A Method of Controlling Microbial Pathogens on Living Plant Tissue

Abstract

A method of controlling microbial pathogens on living plant tissue comprising treating said plant tissue with an aqueous formulation comprising a diacyl peroxide and a hydroperoxide selected from hydrogen peroxide and organic hydroperoxides.

Claims

1. A method of controlling microbial pathogens on living plant tissue comprising treating said plant tissue with an aqueous formulation comprising a diacyl peroxide and a hydroperoxide selected from hydrogen peroxide and organic hydroperoxides.

2. The method according to claim 1 wherein the hydroperoxide is hydrogen peroxide.

3. The method according to claim 1, wherein the aqueous formulation comprises (a) 0.00001-5.0 wt % of the diacyl peroxide and (b) 0.00001-1.0 wt % of the hydroperoxide.

4. The method according to claim 1 wherein the aqueous formulation is an aqueous suspension.

5. The method according to claim 1 wherein the diacyl peroxide is dibenzoyl peroxide.

6. The method according to claim 1 wherein the diacyl peroxide is di(4-methylbenzoyl) peroxide.

7. The method according to claim 1 wherein the diacyl peroxide is dilauroyl peroxide.

8. The method according to claim 1 wherein the diacyl peroxide has a d50 particle diameter in the range 0.01-200 micrometers.

9. The method according to claim 1 wherein the plant tissue is a seed, a tuber, a cutting, a growing plant, or a rooting stock.

10. The method according to claim 1 wherein the plant tissue is potato plant tissue.

11. The method according to claim 1 wherein the plant tissue is tomato plant tissue.

12. The method according to claim 1 wherein the plant tissue is grapevine plant tissue.

13. A method for the treatment of tomato plants against Phythophthora Infestans by treating said plants with an aqueous formulation comprising a diacyl peroxide and a hydroperoxide selected from hydrogen peroxide and organic hydroperoxides.

14. A method for the treatment of potato plants against Phythophthora Infestans by treating said plants with an aqueous formulation comprising a diacyl peroxide and a hydroperoxide selected from hydrogen peroxide and organic hydroperoxides.

15. A method for the treatment of grapevines against Plasmopora Viticola by treating said plants with an aqueous formulation comprising a diacyl peroxide and a hydroperoxide selected from hydrogen peroxide and organic hydroperoxides.

Description

EXAMPLES

[0040] In four experiments, the following aqueous formulations were prepared and applied on tomato plants.

[0041] In Comparative Experiment 1, a formulation containing 11.5 wt % perglutaric acid (PGA) and 27 wt % H.sub.2O.sub.2 was prepared and subsequently diluted 1578 times with water.

[0042] In Comparative Experiment 2, a formulation containing 11.5 wt % perglutaric acid and 27 wt % H.sub.2O.sub.2 was prepared and subsequently diluted 157.8 times with water.

[0043] In Experiment 3, a formulation containing 9.9 wt % dibenzoyl peroxide with an average particle size (d50) of 4 microns and 0.71 wt % hydrogen peroxide was prepared and subsequently diluted 40 times with water.

[0044] In Experiment 4, a formulation containing 9.75 wt % dibenzoyl peroxide (BPO) with an average particle size (d50) of 4 microns, 0.28 wt % perglutaric acid and 0.67 wt % H.sub.2O.sub.2 was prepared and subsequently diluted 40 times with water. The formulations of experiments 3 and 4 were prepared by milling BPO, followed by adding the other ingredients.

[0045] The tomato plants were grown in an artificial substrate (glass wool). Per glass wool block, one tomato plant was planted. The trial was executed in 3 replicates. Each replicate counted 3 tomato plants.

[0046] The plants were artificially inoculated (crop height around 40 cm) with 5.000 P. infestans spores per ml. Each plant was sprayed with 5 ml inoculum (25.000 spores/plant).

[0047] The trial consisted of 5 fungicide treatments, 3 application intervals before inoculation and 2 application intervals after inocculation and three replicates. The formulations were applied in the amounts given above. Ethylan 1008 was added prior to their application in an amount which resulted in an Ethylan 1008 coverage 0.9 l/ha.

[0048] Application interval before inoculation: 7 days, 3 days and 1 day

[0049] Application interval after inoculation: 12 and 36 hours

[0050] Single applications were carried out. The spray volume was 300 l/ha and the pressure was 2.5 bar. The nozzles were placed at a distance of 50 cm.

[0051] The assessment was done 8 days after the inoculation. During the assessment event, the inoculated and also sprayed leaf layers were monitored on the visual presence of P. infestans. The two highest treated leaf layers were assessed. Tables 1 and 2 show the results of this trial.

TABLE-US-00001 TABLE 1 Infection level (%) of P. infestans in the foliage (tomato plants) after singular treatments on three dates before artificial inoculation. The infection level in the untreated plants was 21%. Presented is the average of 3 replicates. 7 days before 3 days before 1 day before experiment inoculation inoculation inoculation 1 (comp) 20 16.9 12.8 2 (comp) 23.6 18.1 8.9 3 6.5 3.6 1.1 4 9.7 5.1 0.8

[0052] These results show that the best preventive protection is obtained with formulations comprising BPO and hydrogen peroxide.

TABLE-US-00002 TABLE 2 Infection level (%) of P. infestans in the foliage (tomato plants) after singular treatments on two dates after artificial inoculation. The infection level in the untreated plants was 21%. Presented is the average of 3 replicates. 12 hours after 36 hours after experiment inoculation inoculation 1 (comp) 8.9 8.0 2 (comp) 1.1 25.6 3 16.4 7.7 4 14.6 10.5

[0053] These results show that the best curative protection is obtained with a combination of BPO and hydrogen peroxide.