Method of controlling phytopathogenic diseases on turfgrass

Abstract

The present invention relates to a method of controlling bacterial wilt on turfgrass, in particular low to moderate disease pressure, using an effective non-phytotoxic amount of (A) chlorothalonil and (B) acibenzolar-s-methyl.

Claims

1. A method for controlling or suppressing bacterial wilt in cool-season turfgrass, comprising applying to the cool-season turfgrass or to the locus of the cool-season turfgrass, a turf quality improving non-phytotoxic amount of acibenzolar-S-methyl applied at a rate of from 4 to 20 g/ha.

2. The method of claim 1, wherein the acibenzolar-S-methyl is applied pre-bacterial wilt or under low to moderate bacterial wilt conditions.

3. The method of claim 1, which further comprises application of chlorothalonil.

4. The method of claim 1, wherein acibenzolar-S-methyl is applied simultaneously together, separately, or in succession with other active ingredients.

5. The method of claim 1, using a composition comprising acibenzolar-S-methyl.

6. The method of claim 5, wherein the composition further comprises adjuvants, solvents, carrier, surfactants or extenders.

7. The method according to claim 6, wherein the composition comprises from 0.01 to 90% by weight of the acibenzolar-S-methyl, from 10 to 99.99% of a carrier and from 0 to 20% of a surfactant.

8. The method of claim 1, wherein acibenzolar-S-methyl is applied at the rate of from 5 to 16 g/ha.

9. The method of claim 1, wherein acibenzolar-S-methyl is applied at intervals of from 5 to 21 days, either pre-bacterial wilt or under low to moderate bacterial wilt conditions, during the turf growing season.

10. The method of claim 9, wherein 6 to 8 applications of acibenzolar-S-methyl is applied at intervals of from 7 to 14 days.

11. The method according to claim 1, wherein the turfgrass is an annual or perennial Gramineae belonging to at least one of the genera Agropyron, Agrostis, Axonopus, Bromus, Buchloe, Cynodon, Eremochloa, Festuca, Lolium, Paspulum, Pennisetum, Phleum, Poa, Stenotaphrum or Zoysia.

12. The method according to claim 1, wherein the bacterial wilt is caused by Acidovorax spp. or Xanthomonas spp.

Description

FORMULATION EXAMPLE

(1) TABLE-US-00001 Suspension concentrate Active ingredients 40% Propylene glycol 10% Nonylphenol polyethylene glycol 6% ether (15 mol of ethylene oxide) Sodium lignosulfonate 10% Carboxymethylcellulose 1% Silicone oil (in the form of a 1% 75% emulsion in water) Water 32%

(2) In preparing and SC, the finely ground active ingredients are mixed with the adjuvants, giving a suspension concentrate from which suspensions of any desired dilution can be obtained by dilution with water. Using such dilutions, living plants as well as plant propagation material can be treated and protected against infestation by microorganisms, by spraying, pouring or immersion.

BIOLOGICAL EXAMPLES

(3) Enhanced control or suppression of bacterial wilt in turf is claimed when acibenzolar-S-methyl is applied alone or in combination with other chemistries.

Example 1. Protective Applications of Daconil Action for Control of Bacterial Wilt (Acidovorax avenae) on Creeping Bentgrass

(4) A trial was conducted with Daconil Action (chlorothalonil plus acibenzolar-S-methyl) on creeping bentgrass (variety A4). Plants were treated with Daconil Action at 3.5 fluid ounces per 1000 square feet of turf. Daconil Action contains 54% chlorothalonil and 0.176% acibenzolar-S-methyl. Daconil Action applied at 3.5 fluid ounces per 1000 square feet of turf is equivalent to 8230 g of chlorothalonil and 16.5 g of acibenzolar-S-methyl per ha.

(5) Applications were made using a spray volume of 1.5 gallons/1000 square feet. Preventative treatments were initiated with a first application followed by a second application made 15 days later, end date included. Plants were inoculated nine days after the second preventative treatment (end date included) by dipping scissors in a suspension of the pathogen (Acidovorax avenae) grown in nutrient broth for approximately 24 hours and adjusted to an OD of 0.6 at 600 nm. After trimming turf with infested scissors the grass was also sprayed lightly with the remaining bacterial suspension. Pots were placed into the dew chamber for 2 days at 29 C. Pots were then moved to a germinator set at 32 C. Disease symptoms were observed and a rating was taken 4 days after inoculation. Disease severity was significantly lower than the inoculated untreated check in pots treated with Daconil Action. The third application was made 7 days after the plants were inoculated (end date included). Plants were then moved to a different growth chamber set to 28 C and 95% RH night and 30 C and 80% RH day (12 hour day/night). The 4th and final application was made 15 days after the third application (end date included). Daconil Action significantly controlled bacterial wilt (Acidovorax avenae) on creeping bentgrass.

(6) TABLE-US-00002 TABLE 1 Percentage of creeping bentgrass (Variety A4) shoots demonstrating symptoms and turf quality ratings. Rate oz/ % Turf Quality 1000 sq. Disease (0-9 Scale) ft. turf. 6-June 6-June 11-June 18-June Check 1.8 d* 7.62 a 6.06 a 5.56 a Noninoculated Check 50 ab 3.06 de 2.43 d 2.18 c Inoculated Daconil Action 3.5 24 c 4.75 bc 5.06 ab 5.18 a Daconil 3.6 63 a 2.75 e 1.81 d 2.52 bc Weather Stik *Means followed by same letter do not significantly differ (P = .05, LSD)

(7) Although the invention has been described with reference to preferred embodiments and examples thereof, the scope of the present invention is not limited only to those described embodiments. As will be apparent to persons skilled in the art, modifications and adaptations to the above-described invention can be made without departing from the spirit and scope of the invention, which is defined and circumscribed by the appended claims. All publications cited herein are hereby incorporated by reference in their entirety for all purposes to the same extent as if each individual publication were specifically and individually indicated to be so incorporated by reference.