Transcript Formulated KAOLIN particle film: A BIO RATIONAL

A new bio-rational fungicide formulation of potassium bicarbonate for horticultural crops, vines and ornamentals
Dr Jean-Pierre Laffranque and Dr Steve W. Shires
INTRODUCTION
APPLE SCAB (Venturia inaequalis)
• Two field trials in Belgium in 2002 and two in Austria in 2004
• Standard reference product: Captan at 1000 g a.i./ha and Kresoximmethyl at 100 g a.i./ha
• A total of 10 or 11 sprays were applied at 7 to 12 days intervals.
• Potassium bicarbonate is a naturally occurring inorganic salt found in soil, water, sediments, plant and animal tissues.
• Registered by both CODEX and the EU as a food additive, classified as GRAS (Generally Recognised As Safe) in the USA.
• Indistinguishable from natural potassium and bicarbonate, therefore exempt from residue tolerances (MRLs) in USA.
• Soluble powder formulation containing 85% potassium bicarbonate, is now registered and commercialised in the USA, and is being
developed in Europe under the brand name of Armicarb 85SP®.
100%
80%
• Mode of action related to osmotic and pH effects on fungal hyphae and spores, non site specific, therefore resistance is extremely unlikely.
• Research to find a formulation that gives optimum spreading and penetration carried out by Cornell University and Church & Dwight Co. Ltd
Figure 3: Control of apple scab (2 trials)
RESULTS
80% 81%
81%
67%
60%
Standard reference
product
40%
• High crop selectivity
• High scab infestation
• Potassium bicarbonate activity similar to standards (Fig. 3).
Potassium bicarbonate
(3825 to 4250 g a.i./ha)
20%
0%
Leaf incidence
Fruit incidence
VINE POWDERY MILDEW (Uncinula necator)
• Reference products: Captan and Kresoxim-methyl
• Untreated check incidence: Fruits: 100% Leaves: 100%
• 13 field trials were conducted in Austria (2), France (5), Spain (1) and Switzerland (5) in 2003
and 2004.
STRAWBERRY POWDERY MILDEW (Sphaerotheca macularis)
Apples
• 10 trials were conducted in France (7), Belgium (2), Spain (1)
• Strawberries were grown under plastic.
• Application rates for potassium bicarbonate were between
2125 to 4250 g/ha.
• Two to eight sprays at one week intervals
• Potassium Bicarbonate application rate: 4250 g a.i./ha in Austria and Switzerland; 5100 g
a.i./ha in France and Spain
 3 to 10 applications at 8 to 14 day intervals
 Comparison with standard reference products: Sulphur at 10 kg a.i./ha; Spiroxamine at
250 g a.i./ha; Penconazol at 25 g a.i./ha
Grapes infected with powdery mildew
RESULTS on Vine Powdery Mildew
• Crop selectivity was generally good, although moderate phytotoxicity observed in two trials that had been sprayed twice within two days
• Potassium bicarbonate at 4250 and 5100 g a.i./ha provided good control of powdery mildew (Figs. 1 and 2)
• Overall efficacy was numerically but not statistically slightly lower than the standard products
RESULTS
• Crop selectivity was excellent in all trials
• Potassium bicarbonate gave good control in all French
trials where natural substrate was used
• In Spain potassium bicarbonate was superior to the
standard sulphur and in Belgium it was superior to
myclobutanil but inferior to kresoxim-methyl (Fig. 4)
Figure 4: Control of powdery mildew in strawberry (leaf level)
in Belgium (2 trials)
Potassium bicarbonate
4250 g a.i./ha
100%
85%
80%
60%
67%
40%
51%
Myclobutanil
60 g a.i./ha
Kresoxim-methyl
150 g a.i./ha
20%
0%
Untreated check incidence: Leaves: 72%
• French trials confirmed that potassium bicarbonate performs best when applied preventatively
CONCLUSIONS
Figure 1: Control of vine powdery mildew
in Northern Europe (7 trials)
100%
100%
80%
Figure 2: Control of vine powdery mildew
in Southern Europe (6 trials)
89%
99%
89%
96%
80%
60%
60%
40%
40%
20%
ab
a
a
a
0%
Bunches
Potassium bicarbonate 4250 g a.i./ha
Leaves
Standard reference product
• Reference products: Penconazol or Spiroxamine
• Untreated check severity (pest pressure):
Bunches: 33%
Leaves: 51%
20%
74%
78%
81%
88%
• The recently developed 85SP formulation of potassium bicarbonate provides
commercially acceptable control of some key diseases.
Efficacy trial on Cucumbers Powdery mildew
(Erysiphe cichoracarum)
• In vines, potassium bicarbonate applied at 4250 to 5100 g a.i./ha gave similar or only
slightly reduced control of powdery mildew compared with the standards.
• In apples, 3825 to 4250 g a.i./ha of potassium bicarbonate gave similar control of
scab on fruits but slightly inferior on leaves compared with the standards.
• In strawberries, 2125 to 4250 g a.i./ha provided high powdery mildew protection
ab
a
a
a
0%
Bunches
Potassium bicarbonate 5100 g a.i./ha
Leaves
Sulphur 10000g a.i./ha
Untreated check severity (pest pressure):
Bunches: 51%
Leaves: 27%
• Potassium bicarbonate is a naturally occurring inorganic salt and the concentrations
used in agriculture are unlikely to have any adverse effects on man or the
environment.
• Exemption from residue tolerances have been granted in the USA and a similar
request has been made to the European authorities.
• Other trials ongoing in Europe are demonstrating interesting efficacy against
powdery mildew in vegetables (e.g. cucurbits) and Botrytis in vines.
Untreated check
Formulated potassium
bicarbonate at 3 kg/ha