Forecasting Young Apple Tree Bud Status with a Visible/Near-Infrared Spectrometer

Being able to ascertain the physiological condition of the buds on a young apple tree before bud burst could help farmers manage their orchards more efficiently, especially if they could do so without destroying the buds in the process. The experiments carried out in this study were conducted with the aim of distinguishing shoot from non-shoot buds before bud burst using a visible/near-infrared spectrometer, a device that does not destroy the buds being tested. Tests on spring-planted (April 30, 2021) trees were conducted to check shoot and non-shoot bud physiology and the winter dormancy of young ‘Jonagold’, ‘Miyabi Fuji’ and ‘Orin’ apple trees. The light absorbance of the shoot buds before bud burst was much lower than the light absorbance of the non-shoot buds as checked on the visible/near-infrared spectrometer. The highest first factor effect was determined by a PCA test conducted on shoot and non-shoot ‘Jonagold’ buds (99.9%) at a range of 640-652 nm, ‘Miyabi Fuji’ buds (99.7%) at 654-680 nm and ‘Orin’ buds (99.6%) at 704-766 nm seven days before bud burst. We also found that the highest level of accuracy, using the Classifier analysis, between shoot and non-shoot ‘Jonagold’ buds (76.6%) was one day before bud burst, for ‘Miyabi Fuji’ buds (82.1%) it was three days before and for ‘Orin’ buds (76.3%) it was two days before. These findings suggest that growers can more effectively manage the development of the young trees in their orchards with a visible/near-infrared spectrometer.

Phosphonate treatment effects on Phytophthora root rot control, phosphite residues and Phytophthora cactorum inoculum in young apple orchards

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 phosphorous acid/tree), and two different dosages of the ammonium phosphonate sprays (~ 4.8 g or 12 g 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 with P. cactorum root DNA quantities (P ≤ 0.001). Phosphite fruit residues were less than 31 ppm for all treatments, with the trunk paint treatment (80 g phosphorous acid/tree applied annually) yielding significantly lower residues than the higher dosage foliar sprays (~12 g a.i/tree). Twenty-one months post-treatment, most of the phosphonate treatments in all of the trials similarly significantly reduced P. cactorum DNA quantities estimated directly from roots, but not from soil based on soil baiting DNA analysis. Pathogen quantities in fine feeder roots did not differ significantly from those in higher-order roots (< 5 mm dia.). Phytophthora cactorum DNA quantities estimated using DNA quantification directly from roots were significantly correlated (P < 0.0001) with those obtained through root leaf baiting DNA analysis, and to a lesser extent with soil leaf baiting DNA quantities (P = 0.025).

Weed Occurrence in a Young Apple Orchard Mulched With Two Different Organic Materials

In this study, conducted at the Research Station of the Wrocław University of Environmental and Life Sciences, Poland, we sought to determine the communities of weed species and their temporal occurrence in a young apple orchard mulched with spent mushroom compost or Miscanthus straw applied to tree rows. A herbicide fallow treatment was used as a control. During the first year of application, both organic mulches protected against the germination of weed seeds stored within the soil. In subsequent years, however, annual weeds occurred in the mulched tree rows, the most aggressive of which was Chenopodium album L. Annual increases in population densities were noted over the 4 subsequent years of research, particularly in the rows receiving spent mushroom compost. Perennial species in the family Poaceae and genus Malva were present in soil receiving both organic mulches. Trifolium repens L. was the perennial weed most often noted in the Miscanthus mulch, whereas Taraxacum officinale Web. was more characteristic of the spent mushroom compost. Commencing from the spring of the third year following apple tree planting, weed infestation associated with the spent mushroom compost was similar to that observed in the herbicide fallow, thus necessitating three annual applications of herbicide to further maintain the orchard. The insufficient weed suppression obtained with this mulch precludes its recommendation as an effective weed management system. Although Miscanthus straw provided extended tree row protection from weed infestation, herbicide intervention was also required. Notably, however, despite the fact that Miscanthus straw provided conditions more favorable to tree growth, apple tree yields and fruit quality tended to be similar under the three investigated orchard soil management systems.

Survey of apple collar and rootstock blight in Serbia

Apple production in Serbia is characterized by the introduction of new technologies and the establishment of intensive plantations based on modern systems. In intensive apple production systems, sudden and rapid decay of young apple trees exhibiting collar and rootstock blight symptoms in the first few years after planting is becoming a prevalent issue. However, knip or nursery trees with lateral branches (feathers) on rootstock M.9 i.e. oneto five-year old are most seriously affected. Based on a longitudinal survey of young apple plantations in Serbia and the results of pathogen detection and identification using conventional and molecular methods, the plant pathogenic bacterium Erwinia amylovora was found as the causative agent. By increasing the incidence of collar and rootstock blight in young apple trees, E. amylovora is gaining importance as the most destructive disease in apple production. In order to control E. amylovora effectively and apply appropriate control measures, it is necessary to survey the development of lesser-known symptoms caused by this pathogen, which are becoming prevalent in Serbian agroecological conditions.

Modulation of gelatinized wheat starch digestion and fermentation profiles by young apple polyphenols in vitro

To evaluate the effect of young apple polyphenols (YAP) on starch digestion and gut microbiota, complexes of native wheat starch (NWS) with YAP, and their main components chlorogenic acid (CA) and phlorizin (P) were fabricated and gelatinized.