USE OF A CATIONIC POLYSACCHARIDE COMPOUND AS A FUNGICIDE, PESTICIDE, ALGAECIDE, DESSICANT AND FOR EXTENDING THE SHELF LIFE OF FRUITS AND VEGETABLES

Abstract

The invention relates to the use of known cationic polysaccharide compounds as fungicides, pesticides, algaecides, dessicants and for extending the shelf life of fruit and vegetables.

Claims

1. A method for controlling fungi, pests, or algae on fruits and/or vegetables: dessicating fruits and/or vegetables: or extending shelf life of fruits and/or vegetables by applying to fruits and/or vegetables a cationic polysaccharide compound which contains, per monosaccharide unit, on average at least 0.1 cationic group of the formula:
-A-N.sup.+R.sup.1R.sup.2R.sup.3 or —C(═NR.sup.4)—NR.sup.1R.sup.2 in which formula: A represents a straight-chain or branched C.sub.2-C.sub.6 alkylene group which is optionally preceded by a carbonyl group or optionally interrupted by one or two oxygen atoms or imino or alkylimino groups and optionally substituted by one or two hydroxyl groups or amine groups or a carboxyl or carbamoyl group; or A represents the residue of a monosaccharide unit; R.sup.1 and R.sup.2 each represent hydrogen methyl, carboxymethyl, phosphonomethyl, ethyl, hydroxyethyl, propyl, isopropl, allyl, hydroxypropyl or dihydroxypropyl or, together with the nitrogen atom, form a pyrrolidino, piperidino, piperazino, N′-alkylpiperazino, N′-(hydroxyalkyl)piperazino, N′-(aminoalkyl)piperazino, morpholino or hexamethyleneamino group; R.sup.3 represents hydrogen, C.sub.1-C.sub.18 alkyl, C.sub.3-C.sub.18 alkenyl, alkynyl or cycloalkyl, C.sub.4-C.sub.18 cycloalkyl-alkyl or C.sub.7-C.sub.18 aralkyl or a group of the formula -A-Fruc, where A has the above-mentioned meaning and Fruc represents a fructan residue bonded via oxygen; and R.sup.4 represents hydrogen, methyl, ethyl, hydroxyethyl, hydroxypropyl or dihydroxypropyl; where the amine nitrogen atoms can be uncharged or protonated or quarternised with methyl, ethyl, hydroxyethyl, hydroxypropyl or dihydroxypropyl; wherein the polysaccharide compound has a solubility in water of at least 20 wt-% at a temperature of 25° C.

2. The method according to claim 1 wherein the polysaccharide compound is selected from the group consisting of sucrose, trehalose, lactose, fructan, dextran, maltodextrin, amylose and cellulose and wherein each polysaccharide contains, per monosaccharide unit, on average at least 0.1 cationic group of the formula:
-A-N.sup.+R.sup.1R.sup.2R.sup.3 or —C(═NR.sup.4)—NR.sup.1R.sup.2.

3. The method according to claim 2 wherein the polysaccharide compound is fructan which contains, per monosaccharide unit, on average at least 0.1 cationic group of the formula:
-A-N.sup.+R.sup.1R.sup.2R.sup.3.

4. The method according to claim 1, wherein the polysaccharide compound contains, per monosaccharide unit, on average from 0.1 to 2.5, more preferably on average from 0.2 to 2.0 and especially preferred from 0.35 to 1.5 cationic group.

5. The method according to claim 1, wherein the polysaccharide compound is characterized in that A is bonded to an oxygen atom of the monosaccharide unit.

6. The method according to claim 1, wherein the polysaccharide compound is characterized in that R.sup.1 and R.sup.2 each represent methyl or ethyl.

7. The method according to claim 1, wherein the polysaccharide compound is characterized in that A represents ethylene or 2-hydroxypropylene.

8. The method according to claim 1, wherein the polysaccharide compound is characterized in that R.sup.1, R.sup.2 and R.sup.3 each represent methyl or ethyl.

9. The method according to claim 1, wherein the polysaccharide compound has a degree of polymerization from 2 to 1000, preferably from 3 to 60 and most preferably from 3 to 15 monosaccharide units.

10. The method according to claim 1 wherein the cationic polysaccharide compound curatively or preventively controls a phytopathogenic fungi.

11. The method according to claim 10, wherein the phytopathogenic fungi is an Ascomycota.

12. The method according to claim 10 wherein the phytopathogenic fungi is powdery mildew.

13. The method according to claim 1, wherein the cationic polysaccharide compound controls insects.

14. (canceled)

15. The method according to claim 13, wherein the cationic polysaccharide compound is applied via a spray application.

16. (canceled)

Description

EXAMPLES

Example 1

[0098] Method: Cucumber plants were planted in pots and reared on tables in a greenhouse with fully controlled climatic conditions. The trial was randomised with 2 replicates and 3 plants per plot, following GEP standards. Of each plant one leaf on the upper leaf level was chosen for treatment for uniformity of size, age, vigour and health by optical appearance. Each of these leaves was treated once with the test sample applied to the whole upper leaf surface. Aqueous concentrates of cationic polymer and their spray solutions were prepared having the following compositions:

TABLE-US-00001 Table 1-1 Tested formulations. Active Product/ matter in Formulation (=FL); (w/w %) Component component Supplier FL1 FL 2 FL 3 FL 4 FL 5 Chitosan 1 Sigma- 1.0 0 0 0 0 (medium MW Aldrich product; 50-190 kD) Lupasol ® HF 56 BASF 0 50 0 0 0 Quatin ® 350 40 COSUN 0 0 50 0 0 TQ Biobased Products Quatin ® 680 40 COSUN 0 0 0 50 0 TQ Biobased Products Quatin ® 1280 35 COSUN 0 0 0 0 50 TQ Biobased Products Water 99 50 50 50 50 Sum 100 100 100 100 100 pH 4.3* 7.5* 4.6 4.6 4.1 Dilution rate to 50 50 50 50 50 prepare spray solution (ml/l) *pH adjusted with acetic acid

[0099] Due to increase of viscosity, handling of chitosan solutions with an active matter content significantly larger than 1 w/w % is difficult. Moreover, application volumes are limited in practice. Therefore we have chosen to apply as a reference a 1% chitosan solution to be applied also at the same volume rate as the other concentrates.

[0100] Quatin samples of commercially available cationic inulin (hydroxypropyl trimonium inulin) were obtained from of Cosun Biobased products.

[0101] For reference, a commercial aqueous solution of cationic polyethyleneimine (Lupasol® HF) was obtained from BASF.

[0102] For better coverage of the leaf surface all concentrates in table 1-1 were tank-mixed with the commercial wetting agent Breakthru® S240 (a polyalkyleneoxide modified peptamethyltrisiloxane from Evonik) with a rate of 0.1 ml/L to obtain the spray solution. Breakthru® S240 was also tested on its own. That is without a test product as mixing partner. A commercial sulphur based and contact active product (SUFRAN JET® WG 80) was employed as a bench mark with its recommended rate. The spray solution was prepared by diluting the recommended amount in tap water (1.5 g/L). The spray solutions were applied with a manual pump sprayer with a spray volume of 1000 L/ha to visible coverage of the upper leaf surface. Leaves were treated with the test samples prior to inoculation with a fungal pathogen. 24 hours after the application one half side along the middle vein of each treated leaf was artificially inoculated with spores of Powdery Mildew (Sphaerotheca fuliginea) at a density of 10000 spores/ml.

[0103] The inoculated leaf side was assessed visually 11 days after inoculation for % leaf area showing mycelium growth. The % control was calculated using the formula of Abbott (ABBOTT, W. S. (1925): A method of computing the effectiveness of an insecticide. Journal of economic Entomology, 18, 265-267).

Control %=(1−(value in treated/value in untreated))*100

[0104] The tank mix component Breakthru S240 alone (treatment line 2) had did not provide any control of the development of the fungal pathogen. The test samples FL2, FL3, FL4, F16—each combined with the tankmix components Breakthru S240—achieved control levels of 100%, 70%, 97% and 97%, respectively. The commercial reference product (Sufran Jet WG 80) provided 100% control. These results are presented in Table 1-2.

TABLE-US-00002 TABLE 1-2 Efficacy of test samples against Powdery Mildew on Cucumber % Control (Abbott) FL Product/Component 11 days after inoculation — UNTREATED 5.6% infested leaf area — BREAK THRU S 240 0 FL 1 Chitosan (medium MW product) 0 FL 2 LUPASOL ® HF 100 FL 3 QUATIN  ® 350 TQ 70 FL 4 QUATIN ® 680 TQ 97 FL 6 QUATIN ® 1280 TQ 97 — SUFRAN JET WG 80 100

[0105] All Quatin products had an inhibiting effect on the development of the fungal pathogen on the treated leaf area when applied in a protective timing. In some cases, the inhibiting effect was similar to a proven contact acting reference product. Test samples inhibited the development of the fungus, thus functioned protectively. The efficacy cannot attributed to the wetting agent Breakthru S240, since applied on its own, this product has no efficacy. The fungicidal activity of cationic inulin is surprising since, based on its chemistry, not expected and not known yet.

Example 2

[0106] Method: Cucumber plants were planted in pots and reared on tables in a greenhouse with fully controlled climatic conditions. The trial was randomised with 4 replicates and 3 plants per plot, following GEP standards. Of each plant one leaf on the upper leaf level was chosen for treatment for uniformity of size, age, vigour and health by optical appearance. On each of these leaves one half side along the middle vein of the upper leaf surface was treated with a test sample. The other half side was covered during application, thus not treated and served as untreated control. A second application in the same manner as the first was applied once the 1.sup.st spray had dried. This was for the purpose of a more complete coverage of the treated leaf surface with active material.

[0107] Following test samples from example 1 and dilutions rates to obtain the spray solution were selected for testing:

TABLE-US-00003 TABLE 2-1 Tested formulations. Formulations: FL 2 FL 3 FL 4 Active matter Lupasol ® HF Quatin ® 350 TQ Quatin ® 680 TQ Dilution rate to 50 50 25 prepare spray solution (ml/l)

[0108] For better coverage of the leaf surface all concentrates were tank-mixed with the commercial wetting agent Breakthru® S240 (Evonik), but this time with a rate of 0.05 ml/L to obtain the spray solution. Breakthru® S240 was also tested on its own. That is without a test product as mixing partner.

[0109] In a similar way as in example 1, Lupasol® HF and SUFRAN JET® WG 80 were chosen as references. In this example, the spray solution of SUFRAN JET® WG 80 was prepared by diluting 1.0 g/L product in tap water. The spray solutions were applied with a manual pump sprayer with a spray volume of 1000 L/ha to visible coverage of the upper leaf surface. 24 hours after the 2nd applications each of the treated leaves—the whole upper leaf surface—was artificially inoculated with spores of Powdery Mildew (Sphaerotheca fuliginea) at a density of 100000 spores/ml. The treated leaf area was assessed visually 8 and 13 days after the day of inoculation as % leaf area covered with mycelium. These results are presented in Table 2-2.

TABLE-US-00004 TABLE 2-2 Efficacy of test samples against Powdery Mildew on Cucumber % Control % Control % Control (Abbott) (Abbott) (Abbott) 8 days after 13 days after 21 days after FL Product/Component inoculation inoculation inoculation — UNTREATED 35% 81% 99% infested infested infested leaf area leaf area leaf area — BREAK THRU S 240 44 32 14 FL 2 LUPASOL HF + 98 91 97 BREAK THRU S 240 FL 3 QUATIN 350 TQ + 90 89 92 BREAK THRU S 240 FL 4 QUATIN 680 TQ + 98 95 96 BREAK THRU S 240 — SUFRAN JET 100 100 100

[0110] The trial in example 2 showed strong disease pressure with the infested leaf area increasing from 0% at time of application to 35% on day 8 after inoculation to 81% on day 13.

[0111] The tank mix component Breakthru S240 alone (treatment line 2) had a minor effect on the development of the fungal pathogen of 44 and 32% control at 8 and 13 days after inoculation, respectively.

[0112] The Quatin test samples, however, achieved control levels of 90% and 98% (8 days after inoculation), 89% and 95% (13 days after inoculation), 92% and 96% (21 days after inoculation), respectively.

[0113] The commercial reference product (Sufran Jet) provided 100% control at the same dates.