 ⁹ spores / ml is apparently so high that halving the same did not affect the effect. On the basis of the experiment, it can not be ascertained which of the two fungal species produced the greater effect when treated with Bb + Ma, since the killed larvae were not found in the vessels. (The larvae are still very small in the stage when they are killed and rot very quickly in the moist sand.) However, a synergistic effect of these fungi may be present in practice, if the soil type may affect the action of the fungi the fungus species influences differently.

Claims (5)

1. A method for controlling large cabbage larvae (Delia folralis) and cabbage fly (Delia radicum) in the nutrient medium, characterized in that fungi of the species Beauveria bassiana (DSM 4646, DSM 4647, DSM 4648) and / or Metarhizium anisopliae (DSM No. 4649, DSM 4650, DSM 4651), optionally together with a biocompatible carrier, are added to the nutrient medium. 2. The method according to claim 1, characterized in that the fungal species are added to the nutrient medium as an aqueous suspension in a concentration of at least 10 ³ spores / ml. 3. The method according to claim 1 or 2, characterized in that the fungal spore suspension is administered in a minimum amount of 15 ml / seedling. 4. The method according to claim 1 or 2, characterized in that the roots of the seedlings are immersed in the fungal spore solution. 5. Use of the fungus species Beauveria bassiana (DSM 4646, DSM 4647, DSM 4648) and / or Metrahizium anisopliae (DSM 4649, DSM 4650, DSM 4651), characterized in that they are used to control larvae of the large cabbage located in the sewing medium (Delia folralis) and the cabbage root fly (Delia radicum).