Phosphonate Treatment Effects on Phytophthora Root Rot Control, Phosphite Residues and Phytophthora cactorum Inoculum in Young Apple Orchards
| Autor: | Mark Mazzola, J.P.B. Wessels, Makomborero Nyoni, Adéle McLeod |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
Pathogen detection biology Phytophthora cactorum food and beverages Plant Science biology.organism_classification 01 natural sciences 010602 entomology Horticulture Disease management (agriculture) Root rot Subject areas Phytophthora Agronomy and Crop Science 010606 plant biology & botany |
| Zdroj: | Plant Disease. 105:3835-3847 |
| ISSN: | 1943-7692 0191-2917 |
| DOI: | 10.1094/pdis-01-21-0067-re |
| Popis: | Phytophthora root rot, caused by Phytophthora cactorum, is an economically important disease on young apple trees. Limited information is available on the effect of different phosphonate application methods and dosages on disease control, fruit and root phosphite concentrations, and soil and root pathogen inoculum levels. Evaluation of phosphonate treatments in three apple orchard trials (two in the Grabouw and one in the Koue Bokkeveld region) showed that foliar sprays (ammonium or potassium phosphonate), trunk sprays and trunk paints, were equally effective at increasing trunk diameter in one trial and yield in a second trial over a 25-month period. Foliar ammonium and potassium phosphonate sprays (12 g of phosphorous acid/tree), and two different dosages of the ammonium phosphonate sprays (∼4.8 g or 12 g of phosphorous acid/tree) were all equally effective at improving tree growth. The addition of a bark penetrant (polyether-polymethylsiloxane-copolymer) to trunk sprays did not improve the activity of trunk sprays. The low dosage ammonium phosphonate foliar spray (∼4.8 g a.i./tree) was the only treatment that, in general, yielded significantly lower root phosphite concentrations than the other phosphonate treatments. Root phosphite concentrations were significantly positively correlated (P < 0.0001) with an increase in trunk diameter and negatively (P < 0.0001) with P. cactorum root DNA quantities. Phosphite fruit residues were |
| Databáze: | OpenAIRE |
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