USE OF A COLEOPTERAN ACTIVE BACILLUS THURINGIENSIS FOR CONTROLLING THE CEREAL LEAF BEETLE OULEMA MELANOPA L. (LEMA MELANOPA (L.))

Abstract: This invention relates to the use of a coleopteran active B. thuringiensis or its delta endotoxin in controlling the cereal leaf beetle Oulema melanopa (L.) (Lema melanopa (L.)). Generally this is done in grasses, and especially in cereal crops.

Description: Title: Use of a coleopteran active Bacillus thuringiensis for controlling the cereal leaf beetle Oulema melanopa L. (Lema melanopa CL. ) . FIELD OF THE INVENTION This invention relates to the use of a coleop¬ teran active B. thurinσiensis or its delta endotoxin in controlling the cereal leaf beetle Oulema melanopa (L.) (Lema melanopa CL. ) ) , a method of controlling Oulema melanopa (L. ) (Lema melanopa (L.) ) by applying an effective amount of coleopteran active B. thuringiensis or its delta endotoxin to an area infested by Oulema melanopa (L. ) (Lema melanopa (L. ) ) , and insecticidal compositions for controlling Oulema melanopa (L. ) (Lema melanopa (L.) ) . BACKGROUND OF THE INVENTION Commercial preparations of Bacillus thuringiensis are used worldwide for biological control of pest insects. The advantages of these bacterial insecticides are that they are highly selective for a very limited range of target insects and are biodegradable. Commercial preparations of Bacillus thuringiensis can be applied right up to the time of harvest with no adverse effects. Bacillus thuringiensis is a rod shaped, aerobic, spore forming bacterium uniquely characterized by the production during the sporulation process of one or more inclusions, referred to as parasporal crystals. These crystals are compo¬ sed of high molecular weight proteins, referred to as delta- endotoxins. The delta-endotoxiήs are the active ingredient in available commercial preparations of Bacillus thuringiensis. Many B. thuringiensis strains with different insect host spectra have been identified. They are classified into different subspecies based on their flagellar antigens. Of particular interest is Bacillus thuringiensis subspecies kurstaki and subspecies aizawai used for the control of lepidopteran pest insects, Bacillus thuringiensis subspecies israelensis used for the control of dipteran pest insects and Bacillus thuringiensis subspecies tenebrionis and Bacillus 5 thuringiensis subspecies San Diego used for the control of coleopteran pest insects. The first isolation of a coleopteran toxic Bacillus thuringiensis was reported in 1983 (A. Krieg et al., Z. ang. Ent. 96, 500-508, European Patent Publication EP 0149162 A2) . 10 The isolate, which was designated Bacillus thuringi¬ ensis subsp. tenebrionis, has been deposited with the German Collection of Microorganisms under accession number DSM 2803. Bacillus thuringiensis subsp. tenebrionis was isolated in 1982 from a dead pupa of the mealworm, Tenebrio molitor (Tenebrioni- 15 dae, Coleoptera) . The strain produces within each . cell one spore and one insecticidal parasporal crystal which is of flat plate-like form with an edge length of about 0.8 μm to 1.5 μm. It belongs to serotype H8a,8b and pathotype C of Bacillus thuringiensis (Krieg et al., System.Appl.Microbiol. 9, 138- 20141, 1987, US patent 4,766,203, 1988). It is only toxic against certain leaf eating larvae (Chrvsomelidae) , but ineffective against caterpillars (Lepi- doptera) , mosquitoes (Diptera) or other insects.. Coleopteran active Bacillus thuringiensis has been 25 shown to be an effective control agent for the Colorado potato beetle larvae. After uptake of crystals and spores from coleopteran active Bacillus thuringiensis or isolated crystals larvae, and to a certain extent adults, of the Colorado potato beetle (Leptinotarsa decemlineata ) stop feeding. Larvae stages 30 L1-L3 die within 1-3 days (Schnetter et al., in "Fundamental & applied aspects of invertebrate pathology", eds. R.A. Samson et al., Proceedings of the 4th Int. colloquium of Invertebrate Pathology, p. 555, 1986) . The activity of B_ t _ thuringiensis subsp tenebrionis and 5 San Diego has further been confirmed against the elm leaf beetle Xanthogaleruca luteola. However, it has also been found that coleopteran active B. thuringiensis does not exhibit activity towards all insects within the Chrysomelidae. It has for example been found that it has no activity towards the small black flea beetle, Phyllotre- ta atra and the small striped flea beetle, Phyllotreta undula- ta, and only minor activity against the banded cucumber beetle, Diabrotica balteata, and the asparagus beetle, Crioseres asparagi. Four commercial products ofcoleopteran active Bacillus thuringiensis have been developed for the control of coleopte¬ ran pests. N0V0D0R ® from Novo Biokontrol, Novo Nordisk A/S, TRIDENT ® from Sandoz, and DiTerra ® from Abbott Laboratories Inc. all based on Bacillus thuringiensis subspecies tenebrio- nis, and the commercial product M-one ® from Mycogen Corporation based on a closely related strain Bacillus thuringiensis subsp. San Diego. SUMMARY OF THE INVENTION It has now been found that coleopteran active B. thuringiensis delta endotoxin exhibits activity towards a cereal leaf beetle Oulema melanopa (L.) (Lema melanopa (L.) ) . This invention consequently relates to the use of coleopteran active B. thuringiensis or its delta endotoxin in controlling the cereal leaf beetle Oulema melanopa (L.) (Lema melanopa (L. ) ) . Generally this is done in grasses, and especially in cereal crops. The present invention also relates to a method of controlling the cereal leaf beetle Oulema melanopa (L. ) (Lema melanopa (L. ) ) by applying an effective amount of a coleopteran active B. thuringiensis or its delta endotoxin to an area infested by Oulema melanopa (L. ) (Lema melanopa (L. ) ) . The invention further relates to insecticidal co posi- tions for controlling the cereal leaf beetle Oulema melanopa .L. ) (Lema melanopa i_L___L) • DETAILED DESCRIPTION OF THE INVENTION As indicated above the present invention in its first aspect relates to the use of coleopteran active B. thuringien- sis products such as, NOVODOR ® , for controlling the cereal leaf beetle Oulema melanopa (L.) (Lema melanopa (L.) ) . This beetle attacks the leaves of plants belonging to the grasses (mono¬ cotyledons) , and consequently such products may generally be applied to grasses. Of special economic importance are cereal crops belonging to the grasses, such as wheat, barley, oat, rye, rice, etc. , where the use ofcoleopteran active B. thuringi¬ ensis products is of special value. The cereal leaf beetle Oulema melanopa (L. ) (Lema melanopa (L.) ) belongs to the family Chrysomelidae. It is known as a serious pest widely distributed on the Eurasian continent from Sweden in the north to a latitude about Morocco, and from France to China, North Africa, and the north easterly parts of the U.S.A.. In its second aspect the invention relates to a method of controlling the leaf beetle Oulema melanopa (L.) (Lema melanopa (L.) ) by applying an effective amount of a coleopteran active B. thuringiensis product to an area infested with said cereal leaf beetle. In this context the expression "effective amount" should be understood as single or repeated applica¬ tions of from 0.5 1/ha to 8 1/ha of flowable preparations or 0.25 kg/ha to 4kg/ha of powder or granular preparations. The invention in its third aspect relates to pestici- dal compositions or preparations comprising the coleopteran active B. thuringiensis delta endotoxin product in admixture with an agriculturally acceptable diluent or carrier for use in controlling Oulema melanopa (L.) (Lema melanopa (L.) ) . The compositions of the invention can take any form known in the art for the formulation of agrochemicals, for example, a suspension, a dispersion, an aqueous emulsion, a dusting powder, a dispersible powder, an emulsifiable con- centrate or granules. Moreover they can be in a suitable form for direct application or as a concentrate or primary composi¬ tion which requires dilution with a suitable quantity of water or other diluent before application. The concentration of the insecticidally active B. thuringiensis delta endotoxin in the compositions of the present invention .when used alone or in combination with another pesticide, as applied to plants is preferably within the range from about 0.5 to about 25 per cent by weight, especially 1 to 15 per cent by weight. The coleopteran active B. thuringiensis preparation or the compositions of the invention can be applied directly to the plant by, for example, spraying or dusting at the time when the pest has begun to appear on the plant. The preferred mode of application is by spraying. It is generally important to obtain good control of pests in the early stages of pest development as this most effectively prevents crop damage. The invention is illustrated in the following example showing a specific embodiment of this invention. The example should in no way be construed as limiting for the scope of the invention as defined in the appended claims. Example 1 In a field trial the product NOVODOR ® FC was evaluated for its efficacy against the LI & L2 larval stages of the cereal leaf beetle Oulema melanopa (L.) (Lema melanopa (L.) ) . In the trial the insecticide was applied to various cereal crops as indicated below: The NOVODOR ® FC product is an aqueous flowable concen¬ trate formulated with microbial stabilizers, detergents and suspension aids. Crop : Spring Wheat 2 varieties Spring Barley 1 variety Winter Wheat 2 varieties Tricale - 8 varieties For comparison 3 traditional pesticides DECIS ® (from Roussel Uclaf) , KARATE ® (from ICI) , and SUMIALFA ® (from SUMITOMO) were also tested, all these pesticides are of the pyrethroid type well known in the art. The pesticides were applied in a single application in the following doses: Product Dose 1/ha NOVODOR ® FC 2.5 NOVODOR ® FC 5.0 DECIS ® 2.5EC 250 ml/ha KARATE ® 2.SEC 250 ml/ha SUMIALFA ® 5EC 200 ml/ha and at the 50% hatching time for the larvae. The evaluation was performed according to the following procedure: The numbers of larvae dead or alive at 1, 3, 5, 10 & 14 days post spray were counted, and the percentage of dead larvae computed as an average of 13 experiments for the NOVODOR ® FC product, and as an average of 3 experiments for the traditional products. The results are presented in Table I below: TABLE I Product Dose % dead after days (av. of 13 reps) 1/ha 1 3 5 10 14 NOVODOR ® FC 2.5 80 90 100 95 85 NOVODOR ® FC 5.0 80 95 100 100 85 Pyrethroids av. of 3 100 100 100 100 100 Observations: Larvae alive but not motile for NOVODOR ® FC Dead larvae observed amongst the live & non motile forms Larvae mostly dead, some non motile forms Most leaves free of larvae; few L2 & L3 larvae seen Few L3 & L4 larvae seen. Damage negligible. From the results it is apparent that NOVODOR ® FC at 2.5 & 5.0 1/ha gave excellent control of Oulema melanopa (L. ) (Lema melanopa (L. ) ) larvae, thereby reducing the foliar damage from their attack to negligible proportions.

Claims: PATENT CLAIMS 1. Use of at least one coleopteran active Bacillus thuringiensis or its delta endotoxin for controlling the cereal leaf beetle Oulema " melanopa (L.) (Lema melanopa (L.) ) . 2. Use according to claim 1, wherein said coleopteran active Bacillus thuringiensis is Bacillus thuringiensis sub¬ species tenebrionis or Bacillus thuringiensis subsp. San Diego, preferably Bacillus thuringiensis subspecies tenebrionis. 3. Use according to any of claims 1 or 2 in grasses. 4. Use according to any of claims 1 to 3 in cereal crops. 5. A method for controlling the cereal leaf beetle Oulema melanopa (L.) (Lema melanopa (L.) ) , wherein an effective amount of a coleopteran active Bacillus thuringiensis product is applied to plants infested with Oulema melanopa (L.) (Lema melanopa (L.) ) . 6. The method of claim 5, wherein said coleopteran active Bacillus thuringiensis product originates from Bacillus thu¬ ringiensis subspecies tenebrionis or Bacillus thuringiensis subsp. San Diego, preferably Bacillus thuringiensis subspecies tenebrionis. 7. The method of claim 6, wherein a liquid product is applied in an amount of 0.51/ha to 8 1/ha, preferably 0.51/ha to 4 1/ha. 8. The method of claim 6, wherein a flowable powder or granular product is applied in an amount of 0.25 kg/ha to 5 kg/ha, preferably 0.5 kg/ha to 2 kg/ha. 9. The method of claim 6, wherein a wetable powder product is applied in an amount of 0.25 kg/ha to 5 kg/ha, preferably 0.5 kg/ha to 2 kg/ha. 510. The method of claim 6, 7, 8, or 9, wherein the product is applied repeatedly with intervals. 11. A pesticidal composition for controlling the leaf beetle Oulema melanopa (L.) (Lema melanopa (L. ) ) compri- 0 sing the delta endotoxin of a coleopteran active Bacillus thuringiensis in admixture with an acceptable carrier. 12. The composition of claim 11, wherein said coleopteran active Bacillus thuringiensis is Bacillus thurin- 5 giensis subspecies tenebrionis or Bacillus thuringiensis subsp. San Diego, preferably Bacillus thuringiensis subspecies tenebrionis.

Inventors: RUGH SUSANNE, RUGH, SUSANNE
Applicants: NOVONORDISK AS, NOVO NORDISK A/S
Application year: 1991
Main classification: A01N63
IPC codes: A01N63, C07K14