Antifungal effect of the cumulative application of biostimulant and fertilizers on young cocoa fruits rot at Tafissou site, Centre-East of Côte d'Ivoire

The use of biostimulants as an alternative way to chemical, often toxic, remains one of the best approaches to control cocoa black pod disease caused by Phytophthora spp. This study has been carried out to evaluate the effect of biostimulant’s applications number and the cumulative action in case of applying previously fertilizers. The experimental design consisted of a Fischer block with six treatments (T01, T02, T1, T2, T3 and T4) and repeated three times. This design was replicated on two sites, one with previous fertilizer (DAE) and the other without previous fertilizer (DSE). Observations were made monthly on each test tree. The biostimulant Banzai was applied for 3 or 4 consecutive months depending on the treatment at each site. The data collected included the total number of cherelles produced and the number of rotten cherelles. From these, data were deduced the rates of healthy cherelles on which the Kruskal-Wallis test was applied to compare treatments between them and between sites. The results showed that four applications of the biostimulant with fertilizer provided better control than three applications without fertilizer. The results also showed that the majority of treatments at the DAE site were more effective than treatments at the DSE site. In conclusion, four applications Banzai coupled with fertilizer have achieved the best rates of healthy cherelles whatever the site. Regarding the cumulative effect of the previous fertilizer with Banzai, treatments of the site with the previous fertilizer were still better than the treatment site without fertilizer.

The second outbreak of the poplar leafminer Phyllonorycter populifoliella in St. Petersburg

Исследовались популяционные характеристики, факторы смертности и пищевые предпочтения минирующей листья тополя тополёвой нижнесторонней моли-пестрянки Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) в Санкт-Петербурге в связи с развитием второй в истории насаждений города вспышки массового размножения этого вредителя. В разных районах Санкт-Петербурга были заложены пробные площади с разной интенсивностью повреждения, варьирующей в среднем от 5,2 до 21,7 мин/лист. На каждой пробной площади в первые дни после начала лёта первого поколения (первая декада августа) срезались по две ветви в нижней части кроны с каждого дерева на которых анализировались мины 50 листьев для установления причин гибели и доли выживших особей. На всех пробных участках (за одним исключением) был один вид тополя - тополь берлинский Populus × berolinensis. Именно этот вид наиболее интенсивно повреждался Ph. populifoliella. Вспышка размножения в 2017-2019 гг., локализованная в Невском районе, постепенно распространяется по территории города, имея выраженный мозаичный характер,однако причины этой мозаичности распространения не ясны. Плотность популяции вредителя в Невском районе за последние годы существенно увеличилась. Наиболее успешно проходит развитие на деревьях с высокой плотностью популяции вредителя. С одного листа на таких участках вылетает 7 и более бабочек (36-52%) от начавших развиваться личинок), тогда как при меньшей плотности (в среднем 5 и 11 мин/лист) вылет составляет 8 и 19% соответственно. Это позволяет сделать предположение о ведущей роли состояния кормовых деревьев в развитии тополёвой моли. В отношении остальных факторов, влияющих на смертность, не удалось выявить их выраженного воздействия на плотность популяции. Population characteristics, mortality factors, and food preferences of the moth Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) mining leaves of poplar in St. Petersburg were studied under conditions of the second outbreak of this pest in the history of the urban plantings in St. Petersburg. In different districts of St. Petersburg, sample plots were established with different intensity of damage by the poplar leafminer, varying from 5.2 to 21.7 mines per leaf. On each sample plot, in the first days after the beginning of the flight of the first generation adults (the first ten days of August), two branches were cut in the lower part of the crown from each test tree, on which mines of at least 50 leaves were collected and analyzed to establish the causes of death and the proportion of the surviving individuals. With one exception, all sample plots were represented by one poplar species - the Berlin poplar Populus × berolinensis. This species was most intensively damaged by Ph. populifoliella . Outbreak in 2017- 2019 was initially localized in the Nevsky District and then gradually spread throughout the city, having the pronounced mosaic character, however, the reasons for the mosaic distribution of the outbreak are unclear. The density of the pest population has increased significantly in the Nevsky District over the past years. Development of the moth is most successful on trees with a high population density of the pest. Seven or more adult moths emerge from one leaf in such areas (36-52% of the larvae that begun to develop), while at a lower density (on average, 5-11 mines per leaf), the emergence was 8 and 19%, respectively. This finding allows us to assume the leading role of the state of forage trees in the development of the poplar leafminer. Contribution of the other factors affecting larval mortality was not possible to evaluate.

BIOINOCULATION RESPONSE ON GROWTH OF ADENENTHERA PAVONINA SEEDLINGS UNDER NURSERY CONDITIONS

The present study consists of the experiments on application of mineral solubilizing and plant growth hormone producing microbial strains in individual and /or combination under glass house conditions and their impact on enhancement in plant productivity of Adnenthera pavonina. Among microbial strains taken for the study, 6 phosphate solubilizing fungi, 4 iron ore leaching fungi, 5 phsophate solubilising bacteria and 11 isolates of Rhizobia had been used. Screening of ten fungal species and 5 bacterial isolates for their effects on growth of Adnenthera pavonine, done under pot culture in green house conditions, elucidated the best performance of Penicillum crysogenum Thom. 1 and Cunninghmella elegans Lendn. Combination of selected microbial inoculants for the individual test tree species were evaluated for their individual performance and /or in combination with the other selected inoculants in specific ratio of their inoculums. Under the dual inoculation experiment, selected mineral solubilisers (fungi/bacteria) were evaluated along with the combination of different isolates of Rhizobium and resulted selection of Penicillium chrysogenum and Cunnighmella elegans in 1:1 combination for better growth and development of seedlings under nursery conditions. The impact of Rhizobium inoculation alone or in combination with these fungal strains could not be observed and interpreted. However, the outcome the present study done under controlled experimental conditions may provide the plausible approach towards the development of nursery package and practice for development of quality planting material of this tree speices may be useful for the transplantation programe of revegetation of degraded land and environment.

Assessing lean and positional error of individual mature Douglas-fir (Pseudotsuga menziesii) trees using active and passive sensors

There is a growing demand for point cloud data that can produce reliable single-tree measurements. The most common platforms for obtaining such data are unmanned aircraft systems with passive sensors (UAS), unmanned aircraft equipped with aerial lidar scanners (ALS), and mobile lidar scanners (MLS). Our objectives were to compare the capabilities of the UAS, ALS, and MLS to locate treetops and stems and to estimate tree lean. The platforms were used to produce overlapping point clouds of a mature Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand, from which 273 trees were manually identified. Control trees were used to test tree detection accuracy of four algorithms and the number of stems detectable using each platform. Tree lean was calculated in two ways: using the stem location near the canopy and using the treetop. The treetops were detected more accurately from ALS and UAS clouds than from MLS, but the MLS outperformed ALS and UAS in stem detection. The platform influenced treetop detection accuracy, whereas the algorithms did not. The height estimates from the ALS and MLS were correlated (R2 = 0.96), but the MLS height estimates were unreliable, especially as distance from the scanner increased. The lean estimates using the stem locations or treetop locations produced analogous distributions for all three platforms.

Design, Construction, and Evaluation of a Three-Dimensional Vibratory Harvester for Tree Fruit

HighlightsThree-dimensional excitation response of tree can be generated by orthogonal eccentric blocks.The three-dimensional vibratory harvester prototype was built, and the vibration response and harvesting test were carried out.Three-dimensional excitation applied to single main branch of the tree can result in high vibration on the whole tree. Abstract. To solve the problems associated with the mechanical harvesting of fruit, improve the harvesting efficiency, and reduce the damage to trees in the process of harvesting, a three-dimensional shaking mechanism with orthogonal eccentric blocks was designed. Three-dimensional excitation is generated to ensure that the fruit trees are subjected to noncircular excitation forces in different directions and further improve the fruit harvesting percentage. Firstly, the overall structure of the three-dimensional shaking mechanism with orthogonal eccentric blocks was designed, and the steady state response of the vibration system was obtained by establishing the dynamics model of the shaking mechanism-tree system. According to the vibration amplitude of the fruit tree under the action of three-dimensional shaking mechanism, the mass moment of the eccentric blocks, which are the key parts of the harvester, was determined to be 0.56 kg·m, and the size of the eccentric blocks was calculated. The hydraulic motors and cylinders that drive the shaking mechanism of the harvester were specified. Then a vibratory harvester prototype was assembled, and a vibration response test was carried out. The results showed that different branches of the test tree could obtain large acceleration magnitudes with low dispersion degree, which verified the effectiveness of the three-dimensional vibratory harvester. Finally, a harvesting test was conducted on a grapefruit tree. When the speed of the hydraulic motor to drive the shaking mechanism was 470 rev·min-1 and the shaking time was 10 s, the harvesting percentage reached 76.5%. Keywords: Acceleration response, Fruit harvester, Hydraulic system, Orthogonal eccentric blocks, Three-dimensional shaking mechanism.

TREE SPECIES RECOGNITION IN SPECIES RICH AREA USING UAV-BORNE HYPERSPECTRAL IMAGERY AND STEREO-PHOTOGRAMMETRIC POINT CLOUD

Recognition of tree species and geospatial information of tree species composition is essential for forest management. In this study we test tree species recognition using hyperspectral imagery from VNIR and SWIR camera sensors in combination with 3D photogrammetric canopy surface model based on RGB camera stereo-imagery. An arboretum forest with a high number of tree species was used as a test area. The imagery was acquired from the test area using UAV-borne cameras. Hyperspectral imagery was calibrated for providing a radiometrically corrected reflectance mosaic, which was tested along with the original uncalibrated imagery. Alternative estimators were tested for predicting tree species and genus, as well as for selecting an optimal set of remote sensing features for this task. All tested estimators gave similar trend in the results: the calibrated reflectance values performed better in predicting tree species and genus compared to uncorrected hyperspectral pixel values. Furthermore, the combination of VNIR, SWIR and 3D features performed better than any of the data sets individually, with calibrated reflectances and original pixel values alike. The highest proportion of correctly classified trees was achieved using calibrated reflectance features from VNIR and SWIR imagery together with 3D point cloud features: 0.823 for tree species and 0.869 for tree genus.

Morphometric variability of narrow-leaved ash samaras at the test-tree level

The aim of this research is to assess F. angustifolia test tree variability based on the morphometric traits and shape of samara from the locality Karapandza. Twenty adult trees were randomly selected. From each individual 100 fully developed samaras were analyzed. The following traits were analyzed: the length and width of samara, the length of seed, ratio between the length of seed and samara, the weight of 100 seeds by individual, samara shape and samara top shape. The obtained results indicated a considerable variability within the studied individuals at the level of samara morphometric traits. Considering that all sampled individuals were from the same populations we could suppose that this variability was not induced by different environmental factors (climate or soil), then with the existence of specific genotypes. Classification based on samara size says that our individuals could belong to large size samaras, i.e. the type known as f. macrocarpa. However, since there is no uniformity of samara shapes within the majority of studied individuals we cannot classify them in accordance with samara shape classification.