Effect of condit soil improver on growth, yield and leaf mineral content of two summer pear cvs. with interstocks

The study involving 2 pear cultivars was conducted in 2006–2016. ‘Radana’ and ‘Clapp’s Favourite’ were planted in the spring 2006 in the Experimental Station next to Wrocław (south-western Poland) on Quince S1 and Caucasian pear seedlings with 2 interstocks – ‘Doyenne du Comice’ and ‘Pyrodwarf’. An annual dose of 3 tonnes per hectare of Condit Basic bio-fertilizer was applied onto the tree row soil surface at the beginning of March 2012, i.e., starting from the 7th year after the planting. The study objective was to evaluate effect of Condit preparation on summer pear tree cultivars which are not compatible with Quince, and to assess interstock suitability in their context. The yields obtained in the first eleven years following tree planting were the most abundant for ‘Radana’ on Caucasian pear and on Quince with ‘Doyenne du Comice’ interstock. When applied for 5 years, Condit increased the leaf surface area, however a significant difference was exhibited only by ‘Radana’ on the Caucasian pear. This soil improver did not affect tree growth and yielding; total chlorophyll content; foliar Mg, P, Ca, and K; and mean fruit mass across the investigated treatment combinations.

Bird-window collisions: Mitigation efficacy and risk factors across two years

Background Research on bird-window collision mitigation is needed to prevent up to a billion bird fatalities yearly in the U.S. At the University of Utah campus (Salt Lake City, Utah, USA), past research documented collisions, especially for Cedar Waxwings (Bombycilla cedrorum) drawn to fruiting ornamental pears in winter. Mirrored windows, which have a metallic coating that turns window exteriors into mirrors, had frequent collisions, which were mitigated when Feather Friendly®bird deterrent markers were applied. Bird-friendly windows–ORNILUX®ultraviolet (UV) and fritted windows–also reduced collisions when data were collected across fall and winter. Extending this prior research, we evaluated additional mitigation and tested the replicability of effects for pear trees, mirrored windows, and bird-friendly windows across two years. Methods Using published data from eight buildings monitored for collisions in year 1 (Fall and Winter, 2019–2020), we added another year of monitoring, Fall and Winter, 2020–2021. Between years, Feather Friendly®mitigation markers were added to collision-prone areas of two buildings, including both mirrored and transparent windows. Results The two buildings that received new Feather Friendly®mitigation had significantly fewer collisions post-mitigation. Control areas also had nonsignificant decline in collisions. The interaction of area (mitigation vs. control) by time (year 1 vs. 2) was significant, based on generalized estimating equations (GEE). The total yearly collisions across all eight buildings declined from 39 to 23. A second GEE analysis of all 8 buildings showed that mirrored windows, pear trees, and bird-friendly windows were each significant when analyzed separately. The best-fit model showed more collisions for mirrored windows and fewer collisions for bird-friendly windows. We found pear tree proximity to be related to more collisions in winter than fall. In addition, pear trees showed reduced collisions from year 1 to 2, consistent with new mitigation for two of three buildings near pear trees. Discussion Feather Friendly® markers can mitigate collisions with transparent windows, not only mirrored windows, compared to unmitigated areas over 2 years. Results also underscore the dangers of pear tree proximity and mirrored windows and the efficacy of bird-friendly windows. Thus, bird collisions can be prevented by window mitigation, permanent bird-friendly windows, and landscape designs that avoid creating ecological traps.

Researches of soil fertilization and top dressing in pear orchards (literature review)

Biological, meteorological and agro-technical factors have an impact on the nutrition level of fruit and berry crops. To reach high productivity, agricultural crops are to be provided with nutrient substances in a proper form and optimal amount. The addition of important components at critical stages of the plant development gives an impulse to create high and quality yield. Fertilization is aimed at satisfying the feeding needs of the trees in certain soil-climatic conditions; the dose is determined for separate elements according to the peculiarities of a fruit crop, a pomological cultivar, a rootstock and a tree age, also mineral nutrition elements in the soil and the possibility for a fruit crop to use them are taken into consideration. The nutrient requirements of fruit trees vary during the growing season. From the moment of budding to flowering, the need for nitrogen increases, the need for potassium and phosphorus constantly increases during the growing season. Rational mineral fertilization in pear-tree orchards should be based on the results of the soil and leaf analyses as well as on a visual estimation of the growth and fruit bearing of the trees (for example, nitrogen, iron). Unfortunately, it is very common for gardens to be fertilized blindly, without controlling the nutrient content of the soil. Excessive fertilization can both decrease fruit yielding capacity and quality and pollute the environment because of the accumulation of fertilizers in the soil and their washing out into soil and surface waters. The survey of literature sources concerning the effect of soil fertilization and top dressing on the growth and general productivity of pear-tree orchards was made. As a result of the analysis made, it has been established that at present no recommendation as to the application of fertilization in pear-tree orchards is available, because most of them were suggested for apple-tree and pear-tree orchards together. However, there is a difference in mineral nutrition of a pear-tree, in particular those on weak rootstock. Which is why, it is relevant to consider the issue of the development of an optimal fertilization system of intensive pear-tree orchards on a vegetative rootstock

First Report of Bleeding Canker of Pear Tree Trunks Caused by Dickeya fangzhongdai in Korea

Pears (Pyrus pylifolia L.) are cultivated nationwide as one of the most economically important fruit trees in Korea. At the end of October 2019, bleeding canker was observed in a pear orchard located in Naju, Jeonnam Province (34°53′50.54″ N, 126°39′00.32″ E). The canker was observed on trunks and branches of two 25-year-old trees, and the diseased trunks and branches displayed partial die-back or complete death. When the bark was peeled off from the diseased trunks or branches, brown spots or red streaks were found in the trees. Bacterial ooze showed a rusty color and the lesion was sap-filled with a yeasty smell. Trunks displaying bleeding symptoms were collected from two trees. Infected bark tissues (3 × 3 mm) from the samples were immersed in 70% ethanol for 1 minute, rinsed three times in sterilized water, ground to fine powder using a mortar and pestle, and suspended in sterilized water. After streaking each suspension on Luria-Bertani (LB) agar, the plates were incubated at 25°C without light for 2 days. Small yellow-white bacterial colonies with irregular margins were predominantly obtained from all the samples. Three representative isolates (ECM-1, ECM-2 and ECM-3) were subjected to further characterization. These isolates were cultivated at 39 C, and utilized (-)-D-arabinose, (+) melibiose, (+)raffinose, mannitol and myo-inositol but not 5-keto-D-gluconate, -gentiobiose, or casein. These isolates were identified as Dickeya sp. based on the sequence of 16S rRNA (MT820458-820460) gene amplified using primers 27f and 1492r (Heuer et al. 2000). The 16S rRNA sequences matched with D. fangzhongdai strain ND14b (99.93%; CP009460.1) and D. fangzhongdai strain PA1(99.86%; CP020872.1). The recA, fusA, gapA, purA, rplB, and dnaX genes and the intergenic spacer (IGS) regions were also sequenced as described in Van der wolf et al. (2014). The recA (MT820437-820439), fusA (MT820440-820442), gapA (MT820443-820445), purA (MT820446-820448), rplB (MT820449-820451), dnaX (MT820452-820454) and IGS (MT820455-820457) sequences matched with D. fangzhongdai strains JS5, LN1 and QZH3 (KT992693-992695, KT992697-992699, KT992701-992703, KT992705-992707, KT992709-992711, KT992713-992715, and KT992717-992719, respectively). A neighbor-joining phylogenetic analysis based on the concatenated recA, fusA, gapA, purA, rplB, dnaX and IGS sequences placed the representative isolates within a clade comprising D. fangzhongdai. ECM-1 to 3 were grouped into a clade with one strain isolated from waterfall, D. fangzhongdai ND14b from Malaysia. Pathogenicity test was performed using isolate ECM-1. Three two-year-old branches and flower buds on 10-year-old pear tree (cv. Nittaka), grown at the National Institute of Horticultural and Herbal Science Pear Research Institute (Naju, Jeonnam Province in Korea), were inoculated with 10 μl and 2 μl of a bacterial suspension (108 cfu/ml), respectively, after wounding inoculation site with a sterile scalpel (for branch) or injecting with syringe (for flower bud). Control plants were inoculated with water. Inoculated branches and buds in a plastic bag were placed in a 30℃ incubator without light for 2 days (Chen et al. 2020). Both colorless and transparent bacterial ooze and typical bleeding canker were observed on both branches and buds at 3 and 2 weeks post inoculation, respectively. No symptoms were observed on control branches and buds. This pathogenicity assay was conducted three times. We reisolated three colonies from samples displaying the typical symptoms and checked the identity of one by sequencing the dnaX locus. Dickeya fangzhongdai has been reported to cause bleeding canker on pears in China (Tian et al. 2016; Chen et al. 2020). This study will contribute to facilitate identification and control strategies of this disease in Korea. This is the first report of D. fangzhongdai causing bleeding canker on pears in Korea.